Patent Publication Number: US-10323493-B2

Title: Method of forming lateral boreholes from a parent wellbore

Description:
STATEMENT OF RELATED APPLICATIONS 
     This application is filed as a Divisional of U.S. Ser. No. 15/009,623 field Jan. 28, 2016. That application is entitled “Method of Forming Lateral Boreholes From a Parent Wellbore.” 
     The parent application claimed the benefit of U.S. Provisional Patent Appl. No. 62/198,575 filed Jul. 29, 2015. That application is entitled “Downhole Hydraulic Jetting Assembly, and Method for Forming Mini-Lateral Boreholes.” The parent application also claims the benefit of U.S. Provisional Patent Appl. No. 62/120,212 filed Feb. 24, 2015 of the same title. 
     This application is also filed as a continuation-in-part of U.S. patent application Ser. No. 14/612,538 filed Feb. 3, 2015. That application is entitled “Method of Testing a Subsurface Formation for the Presence of Hydrocarbon Fluids.” That application, in turn, is a Divisional of U.S. Pat. No. 8,991,522 issued Mar. 31, 2015. 
     These applications are all incorporated by reference herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     This section is intended to introduce selected aspects of the art, which may be associated with various embodiments of the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present disclosure. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art. 
     Field of the Invention 
     The present disclosure relates to the field of well completion. More specifically, the present disclosure relates to the completion and stimulation of a hydrocarbon-producing formation by the generation of small diameter boreholes from an existing wellbore using a hydraulic jetting assembly. The present disclosure further relates to the controlled generation of multiple lateral boreholes that extend many feet into a subsurface formation, in one trip. 
     Discussion of Technology 
     In the drilling of an oil and gas well, a near-vertical wellbore is formed through the earth using a drill bit urged downwardly at a lower end of a drill string. After drilling to a predetermined bottomhole location, the drill string and bit are removed and the wellbore is lined with a string of casing. An annular area is thus formed between the string of casing and the formation penetrated by the wellbore. Particularly in a vertical wellbore, or the vertical section of a horizontal well, a cementing operation is conducted in order to fill or “squeeze” the entire annular volume with cement along part or all of the length of the wellbore. The combination of cement and casing strengthens the wellbore and facilitates the zonal isolation, and subsequent completion, of certain sections of potentially hydrocarbon-producing pay zones behind the casing. 
     Within the last two decades, advances in drilling technology have enabled oil and gas operators to economically “kick-off” and steer wellbore trajectories from a generally vertical orientation to a generally horizontal orientation. The horizontal “leg” of each of these wellbores now often exceeds a length of one mile. This significantly multiplies the wellbore exposure to a target hydrocarbon-bearing formation (or “pay zone”). For example, for a given target pay zone having a (vertical) thickness of 100 feet, a one mile horizontal leg exposes 52.8 times as much pay zone to a horizontal wellbore as compared to the 100-foot exposure of a conventional vertical wellbore. 
       FIG. 1A  provides a cross-sectional view of a wellbore  4  having been completed in a horizontal orientation. It can be seen that a wellbore  4  has been formed from the earth surface  1 , through numerous earth strata  2   a ,  2   b , . . .  2   h  and down to a hydrocarbon-producing formation  3 . The subsurface formation  3  represents a “pay zone” for the oil and gas operator. The wellbore  4  includes a vertical section  4   a  above the pay zone, and a horizontal section  4   c . The horizontal section  4   c  defines a heel  4   b  and a toe  4   d  and an elongated leg there between that extends through the pay zone  3 . 
     In connection with the completion of the wellbore  4 , several strings of casing having progressively smaller outer diameters have been cemented into the wellbore  4 . These include a string of surface casing  6 , and may include one or more strings of intermediate casing  9 , and finally, a production casing  12 . (Not shown is the shallowest and largest diameter casing referred to as conductor pipe, which is a short section of pipe separate from and immediately above the surface casing.) One of the main functions of the surface casing  6  is to isolate and protect the shallower, fresh water bearing aquifers from contamination by any wellbore fluids. Accordingly, the conductor pipe and the surface casing  6  are almost always cemented  7  entirely back to the surface  1 . 
     The process of drilling and then cementing progressively smaller strings of casing is repeated several times until the well has reached total depth. In some instances, the final string of casing  12  is a liner, that is, a string of casing that is not tied back to the surface  1 . The final string of casing  12 , referred to as a production casing, is also typically cemented  13  into place. In the case of a horizontal completion, the production casing  12  may be cemented, or may provide zonal isolation using external casing packers (“ECP&#39;s), swell packers, or some combination thereof. 
     Additional tubular bodies may be included in a well completion. These include one or more strings of production tubing placed within the production casing or liner (not shown in  FIG. 1A ). In a vertical well completion, each tubing string extends from the surface  1  to a designated depth proximate the production interval  3 , and may be attached to a packer (not shown). The packer serves to seal off the annular space between the production tubing string and the surrounding casing  12 . In a horizontal well completion, the production tubing is typically landed (with or without a packer) at or near the heel  4   b  of the wellbore  4 . 
     In some instances, the pay zone  3  is incapable of flowing fluids to the surface  1  efficiently. When this occurs, the operator may install artificial lift equipment (not shown in  FIG. 1A ) as part of the wellbore completion. Artificial lift equipment may include a downhole pump connected to a surface pumping unit via a string of sucker rods run within the tubing. Alternatively, an electrically-driven submersible pump may be placed at the bottom end of the production tubing. Gas lift valves, hydraulic jet pumps, plunger lift systems, or various other types of artificial lift equipment and techniques may also be employed to assist fluid flow to the surface  1 . 
     As part of the completion process, a wellhead  5  is installed at the surface  1 . The wellhead  5  serves to contain wellbore pressures and direct the flow of production fluids at the surface  1 . Fluid gathering and processing equipment (not shown in  FIG. 1A ) such as pipes, valves, separators, dehydrators, gas sweetening units, and oil and water stock tanks may also be provided. Subsequent to completion of the pay zone(s) followed by installation of any requisite downhole tubulars, artificial lift equipment, and the wellhead  5 , production operations may commence. Wellbore pressures are held under control, and produced wellbore fluids are segregated and distributed appropriately. 
     Within the United States, many wells are now drilled principally to recover oil and/or natural gas, and potentially natural gas liquids, from pay zones previously thought to be too impermeable to produce hydrocarbons in economically viable quantities. Such “tight” or “unconventional” formations may be sandstone, siltstone, or even shale formations. Alternatively, such unconventional formations may include coalbed methane. In any instance, “low permeability” typically refers to a rock interval having permeability less than 0.1 millidarcies. 
     In order to enhance the recovery of hydrocarbons, particularly in low-permeability formations, subsequent (i.e., after perforating the production casing or liner) stimulation techniques may be employed in the completion of pay zones. Such techniques include hydraulic fracturing and/or acidizing. In addition, “kick-off” wellbores may be formed from a primary wellbore in order to create one or more new directionally or horizontally completed boreholes. This allows a well to penetrate along the plane of a subsurface formation to increase exposure to the pay zone. Where the natural or hydraulically-induced fracture plane(s) of a formation is vertical, a horizontally completed wellbore allows the production casing to intersect, or “source,” multiple fracture planes. Accordingly, whereas vertically oriented wellbores are typically constrained to a single hydraulically-induced fracture plane per pay zone, horizontal wellbores may be perforated and hydraulically fractured in multiple locations, or “stages,” along the horizontal leg  4   c.    
       FIG. 1A  demonstrates a series of fracture half-planes  16  along the horizontal section  4   c  of the wellbore  4 . The fracture half-planes  16  represent the orientation of fractures that will form in connection with a perforating/fracturing operation. According to principles of geo-mechanics, fracture planes will generally form in a direction that is perpendicular to the plane of least principal stress in a rock matrix. Stated more simply, in most wellbores, the rock matrix will part along vertical lines when the horizontal section of a wellbore resides below 3,000 feet, and sometimes as shallow as 1,500 feet, below the surface. In this instance, hydraulic fractures will tend to propagate from the wellbore&#39;s perforations  15  in a vertical, elliptical plane perpendicular to the plane of least principle stress. If the orientation of the least principle stress plane is known, the longitudinal axis of the leg  4   c  of a horizontal wellbore  4  is ideally oriented parallel to it such that the multiple fracture planes  16  will intersect the wellbore at-or-near orthogonal to the horizontal leg  4   c  of the wellbore, as depicted in  FIG. 1A . 
     The desired density of perforated and fractured intervals within the pay zone  3  along the horizontal leg  4   c  is optimized by calculating:
         the estimated ultimate recovery (“EUR”) of hydrocarbons each fracture will drain, which requires a computation of the Stimulated Reservoir Volume (“SRV”) that each fracture treatment will connect to the wellbore via its respective perforations; less   any overlap with the respective SRV&#39;s of bounding fracture intervals; coupled with   the anticipated time-distribution of hydrocarbon recovery from each fracture; versus   the incremental cost of adding another perforated/fractured interval.
 
The ability to replicate multiple vertical completions along a single horizontal wellbore is what has made the pursuit of hydrocarbon reserves from unconventional reservoirs, and particularly shales, economically viable within relatively recent times. This revolutionary technology has had such a profound impact that currently Baker Hughes Rig Count information for the United States indicates only about one-fourth (26%) of wells being drilled in the U.S. are classified as “Vertical”, whereas the other three-fourths are classified as either “Horizontal” or “Directional” (62% and 12%, respectively). That is, horizontal wells currently comprise approximately two out of every three wells being drilled in the United States.
       

     The additional costs in drilling and completing horizontal wells as opposed to vertical wells is not insignificant. In fact, it is not at all uncommon to see horizontal well drilling and completion (“D &amp; C”) costs top multiples (double, triple, or greater) of their vertical counterparts. Depending on the geologic basin, and particularly the geologic characteristics that govern such criteria as drilling penetration rates, required drilling mud rheology, casings design and cementation, etc., significant additional costs for drilling and completing horizontal wells include those involved in controlling the radius of curvature of the kick-off, and guidance of the bit and drilling assembly (including MWD and LWD technologies) in initially obtaining, then maintaining the preferred at-or-near horizontal trajectory of the wellbore  4  within the pay zone  3 , and the overall length of the horizontal section  4   c . The critical process of obtaining wellbore isolation between frac stages, as with additional cementing and/or ECP&#39;s, are often significant additions to the increased completion expenses, as are costs for “plug-and-perf” or sleeve or port (typically ball-drop actuated) completion systems. 
     In many cases, however, the greatest single cost in drilling and completing horizontal wells is the cost associated with pumping the multiple hydraulic fracture treatments themselves. It is not uncommon for the sum of the costs of a given horizontal well&#39;s hydraulic fracturing treatments to approach, or even exceed, 50% of its total drilling and completion cost. 
     Crucial to the economic success of any horizontal well is the achievement of satisfactory hydraulic fracture geometries within the pay zone being completed. Many factors can contribute to the success or failure in achieving the desired geometries. These include the rock properties of the pay zone, pumping constraints imposed by the wellbore&#39;s construction and/or surface pumping equipment, and characteristics of the fracturing fluids. In addition, proppants of various mesh (sieve) sizes are typically added to the fracturing mixture to maintain the hydraulic pressure-induced fracture width in a “propped open” state, thereby increasing the fracture&#39;s conductive capacity for producing hydrocarbon fluids. 
     Often, in order to achieve desired fracture characteristics (fracture width, fracture conductivity, and particularly, fracture half-length) within the pay zone, an overall fracture height must be created that considerably exceeds the boundaries of the pay zone. Fortunately, vertical out-of-zone fracture height growth is usually confined to a few multiples of the overall pay formation&#39;s thickness (i.e., ten&#39;s or hundreds&#39; of feet), and thereby cannot pose a threat to contamination of much shallower fresh water sources, almost always separated from the pay zone by multiple thousands of feet of rock formations. See K. Fisher and N. Warpinski, “ Hydraulic Fracture Height Growth: Real Data ,” SPE Paper No. 145,949, SPE Annual Technical Conference and Exhibit, Denver Colo. (Oct. 30-Nov. 2, 2012). 
     Nevertheless, this increases the amount of fracturing fluid and proppant needed at the various “frac” stages, and further increases the required pumping horsepower. It is known that for a typical fracturing job, significant volumes of fracturing fluids, fluid additives, proppants, hydraulic (“pumping”) horsepower (or, “HHP”), and their correlative costs are expended on non-productive portions of the fractures. This represents a multi-billion dollar problem each year within the U.S. alone. 
     Further complicating the planning of a horizontal wellbore are the uncertainties associated with fracture geometries within unconventional reservoirs. Many experts believe, based on analyses of real-time data from both tilt meter and micro-seismic surveys, that fracture geometries in less permeable, and particularly, more brittle, unconventional reservoirs can yield highly complex fracture geometries. That is, as opposed to the relatively simplistic bi-wing elliptical model perceived to fit most conventional reservoirs (and as shown in the idealistic rendition in  FIG. 1A ), fracture geometries in unconventional reservoirs can be frustratingly unpredictable. 
     In most cases, far-field fracture length and complexity is deemed detrimental (rather than beneficial) due to excessive fluid leak-off and/or reduced fracture width that can cause early screen-outs. Hence, whether fracture complexity (or, the lack thereof) enhances or reduces the SRV that the fracture network will enable the wellbore to drain is typically determined on a case-by-case (e.g., reservoir-by-reservoir) basis. 
     Thus, it is desirable, particularly in horizontal wellbore completions for tight reservoirs, to obtain greater control over the geometric growth of the primary fracture network extending perpendicularly outward from the horizontal leg  4   c . It is further desirable to extend the length of the fracture network azimuth without significantly trespassing the horizontal pay zone  3  boundaries. Further, it is desirable to decrease the well density required to drain a given reservoir volume by increasing the effectiveness of the fracture network between wellbores through the use of two or more hydraulically-jetted mini-laterals along a horizontal leg. Still further, it is desirable to provide this guidance, constraint, and enhancement of SRV&#39;s by the creation of one or more mini-lateral boreholes as a replacement of conventional casing portals provided by the use of conventional completion procedures requiring perforations, sliding sleeves, and the like. 
     Accordingly, a need exists for a downhole assembly having a jetting hose and a whipstock, whereby the assembly can be conveyed into any wellbore interval of any inclination, including an extended horizontal leg. A need further exists for a hydraulic jetting system that provides for substantially a 90° turn of the jetting hose opposite the point of a casing exit, preferably utilizing the entire casing inner diameter as the bend radius for the jetting hose, thereby providing for the maximum possible inner diameter of jetting hose, and thus providing the maximum possible hydraulic horsepower to the jetting nozzle. A need further exists for a system that includes a whipstock deployable on a string of coiled tubing, wherein the whipstock can be reoriented in discreet, known increments, and not depend upon pipe rotation at the surface translating downhole. 
     Additional needs exist that, in certain embodiments, are addressed herein. A need exists for improved methods of forming lateral wellbores using hydraulically directed forces, wherein the desired length of jetting hose can be conveyed even from a horizontal wellbore. Further, a need exists for a method of forming mini-lateral boreholes off of a horizontal leg that assist in confining subsequent SRV&#39;s up to, but not significantly beyond, pay zone boundaries. Still further, a need exists for a method by which a whipstock and jetting hose can be conveyed and operated with hydraulic and/or mechanical push forces that enable movement of the jetting nozzle and connected hose into the formation, retrieved, re-oriented and re-deployed and re-operated multiple times at as many parent wellbore depths and mini-lateral azimuth orientations as desired, to generate multiple mini-lateral bore holes within not only vertical, but highly directional and even horizontal portions of wellbores in a single trip. A need further exists to be able to convey the jetting hose in an uncoiled state, such that the bend radius within the production casing and along the whipstock is the tightest bending constraint the hose must satisfy. 
     A need further exists for a method of hydraulically fracturing mini-lateral boreholes jetted off of the horizontal leg of a wellbore immediately following lateral borehole formation, and without the need of pulling the jetting hose, whipstock, and conveyance system out of the parent wellbore. A need further exists for a method of contouring clusters of lateral boreholes&#39; paths based upon real-time analysis of geophysical (micro-seismic and/or tiltmeter and/or ambient micro-seismic) descriptions of resultant SRV development (or lack thereof) from pumping a given stimulation (frac) stage. Additionally, a need exists for a method of optimizing the recompletion of an existing horizontal well by optimizing the placement and contouring of new lateral borehole clusters/stimulation stages based upon the performance (or, more specifically, non-performance such as observed by production logging or permanent ambient micro-seismic installations) of existing conventional perforation clusters and their respective stimulation stage&#39;s SRV. Stated another way, a need exists for a method of remotely controlling the erosional excavation path of the jetting nozzle and connected hydraulic hose, such that a lateral borehole, or multiple lateral borehole “clusters,” can be contoured to best control the SRV geometry resulting from a subsequent stimulation treatment stage. 
     SUMMARY OF THE INVENTION 
     The systems and methods described herein have various benefits in the conducting of oil and gas well completion activities. In the present disclosure, a method of forming a lateral borehole in a pay zone is first claimed. The pay zone exists within an earth subsurface. In one embodiment, the method first comprises determining a depth of the pay zone in a subsurface formation. The pay zone defines a rock matrix that has been identified as holding, or at least potentially holding, hydrocarbon fluids or organic-rich rock. In one aspect, the method also includes determining a thickness of the pay zone. 
     The method additionally includes forming a wellbore within the pay zone. In a preferred embodiment, the wellbore has deviated section or, more preferably, is completed horizontally. In these instances, forming the wellbore means forming a parent wellbore at an angle offset from vertical, or even forming a wellbore along a generally horizontal plane. 
     The method further includes conveying a hydraulic jetting assembly into the wellbore on a working string. Preferably, the working string is a string of coiled tubing having a sheath for holding electrical wires and, optionally, fiber optic data cables. 
     The downhole hydraulic jetting assembly is useful for jetting multiple lateral boreholes from an existing parent wellbore into the subsurface formation. The assembly is basically comprised of two synergetic systems:
         (1) an internal hose system (“the internal system”), which defines an elongated jetting hose having at its proximal end a jetting fluid inlet, and at its terminal end a jetting nozzle configured to be directed to and through a parent wellbore exit location; and   (2) an external hose conveyance, deployment and retrieval system (“the external system”) that is run on the working string to provide the defined path of travel (including a whipstock) within a wellbore, with the external system being configured to carry the elongated jetting hose into a wellbore and “push” it against a whipstock set in the wellbore to urge the jetting nozzle forward into the surrounding formation.       

     In the case of a cased wellbore, a window is formed through the casing using the jetting hose and connected nozzle, followed by the formation of a lateral borehole out into a hydrocarbon-bearing pay zone. The configuration and operation of these two synergetic systems provide that the whipstock may be re-oriented and/or re-located, and the jetting hose re-deployed into the casing and re-retrieved, for the jetting of multiple casing exits and lateral boreholes in the same trip. 
     As noted, the internal system comprises a jetting hose having a proximal end and a distal end. A fluid inlet resides at the proximal end, while a jetting nozzle is disposed at the distal end. Preferably, a power supply such as a battery pack resides at the proximal end for providing power to electrical components of the jetting assembly. 
     The external system comprises a pair of tubular bodies. These represent an outer conduit and an inner conduit. The outer conduit has an upper end configured to be operatively attached to the working string, or “tubing conveyance medium,” for running the jetting hose assembly into the production casing, a lower end, and an internal bore there between. The inner conduit resides within the bore of the outer conduit and serves as a jetting hose carrier. The jetting hose carrier slidably receives the jetting hose during operation. 
     A micro-annulus is formed between the jetting hose and the surrounding jetting hose carrier. The micro-annulus is sized to prevent buckling of the jetting hose as it slides within the jetting hose carrier during operation of the assembly. The micro-annulus is further configured to allow the operator to control the amount and flow direction of hydraulic fluid between the jetting hose and the surrounding inner conduit, which then converts to a fluid force that can either: (1) maintain the jetting hose in a taught configuration as it is urged downstream; or (2) urge the jetting hose in an upstream direction as it is retrieved back into the inner conduit. 
     The jetting hose assembly also includes a whipstock member. The whipstock member is disposed below the lower end of the outer conduit. The whipstock member includes a concave face for receiving and directing the jetting nozzle and connected hose during operation of the assembly. 
     The jetting hose assembly is configured to (i) translate the jetting hose out of the jetting hose carrier and against the arcuate whipstock face by a translation force to a desired point of wellbore exit, (ii) upon reaching the desired point of wellbore exit, direct jetting fluid through the jetting hose and the connected jetting nozzle until an exit is formed, (iii) continue jetting along an operator&#39;s designed geo-trajectory forming a lateral borehole into the rock matrix within the pay zone, and then (iv) pull the jetting hose back into the jetting hose carrier after a lateral borehole has been formed to allow the location of the whipstock device within the wellbore to be adjusted. 
     In one aspect, the whipstock is configured so that a face of the whipstock provides a bend radius for the jetting hose across the entire wellbore. In the case of a cased hole, the jetting hose will bend across the entire inner diameter of the production casing. Thus, the hose contacts the production casing on one side, bends along the face of the whipstock, and then extends to a casing exit on an opposite side of the production casing. This jetting hose bend radius spanning the entire I.D. of the production casing provides for utilization of the greatest possible diameter of jetting hose, which in turn provides for maximum delivery of hydraulic horsepower through the jetting hose to the jetting nozzle. 
     The external system is configured such that it contains, conveys, deploys, and retrieves the jetting hose of the internal system in such a way as to maintain the hose in an uncoiled state. Thus, the minimum bend radius that the hose must satisfy is that of the bend radius within the production casing, along the whipstock face, at the point of a desired casing exit. In addition, the coiled tubing-based conveyance of these synergetic internal/external systems provides for simultaneous running of other conventional coiled tubing tools in the same tool string. These may include a packer, a mud motor, a downhole (external) tractor, logging tools, and/or a retrievable bridge plug residing below the whipstock member. 
     Returning to the method at hand, the method also comprises setting the whipstock at a desired first casing exit location along the wellbore. The face of the whipstock bends the jetting hose substantially across the entire inner diameter of the wellbore while the jetting hose is translated out of the jetting hose carrier. The method additionally includes translating the jetting hose out of the jetting hose carrier to advance the jetting nozzle to the face of the whipstock. The method then includes injecting hydraulic jetting fluid through the jetting hose and connected jetting nozzle, thereby excavating a lateral borehole within the rock matrix in the pay zone. 
     The method also includes further injecting the jetting fluid while further translating the jetting hose and connected jetting nozzle through the jetting hose carrier and along the face of the whipstock. In this way, a first lateral borehole that extends at least 5 feet from the horizontal wellbore is formed. 
     In the present disclosure, a unique electric-driven, rotatable jetting nozzle is optionally provided for the external system. The nozzle can emulate the hydraulics of conventional hydraulic perforators, thereby precluding the need for a separate run with a milling tool to form a casing exit. The nozzle optionally includes rearward thrusting jets about the body to enhance forward thrust and borehole cleaning during mini-lateral formation, and to provide clean-out and, possibly, borehole expansion, during pull-out. 
     Within the external system, regulation of the hydraulic forces of both: (a) the jetting fluid&#39;s hydraulic force that urges the internal hose system downstream; and, (b) the hydraulic fluid&#39;s hydraulic force that urges the hose system back upstream, are both controlled with valves at the top and base of the carrier system, and seal assemblies both at the top of the jetting hose and at the base of the carrier system. In addition, the external system may include an internal tractor system that provides a mechanical force for selectively urging the jetting hose upstream or downstream. 
     It is observed that known jetting systems generally rely only on “slack-off” weight of a continuous coiled tubing and/or jetting hose string for “push” force. However, this source of propulsion would be quickly dissipated by helical buckling (e.g., due to friction forces between the jetting hose and wellbore tubulars) in a highly directional or horizontal wellbore. Once the point of helical buckling is reached, supplemental push force from additional slack-off of the string tied to the surface is no longer attainable. The “can&#39;t-push-a-rope” limitation of other systems is uniquely overcome herein by the combination of hydraulic and mechanical (tractor) forces, enabling the formation of mini-laterals off of an extended-reach horizontal wellbore. 
     The hydraulic jetting assembly herein is able to generate lateral bore holes in excess of 10 feet, or in excess of 25 feet, and even in excess of 300 feet, depending on the length of the jetting hose and its jetting hose carrier. Length of penetration and penetration rate itself may also be influenced by the hydraulic jetting-resistance qualities of the host rock. These jetting-resistance qualities may include compressive strength, pore pressure, cementation, and other features inherent to the lithology of the host rock matrix. In any instance, the lateral boreholes may have a diameter of about 1.0″ or greater and may be formed at penetration rates much higher than any of the systems that have preceded it that have in common completing a 90° turn of the jetting hose within the production casing. 
     The present system will have the capacity to generate lateral boreholes from portions of horizontal and highly directional parent wellbores heretofore thought unreachable. Anywhere to which conventional coiled tubing can be tractored within a cased wellbore, lateral boreholes can now be hydraulically jetted. Similarly, superior efficiencies will be captured as multiple intervals of lateral boreholes are formed from a single trip. Wherever satisfactory fracturing hydraulics (pump rates and pressures) are attainable via the coiled tubing-casing annulus, the entire horizontal leg of a newly drilled well may be “perforated and fractured” in stages without need of frac plugs, sliding sleeves or dropped balls. 
     In one embodiment, multiple lateral boreholes and, optionally, side mini-lateral boreholes, together form a network or cluster of ultra-deep perforations in the rock matrix. Such a network may be designed by the operator to optimally drain a pay zone. Preferably, the lateral boreholes extend away from the parent wellbore at a normal, or right, angle, and extend to an upper or lower boundary of the pay zone. Other angles may be used as well to take advantage of the richest portions of a pay zone. In any respect, the method may then include producing hydrocarbons. Where multiple boreholes are formed at different orientations from the wellbore and at different depths, hydrocarbons may be produced from a network of lateral boreholes. Moreover, the operation may choose to conduct subsequent formation fracturing operations from the lateral boreholes, thereby further extending the SRV. 
     In one aspect, geometries of lateral boreholes and side min-lateral boreholes are customized within the host pay zone. The boreholes can then optimally receive a subsequent stimulation (particularly, hydraulic fracturing) treatments. This, in turn, enables optimization of the resultant Stimulated Reservoir Volume (“SRV”) to be obtained from each pumping stage. During fracturing, the operator may receive real-time geophysical data, such as micro-seismic, tiltmeter, and/or ambient micro-seismic data, indicative of the effectiveness of formation treatments and SRV development. In one aspect, during a horizontal wellbore&#39;s completion or re-completion, real-time customization of the next cluster&#39;s lateral borehole geometries may be conducted prior to pumping a next stage. 
     In one embodiment, hydrocarbons are produced from the wellbore for a period of time before the lateral borehole is formed. Thus, a novel “re-fracturing” method is provided. 
     In a variation, the method comprises:
         forming perforations along the horizontal wellbore in sequential stages using one or more perforating guns;   hydraulically fracturing the rock matrix along the horizontal wellbore through the perforations in sequential stages;   conducting a flowback operation to at least partially remove hydraulic fluids injected in connection with the hydraulic fracturing; and   optionally, producing hydrocarbon fluids for a period of time before forming the lateral borehole.       

     In another alternate embodiment, the method further comprises:
         retracting the jetting hose and connected nozzle from the first casing exit after forming the first lateral borehole;   re-orienting the whipstock at the desired first location;   injecting hydraulic jetting fluid through the jetting hose and connected nozzle, thereby forming a second casing exit;   further injecting the jetting fluid through the jetting hose and connected nozzle, thereby excavating rock matrix in the pay zone; and;   still further injecting the jetting fluid while advancing the jetting hose and connected nozzle, thereby forming a second lateral borehole that also extends at least 5 feet from the horizontal wellbore from the second casing exit.       

     In this embodiment, each of the first and second lateral boreholes may have an internal diameter of between about 0.4 and 2.5 inches. In one aspect, the second lateral borehole is offset from the first lateral borehole by between 10-degrees and 180-degrees. The method may then further include producing hydrocarbon fluids from the first and second lateral boreholes together. 
     In another alternate embodiment, the method further comprises:
         retracting the jetting hose and connected nozzle from the first casing exit after forming the first lateral borehole;   retracting the jetting hose and connected nozzle from the first casing exit;   moving the whipstock to a desired second location, preferably further uphole;   injecting hydraulic jetting fluid through the jetting hose and connected nozzle, thereby forming a second casing exit at the second location;   further injecting the jetting fluid through the jetting hose and connected nozzle, thereby excavating rock matrix in the pay zone at the second location; and   still further injecting the jetting fluid while advancing the jetting hose and connected nozzle, thereby forming a second lateral borehole that also extends at least 5 feet from the horizontal wellbore along the second desired location.       

     In this embodiment, the first and second lateral boreholes may be separated by about 5 to 200 feet. Preferably, each of the first and second lateral boreholes is at least 25 feet in length and, more preferably, at least 100 feet in length. 
     In any of the above embodiments, the method may further comprise injecting fracturing fluids through an annulus formed between the external conduit and the surrounding production casing, and injecting the fracturing fluids into one or more lateral boreholes at an injection pressure sufficient to part the rock matrix in the pay zone. The hydraulic jetting assembly may further comprise a packer or a retrievable bridge plug disposed below the whipstock member, and the method may further comprise setting the packer or bridge plug before injecting a fracturing fluid. Alternatively or in addition, an acid treatment may be washed down through the annular region and into the lateral boreholes, preferably prior to fracturing. Given the system&#39;s ability to controllably “steer” a jetting nozzle and thereby contour the path of a lateral borehole (or, “clusters” of boreholes), fracturing fluids can be more optimally “guided” and constrained within a pay zone. 
     In any of the above methods, the translation force used in moving the jetting hose out of the jetting hose carrier may be a hydraulic force. The jetting hose and associated jetting hose carrier are preferably each at least 10 feet in length and, more preferably, at least 50 feet in length. 
     In one embodiment, the jetting hose assembly further comprises a main control valve. The main control valve is disposed proximate the upper end of the outer conduit, and is movable between a first position and a second position. In the first position the main control valve directs jetting fluids pumped into the wellbore into the jetting hose, while in the second position the main control valve directs hydraulic fluid pumped into the wellbore into the annular region formed between the jetting hose carrier and the surrounding outer conduit. Placement of the main control valve in its first position allows an operator to pump jetting fluids into the working string, through the main control valve, and against the upper seal assembly in the micro-annulus, thereby pistonly pushing the jetting hose and connected nozzle downhole in an uncoiled state while directing jetting fluids through the nozzle. Placement of the main control valve in its second position allows an operator to pump hydraulic fluids into the working string, through the main control valve, into the annular region between the jetting hose carrier and the surrounding outer conduit, through the pressure regulator valve and into the micro-annulus, thereby pulling the jetting hose back up into the inner conduit in its uncoiled state. 
     In one preferred embodiment, the translation force comprises both the hydraulic force and a separate mechanical force. In this instance, the jetting hose assembly further comprises an internal tractor system residing downstream from the lower end of the outer conduit. The internal tractor system comprises an inner conduit portion defining a part of the jetting hose carrier for receiving the jetting hose, an outer conduit portion defining a part of the outer conduit, the outer conduit portion having a star-shaped profile defining a plurality of radially-disposed prongs, a wiring chamber housing electrical wires, data cables, or both within one of the plurality of prongs, and at least one pair of grippers residing within opposing prongs, with each gripper being configured to engage and mechanically move the jetting hose along the jetting hose carrier when rotatably actuated. 
     In one embodiment, the hydraulic jetting assembly further comprises a docking station located at an upper end of the external system. The docking station is configured to mate with the battery pack. The docking station having a micro-processor and is in communication with an operator at the surface by means of the electrical wires, the data cables or both of the coiled tubing. In this arrangement, the method may further comprise:
         sending commands from the surface to the docking station;   sending data from a logging tool downstream from the whipstock to the docking station; and   sending data from the docking station to the surface.       

     The docking station preferably also houses a micro-processor along with a micro-transmitter, a micro-receiver, an electrical current regulator, or combinations thereof. The docking station may be configured to transfer: (1) power to the battery pack, said power either originating from generation at the surface, or from generation by a mud turbine below the whipstock member, said power being transmitted via electrical wiring provided along the external system; and (2) data to and from the micro-transmitter and micro-receiver in the docking station, between one or more geo-spatial chips housed at or near the nozzle and the operator at the surface. The micro-transmitter housed in the battery pack is configured to wirelessly transmit the data received from the micro-receiver to a micro-receiver housed in the docking station. The docking station is configured to further transmit the data to a processor at the surface (i) wirelessly, (ii) via electrical wires bundled in the coiled tubing, or (iii) via data cables bundled in the coiled tubing. 
     In one arrangement, the method further comprises
         obtaining geo-mechanical data for the pay zone, the data comprising porosity, permeability, Poisson ratio, modulus of elasticity, shear modulus, Lame&#39; constant, Vp/Vs, or combinations thereof;   conducting a geo-mechanical analysis of the rock matrix in the pay zone to determine a direction of least minimum principle stress; and   forming at least two lateral boreholes in the pay zone using the downhole hydraulic jetting assembly by steering the nozzle (i) in a direction perpendicular to the direction of least minimum principle stress, or (ii) in a direction parallel to the direction of least minimum principle stress.       

     In one arrangement, a longitudinal axis of the horizontal wellbore is oriented parallel to the plane of least principle stress of the rock matrix comprising the pay zone. In addition, the first lateral borehole is formed in a direction perpendicular to the plane of least principle stress of the rock matrix. Conducting a geo-mechanical analysis of the rock matrix may comprise creating a finite element mesh representing the pay zone, wherein the mesh defines a plurality of nodes representing points in space. Each point has potential displacement in more than one direction. The analysis may further involve predicting changes in the stress profile within the rock matrix as a result of the formation of the lateral boreholes. 
     In another arrangement, the downhole hydraulic jetting assembly and the methods herein operate in conjunction with a guidance system. The guidance system includes the use of at least three longitudinally oriented actuator wires connected to a distal end of the jetting nozzle. The actuator wires are equi-distantly spaced about the circumference of the jetting hose at its distal end, and are fabricated from a conductive material that contracts in response to electrical current. Differing amounts of electrical current directed through the actuator wires will induce a bending moment to orient the jetting nozzle in a desired direction. In this arrangement, the micro-processor is configured to control electrical current regulators feeding current to the respective actuator wires. This, in turn, controls a geo-orientation of the nozzle for directional hydraulic boring. 
     In one aspect of the guidance system, geo-location signals are sent by one or more geo-spatial chips residing along or near the nozzle. The geo-location signals are indicative of the location of the nozzle, its orientation, or both. The geo-location signals are transmitted as data from the geo-spatial chips to the micro-receiver in the battery pack. Signals may be sent via electrical wiring or data cables bundled in the jetting hose. The micro-transmitter housed in the battery pack&#39;s end cap is configured to wirelessly transmit the data received from the micro-receiver to a corresponding micro-receiver housed in the docking station. In addition, the docking station may be configured to further transmit the data to a processor at the surface. This geo-date may be sent wirelessly, via electrical wires bundled in the coiled tubing, or via data cables bundled in the coiled tubing. 
     Geo-trajectory instructions may likewise be sent from a control system residing either at the surface, or in the micro-processor residing in the docking station, downhole. The control system sends signals to one or more current regulators for regulating an amount of current to be sent to each individual actuator wire downhole. Contraction of each of the actuator wires is in direct proportion to an amount of electrical current each wire receives. The contraction, in turn, creates a bending moment, thereby enabling geo-steering of the nozzle according to a desired trajectory. In a preferred embodiment, the bending moment applied to the distal end of the jetting hose is controlled by an operator at the surface through the delivery of geo-trajectory signals sent to a micro-transmitter in the docking station. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the present inventions can be better understood, certain illustrations, charts and/or flow charts are appended hereto. It is to be noted, however, that the drawings illustrate only selected embodiments of the inventions and are therefore not to be considered limiting of scope, for the inventions may admit to other equally effective embodiments and applications. 
         FIG. 1A  is a cross-sectional view of an illustrative horizontal wellbore. Half-fracture planes are shown in 3-D along a horizontal leg of the wellbore to illustrate fracture stages and fracture orientation relative to a subsurface formation. 
         FIG. 1B  is an enlarged view of the horizontal portion of the wellbore of  FIG. 1A . Conventional perforations are replaced by ultra-deep perforations, or mini-lateral boreholes, to create fracture wings. 
         FIG. 2  is a longitudinal, cross-sectional view of a downhole hydraulic jetting assembly of the present invention, in one embodiment. The assembly is shown within a horizontal section of a production casing. The jetting assembly has an external system and an internal system. 
         FIG. 3  is a longitudinal, cross-sectional view of the internal system of the hydraulic jetting assembly of  FIG. 2 . The internal system extends from an upstream battery pack end cap (that mates with the external system&#39;s docking station) at its proximal end to an elongated hose having a jetting nozzle at its distal end. 
         FIG. 3A  is a cut-away perspective view of the battery pack section of the internal system of  FIG. 3 . 
         FIG. 3B-1  is a cut-away perspective view of a jetting fluid inlet located between the base of the battery pack section and the jetting hose. A jetting fluid receiving funnel is shown for receiving fluids into the jetting hose of the internal system of  FIG. 3 . 
         FIG. 3B-1 . a  is an axial, cross-sectional view of the internal system of  FIG. 3  taken at the top of the bottom end cap of the battery pack section. 
         FIG. 3B-1 . b  is an axial, cross-sectional view of the internal system of  FIG. 3  taken at the top of the jetting fluid inlet. 
         FIG. 3C  is a cut-away perspective view of an upper portion of the internal system of  FIG. 3 , from the base of the jetting hose&#39;s fluid receiving funnel through the jetting hose&#39;s upper seal assembly. 
         FIG. 3D-1  presents a cross-sectional view of a bundled jetting hose, with electrical wiring and data cabling, as may be used in the internal system of  FIG. 3 . 
         FIG. 3D-1   a  is an axial, cross-sectional view of the bundled jetting hose of  FIG. 3D-1 . Both electrical wires and fiber optical (or data) cables are seen. 
         FIG. 3E  is an expanded cross-sectional view of the terminal end of the jetting hose of  FIG. 3D-1 , showing the jetting nozzle of the internal system of  FIG. 3 . The bend radius of the jetting hose is shown within a cut-away section of the whipstock of the external system of  FIG. 3 . 
         FIGS. 3F-1   a  through  3 G- 1   c  present enlarged, cross-sectional views of the jetting nozzle of  FIG. 3E , in various embodiments. 
         FIG. 3F-1   a  is an axial, cross-sectional view showing a basic nozzle body. The nozzle body includes a rotor and a surrounding stator. 
         FIG. 3F-1   b  is a longitudinal, cross-sectional view of a jetting nozzle, taken across line C-C′ of  FIG. 3F-1   a . Here, the nozzle uses a single discharge slot at the tip of the rotor. The nozzle also includes bearings between the rotor and the surrounding stator. 
         FIG. 3F-1   c  is a longitudinal cross-sectional view of the jetting nozzle of  FIG. 3F-1   b , in a modified embodiment. Here, the jetting nozzle includes a geo-spatial chip, and is shown connected to a jetting hose via welding. 
         FIG. 3F-1   d  is an axial, cross-sectional view of the jetting hose of  FIG. 3F-1   c , taken across line c-c′. 
         FIGS. 3F-2   a  and  3 F- 2   b  present longitudinal, cross-sectional views of the nozzle of  FIG. 3E , in an alternate embodiment. Along with a single discharge slot at the tip of the rotor, five rearward thrust jets are placed in the body of the stator, actuated by forward displacement of a slideable nozzle throat insert against a slideable collar and biasing mechanism. 
       In  FIG. 3F-2   a , the insert and collar are in their closed position. In  FIG. 3F-2   b , the insert and collar are in their open position allowing fluid to flow through the rearward thrust jets. The jets are opened when a sufficient pumping pressure overcomes the resistance of a spring. 
         FIG. 3F-2   c  is an axial, cross-sectional view of the nozzle of  FIG. 3F-2   a . Five rearward thrust jets are shown for generating a rearward thrust force. 
         FIGS. 3F-3   a  and  3 F- 3   c  provide longitudinal, cross-sectional views of the jetting nozzle of  FIG. 3E , in another alternate embodiment. Here, multiple rearward thrust jets residing in both the stator body and the rotor body are used. In this arrangement, an electromagnetic force pulling on a magnetic collar, biased by a spring, is used for opening/closing the rearward thrust jets. 
       In  FIG. 3F-3   a , the collar of the jetting nozzle is in its closed position. In  FIG. 3F-2   b , the collar is in its open position allowing fluid to flow through the rearward thrust jets. 
         FIGS. 3F-3   b  and  3 F- 3   d  show axial, cross-sectional views of the jetting nozzle correlative to  FIGS. 3F-3   a  and  3 F- 3   c , respectively. Eight rearward thrust jets are seen. This embodiment provides for intermittent alignment of the four jetting ports in the rotor with either of the two sets of four jetting ports in the stator to produce a pulsating rearward thrust flow. 
         FIG. 3G-1   a  is an axial, cross-sectional view showing a basic collar body for a jetting collar that can be placed within a length of jetting hose. The collar body again includes a rotor and a surrounding stator. The view is taken across line D-D′ of  FIG. 3G-1   b.    
         FIG. 3G-1   b  is a longitudinal, cross-sectional view of the jetting collar of  FIG. 3G-1   a . As with the jetting nozzle of  FIGS. 3F-3   a  through  3 F- 3   d , two sets of four jetting ports in the stator intermittently align with the four jetting ports in the rotor to produce pulsating rearward thrust flow. 
         FIG. 3G-1   c  is an axial, cross-sectional view of the jetting nozzle of  FIG. 3G-1   b , taken across line d-d′. 
         FIG. 4  is a longitudinal, cross-sectional view of the external system of the downhole hydraulic jetting assembly of  FIG. 2 , in one embodiment. The external system resides within production casing of the horizontal leg of the wellbore of  FIG. 2 . 
         FIG. 4A-1 . is an enlarged, longitudinal cross-sectional view of a portion of a bundled coiled tubing conveyance medium which conveys the external system of  FIG. 4  into and out of the wellbore. 
         FIG. 4A-1   a  is an axial, cross-sectional view of the coiled tubing conveyance medium of  FIG. 4A-1 . In this embodiment, an inner coiled tubing is “bundled” concentrically with both electrical wires and data cables within a protective outer layer. 
         FIGS. 4A-2  is another axial, cross-sectional view of the coiled tubing conveyance medium of  FIG. 4A-1   a , but in a different embodiment. Here, the inner coiled tubing is “bundled” eccentrically within the protective outer layer to provide more evenly-spaced protection of the electrical wires and data cables. 
         FIG. 4B-1  is a longitudinal, cross-sectional view of a crossover connection, which is the upper-most member of the external system of  FIG. 4 . The crossover section is configured to join the coiled tubing conveyance medium of  FIG. 4A-1  to a main control valve. 
         FIG. 4B-1   a  is an enlarged, perspective view of the crossover connection of  FIG. 4B-1 , seen between cross-sections E-E′ and F-F′. This view highlights the wiring chamber&#39;s general transition in cross-sectional shape from circular to elliptical. 
         FIG. 4C-1  is a longitudinal, cross-sectional view of the main control valve of the external system of  FIG. 4 . 
         FIG. 4C-1   a  is a cross-sectional view of the main control valve, taken across line G-G′ of  FIG. 4C-1 . 
         FIG. 4C-1   b  is a perspective view of a sealing passage cover of the main control valve, shown exploded away from  FIG. 4C-1   a.    
         FIG. 4D-1  is a longitudinal, cross-sectional view of a jetting hose carrier section of the external system of  FIG. 4 . The jetting hose carrier section is attached downstream of the main control valve. 
         FIG. 4D-1   a  shows an axial, cross-sectional view of the main body of the jetting hose carrier section, taken along line H-H′ of  FIG. 4D-1 . 
         FIG. 4D-1   b  is an enlarged view of a portion of the jetting hose carrier section of  FIG. 4D . 1 . A docking station of the external system is more clearly seen. 
         FIG. 4D-2  is an enlarged, longitudinal, cross-sectional view of the external system&#39;s jetting hose carrier section of  FIG. 4D-1 , with inclusion of the jetting hose of the internal system from  FIG. 3 . 
         FIG. 4D-2   a  provides an axial, cross-sectional view of the jetting hose carrier section of  FIG. 4D-1 , with the jetting hose residing therein. 
         FIG. 4E-1  is a longitudinal, cross-sectional view of selected portions of the external system of  FIG. 4 . Visible are a jetting hose pack-off section, and an outer body transition from the preceding circular body (I-I′) of the jetting hose carrier section to a star-shaped body (J-J′) of the jetting hose pack-off section 
         FIG. 4E-1   a  is an enlarged, perspective view of the transition between lines I-I′ and J-J′ of  FIG. 4E-1 . 
         FIG. 4E-2  shows an enlarged view of a portion of the jetting hose pack-off section. Internal seals of the pack-off section conform to the outer circumference of the jetting hose ( FIG. 3 ) residing therein. A pressure regulator valve is shown schematically adjacent the pack-off section. 
         FIG. 4F-1  is a further downstream longitudinal, cross-sectional view of the external system of  FIG. 4 . The jetting hose pack-off section and the outer body transition from  FIG. 4E-1  are again shown. Also visible here is an internal tractor system. Note each of the aforementioned components are shown with a longitudinal cross-sectional view of the jetting hose of  FIG. 3  residing therein. 
         FIG. 4F-2  is an enlarged, longitudinal, cross-sectional view of a portion of the internal tractor system of  FIG. 4 -F 1 , again with a cross-section of the jetting hose residing therein. An internal motor, gear and gripper assembly is also shown. 
         FIG. 4F-2   a  is an axial, cross-sectional view of the internal tractor system of  FIG. 4F-2 , taken across line K-K′ of  FIGS. 4F-1 and 4F-2 . 
         FIG. 4F-2   b  is an enlarged half-view of a portion of the internal tractor system of  FIG. 4F-2   a.    
         FIG. 4G-1  is still a further downstream longitudinal, cross-sectional view of the external system of  FIG. 4 . This view shows a transition from the internal tractor to an upper swivel, followed by the upper swivel of the external system. 
         FIG. 4G-1   a  depicts a perspective view of the outer body transition between the internal tractor system to the upper swivel. This is a star-shape (L-L′) to a circle-shape (M-M′) transition of the outer body. 
         FIG. 4G-1   b  provides an axial, cross-sectional view of the upper swivel of  FIG. 4 -G 1 , taken across line N-N′. 
         FIG. 4H-1  is a cross-sectional view of a whipstock member of the external system of  FIG. 4 , but shown vertically instead of horizontally. The jetting hose of the internal system ( FIG. 3 ) is shown bending across the whipstock, and extending through a window in the production casing. The jetting nozzle of the internal system is shown affixed to the distal end of the jetting hose. 
         FIG. 4H-1   a  is an axial, cross-sectional view of the whipstock member, with a perspective view of sequential axial jetting hose cross-sections depicting its path downstream from the center of the whipstock member at line O-O′ to the start of the jetting hose&#39;s bend radius as it approaches line P-P′. 
         FIG. 4H-1   b  depicts an axial, cross-sectional view of the whipstock member at line P-P′. 
         FIG. 4I-1  is a longitudinal, cross-sectional view of a bottom swivel within the external system of  FIG. 4 , residing just downstream of slips (shown engaging the surrounding production casing) near the base of the preceding whipstock member. 
         FIG. 4I-1   a  provides an axial, cross-sectional view of a portion of the bottom swivel of  FIG. 4I-1 , taken across line Q-Q′. 
         FIG. 4J  is another longitudinal view of the bottom swivel of  FIG. 4I-1 . Here, the bottom swivel is connected to a transition section, which in turn is connected to a conventional mud motor, an external tractor, and a logging sonde, thus completing the entire downhole tool string. For simplification, neither a packer nor a retrievable bridge plug has been included in this configuration. 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
     Definitions 
     As used herein, the term “hydrocarbon” refers to an organic compound that includes primarily, if not exclusively, the elements hydrogen and carbon. Hydrocarbons generally fall into two classes: aliphatic, or straight chain hydrocarbons, and cyclic, or closed ring hydrocarbons, including cyclic terpenes. Examples of hydrocarbon-containing materials include any form of natural gas, oil, coal, and bitumen that can be used as a fuel or upgraded into a fuel. 
     As used herein, the term “hydrocarbon fluids” refers to a hydrocarbon or mixtures of hydrocarbons that are gases or liquids. For example, hydrocarbon fluids may include a hydrocarbon or mixtures of hydrocarbons that are gases or liquids at formation conditions, at processing conditions, or at ambient conditions. Hydrocarbon fluids may include, for example, oil, natural gas, condensate, coal bed methane, shale oil, shale gas, and other hydrocarbons that are in a gaseous or liquid state. 
     As used herein, the term “fluid” refers to gases, liquids, and combinations of gases and liquids, as well as to combinations of gases and solids, and combinations of liquids and solids. 
     As used herein, the term “subsurface” refers to geologic strata occurring below the earth&#39;s surface. 
     The term “subsurface interval” refers to a formation or a portion of a formation wherein formation fluids may reside. The fluids may be, for example, hydrocarbon liquids, hydrocarbon gases, aqueous fluids, or combinations thereof. 
     The terms “zone” or “zone of interest” refer to a portion of a formation containing hydrocarbons. Sometimes, the terms “target zone,” “pay zone,” or “interval” may be used. 
     As used herein, the term “wellbore” refers to a hole in the subsurface made by drilling or insertion of a conduit into the subsurface. A wellbore may have a substantially circular cross section, or other cross-sectional shape. As used herein, the term “well,” when referring to an opening in the formation, may be used interchangeably with the term “wellbore.” 
     The term “jetting fluid” refers to any fluid pumped through a jetting hose and nozzle assembly for the purpose of erosionally boring a lateral borehole from an existing parent wellbore. The jetting fluid may or may not contain an abrasive material. 
     The term “abrasive material” or “abrasives” refers to small, solid particles mixed with or suspended in the jetting fluid to enhance erosional penetration of: (1) the pay zone; and/or (2) the cement sheath between the production casing and pay zone; and/or (3) the wall of the production casing at the point of desired casing exit. 
     The terms “tubular” or “tubular member” refer to any pipe, such as a joint of casing, a portion of a liner, a joint of tubing, a pup joint, or coiled tubing. 
     The terms “lateral borehole” or “mini-lateral” or “ultra-deep perforation” (“UDP”) refer to the resultant borehole in a subsurface formation, typically upon exiting a production casing and its surrounding cement sheath in a parent wellbore, with said borehole formed in a known or prospective pay zone. For the purposes herein, a UDP is formed as a result of hydraulic jetting forces erosionally boring through the pay zone with a jetting fluid directed through a jetting hose and out a jetting nozzle affixed to the terminal end of the jetting hose. Preferably, each UDP will have a substantially normal trajectory relative to the parent wellbore. 
     The terms “steerable” or “guidable”, as applied to a hydraulic jetting assembly, refers to a portion of the jetting assembly (typically, the jetting nozzle and/or the portion of jetting hose immediately proximal the nozzle) for which an operator can direct and control its geo-spatial orientation while the jetting assembly is in operation. This ability to direct, and subsequently re-direct the orientation of the jetting assembly during the course of erosional excavation can yield UDP&#39;s with directional components in one, two, or three dimensions, as desired. 
     The terms “perforation cluster” or “UDP cluster” refer to a designed grouping of lateral boreholes off a parent well casing. These groupings are ideally designed to receive and transmit a specific “stage” of a stimulation treatment, usually in the course of completing or recompleting a horizontal well by hydraulic fracturing (or “fracking”). 
     The term “stage” references a discreet portion of a stimulation treatment applied in completing or recompleting a specific pay zone, or specific portion of a pay zone. In the case of a cased horizontal parent wellbore, up to 10, 20, 50 or more stages may be applied to their respective perforation (or UDP) clusters. Typically, this requires some form of zonal isolation prior to pumping each stage. 
     The terms “contour” or “contouring” as applied to individual UDP&#39;s, or groupings of UDP&#39;s in a “cluster”, refers to steerably excavating the UDP (or lateral borehole) so as to optimally receive, direct, and control stimulation fluids, or fluids and proppants, of a given stimulation (typically, fracking) stage. This ability to ‘ . . . optimally receive, direct, and control . . . ’ a given stage&#39;s stimulation fluids is designed to retain the resultant stimulation geometry “in zone”, and/or concentrate the stimulation effects where desired. The result is to optimize, and typically maximize, the Stimulated Reservoir Volume (“SRV”). 
     The terms “real time” or “real time analysis” of geophysical data (such as micro-seismic, tiltmeter, and or ambient micro-seismic data) that is obtained during the course of pumping a stage of a stimulation (such as fracking) treatment means that results of said data analysis can be applied to: (1) altering the remaining portion of the stimulation treatment (yet to be pumped) in its pump rates, treating pressures, fluid rheology, and proppant concentration in order to optimize the benefits therefrom; and, (2) optimizing the placement of perforations, or contouring the trajectories of UDP&#39;s, within the subsequent “cluster(s)” to optimize the SRV obtained from the subsequent stimulation stages. 
     DESCRIPTION OF SPECIFIC EMBODIMENTS 
     A downhole hydraulic jetting assembly is provided herein. The jetting assembly is designed to direct a jetting nozzle and connected hydraulic hose through a window formed along a string of production casing, and then “jet” one or more boreholes outwardly into a subsurface formation. The lateral boreholes essentially represent ultra-deep perforations that are formed by using hydraulic forces directed through a flexible, high pressure jetting hose, having affixed to its distal end a high pressure jetting nozzle. The subject assembly capitalizes on a single hose and nozzle apparatus to continuously jet, optionally, both a casing exit and the subsequent lateral borehole. 
       FIG. 1A  is a schematic depiction of a horizontal well  4 , with wellhead  5  located above the earth&#39;s surface  1 , and penetrating several series of subsurface strata  2   a  through  2   h  before reaching a pay zone  3 . The horizontal section  4   c  of the wellbore  4  is depicted between a “heel”  4   b  and a “toe”  4   d . Surface casing  6  is shown as cemented  7  fully from the surface casing shoe  8  back to surface  1 , while the intermediate casing string  9  is only partially cemented  10  from its shoe  11 . Similarly, production casing string  12  is only partially cemented  13  from its casing shoe  14 , though sufficiently isolating the pay zone  3 . Note how in the  FIG. 1A  depiction of a typical horizontal wellbore, conventional perforations  15  within the production casing  12  are shown in up-and-down pairs, and are depicted with subsequent hydraulic fracture half-planes  16 . The half-planes  16  are sometimes referred to in the industry as “frac wings.” 
       FIG. 1B  is an enlarged view of the lower portion of the wellbore  4  of  FIG. 1A . Here, the horizontal section  4   c  between the heel  4   b  and the toe  4   d  is more clearly seen. In this depiction, application of the subject apparati and methods herein replaces the conventional perforations ( 15  in  FIG. 1A ) with pairs of opposing horizontal UDP&#39;s  15  as depicted in  FIG. 1B , again with subsequently generated fracture half-planes  16 . Specifically depicted in  FIG. 1B  is how the half-planes  16  are now better confined within the pay zone  3 , while reaching much further out from the horizontal wellbore  4   c  into the pay zone  3 . Stated another way, in-zone fracture propagation is significantly enhanced by the pre-existence of the UDP&#39;s  15  as generated by the assembly and methods disclosed herein. 
       FIG. 2  provides a longitudinal, cross-sectional view of a downhole hydraulic jetting assembly  50  of the present invention, in one embodiment. The jetting assembly  50  is shown residing within a string of production casing  12 . The production casing  12  may have, for example, a 4.5-inch O.D. (4.0-inch I.D.). The production casing  12  is presented along a horizontal portion  4   c  of the wellbore  4 . As noted in connection with  FIGS. 1A and 1B , the horizontal portion  4   c  defines a heel  4   b  and a toe  4   d.    
     The jetting assembly  50  generally includes an internal system  1500  and an external system  2000 . The jetting assembly  50  is designed to be run into a wellbore  4  at the end of a working string, sometimes referred to herein as a “conveyance medium.” Preferably, the working string is a string of coiled tubing  100 . The conveyance medium  100  may be conventional coiled tubing. Alternatively, a “bundled” product that incorporates electrically conductive wiring and data conductive cables (such as fiber optic cables) around the coiled tubing core, protected by an erosion/abrasion resistant outer layer(s), such as PFE and/or Kevlar, or even another (outer) string of coiled tubing may be used. It is observed that fiber optic cables have a practically negligible diameter, and are oilfield-proven to be efficient in providing direct, real-time data transmission and communications with downhole tools. Other emerging transmission media such as carbon nanotube fibers may also be employed. 
     Other conveyance media may be used for the jetting assembly  50 . These include, for example, a standard e-coil system, a customized FlatPAK® assembly, PUMPTEK&#39;s® Flexible Steel Polymer Tubing (“FSPT”) or Flexible Tubing Cable (“FTC”) tubing. Alternatively, tubing have PTFE (Polytetrafluorethylene) and Kevlar®-based materials, or Draka Cableteq USA, Inc.&#39;s® Tubing Encapsulated Cable (“TEC”) system may be used. In any instance, it is desirable that the conveyance medium  100  be flexible, somewhat malleable, non-conductive, pressure resistant (to withstand high pressure fracturing fluids optionally being pumped down the annulus), temperature resistant (to withstand bottom hole wellbore operating temperatures, often in excess of 200° F., and sometimes exceeding 300° F.), chemical resistant (at least in resistance to the additives included in the frac fluids), friction resistant (to minimize the downhole pressure loss due to friction while pumping the frac treatment), erosion resistant (to withstand the erosive effects of afore-mentioned annular fracturing fluids) and abrasion resistant (to withstand the abrasive effects of proppants suspended in the aforementioned annular fracturing fluids). 
     If a standard coiled tubing string is employed, communications and data transmission may be accomplished by hydro-pulse technology (or so-called mud-pulse telemetry), acoustic telemetry, EM telemetry, or some other remote transmission/reception system. Similarly, electricity for operating the apparatus may be generated downhole by a conventional mud motor(s), which would allow the electrical circuitry for the system to be confined below the end of the coiled tubing. The present hydraulic jetting assembly  50  is not limited by the data transmission system or the power transmission or the conveyance medium employed unless expressly so stated in the claims. 
     It is preferred to maintain an outer diameter of the coiled tubing  100  that leaves an annular area within the approximate 4.0″ I.D. of the casing  12  that is greater than or equal to the cross-sectional area open to flow for a 3.5″ O.D. frac (tubing) string. This is because, in the preferred method (after jetting one or more, preferably two opposing mini-laterals, or even specially contoured “clusters” of small-diameter lateral boreholes), fracture stimulation can immediately (after repositioning the tool string slightly uphole) take place down the annulus between the coiled tubing conveyance medium  100  plus the external system  2000 , and the well casing  12 . For 9.2#, 3.5″ O.D. tubing (i.e., frac string equivalent), the I.D. is 2.992 inches, and the cross-sectional area open to flow is 7.0309 square inches. Back-calculating from this same 7.0309 in 2  equivalency yields a maximum O.D. available for both the coiled tubing conveyance medium  100  and the external system  2000  (having generally circular cross-sections) of 2.655″. Of course, a smaller O.D. for either may be used provided such accommodate a jetting hose  1595 . 
     In the view of  FIG. 2 , the assembly  50  is in an operating position, with a jetting hose  1595  being run through a whipstock  1000 , and a jetting nozzle  1600  passing through a first window “W” of the production casing  12 . At the end of the jetting assembly  50 , and below the whipstock  1000 , are several optional components. These include a conventional mud motor  1300 , an external (conventional) tractor  1350  and a logging sonde  1400 . These components are shown and described more fully below in connection with  FIG. 4 . 
       FIG. 3  is a longitudinal, cross-sectional view of the internal system  1500  of the hydraulic jetting assembly  50  of  FIG. 2 . The internal system  1500  is a steerable system that, when in operation, is able to move within and extend out of the external system  2000 . The internal system  1500  is comprised primarily of:
         (1) power and geo-control components;   (2) a jetting fluid intake;   (3) the jetting hose  1595 ; and   (4) the jetting nozzle  1600 .       

     The internal system  1500  is designed to be housed within the external system  2000  while being conveyed by the coiled tubing conveyance medium  100  and the attached external system  2000  in to and out of the parent wellbore  4 . Extension of the internal system  1500  from and retraction back into the external system  2000  is accomplished by the application of: (a) hydraulic forces; (b) mechanical forces; or (c) a combination of hydraulic and mechanical forces. Beneficial to the design of the internal  1500  and external  2000  systems comprising the hydraulic jetting apparatus  50  is that transport, deployment, or retraction of the jetting hose  1595  never requires the jetting hose to be coiled. Specifically, the jetting hose  1595  is never subjected to a bend radius smaller than the I.D. of production casing  12 , and that only incrementally while being advanced along the whipstock  1050  of the jetting hose whipstock member  1000  of the external system  2000 . Note the jetting hose  1595  is typically ¼th″ to ⅝ths″ ID., and up to approximately 1″ O.D., flexible tubing that is capable of withstanding high internal pressures. 
     The internal system  1500  first includes a battery pack  1510 .  FIG. 3A  provides a cut-away perspective view of the battery pack  1510  of the internal system  1500  of  FIG. 3 . Note this section  1510  has been rotated 90° from the horizontal view of  FIG. 3  to a vertical orientation for presentation purposes. An individual AA battery  1551  is shown in a sequence of end-to-end like batteries forming the battery pack  1550 . Protection of the batteries  1551  is primarily via a battery pack casing  1540  which is sealed by an upstream battery pack end cap  1520  and a downstream battery pack end cap  1530 . These components ( 1540 ,  1520 , and  1530 ) present exterior faces exposed to the high pressure jetting fluid stream. Accordingly, they are preferably constructed of or are coated with a non-conductive, highly abrasion/erosion/corrosion resistant material. 
     The upstream battery pack end cap  1520  has a conductive ring about a portion of its circumference. When the internal system  1500  is “docked” (i.e., matingly received into a docking station  325  of the external system  2000 ) the battery pack end cap  1520  can receive and transmit current and, thus, re-charge the battery pack  1550 . Note also that the end caps  1520  and  1530  can be sized so as to house and protect any servo, microchip, circuitry, geospatial or transmitter/receiver components within them. 
     The battery pack end-caps  1520 ,  1530  may be threadedly attached to the battery pack casing  1540 . The battery pack end-caps  1520 ,  1530  may be constructed of a highly erosive- and abrasive-resistant, high pressure material, such as titanium, perhaps even further protected by a thin, highly erosive- or abrasive-resistant coating, such as polycrystalline diamond. The shape and construction of the end-caps  1520 ,  1530  are preferably such that they can deflect the flow of high pressure jetting fluid without incurring significant wear. The upstream end cap  1520  must deflect flow to an annular space (not shown in  FIG. 3 ) between the battery casing  1540  and a surrounding jetting hose conduit  420  (seen in  FIG. 3C ) of a jetting hose carrier system (shown at  400  in  FIG. 4D-1 ). The downstream end-cap  1530  bounds part of the flow path of the jetting fluid from this annular space down into the I.D. of the jetting hose  1595  itself through a jetting fluid receiving (or, “intake”) funnel (shown at  1570  in  FIG. 3B-1 ). 
     Thus, the path of the high pressure hydraulic jetting fluid (with or without abrasives) is as follows:
         (1) Jetting fluid is discharged from a high pressure pump at the surface  1  down the I.D. of the coiled tubing conveyance medium  100 , at the end of which it enters the external system  2000 ;   (2) Jetting fluid enters the external system  2000  through a coiled tubing transition connection  200 ;   (3) Jetting fluid enters the main control valve  300  through a jetting fluid passage  345 ;   (4) Because the main control valve  300  is positioned to receive jetting fluid (as opposed to hydraulic fluid), a sealing passage cover  320  will be positioned to seal a hydraulic fluid passage  340 , leaving the only available fluid path through the jetting fluid passage  345 , the discharge of which is sealingly connected to the jetting hose conduit  420  of the jetting hose carrier system  400 ;   (5) Upon entering the jetting hose conduit  420 , the jetting fluid will first pass by a docking station  325  (which is affixed within the jetting hose conduit  420 ) through the annulus between the docking station  325  and the jetting hose conduit  420 ;   (6) Because the jetting hose  1595  itself resides in the jetting hose conduit  420 , the high pressure jetting fluid must now either go through or around the jetting hose  1595 ; and   (7) Because of the internal system&#39;s  1500  seal  1580 U, which seals the annulus between the jetting hose  1595  and the jetting hose conduit  420 , jetting fluid cannot go around the jetting hose  1595  (note this hydraulic pressure on the seal assembly  1580  is the force that tends to pump the internal system  1500 , and hence the jetting hose  1595 , “down the hole”) and thus jetting fluid is forced to go through the jetting hose  1595  according to the following path:
           (a) jetting fluid first passes the top of the internal system  1500  at the upstream battery pack end cap  1520 ,   (b) jetting fluid then passes through the annulus between the battery pack casing  1540  and the jetting hose conduit  420  of the jetting hose carrier system  400 ;   (c) after jetting fluid passes the downstream battery pack end cap  1530 , it is forced to flow between battery pack support conduits  1560 , and into a jetting fluid receiving funnel  1570 ; and   (d) because the jetting fluid receiving funnel  1570  is rigidly and sealingly connected to the jetting hose  1595 , jetting fluid is forced into the I.D. of jetting hose  1595 .   
               

     Worthy of note in the above-described jetting fluid flow sequence are the following initiation conditions:
         (i) an internal tractor system  700  is first engaged to translate a discreet length of jetting hose  1595  in a downstream direction, such that the jetting nozzle  1600  and jetting hose  1595  enter the jetting hose whipstock  1000  and specifically, after traveling a fixed distance within the inner wall (shown at  1020  in  FIG. 4H-1 ), are forced radially outward to engage first the interior wall of production casing  12  and then engage the upper curved face  1050 . 1  of whipstock member  1050 , at which point,   (ii) the jetting hose  1595  is curvedly ‘bent’ approximately 90°, assuming its pre-defined bend radius (shown at  1599  in  FIG. 4H-1 ) and directing the jetting nozzle  1600  attached to its terminal end to engage the precise point of desired casing exit “W” within the I.D. of the production casing  12 ; at which point   (iii) increased torque within the internal tractor system&#39;s  700  gripper assemblies  750  is then realized, a signal for which is immediately conveyed electronically to the surface, signaling the operator to shut down rotation of the grippers (illustrative griper seen at  756  in  FIG. 4F-2   b ).
 
(Practically, such shut-down could be pre-programmed into the operating system at a certain torque level.) Note that during stages (i) through (iii), a pressure regulator valve (seen at  610  in  FIG. 4E-2 ) is in an “open” position. This allows hydraulic fluid in the annulus between the jetting hose  1595  and the surrounding jetting hose conduit  420  to bleed-off. Once the tip of jetting nozzle  1600  engages the I.D. (casing wall) of production casing  12 , then the operator may:
   (iv) reverse the direction of rotation of the grippers  756  to translate the jetting hose  1595  back into the jetting hose (or inner) conduit  420 ; and   (v) switch a main control valve  300  to begin pumping hydraulic fluid though the hydraulic fluid passage  340 , down the conduit-carrier annulus  440 , through the pressure regulator valve  610 , and into the jetting hose  1595 /jetting hose conduit  420  annulus  1595 . 420  to both: (1) pump upwards against lower seals  1580 L of the jetting hose&#39;s seal assembly  1580  to re-extend the jetting hose  1595  in a taught position; and, (2) assist the (now reversed) gripper assemblies  750  in positioning the internal system  1500  such that the jetting nozzle  1600  has the desired stand-off distance (preferably less than 1 inch) between itself and the I.D. of the production casing  12  to begin jetting the casing exit.
 
Upon reaching this desired stand-off distance, rotation of grippers  756  ceases, and pressure regulator valve  610  is closed to lock down the internal system at the desired, fixed position for jetting the casing exit “W”.
       

     Referring back to  FIG. 3A , in one embodiment the interior of the downstream end-cap  1530  houses a micro-geo-steering system. The system may include a micro-transmitter, a micro-receiver, a micro-processor, and one or more current regulators. This geo-steering system is electrically or fiber-optically connected to a small geo-spatial IC chip (shown at  1670  in  FIG. 3F-1   c  and discussed more fully below) located in the body of the jetting nozzle  1600 . In this way, nozzle orientation data may be sent from the jetting nozzle  1600  to the micro-processor (or appropriate control system) which, coupled with the values of dispensed hose length, can be used to calculate the precise geo-location of the nozzle at any point, and thus the contour of the UDP&#39;s path. Conversely, geo-steering signals may be sent from the control system (such as a micro-processor in the docking station or at the surface) to modify, through one or more electrical current regulators, individualized current strengths down to each of the (at least three) actuator wires (shown at  1590 A in  FIG. 3F-1   c ), thus redirecting the nozzle as desired. 
     The geo-steering system can also be utilized to control the rotational speed of a rotor body within the jetting nozzle  1600 . As will be described more fully below, the rotating nozzle configuration utilizes the rotor portion  1620  of a miniature direct drive electric motor assembly to also form a throat and end discharge slot  1640  of the rotating nozzle itself. Rotation is induced via electromagnetic forces of a rotor/stator configuration. In this way, rotational speeds can be governed in direct proportion to the current supplied to the stators. 
     As depicted in  FIGS. 3F-1 through 3F-3 , the upstream portion of the rotor (in this depiction, a four-pole rotor)  1620  includes a near-cylindrical inner diameter (the I.D. actually reduces slightly from the fluid inlet to the discharge slot to further accelerate the fluid before it enters the discharge slot) that provides a flow channel for the jetting fluid through the center of the rotor  1620 . This near-cylindrical flow channel then transitions to the shape of the nozzle&#39;s  1600  discharge slot  1640  at its far downstream end. This is possible because, instead of the typical shaft and bearing assembly inserted longitudinally through the center diameter of the rotor  1620 , the rotor  1620  is stabilized and positioned for balanced rotation about the longitudinal axis of the rotor  1620  by a single set of bearings  1630  positioned about the interior of the upstream butt end, and outside the outer diameter of the flow channel (“nozzle throat”)  1650 , such that the bearings  1630  stabilize the rotor body  1620  both longitudinally and axially. 
     Referring now to  FIG. 3B-1   a , and again discussing the internal system  1500 , a cross-sectional view of the battery pack section  1510 , taken across line A-A′ of  FIG. 3B-1  is shown. The view is taken at the top of the bottom end cap  1530  of the battery pack  1510  looking down into a jetting fluid receiving funnel  1570 . Visible in this figure are three wires  1590  extending away from the battery pack  1510 . Using the wires  1590 , power is sent from the “AA”-size lithium batteries  1551  to the geo-steering system for controlling the rotating jet nozzle  1600 . By adjusting current through the wires  1590 , the geo-steering system controls the rate of rotation of the rotor  1620  along with its orientation. 
     Note that because the longitudinal axis of the nozzle&#39;s discharge stream is designed to be continuous to and aligned with that of the nozzle throat, there is virtually no axial moment acting on the nozzle from thrust of the exiting jetting fluid. That is, as the nozzle is designed to operate in an axially “balanced” condition, the torque moment required to actually rotate the nozzle about its longitudinal axis is relatively small. Similarly, in that relatively low rotational speeds (RPM&#39;s) are required for rotational excavation, the electromagnetic force required from the nozzle&#39;s rotor/stator interaction is relatively small as well. 
     Note from  FIG. 3  that the jetting nozzle  1600  is located at the far downstream end of the jetting hose  1595 . Though the diameters of the components of the internal system  1500  must meet some rather stringent diameter constraints, the respective lengths of each component (with the exception of the jetting nozzle  1600  and, if desired, one or more jetting collars) are typically far less restricted. This is because the jetting nozzle  1600  and collars are the only components affixed to the jetting hose  1595  that will ever have to make the approximate 90° bend as directed by the whipstock face  1050 . 1 . All other components of the internal system  1500  will always reside at some position within the jetting hose carrier system  400 , and above the jetting hose pack-off section  600  (discussed below). 
     The length of many of the components can also be adjusted. For example, though the battery pack  1510  in  FIG. 3A  is depicted to house six AA batteries  1551 , a much greater number could be easily accommodated by simply constructing a longer battery pack casing  1540 . Similarly, the battery pack end-caps  1520 ,  1530 , the support columns  1560 , and the fluid intake funnel  1570  may be substantially elongated as well to accommodate fluid flow and power needs. 
     Referring again to the docking station  325 , the docking station  325  serves as a physical “stop” beyond which the internal system  1500  can no longer travel upstream. Specifically, the upstream limit of travel of the internal system  1500  (comprised primarily of the jetting hose  1595 ) is at that point where the upstream battery pack end cap  1520  lodges (or, “docks”) within a bottom, conically-shaped receptacle  328  of the docking station  325 . The receptacle  328  serves as a lower end cap. The receptacle  328  provides matingly conductive contacts which line up with the upstream battery pack end cap  1520  to form a docking point. In this way, a transfer of data and/or electrical power (specifically, to recharge batteries  1551 ) can occur while “docked.” 
     The docking station  325  also has a conically-shaped end-cap  323  at the upstream (proximal) end of the docking station  325 . The conical shape serves to minimizing erosive effects by diverting the flow of jetting fluid around the body thereof, thereby aiding in the protection of the system components housed within the docking station  325 . Depending on the guidance, steering, and communications capabilities desired, an upper portion  323  of the docking station  325  can house the servo, transmission, and reception circuitry and electronics systems designed to communicate directly (either in continuous real time, or only discretely while docked) with counterpart systems in the internal system  1500 . Note, as shown in  FIG. 3 , the O.D. of the cylindrical docking station  325  is approximately equal to that of the jetting hose  1595 . 
     The internal system  1500  next includes a jetting fluid receiving funnel  1570 .  FIG. 3B-1  includes a cut-away perspective view of the jetting fluid receiving funnel  1570 , with an axial cross-sectional view along B-B′ shown as  FIG. 3B-1   b . The jetting fluid receiving funnel  1570  is located below the base of the battery pack section  1510 , shown and described above in connection with  FIG. 3A . As the name implies, the jetting fluid receiving funnel  1570  serves to guide the jetting fluid into the interior of the jetting hose  1595  during the casing exit and mini-lateral formation process. Specifically, the annular flow of jetting fluid (e.g., passing along the outside of battery pack casing  1540  and subsequently the battery pack end cap  1530 , and inside the I.D. of jetting hose conduit  420 ) is forced to transition to flow between the three battery pack support conduits  1560 , because an upper seal (seen in  FIG. 3  at  1580 U) precludes any fluid flow along a path exterior to the jetting hose  1595 . Thus, all flow of jetting fluid (as opposed to hydraulic fluid) is forced between conduits  1560  and into fluid receiving funnel  1570 . 
     In the design of  FIG. 3B-1 , three columnar supports  1560  are used to house the wires  1590 . The columnar supports  1560  also provide an area open to fluid flow. The spacing between the supports  1560  is designed to be significantly greater than that provided by the I.D. of the jetting hose  1595 . At the same time, the supports  1560  have I.D.&#39;s large enough to house and protect up to an AWG #5 gauge wire  1590 . The columnar supports  1560  also support the battery pack  1510  at a specific distance above the jetting fluid intake funnel  1570  and the jetting hose seal assembly  1580 . The supports  1560  may be sealed with sealing end caps  1562 , such that removal of the end caps  1562  provides access to the wiring  1590 . 
       FIG. 3B-1   b  provides a second axial, cross-sectional view of the fluid intake funnel  1570 . This view is taken across line B-B′ of  FIG. 3B-1 . The three columnar supports  1560  are again seen. The view is taken at the top of the jetting fluid inlet, or receiving funnel  1570 . 
     Downstream from the jetting fluid receiving funnel  1570  is a jetting hose seal assembly  1580 .  FIG. 3C  is a cut-away perspective view of the seal assembly  1580 . In the view of  FIG. 3C , columnar support members  1560  and electrical wiring  1590  have been removed for the sake of clarity. However, the receiving funnel  1570  is again seen at the upper end of the seal assembly  1580 . 
     Also visible in  FIG. 3C  is an upper end of the jetting hose  1595 . The jetting hose  1595  has an outermost jetting hose wrap O.D.  1595 . 3  (also seen in  FIG. 3D-1   a ) that, at points, may engage the jetting hose conduit  420 . A micro-annulus  1595 . 420  (shown in  FIGS. 3D-1 and 3D-1   a ) is formed between the jetting hose  1595  and the surrounding conduit  420 . The jetting hose  1595  also has a core (O.D.  1595 . 2 , I.D.  1595 . 1 ) that transmits jetting fluid during the jetting operation. The jetting hose  1595  is fixedly connected to the seal assembly  1580 , meaning that the seal assembly  1580  moves with the jetting hose  1595  as the jetting hose advances into a mini-lateral. 
     As previously described, the upper seal  1580 U of the jetting hose&#39;s seal assembly  1580  (shown as a solid portion with a slightly concave upwards upper face) precludes any continued downstream flow of jetting fluid outside of the jetting hose  1595 . Similarly, the lower seal  1580 L of this seal assembly  1580  (shown as a series of concave-downwards cup faces) precludes any upstream flow of hydraulic fluid from below. Note how any upstream-to-downstream hydraulic pressure from the jetting fluid will tend to expand the jetting fluid intake funnel  1570  and, thus, urge the upper seal  1580 U of the seal assembly  1580  radially outwards to sealingly engage the I.D.  420 . 1  of the jetting hose carrier&#39;s (inner) jetting hose conduit  420 . Similarly, any downstream-to-upstream hydraulic pressure from the hydraulic fluid radially expands bottom cup-like faces making up the lower seal  1580 L to sealingly engage the I.D.  420 . 1  of the jetting hose carrier&#39;s inner conduit  420 . Thus, when jetting fluid pressure is greater than the trapped hydraulic fluid pressure, the overbalance will tend to “pump” the entire assembly “down-the-hole”. Conversely, when the pressure overbalance is reversed, hydraulic fluid pressure will tend to “pump” the entire seal assembly  1580  and connected hose  1595  back “up-the-hole”. 
     Returning to  FIGS. 2 and 3 , the upper seal  1580 U provides an upstream pressure and fluid-sealed connection for the internal system  1500  to the external system  2000 . (Similarly, as will be discussed further below, a pack-off seal assembly  650  within a pack-off section  600  provides a downstream pressure and fluid-sealed connection between the internal system  1500  and the external system  2000 .) The seal assembly  1580  includes seals  1580 U,  1580 L that hold incompressible fluid between the hose  1595  and the surrounding conduit  420 . In this way, the jetting hose  1595  is operatively connected to the coiled tubing string  100  and sealingly connected to the external system  2000 . 
       FIG. 3C  illustrates utility of the sealing mechanisms involved in this upstream seal  1580 . During operation, jetting fluid passes:
         (1) through an annulus  420 . 2  between the battery pack casing  1540  and the jetting hose carrier inner conduit  420 ;   (2) between the battery pack support conduits  1560 ;   (3) into the fluid receiving funnel  1570 ;   (4) down the core  1595 . 1  (ID.) of the jetting hose  1595 ; and   (5) then exits the jetting nozzle  1600 .       

     As noted, the downward hydraulic pressure of the jetting fluid acting upon the axial cross-sectional area of the jetting hose&#39;s fluid receiving funnel  1570  creates an upstream-to-downstream force that tends to “pump” the seal assembly  1580  and connected jetting hose  1595  “down the hole.” In addition, because the components of the fluid receiving funnel  1570  and the supporting upper seal  1580 U of the seal assembly  1580  are slightly flexible, the net pressure drop described above serves to swell and flare the outer diameters of upper seal  1580 U radially outwards, thus producing a fluid seal that precludes fluid flow behind the hose  1595 . 
       FIG. 3D-1  provides a longitudinal, cross-sectional view of the “bundled” jetting hose  1595  of the internal system  1500  as it resides in the jetting hose carrier&#39;s inner conduit  420 . Also included in the longitudinal cross section are perspective views (dashed lines) of electrical wires  1590  and data cables  1591 . Note from the axial cross-sectional view of  FIG. 3D-1   a , that all of the electrical wires  1590  and data cables  1591  in the “bundled” jetting hose  1595  safely reside within the outermost jetting hose wrap  1595 . 3 . 
     In the preferred embodiment, the jetting hose  1595  is a “bundled” product. The hose  1595  may be obtained from such manufacturers as Parker Hannifin Corporation. The bundled hose includes at least three electrically conductive wires  1590 , and at least one, but preferably two dedicated data cables  1591  (such as fiber optic cables), as depicted in  FIGS. 3B-1   b  and  3 D- 1   a . Note these wires  1590  and fiber optic strands  1591  are located on the outer perimeter of the core  1595 . 2  of the jetting hose  1595 , and surrounded by a thin outer layer of a flexible, high strength material or “wrap” (such as Kevlar®)  1595 . 3  for protection. Accordingly, the wires  1590  and fiber optic strands  1591  are protected from any erosive effects of the high-pressure jetting fluid. 
     Moving now down the hose  1595  to the distal end,  FIG. 3E  provides an enlarged, cross sectional view of the end of the jetting hose  1595 . Here, the jetting hose  1595  is passing through the whipstock member  1000 , and ultimately along the whipstock face  1050 . 1  to casing exit “W”. A jetting nozzle  1600  is attached to the distal end of the jetting hose  1595 . The jetting nozzle  1600  is shown in a position immediately subsequent to forming an exit opening, or window “W” in the production casing  12 . Of course, it is understood that the present assembly  50  may be reconfigured for deployment in an uncased wellbore. 
     As described in the related applications, the jetting hose  1595  immediately preceding this point of casing exit “W” spans the entire I.D. of the production casing  12 . In this way, a bend radius “R” of the jetting hose  1595  is provided that is always equal to the I.D. of the production casing  12 . This is significant as the subject assembly  50  will always be able to utilize the entire casing (or wellbore) I.D. as the bend radius “R” for the jetting hose  1595 , thereby providing for utilization of the maximum I.D./O.D hose. This, in turn, provides for placement of maximum hydraulic horsepower (“HHP”) at the jetting nozzle  1600 , which further translates in the capacity to maximize formation jetting results such as penetration rate, or the lateral borehole diameter, or some optimization of the two. 
     It is observed here that there is a consistency of three “touch points” for the bend radius “R” of the jetting hose  1595 . First, there is a touch point where the hose  1595  contacts the I.D. of the casing  12 . This occurs at a point directly opposite and slightly (approximately one casing I.D. width) above the point of casing exit “W.” Second, there is a touch point along a whipstock curved face  1050 . 1  of the whipstock member  1000  itself. Finally, there is a touch point against the I.D. of the casing  12  at the point of casing exit “W,” at least until the window “W” is formed. 
     As depicted in  FIG. 3E  (and in  FIG. 4H-1 ), the jetting hose whipstock member  1000  is in its set and operating position within the casing  12 . (U.S. Pat. No. 8,991,522, which is incorporated herein by reference, also demonstrates the whipstock member  1050  in its run-in position.) The actual whipstock  1050  within the whipstock member  1000  is supported by a lower whipstock rod  1060 . When the whipstock member  1000  is in its set-and-operating position, the upper curved face  1050 . 1  of the whipstock member  1050  itself spans substantially the entire I.D. of the casing  12 . If, for example, the casing I.D. were to vary slightly larger, this would obviously not be the case. The three aforementioned “touch points” of the jetting hose  1595  would remain the same, however, albeit while forming a slightly larger bend radius “R” precisely equal to the (new) enlarged I.D. of casing  12 . 
     As described in greater detail in the co-owned U.S. Pat. No. 8,991,522, the whipstock rod is part of a tool assembly that also includes an orienting mechanism, and an anchoring section that includes slips. Once the slips are set, the orienting mechanism utilizes a ratchet-like action that can rotate the upstream portion of the whipstock member  1000  in discreet 10° increments. Thus, the angular orientation of the whipstock member  1000  within the wellbore may be incrementally changed downhole. 
     In one embodiment, the whipstock  1050  is a single body having an integral curved face configured to receive the jetting hose and redirect the hose about 90 degrees. Note the whipstock  1050  is configured such that, at the point of casing exit when in set and operating position, it forms a bend radius for the jetting hose that spans the entire ID of the parent wellbore&#39;s production casing  12 . 
       FIG. 4H-1  is a cross-sectional view of the whipstock member  1000  of the external system of  FIG. 4 , but shown vertically instead of horizontally. The jetting hose of the internal system ( FIG. 3 ) is shown bending across the whipstock face  1050 , and extending through a window “W” in the production casing  12 . The jetting nozzle of the internal system  1500  is shown affixed to the distal end of the jetting hose  1595 . 
       FIG. 4H-1   a  is an axial, cross-sectional view of the whipstock member  1000 , with a perspective view of sequential axial jetting hose cross-sections depicting its path downstream from the center of the whipstock member  1000  at line O-O′ to the start of the jetting hose&#39;s bend radius as it approaches line P-P′. 
       FIG. 4H-1   b  depicts an axial, cross-sectional view of the whipstock member  1000  at line P-P′. Note the adjustments in location and configuration of both the whipstock member&#39;s wiring chamber and hydraulic fluid chamber from line O-O′ to line P-P′. 
     As noted above, the present assembly  50  is preferably used in connection with a nozzle having a unique design.  FIGS. 3F-1   a  and  3 F- 1   b  provide enlarged, cross-sectional views of the nozzle  1600  of  FIG. 3 , in a first embodiment. The nozzle  1600  takes advantage of a rotor/stator design, wherein the forward portion  1620  of the nozzle  1600 , and hence the forward jetting slot (or “port”)  1640 , is rotated. Conversely, the rearward portion of the nozzle  1600 , which itself is directly connected to jetting hose  1595 , remains stationary relative to the jetting hose  1595 . Note in this arrangement, the jetting nozzle  1600  has a single forward discharge slot  1640 . 
     First,  FIG. 3F-1   a  presents a basic nozzle body having a stator  1610 . The stator  1610  defines an annular body having a proximal end  1611  and series of inwardly facing shoulders  1615  equi-distantly spaced therein. The nozzle  1600  also includes a rotor  1620 . The rotor  1620  also defines a body and has a series of outwardly facing shoulders  1625  equi-distantly spaced therearound. In the arrangement of  FIG. 3F-1   a , the stator  1610  has six inwardly-facing shoulders  1615 , while the rotor  1620  has four outwardly-facing shoulders  1625 . 
     Residing along each of the shoulders  1615  is a small diameter, electrically conductive wire  1616  wrapping the stator&#39;s inwardly facing shoulders (or “stator poles”)  1615  with multiple wraps. Movement of electrical current through the wires  1616  thus creates electro-magnetic forces in accordance with a DC rotor/stator system. Power to the wires is provided from the batteries  1551  (or battery pack  1550 ) of  FIG. 3A . 
     As noted above, the stator  1610  and rotor  1620  bodies are analogous to a direct drive motor. The stator  1610  (in this depiction, a six-pole stator) of this direct drive electric motor analog is included within the outer body of the nozzle  1600  itself, with each pole protruding directly from the body  610 , and commensurately wrapped in electric wire  1616 . The current source for the wire  1616  wrapping the stator poles is derived through the ‘bundled’ electrical wires  1590  of the jetting hose  1595 , and is thereby manipulated by the current regulator and micro-servo mechanism housed in the conically-shaped battery pack&#39;s (downstream) end-cap  1530 . Rotation of the rotor  1620  of the nozzle  1600 , and particularly the speed of rotation (RPM&#39;s), is controlled via induced electro-magnetic forces of a DC rotor/stator system. 
     Note that  FIG. 3F-1   a  could serve as a representative axial cross section of essentially any basic direct current electromagnetic motor, with the central shaft/bearing assembly removed. By eliminating a central shaft and bearings, the nozzle  1600  can now accommodate a nozzle throat  1650  placed longitudinally through its center. The throat  1650  is suitable for conducting high pressure fluid flow. 
       FIG. 3F-1   b  provides a longitudinal, cross-sectional view of the nozzle  1600  of  FIG. 3F-1   a , taken across line C-C′ of  FIG. 3F-1   b . The rotor  1620  and surrounding stator  1610  are again seen. Bearings  1630  are provided to facilitate relative rotation between the stator body  1610  and the rotor body  1620 . 
     It is observed in  FIG. 3F-1   b  that the nozzle throat  1650  has a conically-shaped narrowing portion before terminating in the single fan-shaped discharge slot  1640 . This profile provides two benefits. First, additional non-magnetic, high-strength material may be placed between the throat  1650  and the magnetized rotor portion  1625  of the forward portion of the nozzle body  1620 . Second, final acceleration of the jetting fluid through the throat  1650  is accommodated before entering the discharge slot  1640 . The size, placement, load capacity, and freedom of movement of the bearings  1630  are considerations as well. The forward slot  1640  begins with a relatively semi-hemispherically shaped opening, and terminates at the forward portion of the nozzle  1600  in a curved, relatively elliptical shape (or, optionally, a curved rectangle with curved small ends.) 
     Simulations were conducted with the single planar slot slightly twisted such that the discharge angle(s) of the fluid generated sufficient thrust so as to rotate the nozzle  1600 . The observed problem was that nozzle rotation rates were hypersensitive to changes in fluid flow rates, leaving the concern of instantaneous and frequent overloading (with resultant failure) of the bearings  1630 . The solution was to design, as nearly as possible, a balanced single slot system, such that there is no appreciable axial thrust generated by fluid discharge. In other words, the nozzle  1600  is no longer sensitive to injection rate. 
     At this point it is important to note the basic nozzle design criteria for the flow capacity of the combined flow path comprised of the throat  1650  and slot  1640  elements. That is, that these inner throat  1650  and slot  1640  elements of the nozzle  1600  retain dimensions that can approximate the dimensions, and resultant hydraulics, of conventional hydraulic jet casing perforators. Specifically, the nozzle  1600  depicted in  FIGS. 3F-1   a  and  3 F- 1   b  throat  1650  and slot  1640  dimensions that can approximate the perforating hydraulics obtained by a perforator&#39;s ⅛th-inch orifice. Note that the terminal width of slot  1640  can not only accommodate 100 mesh sand as an abrasive, but the larger sizes such as 80 mesh sand as well. 
     Angles θ SLOT    1641  and θ MAX    1642  are shown in  FIG. 3F-1   b . (These angles are also shown in  FIGS. 3F-2   b  and  3 F- 3   b , discussed below.) Angle θ SLOT    1641  represents the actual angle of the outer edges of the slot  1640 , and angle θ MAX    1642  represents the maximum θ SLOT    1641  achievable within the existing geometric and construction constraints of the nozzle  1600 . In  FIGS. 3F-1   b ,  3 F- 2   b  and  3 F- 3   b , both angles θ SLOT    1641  and θ MAX    1642  are shown at 90 degrees. This geometry, coupled with rotation of the rotor body  1620  (and, consequently, rotation of the jetting slot  1640 ) provides for the erosion of a hole diameter that is at least equal to the nozzle&#39;s outer diameter even at a stand-off (e.g., the distance from the very tip of the nozzle  1600  at the longitudinal center line to the target rock along the same centerline) of zero. 
       FIGS. 3F-2   a  and  3 F- 2   b  provide longitudinal, cross-sectional views of the jetting nozzle of  FIG. 3E , in an alternate embodiment. In this embodiment, multiple ports are used, including both a forward discharge port  1640  and a plurality of rearward thrust jets  1613 , for a modified nozzle  1601 . 
     The nozzle configuration of  FIGS. 3F-2   a  and  3 F- 2   b  is identical to the nozzle configuration  1600  of  FIG. 3F-1   a , with the exception of three additional components:
         (1) the use of rearward thrusting jets  1613 ;   (2) the use of a slideable collar  1633  biased by a biasing mechanism (spring)  1635 ; and   (3) the use of a slideable nozzle throat insert  1631 .
 
The first of these three additional components, rearward thrusting jets  1613 , provide a rearward thrust that effectively drags the jetting hose  1595  along the lateral borehole, or mini-lateral, as it is formed. Preferably, five rearward thrust jets  1613  are used along the body  1610 , although variations of the number and/or exit angles  1614  of the jets  1613  may be utilized.
       

       FIG. 3F-2   c  is an axial, cross-sectional view of the jetting nozzle  1601  of  FIGS. 3F-2   a  and  3 F- 2   b . This demonstrates the star-shaped jet pattern created by the multiple rearward thrust jets  1613 . Five points are seen in the star, indicating five illustrative rearward thrust jets  1613 . 
     Note particularly in a homogeneous host pay zone, the forward (jetting) hydraulic horsepower requirement necessary to excavate fresh rock at a given rate of penetration would be essentially constant. The rearward thrust hydraulic horsepower requirement, however, is constantly increasing in proportion to the growth in length of the mini-lateral. As continued extension of the mini-lateral requires dragging an ever-increasing length of jetting hose  1595  along an ever-increasing distance, the rearward thrusting hydraulic horsepower requirement to maintain forward propulsion of the jetting nozzle  1601  and hose  1595  increases commensurately. 
     It may be required to consume upwards of two-thirds of available horsepower through the rearward thrust jets  1613  in order to extend the jetting hose  1595  and connected nozzles  1601 ,  1602  to the furthest lateral extent. If this maximum requirement is utilized constantly throughout the borehole jetting process, much of the available horsepower will be wasted in the early stages in jetting the bore. This is particularly detrimental when the same jetting nozzle and assembly utilized in rock excavation is also utilized to form the initial casing exit “W.” Further, if the same rearwards jetting forces cutting the ‘points’ of the star-shaped rock excavation are active in the wellbore tubulars (particularly, while jetting the casing exit “W”) significant damage to the nearby tool string (particularly, the whipstock member  1000 ) and the well casing  12  could result. Hence, the optimum design would provide for the activation/deactivation of the rearward thrust jets  1613  when desired, particularly, after the casing exit is formed and after the first 5 or 10 feet of lateral borehole is formed. 
     There are several possible mechanisms by which jet activation/deactivation may be enabled to help conserve HHP and protect the tool string and tubulars. One approach is mechanical, whereby the opening and closing of flow to the jets  1613  is actuated by overcoming the force of a biasing mechanism. This is shown in connection with the spring  1635  of  FIGS. 3F-2   a  and  3 F- 2   b , where a throat insert  1631  and a slideable collar  1633  are moved together to open rearward thrust jets  1613 . Another approach is electromagnetic, wherein a magnetic port seal is pulled against a biasing mechanism (spring  1635 ) by electromagnetic forces. This is shown in connection with  FIGS. 3F-3   a  and  3 F- 3   c , discussed below. 
     The second of the three additions incorporated into the nozzle design of  FIGS. 3F-2   a  and  3 F- 2   b  is that of a slideable collar  1633 . The collar  1633  is biased by a biasing mechanism (spring)  1635 . The function of this collar  1633 , whether directly or indirectly (by exerting a force on the slideable nozzle throat insert  1631 ), is to temporarily seal the fluid inlets of the thrust jets  1613 . Note that this sealing function by the slideable collar  1633  is “temporary”; that is, unless a specific condition determined by the biasing mechanism  1635  is satisfied. As shown in the embodiment presented in  FIGS. 3F-2   a  and  3 F- 2   b , the biasing mechanism  1635  is a simple spring. 
     In  FIG. 3F-2   a , the collar  1633  is in its closed position, while in  FIG. 3F-2   b  the collar  1633  is in its open position. Thus, a specific differential pressure exerted on the cross-sectional area of the slideable nozzle throat insert  1631  has overcome the pre-set compressive force of the spring  1635 . 
     The third of the three additions incorporated into the nozzle  1601  design of  FIGS. 3F-2   a  and  3 F- 2   b  is that of a slideable nozzle throat insert  1631 . The slideable throat insert  1631  has two basic functions. First, the insert  1631  provides an intentional and pre-defined protrusion into the flow path within the nozzle throat  1650 . Second, the insert  1631  provides an erosion- and abrasion-resistant surface within the highest fluid velocity portion of the internal system  1500 . For the first of these functions, the degree of protrusion to be designed into the slideable nozzle throat insert  1631  is a function of at what point in mini-lateral formation the operator anticipates actuating the thrust jets  1613 . 
     To illustrate, suppose that system hydraulics provide for a suitable pump rate of 0.5 BPM through the nozzle  1601  at the point of casing exit “W,” and that this can be sustained at a surface pumping pressure of 8,000 psi. Suppose further that actuation of the thrust jets  1613  in the nozzle  1601  is not required until the nozzle  1601  achieves a lateral distance of 50 feet from the parent wellbore. That is, particularly while jetting the casing exit “W” itself and an abrasive mixture (say, of 1.0 ppg of 100 mesh sand in a 1 pound guar-based fresh water gel system) is being pumped, none of the jets  1613  have been opened (which could risk clogging by the abrasive in the jetting fluid mixture.) Consequently, no abrasives are included in the jetting fluid after it is sure that the nozzle  1600  has sufficiently cleared the casing exit “W”. Accordingly, while jetting the hole in production casing  12  to form casing exit “W”, no rearwards jetting forces from fluids expelled through thrust jets  1613  can pose a threat to unintentionally damage either the jetting hose  1595 , the whipstock member  1000 , or the production casing  12 . 
     Later, after generating the casing exit “W” plus a mini-lateral length of, say, approximately 50 feet, the pump pressure is increased to 9,000 psi, the incremental 1,000 psi increase in surface pumping pressure being sufficient to overcome the force of the biasing mechanism  1635  and act against the cross-sectional area of the protrusion of the insert  1631  to actuate the jets  1613 . Thus, at mini-lateral length of 50 feet from the parent wellbore  4 , the thrust jets  1613  are actuated, and high-pressure rearwards thrust flow is generated through the jets  1613 . 
     Suppose these conditions are sufficient to continue jetting a mini-lateral out to a lateral length of 300 feet. At 300 feet, the length of jetting hose laying against the floor of the mini-lateral is causing a commensurate frictional resistance such that it and the thrust forces generated through the thrust jets  1613  are in approximate equilibrium. (Instrumentation such as tensiometers, for example, would indicate this.) At this point, the pump rate is increased to, say, 10,000 psi, and the rearward thrust jets  1613  remain actuated, but at higher differential pressures and flow rates, thus generating higher pull force on the jetting hose  1595 . 
       FIGS. 3F-3   a  and  3 F- 3   c  provide longitudinal, cross-sectional views of a jetting nozzle  1602 , in yet another alternate embodiment. Here, multiple rearward thrust jets  1613 , and a single forward jetting slot  1640 , are again used. A collar  1633  and spring  1635  are again used for providing selective fluid flow through rearward thrust jets  1613 . 
       FIGS. 3F-3   b  and  3 F- 3   d  provide axial, cross-sectional views of the jetting nozzle  1602  of  FIGS. 3F-3   a  and  3 F- 3   c , respectively. These demonstrate the star-shaped jet pattern created by the multiple jets  1613 . Eight points are seen in the star, indicating two sets of four (alternating) illustrative thrust jets  1613 . In  FIGS. 3F-3   a  and  3 F- 3   b , the collar  1633  is in its closed position, while in  FIGS. 3F-3   c  and  3 F- 3   d  the collar  1633  is in its open position permitting fluid flow through the jets  1613 . The biasing force provided by the spring  1635  has been overcome. 
     The nozzle  1602  of  FIGS. 3F-3   a  and  3 F- 3   c  is similar to the nozzle  1601  of  FIGS. 3F-2   a  and  3 F- 2   b ; however, in the arrangement of  FIGS. 3F-3   a  and  3 F- 3   c , an electro-magnetic force generating a downstream magnetic pull against the slideable collar  1633 , sufficient to overcome the biasing force of the biasing mechanism (spring)  1635 , replaces the hydraulic pressure force against the slideable throat insert  1631  in the jetting nozzle  1601  of  FIGS. 3F-2   a  and  3 F- 2   b.    
     The nozzle  1602  of  FIGS. 3F-3   a  and  3 F- 3   c  presents yet another preferred embodiment of a rotating nozzle  1602 , also suitable for forming casing exits and continued excavation through a cement sheath and host rock formation. In  FIGS. 3F-3   a  and  3 F- 3   c  (and in  FIG. 3G-1 , described in more detail below), it is the electromagnetic force generated by the rotor/stator system that must overcome the spring  1635  force to open hydraulic access to the rearward thrust jets  1613  (and  1713 ). (Note that in  FIG. 3G-1 , depicting an in-line hydraulic jetting collar, discussed more fully below, direct mechanical connection of internal turbine fins  740  to the slideable collar  733  change the biasing criteria to one of differential pressure, as with the jetting nozzle depicted in  FIG. 3F-2   a ). The key here is the ability to keep the fluid inlets to the rearward thrust jets  1613  (and  1713 ) closed until the operator initiates opening them, specifically by increasing the pump rate, such that either (or both) the differential pressure through the nozzle and/or the nozzle rotation speed&#39;s proportional increase of electromagnetic pull on the slideable collars  1633 / 1733  opens access to the fluid inlets of the thrust jets  1613 / 1713 . 
     It is also observed that in the nozzle  1602 , the number of rearward thrust jets  1613 , though also symmetrically placed about the circumference of the rotor  1610 , has been increased from a single set of five to two sets of four. Note that each of the four jets  1613  within each of the two sets are also symmetrically placed about the rotor  1610  circumference, orthogonally relative to each other; hence, the two sets of jets  1613  must overlap. Additionally, the path of each jet now not only travels through the rearward (stator) portion  1610  of the nozzle  1602 , but now also through the forward (rotor) section  1620  of the nozzle  1602 . Note, however, as depicted in  FIGS. 3F-3   b  and  3 F- 3   d , whereas there are eight individual jet passages through the rearward (stator) portion  1610  of the nozzle  1602 , there are only four passing through the forward (rotor) section  1620  of the nozzle  1600 . Hence, rotation of the forward (rotor) section  1620  of the nozzle  1602  will only provide for the alignment of, and subsequent fluid flow through, only one set of four jets  1613  at a time. In fact, for most of a single rotation&#39;s duration, the flow channels of the rotor  1620  will have no access to those of the stator  1610 , and are thereby effectively sealed. The result will be an oscillating (or, “pulsating”) jetting flow through the rearward thrust jets  1613 . 
     The commensurate subtraction of jetting fluid volumes going through the nozzle port  1640  produces a commensurate pulsating forward jetting flow for excavation, as well. The benefits of pulsating flow over and against continuous flow for excavation systems are well documented, and will not be repeated here. Note, however, the subject nozzle design not only captures the rock excavation benefits of a rotating jet, but also the benefits of a pulsating jet. 
     Another embodiment of a thrust collar that employs an electromagnetic force is provided in  FIGS. 3G-1   a  and  3 G- 1   b .  FIGS. 3G-1   a  presents an axial, cross-sectional view of a basic body for a thrust jetting collar  1700  of the internal system  1500  of  FIG. 3 . The view is taken through line D-D′ of  FIG. 3G-1   b . Here, as with the jetting nozzle  1602 , two layers of rearward thrust jets  1713  are again offered. 
     The collar  1700  has a rear stator  1710  and an inner (rotating) rotor  1720 . The stator  1710  defines an annular body having a series of inwardly facing shoulders  1715  equi-distantly spaced therein, while the rotor  1720  defines a body having a series of outwardly facing shoulders  1725  equi-distantly spaced therearound. In the arrangement of  FIG. 3G . 1 . a , the stator body  1710  has six inwardly-facing shoulders  1715 , while the rotor body  1720  has four outwardly-facing shoulders  1725 . 
     Residing along each of the shoulders  1715  is a small diameter, electrically conductive wire  1716  wrapping the stator&#39;s  1710  inwardly facing shoulders (or, “stator poles”)  1715  with multiple wraps. Movement of electrical current through the wires  1716  thus creates electro-magnetic forces in accordance with a DC rotor/stator system. Power to the wires is provided from the batteries  1551  of  FIG. 3A . 
       FIG. 3G-1   b  is a longitudinal, cross-sectional view of the nozzle  1700 .  FIG. 3G-1   c  is an axial cross section intersecting the thrust jets  1713  along line d-d′ of  FIG. 3G-1   b.    
       FIGS. 3G-1   a  thru  3 G- 1   c  show the embodiment of similar concepts for the rotating nozzles  1600 ,  1601 , and  1602 , but with modifications adapting the apparatus for use as an in-line thrust jetting collar  1700 . Note particularly the retention of a flow-through rotor  1725  providing a collar throat  1750 , coupled with a stator  1715  and bearings  1730 . However, the stationary flow channels for the rearward thrusting jets  1713  penetrating the stator  1710  are staggered, being in two sets of four. The single set of four orthogonal jets penetrating the rotor  1725  will, for each full rotation, “match-up” four times each with the jets penetrating the stator  1710 , each match-up providing a four-pronged instantaneous pulsed flow spaced equi-distant about the outer circumference of the collar  1700 . Similar to the rotating nozzle  1602 , the slideable collar  1733  is moved electromagnetically against a biasing mechanism (spring)  1735  to actuate flow through the rearward thrust jets  1713 . 
       FIG. 3G-1   c  is another cross-sectional view, showing the star pattern of the rearward thrust jets  1713 . Eight points are seen. 
     A unique opportunity exists to configure the collar  1733  as either a net power consumer or a net power provider. The former would rely on the battery pack-provided power, just as the jetting nozzle  1600  does, to fire the stator, rotate the rotor, and generate the requisite electromagnetic field. The latter is accomplished by incorporating interior, slightly angled turbine fins  1740  within the I.D. of the rotor  1720 , hence harnessing the hydraulic force of the jetting fluid as it is pumped through the collar  1700 . Such force would be dependent only on the pump rate and the configuration of the turbine fins  1740 . 
     In one aspect, internal turbine fins  1740  are placed equi-distant about the collar throat  1750 , such that hydraulic forces are harnessed both to rotate the rotor  1720  and to supply a net surplus of electrical current to be fed back into the internal system&#39;s circuitry. This may be done by sending excess current back up wires  1590 . The ability to incorporate a rotor/stator configuration into construction of the rearward thrust jet collar enables a full-opening I.D. equal to that of the jetting hose. More than ample hydroelectric power could be obtained to generate the electromagnetic field needed to operate the slideable port collar  1733 , the surplus being available to be fed into the now “closed” electrical system incurred once the internal system  1500  disengages from the docking station  325 . Hence, this surplus hydroelectric power generated by the collar  1700  may beneficially be used to maintain charges of the batteries  1551  in the battery pack  1550 . 
     It is observed that the various nozzle designs  1600 ,  1601 ,  1602  discussed above are designed to jet not only through a rock matrix, but also through the steel casing and the surrounding cement sheath of the wellbore  4   c  in order to reach the rock. The nozzle designs incorporate the ability to handle relatively large mesh-size abrasives through the forward nozzle jetting port  1640  prior to engaging the RTJ&#39;s  1613 . It is understood though that other nozzle designs may be used that accomplish the purpose of forming mini-laterals but which are not so robust as to cut through steel. 
     In the various nozzle designs  1600 ,  1601 ,  1602  discussed above, a single forward port in a hemispherically-shaped nozzle is used. The forward port  1640  is defined by the angles θ MAX  (whereby the width of the jet is equal to the width of the nozzle when the outermost edge of the jet reaches a point forward equivalent to the nozzle tip) and θ SLOT  (the actual slot angle). Note θ SLOT ≤θ MAX . For presentation purposes herein, θ SLOT =θ MAX , such that even if the tip of the rotating nozzle was against the host rock (or casing I.D.) face while jetting, it would still excavate a tunnel diameter equal to the outer (maximum) nozzle diameter. It is this single-plane, rotating slot configuration that will provide a maximum width in order to accommodate ample pass-through capacity for any abrasives that may be incorporated in the jetting fluid. 
     The preferred rearward orifice jet orientation is from 30° to 60° from the longitudinal axis. The rearward thrust jets  1613 / 1713  are designed to be symmetrical about the circumference of the nozzle&#39;s/collar&#39;s stator body  1610 / 1710 . This maintains a purely forwards orientation of the jetting nozzle  1600 ,  1601 ,  1602  along the longitudinal axis. Accordingly, there should be at least three jets  1613 / 1713  spaced equi-distant about the circumference, and preferably at least five equi-distant jets  1613 / 1713 . 
     As noted above, the nozzle in any of its embodiments may be deployed as part of a guidance, or geo-steering, system. In this instance, the nozzle will include at least one geo-spatial IC chip, and will employ at least three actuator wires. The actuator wires  1590 A are spaced equi-distant about the distal end of the jetting hose and extend into the nozzle, and receive electrical current, or excitation, from the electrical wires  1590  already provided in the jetting hose  1595 . 
       FIG. 3F-1   c  is a longitudinal cross-sectional view of the jetting nozzle  1600  of  FIG. 3F-1   b , in a modified embodiment. Here, the jetting nozzle  1600  is shown connected to a jetting hose  1595 . The connection may be a threaded connection; alternatively, the connection may be by means of welding. In  FIG. 3F-1   c , an illustrative weld connection is shown at  1660 . 
     In the arrangement of  FIG. 3F-1   c , the jetting nozzle  1600  includes a geo-spatial IC chip  1670 . The geo-spatial chip  1670  resides within a port seal  1675 . The geo-spatial chip  1670  may comprise a two-axial or a three-axial accelerometer, a bi-axial or a tri-axial gyroscope, a magnetometer, or combinations thereof. The present inventions are not limited by the type or number of geo-spatial chips, or their respective locations within the assembly, used unless expressly so stated in the claims. Preferably, the chip  1670  will be associated with a micro-electro-mechanical system residing on or near the nozzle body such as shown and described in connection with the nozzle embodiments ( 1600 ,  1601 ,  1602 ) described above. 
       FIG. 3F-1   d  is an axial-cross-sectional view of the jetting hose  1590  of  FIG. 3F-1   c , taken across line c-c′. Visible in this view are power wires  1590  and actuator wires  1590 A. Also visible are optional fiber optic data cables  1591 . The wires  1590 ,  1590 A,  1591  may be used to transmit geo-location data from the chip  1670  up to a micro-processor in the battery pack section  1550 , and then wirelessly to a receiver located in the docking station (shown best at  325  in  FIG. 4D-1   b ), wherein the receiver communicates with the micro-processor in the docking station  325 . Preferably, the micro-processor in the docking station  325  processes the geo-location data, and makes adjustments to electrical current in the actuator wires  1590 A (using one or more current regulators), in order to ensure that the nozzle is oriented to hydraulically bore the lateral boreholes in a pre-programmed direction. 
     The micro-transmitter in the battery pack is preferably housed in the battery pack&#39;s downstream end cap  1530 , while the docking station  325  is preferably affixed to the interior of a jetting hose carrier system  400  (described below in connection with  FIGS. 3A, 3B-1 , and  4 D- 1 ). The receiver housed in the docking station  325  may be in electrical or optical connection with a micro-processor at the surface  1 . For example, a fiber optic cable  107  may run along the coiled tubing conveyance system  100 , to the surface  1 , where the geo-location data is processed as part of a control system. 
     The reverse (surface-to-downhole instrumentation) communication is likewise facilitated by hard-wired (again, preferably fiber optic) connection of surface instrumentation, through fiber optic cable  107  within coiled tubing conveyance medium  100  and external system  2000 , to a specific terminus receiver (not shown) housed within the docking station  325 . An adjoining wireless transmitter within the docking station  325  then transmits the operator&#39;s desired commands to a wireless receiver housed within the end cap  1530  of the internal system  1500 . This communication system allows an operator to execute commands setting both the rotational speed and/or the trajectory of the jetting nozzle  1600 . 
     When the nozzle  1600  exits the casing, the operator knows the location and orientation of the nozzle  1600 . By monitoring the length of jetting hose  1590  that is translated out of the jetting hose carrier, integrated with any changes in orientation, the operator knows the geo-location of the nozzle  1600  in the reservoir. 
     In one option, a desired geo-trajectory is first sent as geo-steering command from the surface  1 , down the coiled tubing  100 , and to the micro-processor associated with the docking station  325 . Upon receiving a geo-steering command from the surface  1 , such as from an operator or a surface control system, the micro-processor will forward the signals on wirelessly to a corresponding micro-receiver associated with the battery pack section  1550 . That signal will engage one or more current regulators to alter the current conducted down one, two, or all three of the at least three electric wires  1590 , connected directly to the jetting nozzle  1600 . Note that at least part of these electrical wire connections, preferably segments closest to the jetting nozzle  1600 , are comprised of actuator wires  1590 A, such as the Flexinol® actuator wires manufactured by Dynalloy, Inc. These small diameter, nickel-titanium wires contract when electrically excited. This ability to flex or shorten is characteristic of certain alloys that dynamically change their internal structure at certain temperatures. The contraction of actuator wires is opposite to ordinary thermal expansion, is larger by a hundredfold, and exerts tremendous force for its small size. Given close temperature control under a constant stress, one can get precise position control, i.e., control in microns or less. Accordingly, given (at least) three separate actuator wires  1590 A positioned at-or-near equidistant around the perimeter and within the body of the jetting hose (toward its end, adjacent to the jetting nozzle  1600 ), a small increase in current in any given wire will cause it to contract more than the other two, thereby steering the jetting nozzle  1600  along a desired trajectory. Given an initial depth and azimuth via the geo-spatial IC chip in the nozzle  1600 , a determined path for a lateral borehole  15  may be pre-programmed and executed automatically. 
     Of interest, the actuator wires  1590 A have a distal segment residing along a chamber or sheath, or even interwoven within the matrix of the distal segment of the jetting hose  1595 . Further, the distal end of the actuator wires  1590 A may continue partially into the nozzle body, wrapping the stator poles  1615  to connect to, or even form the electro-magnetic coils  1616 . This is also demonstrated in  FIG. 3F-1   c . In this way, electrical power is provided from the battery pack section  1550  to induce the relative rotational movement between the rotor body and the stator body. 
     As can be seen from the above discussion, an internal system  1500  for a hose jetting assembly  50  is provided. The system  1500  enables a powerful hydraulic nozzle ( 1600 ,  1601 ,  1602 ) to jet away subsurface rock in a controlled (or steerable) manner, thereby forming a mini-lateral borehole that may extend many feet out into a formation. The unique combination of the internal system&#39;s  1500  jetting fluid receiving funnel  1570 , the upper seal  1580 U, the jetting hose  1595 , in connection with the external system&#39;s  2000  pressure regulator valve  610  and pack-off section  600  (discussed below) provide for a system by which advancement and retraction of the jetting hose  1595 , regardless of the orientation of the wellbore  4 , can be accomplished entirely by hydraulic means. Alternatively, mechanical means may be added through use of an internal tractor system  700 , described more fully below. 
     Not only can the above-listed components be controlled to determine the direction of the jetting hose  1595  propulsion (e.g., either advancement or retraction), but also the rate of propulsion. The rate of advancement or retraction of the internal system  1500  may be directly proportional to the rate of fluid (and pressure) bleed-off and/or pump-in, respectively. Specifically, “pumping the hose  1595  down-the-hole” would have the following sequence:
         (1) the micro-annulus  1595 . 420  between the jetting hose  1595  and the jetting hose carrier&#39;s inner conduit  420  is filled by pumping hydraulic fluid through the main control valve  310 , and then through the pressure regulator valve  610 ; then   (2) the main control valve  310  is switched electronically using surface controls to begin directing jetting fluid to the internal system  1500 ; which   (3) initiates a hydraulic force against the internal system  1500  directing jetting fluid through the intake funnel  1570 , into the jetting hose  1595 , and “down-the-hole”; such force being resisted by   (4) compressing hydraulic fluid in the micro-annulus  1595 . 420 ; which is   (5) bled-off, as desired, from surface control of the pressure regulator valve  610 , thereby regulating the rate of “down-the-hole” decent of the internal system  1500 .       

     Similarly, the internal system  1500  can be pumped back “up-the-hole” by directing the pumping of hydraulic fluid through (first) the main control valve  310  and (second) through the pressure regulator valve  610 , thereby forcing an ever-increasing (expanding) volume of hydraulic fluid into the micro-annulus  1595 . 420  between the jetting hose  1595  and the jetting hose conduit  420 , which pushes upwardly against the bottom seals  1580 L of the jetting hose seal assembly  1580 , thereby driving the internal system  1500  back “up-the-hole”. The direction and rate of propulsion of the internal system  1500  by hydraulic means can be either augmented or replaced by propulsion of the internal system  1500  via the mechanical means of the internal tractor system  700 , also described below. 
     Beneficially, once the jetting hose assembly  50  is deployed to a downhole location adjacent a desired point of casing exit “W” within a parent wellbore  4  of any inclination (including at-or-near horizontal), the entire length of jetting hose  1595  can be deployed and retrieved without any assistance from gravitational forces. This is because the propulsion forces used to both deploy and retrieve the jetting hose  1595 , and to maintain its proper alignment while doing so, are either hydraulic or mechanical, as described more fully below. Note also these propelling hydraulic and mechanical forces are available in more than sufficient quantities as to overcome any frictional forces from movement of the internal system  1500  (including, specifically, the jetting hose  1595 ) within the external system  2000  (including, specifically, the jetting hose conduit  420 ) induced by any non-vertical alignment, and to maintain the hose  1595  in a substantially taught state along the hose length within the external system  2000 . Hence, these hydraulic and mechanical propulsion forces overcome the “can&#39;t-push-a-rope” limitation in its entirety 
     Hydraulic force to advance the jetting hose  1595  within and subsequently out of the external system  2000  will be observed any time jetting fluid is being pumped; specifically, force in a plane parallel to the longitudinal axis of the jetting hose  1595 , in an upstream-to-downstream direction, as hydraulic force is exerted against the upstream end-cap of the battery pack  1520 , the fluid intake funnel  1570 , the interior face of the jetting nozzle  1600 , e.g., any internal system  1500  surface that is both: (a) exposed to the flow of jetting fluid; and, (b) having a directional component not parallel to the longitudinal axis of the parent wellbore. As these surfaces are rigidly attached to the jetting hose  1595  itself, this upstream-to-downstream force is conveyed directly to the jetting hose  1595  whenever jetting fluid is being pumped from the surface  1 , down the coiled tubing conveyance medium  100  (seen in  FIG. 2 ), and through the jetting fluid passage  345  within the main control valve  300  (described below in connection with  FIG. 4C-1 ). Note the function of the only other valve in this system, the pressure regulator valve  610  located just upstream of the pack-off seal assembly  650  of pack-off section  600  (seen and described in connection with  FIGS. 4E-1 and 4E-2 ), is simply to release pressure from the compression of hydraulic fluid within the jetting hose  1595 /jetting hose conduit  420  annulus  1595 . 420  (seen in  FIGS. 3D-1   a  and  4 D- 2 ) commensurate with the operator&#39;s desired rate of decent of the internal system  1500 . 
     Conversely, hydraulic forces are operational in propelling the internal system  1500  in a downstream-to-upstream direction whenever hydraulic fluid is being pumped from the surface  1 , down the coiled tubing conveyance medium  100 , and through the hydraulic fluid passage  340  within the main control valve  300 . In this configuration, the pressure regulator valve  610  allows the operator to direct injected fluids into the jetting hose  1595 /jetting hose conduit  420  annulus  1595 . 420  commensurate with the operator&#39;s desired rate of ascent of the internal system  1500 . Thus, hydraulic forces are available to assist in both conveyance and retrieval of the jetting hose  1595 . 
     Similarly, mechanical forces applied by the internal tractor system  700  assist in conveyance, retrieval, and maintaining alignment of the jetting hose  1595 . The close tolerance between the O.D. of the jetting hose  1595  and the I.D. of the jetting hose conduit  420  of jetting hose carrier system  400 , thus defining annulus  1595 . 420 , serves to provide confining axial forces that assist in maintaining the alignment of the hose  1595 , such that the portion of the hose  1595  within the jetting hose carrier system  400  can never experience significant buckling forces. Direct mechanical (tensile) force for both deployment and retrieval of the jetting hose  1595  is applied by direct frictional attachment of grippers  756  of specially-designed gripper assemblies  750  of the internal tractor system  700  to the jetting hose  1595 , discussed below in connection with  FIGS. 4F-1 and 4F-2 . 
     As described above, jetting hose conveyance is also assisted by the hydraulic forces emanating from the rearward thrusting jets  1613  of the jetting nozzle  1601 ,  1602  itself; and, if included, from the rearward thrust jets  1713  of any added jetting collar(s)  1700 . These furthest downstream hydraulic forces serve to advance the jetting hose  1595  forward into the pay zone  3  simultaneously with the creation of the UDP  15  ( FIG. 1B ), maintaining the forward-aimed jetting fluid proximally to the rock face being excavated. The balance between deploying hydraulic energy forward proximate to the nozzle (for excavating new hole) versus rearward (for propulsion) requires balance. Too much rearward propulsion, and there is not enough residual hydraulic horsepower focused forward to excavate new hole. If there is too much forward propulsion expulsion of jetting fluid, there is insufficient fluid available for the rearward thrust jets  1613 / 1713  to generate the requisite horsepower to drag the jetting hose along the lateral borehole. Hence, the ability to redirect either rearward or forward focused hydraulic horsepower through the nozzle in situ as described herein is a major enhancement. 
     For presentation purposes, two configurations of rearward thrust jets  1613 / 1713  have been included herein—one for pulsating flow wherein eight rearward thrust jets, each inclined at 30° from the longitudinal axis and spaced equi-distant about the circumference, are grouped into two sets of four, with rearwards flow alternating (or ‘pulsing’) between the two sets; and one for continuous flow, wherein a single set of five jets, each inclined at 30° from the longitudinal axis and spaced equi-distant about the circumference, are shown. However, other jet numbers and angles may be employed. 
     The  FIG. 3  series of drawings, and the preceding paragraphs discussing those drawings, are directed to the internal system  1500  for the hydraulic jetting assembly  50 . The internal system  1500  provides a novel system for conveying the jetting hose  1595  into and out of a parent wellbore  4  for the subsequent steerable generation of multiple mini-lateral boreholes  15  in a single trip. The jetting hose  1595  may be as short as 10 feet or as long as 300 feet or even 500 feet, depending on the thickness and compressive strength of the formation or the desired geo-trajectory of each lateral borehole. 
     As noted, the hydraulic jetting assembly  50  also provides an external system  2000 , uniquely designed to convey, deploy, and retrieve the internal system  1500  previously described. The external system  2000  is conveyable on conventional coiled tubing  100 ; but, more preferably, is deployed on a “bundled” coiled tubing product ( FIGS. 3D-1   a ,  4 A- 1  and  4 A- 1   a ) providing for real-time power and data transmission. 
     Consistent with the related and co-owned patent documents cited herein, the external system  2000  includes a jetting hose whipstock member  1000  including a whipstock  1050  having a curved face  1050 . 1  that preferably forms the bend radius for the jetting hose  1595  across the entire I.D. of the production casing  12 . The external system  2000  may also include a conventional tool assembly comprised of mud motor(s)  1300 , (external) coiled tubing tractor(s)  1350 , logging tools  1400  and/or a packer or a bridge plug (preferably, retrievable) that facilitate well completion. In addition, the external system  2000  provides for power and data transmission throughout, so that real time control may be provided over the downhole assembly  50 . 
       FIG. 4  is a longitudinal, cross-sectional view of an external system  2000  of the downhole hydraulic jetting assembly  50  of  FIG. 2 , in one embodiment. The external system  2000  is presented within the string of production casing  12 . For clarification,  FIG. 4  presents the external system  2000  as “empty”; that is, without containing the components of the internal system  1500  described in connection with the  FIG. 3  series of drawings. For example, the jetting hose  1595  is not shown. However, it is understood that the jetting hose  1595  is largely contained in the external system during run-in and pull-out. 
     In presenting the components of the external system  2000 , it is assumed that the system  2000  is run into production casing  12  having a standard 4.50″ O.D. and approximate 4.0″ I.D. In one embodiment, the external system  2000  has a maximum outer diameter constraint of 2.655″ and a preferred maximum outer diameter of 2.500″. This O.D. constraint provides for an annular (i.e., between the system  2000  O.D. and the surrounding production casing  12  I.D.) area open to flow equal to or greater than 7.0309 in 2 , which is the equivalent of a 9.2#, 3.5″ frac (tubing) string. 
     The external system  2000  is configured to allow the operator to optionally “frac” down the annulus between the coiled tubing conveyance medium  100  (with attached apparatus) and the surrounding production casing  12 . Preserving a substantive annular region between the O.D. of the external system  2000  and the I.D. of the production casing  12  allows the operator to pump a fracturing (or other treatment) fluid down the subject annulus immediately after jetting the desired number of lateral bores and without having to trip the coiled tubing  100  with attached apparatus  2000  out of the parent wellbore  4 . Thus, multiple stimulation treatments may be performed with only one trip of the assembly  50  in to and out of the parent wellbore  4 . Of course, the operator may choose to trip out of the wellbore for each frac job, in which case the operator would utilize standard (mechanical) bridge plugs, frac plugs and/or sliding sleeves. However, this would impose a much greater time requirement (with commensurate expense), as well as much greater wear and fatigue of the coiled tubing-based conveyance medium  100 . 
     In actuality, rigorous adherence to the (O.D.) constraint is perhaps only essential for the coiled tubing conveyance medium  100 , which may comprise over 90% of the length of the system  50 . Slight violations of the O.D. constraint over the comparatively minute lengths of the other components of the external system  2000  should not impose significant annular hydraulic pressure drops as to be prohibitive. If these outer diameter constraints can be satisfied, while maintaining sufficient inner diameters so as to accommodate the design functionality of each of the components (particularly of the external system  2000 ), and this can be accomplished for a system  50  that operates in the smaller of standard oilfield production casing  4  sizes of 4.5″ O.D., then there should be no significant barriers to adapting the system  50  to any of the larger standard oilfield production casing sizes (5.5″, 7.0″, etc.). 
     Presentation of each of the major components of the external system  2000 , which follows below, will be in an upstream-to-downstream direction. Note in  FIG. 4  the demarcation of the major components of the external system  2000 , with the corresponding Figure(s) herein:
         a. the coiled tubing conveyance medium  100 , presented in  FIGS. 4A-1 and 4A-2 ;   b. the first crossover connection (the coiled tubing transition)  200 , presented in  FIG. 4B-1 ;   c. the main control valve  300 , presented in  FIG. 4C . 1 ;   d. the jetting hose carrier system,  400  with its docking station  325 , presented in  FIGS. 4D-1 and 4D-2 ;   e. the second crossover connection  500  (transitioning the outer body from circular to star-shaped) and the jetting hose pack-off section  600 , presented in  FIGS. 4E-1 and 4E-2 ;   f. the internal tractor system  700  and the third crossover connection  800 , presented in  FIGS. 4F-1 and 4F-2 ;   g. the third crossover connection  800  and the upper swivel  900 , presented in  FIG. 4G-1 ;   h. the whipstock member  1000 , presented in  FIG. 4H-1 ;   i. the lower swivel  1100 , presented in  FIG. 4I-1 ; and, lastly,   j. the transitional connection  1200  to the conventional coiled tubing mud motor  1300  and a conventional coiled tubing tractor  1350 , coupled to a conventional logging sonde  1400 , presented in  FIG. 4J .       

       FIG. 4A-1  is a longitudinal, cross-sectional view of a “bundled” coiled tubing conveyance medium  100 . The conveyance medium  100  serves as a conveyance system for the downhole hydraulic jetting assembly  50  of  FIG. 2 . The conveyance medium  100  is shown residing within the production casing  12  of a parent wellbore  4 , and extending through a heel  4   b  and into the horizontal leg  4   c.    
       FIG. 4A-1   a  is an axial, cross-sectional view of the coiled tubing conveyance medium  100  of  FIG. 4A-1 . It is seen that the conveyance medium  100  includes a core  105 . In one aspect, the coiled tubing core  105  is comprised of a standard 2.000″ O.D. ( 105 . 2 ) and 1.620″ I.D. ( 105 . 1 ), 3.68 lbm/ft. HSt110 coiled tubing string, having a Minimum Yield Strength of 116,700 lbm and an Internal Minimum Yield Pressure of 19,000 psi. This standard sized coiled tubing provides for an inner cross-sectional area open to flow of 2.06 in 2 . As shown, this “bundled” product  100  includes three electrical wire ports  106  of up to 0.20″ in diameter, which can accommodate up to AWG #5-gauge wire, and 2 data cable ports  107  of up to 0.10″ in diameter. 
     The coiled tubing conveyance medium  100  also has an outermost, or “wrap,” layer  110 . In one aspect, the outer layer  110  has an outer diameter of 2.500″, and an inner diameter bonded to and exactly equal to that of the O.D.  105 . 2  of the core coiled tubing string  105  of 2.000″. 
     Both the axial and longitudinal cross-sections presented in  FIGS. 4A-1 and 4A-1   a  presume bundling the product  100  concentrically, when in actuality, an eccentric bundling may be preferred. An eccentric bundling provides more wrap layer protection for the electrical wiring  106  and data cables  107 . Such a depiction is included as  FIG. 4A-2  for an eccentrically bundled coiled tubing conveyance medium  101 . Fortunately, eccentric bundling would have no practical ramifications on sizing pack-off rubbers or wellhead injector components for lubrication into and out of the parent wellbore, since the O.D.  105 . 2  and circularity of the outer wrap layer  110  of an eccentric conveyance medium  101  remain unaffected. 
     The conveyance medium  101  may have, for example, an internal flow area of 2.0612 in 2 , a core wall thickness  105  of 0.190 in 2 , and an average outer wall thickness of 0.25 in 2 . The outer wall  110  may have a minimum thickness of 0.10 in 2 . 
     Note the main design criteria of the conveyance medium, whether concentrically  100  or eccentrically  101  bundled, is to provide real-time power (via electrical wiring  106 ) and data (via data cabling  107 ) transmission capacities to an operator located at the surface  1  while deploying, operating, and retrieving apparatus  50  in the wellbore  4 . For example, in a standard e-coil system, components  106  and  107  would be run within the coiled tubing core  105 , thereby exposing them to any fluids being pumped via the I.D.  105 . 1  of the core  105 . Given the subject method provides for pumping abrasives within a high-pressure jetting fluid (particularly, while eroding casing exit “W” from within production casing  12 ), it is preferred instead to locate components  106  and  107  at the O.D.  105 . 2  of the core  105 . 
     Similarly, the subject method provides for pumping proppants within high pressure hydraulic fracturing fluids down the annulus between the coiled tubing conveyance medium  100  (or  101 ) and production casing  12 . Hence, the protective coiled tubing wrap layer  110  is preferably of sufficient thickness, strength, and erosive resistance to isolate and protect components  106  and  107  during fracturing operations. 
     The present conveyance medium  100  (or  101 ) also maintains a sufficiently large inner diameter  105 . 1  of the core wall  105  such as to avoid appreciable friction losses (as compared to the losses incurred in the internal system  1500  and external system  2000 ) while pumping jetting and/or hydraulic fluids. At the same time, the system maintains a sufficiently small outer diameter  110 . 2  so as to avoid prohibitively large pressure losses while pumping hydraulic fracturing fluids down the annulus between the coiled tubing conveyance medium  100  (or  101 ) and the production casing  12 . Further, the system  50  maintains a sufficient wall thickness for the outer wrap layer  110 , whether it is concentrically or eccentrically wrapped about the inner coiled tubing core  105 , so as to provide adequate insular protection and spacing for the electrical transmission wiring  106  and the data transmission cabling  107 . It is understood that other dimensions and other tubular bodies may be used as the conveyance medium for the external system  2000 . 
     Moving further down the external system  2000 ,  FIG. 4B-1  presents a longitudinal, cross-sectional view of the first crossover connection, the coiled tubing crossover connection  200 .  FIG. 4B-1   a  shows a portion of the coiled tubing crossover connection  200  in perspective view. Specifically, the transition between lines E-E′ and line F-F′ is shown. In this arrangement, an outer profile transitions from circular to oval to bypass the main control valve  300 . 
     The main functions of this crossover connection  200  are as follows:
         (1) To connect the coiled tubing conveyance medium  100  (or  101 ) to the jetting assembly  50  and, specifically, to the main control valve  300 . In  FIG. 4B-1 , this connection is depicted by the steel coiled tubing core  105  connected to the main control valve&#39;s outer wall  290  at connection point  210 .   (2) To transition the electrical cables  106  and data cables  107  from the outside of the core  105  of the coiled tubing conveyance medium  100  (or  101 ) to the inside of the main control valve  300 . This is accomplished with wiring port  220  facilitating the transition of wires/cables  106 / 107  inside outer wall  290 .   (3) To provide an ease-of-access point, such as the threaded and coupled collars  235  and  250 , for the splicing/connection of electrical cables  106  and data cables  107 .
           and   
           (4) To provide separate, non-intersecting and non-interfering pathways for electrical cables  106  and data cables  107  through a pressure- and fluid-protected conduit, that is, a wiring chamber  230 .       

     The next component in the external system  2000  is a main control valve  300 .  FIG. 4C-1  provides a longitudinal, cross-sectional view of the main control valve  300 .  FIG. 4C-1   a  provides an axial, cross-sectional view of the main control valve  300 , taken across line G-G′ of  FIG. 4C-1 . The main control valve  300  will be discussed in connection with both  FIGS. 4C-1 and 4C-1   a  together. 
     The function of the main control valve  300  is to receive high pressure fluids pumped from within the coiled tubing  100 , and to selectively direct them either to the internal system  1500  or to the external system  2000 . The operator sends control signals to the main control valve  300  by means of the wires  106  and/or data cable ports  107 . 
     The main control valve  300  includes two fluid passages. These comprise a hydraulic fluid passage  340  and a jetting fluid passage  345 . Visible in  FIGS. 4C-1, 4C-1   a  and  4 C- 1   b  (longitudinal cross-sectional, axial cross-sectional, and perspective view, respectively) is a sealing passage cover  320 . The sealing passage cover  320  is fitted to form a fluid-tight seal against inlets of both the hydraulic fluid passage  340  and the jetting fluid passage  345 . Of interest,  FIG. 4C-1   b  presents a three-dimensional depiction of the passage cover  320 . This view illustrates how the cover  320  can be shaped to help minimize frictional and erosional effects. 
     The main control valve  300  also includes a cover pivot  350 . The passage cover  320  rotates with rotation of the passage cover pivot  350 . The cover pivot  350  is driven by a passage cover pivot motor  360 . The sealing passage cover  320  is positioned by the passage cover pivot  350  (as driven by the passage cover pivot motor  360 ) to either: (1) seal the hydraulic fluid passage  340 , thereby directing all of the fluid flow from the coiled tubing  100  into the jetting fluid passage  345 , or (2) seal the jetting fluid passage  345 , thereby directing all of the fluid flow from the coiled tubing  100  into the hydraulic fluid passage  340 . 
     The main control valve  300  also includes a wiring conduit  310 . The wiring conduit  310  carries the electrical wires  106  and data cables  107 . The wiring conduit  310  is optionally elliptically shaped at the point of receipt (from the coiled tubing transition connection  200 , and gradually transforms to a bent rectangular shape at the point of discharging the wires  106  and cables  107  into the jetting hose carrier system  400 . Beneficially, this bent rectangular shape serves to cradle the jetting hose conduit  420  throughout the length of the jetting hose carrier system  400 . 
     The next component of the external system  2000  is a jetting hose carrier system  400 .  FIG. 4D-1  is a longitudinal, cross-sectional view of the jetting hose carrier system  400 . The jetting hose carrier system  400  is attached downstream of the main control valve  300 . The jetting hose carrier system  400  is essentially an elongated tubular body that houses the docking station  325 , the internal system&#39;s battery pack section  1550 , the jetting fluid receiving funnel  1570 , the seal assembly  1580  and connected jetting hose  1595 . In the view of  FIG. 4D-1 , only the docking station  325  is visible so that the profile of the jetting hose carrier system  400  itself is more clearly seen. 
       FIG. 4D-1   a  is an axial, cross-sectional view of the jetting hose carrier system  400  of  FIG. 4D . 1 , taken across line H-H′ of  FIG. 4D-1 .  FIG. 4D-1   b  is an enlarged view of a portion of the jetting hose carrier system  400  of  FIG. 4D-1 . Here, the docking station  325  is visible. The jetting hose carrier system  400  will be discussed with reference to each of  FIGS. 4D-1, 4D-1   a  and  4 D- 1   b , together. 
     The jetting hose carrier system  400  defines a pair of tubular bodies. The first tubular body is a jetting hose conduit  420 . The jetting hose conduit  420  houses, protects, and stabilizes the internal system  1500  and, particularly, the jetting hose  1595 . As previously presented in the discussion of the internal system  1500 , it is the size (specifically, the I.D.), strength, and rigidity of this fluid-tight and pressure-sealing conduit  420  that provides the pathway and particularly, the micro-annulus (shown at  1595 . 420  in  FIG. 3D-1   a ,  FIG. 4D-2  and  FIG. 4D-2   a ) for the jetting hose  1595  of internal system  1500  to be “pumped down” and reversibly “pumped up” the longitudinal axis of the external system  2000  as it operates within the production casing  12 . 
     The jetting hose carrier section  400  also has an outer conduit  490 . The outer conduit  490  resides along and circumscribes the inner conduit  420 . In one aspect, the outer conduit  490  and the jetting hose conduit  420  are simply concentric strings of 2.500″ O.D. and 1.500″ O.D. HSt100 coiled tubing, respectively. The inner conduit, or jetting hose conduit  420 , is sealed to and contiguous with the jetting fluid passage  345  of the main control valve  300 . When high pressure jetting fluid is directed by the valve  300  into the jetting fluid passage  345 , the fluid flows directly and only into the jetting hose conduit  420  and then into the jetting hose  1595 . 
     An annular area  440  exists between the inner (jetting hose) conduit  420  and the surrounding outer conduit  490 ). The annular area  440  is also fluid tight, directly sealed to and contiguous with the hydraulic fluid passage  340  of the control valve  300 . When high pressure hydraulic fluid is directed by the main control valve  300  into the hydraulic fluid passage  340 , the fluid flows directly into the conduit-carrier annulus  440 . 
     The jetting hose carrier section  400  also includes a wiring chamber  430 . The wiring chamber  430  has an axial cross-section of an upwardly-bent rectangular shape, and receives the electrical wires  106  and data cables  107  from the main control valve&#39;s  300  wiring conduit  310 . This fluid-tight chamber  430  not only separates, insulates, houses, and protects the electrical wires  106  and data cables  107  throughout the entire length of the jetting hose carrier section  400 , but its cradle shape serves to support and stabilize the jetting hose conduit  420 . Note the jetting hose carrier section  400  wiring chamber  430  and inner (jetting hose) conduit  420  may or may not be attached either to each other, and/or to the outer conduit  490 . 
     In addition to housing and protecting wires  106  and data transmission cables  107 , the wiring conduit  430  within the jetting hose carrier system  400  supports the jetting hose conduit&#39;s  420  horizontal axis at a position slightly above a horizontal axis that would bifurcate the outer conduit  490 . Different types of materials may be utilized in its construction, given its design constraints are significantly less stringent than those for the outer layer(s) of the CT-based conveyance medium, particularly in regard to chemical and abrasion resistance, as the exterior of the wiring conduit  430  will only be exposed to hydraulic fluid—never jetting or fracturing fluids. 
     Additional design criteria for the wiring conduit  430  may be invoked if it is desired for it to be rigidly attached to either the jetting hose conduit  420 , the outer conduit  490 , or both. In one aspect, the wiring conduit  430  has a width of approximately 1.34″, and provides three 0.20″ diameter circular channels for electrical wiring, and two 0.10″ diameter circular channels for data transmission cables. It is understood that other diameters and configurations for the wiring conduit  430  may vary, depending on design objectives, so long as an annular area  440  open to flow of hydraulic fluid is preserved. 
     Also visible in  FIG. 4D-1  is the docking station  325 . The docking station  325  resides immediately downstream of the connection between the main control valve  300  and the jetting hose carrier system  400 . The docking station  325  is rigidly attached within the interior of the jetting hose conduit  420 . The docking station  325  is held in the jetting hose conduit  420  by diagonal supports. The diagonal supports are hollow, the interior(s) of which serving as a fluid- and pressure-tight conduit(s) of leads of electrical wires  106  and data cables  107  into the communications/control/electronics systems of the docking station  325 . This is similar to functions of the battery pack support conduits  1560  of the internal system  1500 . Whether connected to a servo device, a transmitter, a receiver, or other device housed within the docking station  325 , these devices are thereby “hard-wired” via electrical wires  106  and data cables  107  to an operator&#39;s control system (not shown) at the surface  1 . 
       FIG. 4D-2  provides an enlarged, longitudinal cross-sectional view of a portion of the jetting hose carrier system  400  of external system  2000 , depicting its operational hosting of a commensurate length of jetting hose  1595 .  FIG. 4D-2   a  provides an axial, cross-sectional view of the jetting hose carrier system  400  of  FIG. 4D-2 , taken across line H-H′. Note that the cross-sectional view of  FIG. 4D-2   a  matches the cross-sectional view of  FIG. 4D-1   a , except that the conduit  420  in  FIG. 4D-1   a  is “empty,” meaning that the jetting hose  1595  is not shown. 
     The length of the jetting hose conduit  420  is quite long, and should be approximately equivalent to the desired length of jetting hose  1595 , and thereby defines the maximum reach of the jetting nozzle  1600  orthogonal to the wellbore  4 , and the corresponding length of the mini-lateral  15 . The inner diameter specification defines the size of the micro-annulus  1595 . 420  between the jetting hose  1595  and the surrounding jetting hose conduit  420 . The I.D. should be close enough to the O.D. of the jetting hose  1595  so as to preclude the jetting hose  1595  from ever becoming buckled or kinked, yet it must be large enough to provide sufficient annular area for a robust set of seals  1580 L by which hydraulic fluid can be pumped into the sealed micro-annulus  1595 . 420  to assist in controlling the rate of deployment of the jetting hose  1595 , or assisting in hose retrieval. 
     It is the hydraulic forces within the sealed micro-annulus  1595 . 420  that keep the segment of jetting hose (above the internal tractor system  700 ) straight, and slightly in tension. The I.D. of jetting hose conduit  420  can likewise not be too close to the O.D. of the jetting hose  1595  so as to place unnecessarily high frictional forces between the two. The O.D. of the jetting hose conduit  420  (in conjunction with the I.D. of the outer conduit  490 , less the external dimensions of the jetting hose carrier&#39;s wiring chamber  430 ) define the annular area  440  through which hydraulic fluid is pumped. Certainly, if the jetting hose carrier system&#39;s inner conduit  420  O.D. is too large, it thereby invokes undue frictional losses in pumping hydraulic fluid. However, if not large enough, then the inner conduit  420  will not have sufficient wall thickness to support either the inner or outer operating pressures required. Note, for the subject apparatus designed to be deployed in 4.5″ wellbore casing, the inner string is comprised of 1.5″ O.D. and 1.25″ I.D. (i.e., 0.125″ wall thickness) coiled tubing. If this were 1.84#/ft., HSt110, for example, it would provide for an Internal Minimum Yield Pressure rating of 16,700 psi. Similarly, the outer conduit  490  can be constructed of standard coiled tubing. In one aspect, the outer conduit  490  is comprised of 2.50″ O.D. and 2.10″ I.D., thereby providing for a wall thickness of 0.20″. 
     Progressing again uphole-to-downhole, the external system  2000  next includes the second crossover connection  500 , transitioning to the jetting hose pack-off section  600 .  FIG. 4E-1  provides an elongated, cross-sectional view of both the crossover connection (or transition)  500  and the jetting hose pack-off section  600 .  FIG. 4E-1   a  is an enlarged perspective view highlighting the transition&#39;s  500  outer body shape, transitioning from circular- to star-shaped. Axial cross-sectional lines I-I′ and J-J′ illustrate the profile of the transition  500  fittingly matching the dimensions of the outer wall  490  of jetting hose carrier system  400  at its beginning, and an outer wall  690  of the pack-off section  600  at its end. 
       FIG. 4E-2  shows an enlarged portion of the jetting hose pack-off section  600  of  FIG. 4E-1 , and particularly sealing assembly  650 . The transition  500  and the jetting hose pack-off section  600  will be discussed with reference to each of these views together. 
     As its name implies, the main function of the jetting hose pack-off section  600  is to “pack-off”, or seal, an annular space between the jetting hose  1595  and a surrounding inner conduit  620 . The jetting hose pack-off section  600  is a stationary component of the external system  2000 . Through transition  500 , and partially through pack-off section  600 , there is a direct extension of the micro-annulus  1595 . 420 . This extension terminates at the pressure/fluid seal of the jetting hose  1595  against the inner faces of seal cups making up the pack-off seal assembly  650 . Immediately prior to this terminus point is the location of the pressure regulator valve, shown schematically as component  610  in  FIGS. 4E-1 and 4E-2 . It is this valve  610  that serves to either communicate or segregate the annulus  1595 . 420  from the hydraulic fluid running throughout the external system  2000 . The hydraulic fluid takes its feed from the inner diameter of the coiled tubing conveyance medium  100  (specifically, from the I.D.  105 . 1  of coiled tubing core  105 ) and proceeds through the continuum of hydraulic fluid passages  240 ,  340 ,  440 ,  540 ,  640 ,  740 ,  840 ,  940 ,  1040 , and  1140 , then through the transitional connection  1200  to the coiled tubing mud motor  1300 , and eventually terminating at the tractor  1350 . (Or, terminating at the operation of some other conventional downhole application, such as a hydraulically set retrievable bridge plug.) 
     The crossover connection  500  from the jetting hose carrier system  400  to the pack off section  600  is notable for several reasons: 
     First, within this transition  500 , the free flow of hydraulic fluid from the conduit-carrier annulus  440  of the jetting hose carrier section  400  will be re-directed and re-compartmentalized within the upper (triangular-shaped) quadrant of the star-shaped outer conduit  690 . Toward the upstream end of the inner conduit  620  is the pressure regulator valve  610 . The pressure regulator valve  610  provides for increasing or decreasing the hydraulic fluid (and commensurately, the hydraulic pressure) in the micro-annulus  1595 . 420  between the jetting hose  1595  and the surrounding jetting hose conduit  420 . It is the operation of this valve  610  that provides for the internal system  1500  (and specifically, the jetting hose  1595 ) to be “pumped down,” and then reversibly “pumped up” the longitudinal axis of the production casing  12 . 
     The upwardly bent, rectangular-shaped fluid-tight chamber  430  that separates, insulates, houses, and protects the electrical wires  106  and data cables  107  along the length of the jetting hose carrier body  400  is transitioned via wiring chamber  530  into a lower (triangular-shaped) quadrant  630  of the star-shaped outer body  690  of the pack-off section  600 . This preserves the separation, insulation, housing, and protection of the electrical wires  106  and the data cables  107  in the jetting hose pack-off section  600 . The star-shaped outer body  690  forms an annulus between itself and the I.D. of the surrounding production casing  12 . 
     Given the prong-tip-to-opposite-prong-tip distances of the four-pronged star-shaped outer conduit  690  are just slightly less than the I.D. of the production casing  12 , the pack-off section  600  also serves to nearly centralize the jetting hose  1595  in the parent wellbores production casing  12 . As will be explained later, this near-centralization will translate through the internal tractor system  700  so as to beneficially centralize the upstream end of the whipstock member  1000 . 
     Recall the outer diameter of the upstream end of the jetting hose  1595  is hydraulically sealed against the inner diameter of the inner conduit  420  of the jetting hose carrier system  400  by virtue of the jetting hose&#39;s upper  1580 U and lower  1580 L seals, forming a single seal assembly  1580 . The seals  1580 U and  1580 L, being formably affixed to the jetting hose  1595 , travel up and down the inner conduit  420 . Similarly, the outer diameter of the downstream end of the jetting hose  1595  is hydraulically sealed against the inner diameter of the pack-off section&#39;s  600  inner conduit  620  by virtue of the seal assembly  650  of the pack-off section  600 . Thus, when the internal system  1500  is “docked” (i.e., when the upstream battery pack end cap  1520  is in contact with the external system&#39;s docking station  325 ) then the distance between the two seal assemblies  1580 ,  620  approximates the full length of the jetting hose  1595 . Conversely, when the jetting hose  1595  and jetting nozzle  1600  have been fully extended into the maximum length lateral borehole (or UDP)  15  attainable by the jetting assembly  50 , then the distance between the two seal assemblies  1580 ,  620  is negligible. This is because, though the internal system&#39;s jetting hose seal assembly  1580  essentially travels the entire length of the external system&#39;s  2000  jetting hose carrier system  400 , the seal assembly  650  (of the pack-off section  600  in the external system  2000 ) is relatively stationary, as the seal cups comprising seal assembly  650  must reside between opposing seal cup stops  615 . 
     Note further how the alignment of the two opposing sets of seal cups comprising seal assembly  650  (e.g., an upstream set facing upstream, placed back-to-back with a downstream set facing downstream) thereby provides a pressure/fluid seal against differential pressure from either the upstream direction or the downstream direction. These opposing sets of seal cups comprising seal assembly  650  are shown with a longitudinal cross section of jetting hose  1595  running concentrically through them, in the enlarged view of  FIG. 4E-2 . 
     As noted, the pressure maintained in the micro-annulus  1595 . 420  by the pressure regulator valve  610  provides for the hydraulic actions of “pumping the hose down the hole” or, reversibly, “pumping the hose up the hole”. These annular hydraulic forces also serve to mitigate other, potentially harmful forces that could be imposed on the jetting hose  1595 , such as buckling forces when advancing the hose  1595  downstream, or internal burst forces while jetting. Hence, combined with the upper hose seal assembly  1580  and the jetting hose conduit  420 , the jetting hose pack-off section  600  serves to maintain the jetting hose  1595  in an essentially taut condition. Hence, the diameter of the hose  1595  that can be utilized will be limited only by the bend radius constraint imposed by the I.D. of the wellbore&#39;s production casing  12 , and the commensurate pressure ratings of the hose  1595 . At the same time, the length of the hose  1595  that may be utilized is certainly well into the hundreds of feet. 
     Note the most likely limiting constraint of hose  1595  length will not be anything imposed by the external system  2000 , but instead will be the hydraulic horsepower distributable to the rearward thrust jets  1613 / 1713 , such that sufficient horsepower can remain forward-focused for excavating rock. As one might expect, the length (and commensurate volume) of mini-laterals that can be jetted will ultimately be a function of rock strength in the subsurface formation. This length limitation is quite unlike the system posited in U.S. Pat. No. 6,915,853 (Bakke, et al.) that attempts to convey the entirety of the jetting hose downhole in a coiled state within the apparatus itself. That is, in Bakke, et al., the hose is stored and transported while in horizontally stacked, 360° coils contained within the interior of the device. In this case, the bend radius/pressure hose limitations are imposed by (among other constraints), not the I.D. of the casing, but by the I.D. of the device itself. This results in a much smaller hose I.D./O.D., and hence, geometrically less horsepower deliverable to Bakke&#39;s jetting nozzle. 
     In operation, after a UDP  15  has been formed and the main control valve  300  has been shifted to shut-off the flow of hydraulic jetting fluid to the internal system  1500  and is then providing flow of hydraulic fluid to the external system  2000 , the pressure regulator valve  610  can feed flow into the micro-annulus  1595 . 420  in the opposite direction. This downstream-to-upstream force will “pump” the assembly back into the wellbore  4  and “up the hole,” as the bottom, downwards facing cups  1580 L of the seal assembly  1580  will trap flow (and pressure) below them. 
     The next component within the external system  2000  (again, progressing uphole-to-downhole) is an optional internal tractor system  700 .  FIG. 4F-1  provides an elongated, cross-sectional view of the tractor system  700 , downstream from the jetting hose pack-off section  600 .  FIG. 4F-2  shows an enlarged portion of the tractor system  700  of  FIG. 4F-1 .  FIG. 4F-2   a  is an axial, cross-sectional view of the internal tractor system  700 , taken across line K-K′ of  FIGS. 4F-1 and 4F-2 . Finally,  FIG. 4F-2   b  is an enlarged half-view of a portion of the internal tractor system  700  of  FIG. 4F-2   a . The internal tractor system  700  will be discussed with reference to each of these four views together. 
     It is first observed that two types of tractor systems are known. These are the wheeled tractor systems and the so-called inch-worm tractor systems. Both of these tractor systems are “external” systems, meaning that they have grippers designed to engage the inner wall of the surrounding casing (or, if in an open hole, to engage the borehole wall). Tractor systems are used in the oil and gas industry primarily to advance either a wireline or a string of coiled tubing (and connected downhole tools) along a horizontal (or highly deviated) wellbore—either uphole or downhole. 
     In the present assembly  50 , a unique tractor system has been developed which employs “internal,” grippers. This means that gripper assemblies  750  are aimed inwardly, for the purpose of either advancing or retracting the jetting hose  1595  relative to the external system  2000 . The result of this inversion is that the coiled tubing string  100  and attached external system  2000  can now be stationary while the somewhat flexible hose  1595  is being translated in the wellbore  4   c . The outwardly-aimed electrically driven wheels of a conventional (“external”) tractor are replaced with inwardly-aimed concave grippers  756 . The result is the inwardly-aimed concave grippers  756  frictionally attach to the jetting hose  1595 , with subsequent rotation of the grippers  756  propelling the jetting hose  1595  in a direction that corresponds with the direction of rotation. 
     Note specifically the following consequence of this inversion: In a conventional system, the relative movement that occurs is that of the rigidly gripper-attached body (i.e., the coiled tubing) relative to the stationary, frictionally attached body (i.e., the borehole wall). Conversely, the subject internal tractor system is rigidly attached to the stationary body (i.e., the external system  2000 ) and the grippers  756  rotate to move the jetting hose  1595 . Accordingly, when the internal tractor system  700  is actuated, the whipstock member  1000  will already be in its set and operating position; e.g., the slips of the whipstock member  1000  will be engaged with the inner wall of the casing  12 . Hence, all advancement/retraction of the jetting hose  1595  by the tractor system  700  takes place when the external system  2000  itself is set and is stationary within the production casing  12 . 
     It is next observed that the internal tractor system  700  preferably maintains the star-shape profile of the jetting hose pack-off system  600 . The star shape profile of the internal tractor system  700 , with its four points, helps centralizes the tractor system  700  within the production casing  12 . This is beneficial inasmuch as the slips of the whipstock member  1000  (located relatively close to tractor system  700 , due to the short lengths of the third crossover connection (or transition)  800  and upper swivel  900  between them, discussed below) will be engaged when operating the tractor system  700 , meaning that centralization of the tractor system  700  serves to align the defined path of the jetting hose  1595  and precludes any undo torque at the connection with the jetting hose whipstock device  1000 . It is observed in  FIGS. 4F-1 and 4F-2   a  that the position of the jetting hose  1595  is approximately centered, both within the tractor system  700  and, therefore, within the production casing  12 . This places the hose  1595  in optimum position to be either fed into or retracted from the jetting hose whipstock device  1000 . 
     In addition to centralizing the hose  1595 , another function served by the star-shape profile of the tractor system  700  is that it accommodates interior room for placement of two opposing sets of gripper assemblies  750 . Specifically, the gripper assemblies  750  reside inside the ‘dry’ working room of the two side chambers, while simultaneously providing for separate chambers for the electrical wires  106  and data cabling  107  (shown in lower chamber  730 ) and the hydraulic fluid (in upper chamber  740 ). At the same time, ample cross-sectional flow area is preserved between the tractor system  700  and the I.D. of the production casing  12  within their respective annular area  700 . 12  for conducting fracturing fluids. 
     As shown within the 4.5″ production casing  12 , the annular area  700 . 12  open to flow is approximately 10.74 in 2 , equating to an equivalent pipe diameter (I.D.) of 3.69 in. Recall the design objective is to maintain an annular flow area greater than or equal to the interior area of a typical 3.5″ O.D. (2.922″ I.D., 10.2#/ft.) frac string, i.e. 6.706 in 2 . Note then, if the tip-to-tip dimension of opposing prongs of the “star” is, for example, 3.95 in, and (to gain additional internal volume within the four chambers of the tractor system  700 ) the star shape were changed to a perfect square, then the external area of the square would be 7.801 in 2 , and the remaining annular area (open to flow of frac fluid) inside the 4.00″ I.D. production casing would be 4.765 in 2 , which is equivalent to a 2.463″ pipe I.D. Hence, though the base of each triangular chamber within the star shape could be somewhat expanded to provide additional internal volumes or wall thickness, the outer perimeter cannot be completely squared-off and still satisfy the preferred 3.5″ frac string criteria. Note, however, there is no reason the triangular dimensions of each chamber must remain symmetrical; e.g., the dimensions could be varied individually in order to accommodate each chamber&#39;s internal volume requirements, just as long as the 3.5″ frac string requirement is still preferably satisfied. 
     Each of the gripper assemblies  750  is comprised of a miniature electric motor  754 , and a motor mount  755  securing the motor  754  to the outer wall  790 . In addition, each of the gripper assemblies  750  includes a pair of axles. These represent a gripper axle  751  and a gripper motor axle  753 . Finally, each of the gripper assemblies  750  includes gripper gears  752 . 
     The tractor system  700  also includes bearing systems  760 . The bearing systems  760  are placed along the length of inner walls  720 . These bearing systems  760  isolate frictional forces against the jetting hose  1595  at the contact points of the grippers  756 , and eliminate unwanted frictional drag against the inner walls  720 . 
     Rearward rotation of the grippers  756  serve to advance the hose  1595 , while forward rotation of the grippers  756  serves to retract the hose  1595 . Propulsion forces provided by the grippers  756  help advance the jetting hose  1595  by pulling it through the jetting hose carrier system  400 , transition  500 , and pack-off section  600 , and assist in advancing the jetting hose  1595  by pushing it into the lateral borehole  15  itself. 
     The view of  FIG. 4F-1  depicts only two sets of opposing gripper assemblies  750 . However, gripper assemblies  750  may be added to accommodate virtually any length and construction of jetting hose  1595 , depending on compressional, torsional and horsepower constraints. Additional gripper assemblies  750  should add tractor force, which may be desirable for extended length lateral boreholes  15 . Though it is presumed maximum grip force will be obtained when pairs of gripper assemblies  750  are placed axially opposing one another in the same plane (as shown in  FIG. 4F-2 . a ), that is, maximizing a “pinch” force on the jetting hose  1595 , other arrangements/placements of gripper systems  750  are within the scope of this aspect of the inventions. 
     Optionally, the internal tractor system  700  also includes a tensiometer. The tensiometer is used to provide real-time measurement of the pulling tension of the upstream section of hose  1595  and the pushing compression on the downstream section of hose  1595 . Similarly, mechanisms could be included to individualize the applied compressional force of each set of grippers  756  upon the jetting hose  1595 , so as to compensate for uneven wear of the grippers  756 . 
     Again proceeding in presentation of the external system&#39;s  2000  main components from upstream-to-downstream,  FIG. 4G-1  shows a longitudinal, cross-sectional view of the internal tractor-to-upper swivel (or third) crossover connection  800 , and the upper swivel  900  itself.  FIG. 4G-1   a  depicts a perspective view of the crossover connection  800  between its upstream and downstream ends, denoted by lines L-L′ and M-M′, respectively.  FIG. 4G-1   b  presents an axial, cross-sectional view within the upper swivel  900  along line N-N′. The third transition  800  and upper swivel  900  are discussed in connection with  FIGS. 4G-1, 4G-1   a  and  4 G- 1   b  together. 
     The transition  800  functions similarly to previous transitional sections ( 200 ,  500 ) of the external system  2000  discussed herein. For example, the transition  800  comprises an inner wall  820  and a surrounding outer wall  890  and defines a hydraulic fluid channel  840  there between. Suffice it to say the main function of the transition  800  is to convert the axial profile of the star-shaped internal tractor system  700  back to a concentric circular profile as used for the swivel  900 , and to do so within I.D. restrictions that meet the 3.5″ frac string test. 
     The upper swivel  900  simultaneously accomplishes three important functions:
         (1) First, it allows the indexing mechanism to rotate the connected whipstock member  1000  without torqueing any upstream components of the system  50 .   (2) Second, it provides for rotation of the whipstock  1000  while yet maintaining a straight path for the electrical wiring  106  and data cabling  107  through wiring chamber  930  between the transition  800  and the whipstock member  1000 ; while simultaneously providing.   (3) Third, it provides a horseshoe-shaped hydraulic fluid chamber  940  that accommodates rotation of the whipstock member  1000  while yet maintaining a contiguous hydraulic flow path between the transition  800  and the whipstock member  1000 .       

     Desirable for the simultaneous satisfaction of the above design criteria are the double sets of bearings  960  (the inner bearings) and  965  (the outer bearings). In one aspect, the upper swivel  900  has an O.D. of 2.6 in. 
     The outer wall  990  of the upper swivel  900  maintains the circular profile achieved by an outer wall  890  of transition  800 . Similarly, concentric circular profiles are obtained in the upper swivel&#39;s  900  middle body  950  and inner wall  920 . These three sequentially and concentrically smaller cylindrical bodies ( 990 ,  950 , and  920 ) provide for placement of an inner set of circumferential bearings  960  (between the inner wall  920  and the middle body  950 ) and an outer set of circumferential bearings  965  (between the middle body  950  and the outer wall  990 ). The larger cross-sectional area of the middle body  950  allows it to host a horseshoe-shaped hydraulic fluid chamber  940 , and an arc-shaped wiring chamber  930 . The bearings  960 ,  965  facilitate relative rotation of the three sequentially and concentrically smaller cylindrical bodies  990 ,  950 , and  920 . The bearings  960 ,  965  also provide for rotatable translation of the whipstock member  1000  below the upper swivel  900  (also shown in  FIG. 4G-1 ) while in its set and operating position. This, in turn, provides for a change in orientation of subsequent lateral boreholes jetted from a given setting depth in the parent wellbore  4 . Stated another way, the upper swivel  900  allows an indexing mechanism (described in the related U.S. Pat. No. 8,991,522 and incorporated herein in its entirety) to rotate the whipstock member  1000  without torqueing any upstream components of the external system  2000 . 
     It is also observed that the upper swivel  900  provides for rotation of the whipstock member  1000  while yet maintaining a straight path for the electrical wiring  106  and data cabling  107 . The upper swivel  900  also permits the horseshoe-shaped hydraulic fluid chamber  940  to provide for rotation of the whipstock member  1000  while yet maintaining a contiguous hydraulic flow path down to the whipstock member  1000  and beyond. 
     Returning to  FIG. 4 , and as noted above, the external system  2000  includes a whipstock member  1000 . The jetting hose whipstock member  1000  is a fully reorienting, resettable, and retrievable whipstock means similar to those described in the precedent works of U.S. Provisional Patent Application No. 61/308,060 filed Feb. 25, 2010, U.S. Pat. No. 8,752,651 filed Feb. 23, 2011, and U.S. Pat. No. 8,991,522 filed Aug. 5, 2011. Those applications are again referred to and incorporated herein for their discussions of setting, actuating and indexing the whipstock. Accordingly, detailed discussion of the jetting hose whipstock device  1000  will not be repeated herein. 
       FIG. 4H . 1  provides a longitudinal cross-sectional view of a portion of the wellbore  4  from  FIG. 2 . Specifically, the jetting hose whipstock member  1000  is seen. The jetting hose whipstock member  1000  is in its set position, with the upper curved face  1050 . 1  of the whipstock  1050  receiving a jetting hose  1595 . The jetting hose  1595  is bending across the hemispherically-shaped channel that defines the face  1050 . 1 . The face  1050 . 1 , combined with the inner wall of the production casing  12 , forms the only possible pathway within which the jetting hose  1595  can be advanced through and later retracted from the casing exit “W” and lateral borehole  15 . 
     A nozzle  1600  is also shown in  FIG. 411.1 . The nozzle  1600  is disposed at the end of the jetting hose  1595 . Jetting fluids are being dispersed through the nozzle  1600  to initiate formation of a mini-lateral borehole into the formation. The jetting hose  1595  extends down from the inner wall  1020  of the jetting hose whipstock member  1000  in order to deliver the nozzle  1600  to the whipstock member  1050 . 
     As discussed in U.S. Pat. No. 8,991,522, the jetting hose whipstock member  1000  is set utilizing hydraulically controlled manipulations. In one aspect, hydraulic pulse technology is used for hydraulic control. Release of the slips is achieved by pulling tension on the tool. These manipulations were designed into the whipstock member  1000  to accommodate the general limitations of the conveyance medium (conventional coiled tubing)  100 , which can only convey forces hydraulically (e.g., by manipulating surface and hence, downhole hydraulic pressure) and mechanically (i.e., tensile force by pulling on the coiled tubing, or compressive force by utilizing the coiled tubing&#39;s own set-down weight). 
     The jetting hose whipstock member  1000  is herein designed to accommodate the delivery of wires  106  and data cables  107  further downhole. To this end, a wiring chamber  1030  (conducting electrical wires  106  and data cables  107 ) is provided. Power and data are provided from the external system  2000  to conventional logging equipment  1400 , such as a Gamma Ray—Casing Collar Locator logging tool, in conjunction with a gyroscopic tool. This would be attached immediately below a conventional mud motor  1300  and coiled tubing tractor  1350 . Hence, for this embodiment, hydraulic conductance through the whipstock  1000  is desirable to operate a conventional (“external”) hydraulic-over-electric coiled tubing tractor  1350  immediately below, and electrical (and preferably, fiber optic) conductance to operate the logging sonde  1400  below the coiled tubing tractor  1350 . The wiring chamber  1030  is shown in the cross-sectional views of  FIGS. 4H-1   a  and  4 H- 1   b , along lines O-O′ and P-P′, respectively, of  FIG. 4H-1 . 
     Note that this tractor  1350  is placed below the point of operation of the jetting nozzle  1600 , and therefore will never need to conduct either the jetting hose  1595  or high pressure jetting fluids to generate either the casing exit “W” or subsequent lateral borehole. Hence, there are no I.D. constraints for this (bottom) coiled tubing tractor  1350  other than the wellbore itself. The coiled tubing tractor  1350  may be either of the conventional wheel (“external roller”) type, or the gripper (inch worm) type. 
     A hydraulic fluid chamber  1040  is also provided along the jetting hose whipstock member  1000 . The wiring chamber  1030  and the fluid chamber  1040  become bifurcated while transitioning from semi-circular profiles (approximately matching their respective counterparts  930  and  940  of the upper swivel  900 ) to a profile whereby each chamber occupies separate end sections of a rounded rectangle (straddling the whipstock member  1050 ). Once sufficiently downstream of the whipstock member  1050 , the chambers can be recombined into their original circular pattern, in preparation to mirror their respective dimensions and alignments in a lower swivel  1100 . This enables the transport of power, data, and high pressure hydraulic fluid through the whipstock member  1000  (via their respective wiring chamber  1030  and hydraulic fluid chamber  1040 ) down to the mud motor  1300 . 
     Below the whipstock member  1000  and the nozzle  1600  but above the tractor  1350  is an optional lower swivel  1100 .  FIG. 4I-1  is a longitudinal cross-sectional view of the lower swivel  1100 , as it resides between the jetting hose whipstock member  1000  and crossover connection  1200 , and within the production casing  12 . A slip  1080  is shown set within the casing  12 .  FIG. 4I-1   a  is an axial cross-sectional view of the lower swivel  1100 , taken across line Q-Q′ of  FIG. 4I . 1 . The lower swivel  1100  will be discussed with reference to  FIGS. 4I-1 and 4I-1   a  together. 
     The lower swivel  1100  is essentially a mirror-image of the upper swivel  900 . As with the upper swivel  900 , the lower swivel  1100  includes an inner wall  1120 , a middle body  1150 , and an outer wall  1190 . In a preferred embodiment, the outer conduit has an O.D. of 2.60″, or slightly less. The constraint of the O.D. outer conduit  1190  is the self-imposed 3.5″ frac string equivalency test. 
     The middle body  1150  further houses wiring chamber  1130  and a hydraulic fluid chamber  1140 . The fluid chamber  1140  transports hydraulic fluid to crossover connection  1200  and eventually to the mud motor  1300 . 
     The lower swivel  1100  also includes a wiring chamber  1130  that houses electrical wires  106  and data cables  107 . Continuous electrical and/or fiber optic conductance may be desired when real time conveyance of logging data (gamma ray and casing collar locator, “CCL” data, for example) or orientation data (gyroscopic data, for example) is desired. Additionally, continuous electrical and/or fiber optic conductance capacity enables direct downhole assembly manipulation from the surface  1  in response to the real time data received. 
     It is noted that while the inner conduit  920  of the upper swivel  900  defines a hollow core of sufficient dimensions to receive and conduct the jetting hose  1595 , the lower swivel  1100  has no such requirement. This is because in the design of the assembly  50  and the methods of usage thereof, the jetting hose  1595  is never intended to proceed downstream to a point beyond the whipstock member  1050 . Accordingly, the innermost diameter of the lower swivel  1100  may in fact be comprised of a solid core, as depicted in  FIG. 4I-1   a , thereby adding additional strength qualities. 
     The lower swivel  1100  resides between the jetting hose whipstock member  1000  and any necessary crossover connections  1200  and downhole tools, such as a mud motor  1300  and the coiled tubing tractor  1350 . Logging tools  1400 , a packer, or a bridge plug (preferably retrievable, not shown) may also be provided. Note that, depending on the length of the horizontal portion  4   c  of the wellbore  4 , the respective sizes of the conveyance medium  100  and production casing  12 , and hence the frictional forces to be encountered, more than one mud motor  1300  and/or CT tractor  1350  may be needed. 
     The final figure presented is  FIG. 4J .  FIG. 4J  depicts the final transitional component  1200 , the conventional mud motor  1300 , and the (external) coiled tubing tractor  1350 . Along with the tools listed above, the operator may also choose to use a logging sonde  1400  comprised of, for example, a Gamma Ray—Casing Collar Locator and gyroscopic logging tools. The gyroscopic logging tools provide real-time data describing not only the precise downhole location, but the initial alignment of the whipstock face  1050 . 1  of the preceding jetting hose whipstock member  1000 . This data is useful in determining:
         (1) how many degrees of re-alignment, via the whipstock face  1050 . 1  alignment, are desired to direct the initial lateral borehole along its preferred azimuth; and   (2) subsequent to jetting the first lateral borehole, how many degrees of re-alignment are required to direct subsequent lateral borehole(s) along their respective preferred azimuth(s).       

     It is anticipated that, in preparation for a subsequent hydraulic fracturing treatment in a horizontal parent wellbore  4   c , an initial borehole  15  will be jetted substantially perpendicular to and at or near the same horizontal plane as the parent wellbore  4   c , and a second lateral borehole will be jetted at an azimuth of 180° rotation from the first (again, perpendicular to and at or near the same horizontal plane as the parent wellbore). In thicker formations, however, and particularly given the ability to steer the jetting nozzle  1600  in a desired direction, more complex lateral bores may be desired. Similarly, multiple lateral boreholes (from multiple setting points typically close together) may be desired within a given “perforation cluster” that is designed to receive a single hydraulic fracturing treatment stage. The complexity of design for each of the lateral boreholes will typically be a reflection of the hydraulic fracturing characteristics of the host reservoir rock for the pay zone  3 . For example, an operator may design individually contoured lateral boreholes within a given “cluster” to help retain a hydraulic fracture treatment predominantly “in zone.” 
     It can be seen that an improved downhole hydraulic jetting assembly  50  is provided herein. The assembly  50  includes an internal system  1500  comprised of a guidable jetting hose and rotating jetting nozzle that can jet both a casing exit and a subsequent lateral borehole in a single step. The assembly  50  further includes an external system  2000  containing, among other components, a carrier apparatus that can house, transport, deploy, and retract the internal system to repeatably construct the requisite lateral boreholes during a single trip into and out of a parent wellbore  4 , and regardless of its inclination. The external system  2000  provides for annular frac treatments (that is, pumping fracturing fluids down the annulus between the coiled tubing deployment string and the production casing  12 ) to treat newly jetted lateral boreholes. When combined with stage isolation provided by a packer and/or spotting temporary or retrievable plugs, thus providing for repetitive sequences of plug-and-UDP-and-frac, completion of the entire horizontal section  4   c  can be accomplished in a single trip. 
     In one aspect, the assembly  50  is able to utilize the full I.D. of the production casing  12  in forming the bend radius  1599  of the jetting hose  1595 , thereby allowing the operator to use a jetting hose  1595  having a maximum diameter. This, in turn, allows the operator to pump jetting fluid at higher pump rates, thereby generating higher hydraulic horsepower at the jetting nozzle  1600  at a given pump pressure. This will provide for substantially more power output at the jetting nozzle, which will enable:
         (1) optionally, jetting larger diameter lateral boreholes within the target formation;   (2) optionally, achieving longer lateral lengths;   (3) optionally, achieving greater erosional penetration rates; and   (4) achieving erosional penetration of higher strength and threshold pressure (σ M  and P Th ) oil/gas formations heretofore considered impenetrable by existing hydraulic jetting technology.       

     Also of significance, the internal system  1500  allows the jetting hose  1595  and connected jetting nozzle  1600  to be propelled independently of a mechanical downhole conveyance medium. The jetting hose  1595  is not attached to a rigid working string that “pushes” the hose and connected nozzle  1600 , but instead uses a hydraulic system that allows the hose and nozzle to travel longitudinally (in both upstream and downstream directions) within the external system  2000 . It is this transformation that enables the subject system  1500  to overcome the “can&#39;t-push-a-rope” limitation inherent to all other hydraulic jetting systems to date. Further, because the subject system does not rely on gravitational force for either propulsion or alignment of the jetting hose/nozzle, system deployment and hydraulic jetting can occur at any angle and at any point within the host parent wellbore  4  to which the assembly  50  can be “tractored” in. 
     The downhole hydraulic jetting assembly allows for the formation of multiple mini-laterals, or bore holes, of an extended length and controlled direction, from a single parent wellbore. Each mini-lateral may extend from 10 to 500 feet, or greater, from the parent wellbore. As applied to horizontal wellbore completions in preparation for subsequent hydraulic fracturing (“frac”) treatments in certain geologic formations, these small lateral wellbores may yield significant benefits to optimization and enhancement of fracture (or fracture network) geometry and subsequent hydrocarbon production rates and reserves recovery. By enabling: (1) better extension of the propped fracture length; (2) better confinement of the fracture height within the pay zone; (3) better placement of proppant within the pay zone; and (4) further extension of a fracture network prior to cross-stage breakthrough, the lateral boreholes may yield significant reductions of the requisite fracturing fluids, fluid additives, proppants, hydraulic horsepower, and hence related fracturing costs previously required to obtain a desired fracture geometry, if it was even attainable at all. Further, for a fixed input of fracturing fluids, additives, proppants, and horsepower, preparation of the pay zone with lateral boreholes prior to fracturing could yield significantly greater Stimulated Reservoir Volume, to the degree that well spacing within a given field may be increased. Stated another way, fewer wells may be needed in a given field, providing a significance of cost savings. Further, in conventional reservoirs, the drainage enhancement obtained from the lateral boreholes themselves may be sufficient as to preclude the need for subsequent hydraulic fracturing altogether. 
     As an additional benefit, the downhole hydraulic jetting assembly  50  and the methods herein permit the operator to apply radial hydraulic jetting technology without “killing” the parent wellbore. In addition, the operator may jet radial lateral boreholes from a horizontal parent wellbore as part of a new well completion. Still further, the jetting hose may take advantage of the entire I.D. of the production casing. Further yet, the reservoir engineer or field operator may analyze geo-mechanical properties of a subject reservoir, and then design a fracture network emanating from a customized configuration of directionally-drilled lateral boreholes. 
     The hydraulic jetting of lateral boreholes may be conducted to enhance fracture and acidization operations during completion. As noted, in a fracturing operation, fluid is injected into the formation at pressures sufficient to separate or part the rock matrix. In contrast, in an acidization treatment, an acid solution is pumped at bottom-hole pressures less than the pressure required to break down, or fracture, a given pay zone. (In an acid frac, however, pump pressure intentionally exceeds formation parting pressure.) Examples where the pre-stimulation jetting of lateral boreholes may be beneficial include:
         (a) prior to hydraulic fracturing (or prior to acid fracturing) in order to help confine fracture (or fracture network) propagation within a pay zone and to develop fracture (network) lengths a significant distance from the parent wellbore before any boundary beds are ruptured, or before any cross-stage fracturing can occur; and   (b) using lateral boreholes to place stimulation from a matrix acid treatment far beyond the near-wellbore area before the acid can be “spent,” and before pumping pressures approach the formation parting pressure.       

     The downhole hydraulic jetting assembly  50  and the methods herein permit the operator to conduct acid fracturing operations through a network of lateral boreholes formed through the use of a very long jetting hose and connected nozzle that is advanced through the rock matrix. In one aspect, the operator may determine a direction of a pressure sink in the reservoir, such as from an adjacent producer. The operator may then form one or more lateral boreholes in an orthogonal direction, and then conduct acid fracturing through that borehole. In this instance, fractures will open in the direction of the pressure sink. 
     The operator may alternatively consider or determine a flux-rate of acid (or other formation-dissolving fluid) in the rock matrix. In this instance, the acid is not injected at a formation parting pressure, but allows wormholes to form in the direction of the pressure sink. The operator may also conduct the steps of creating a pressure boundary in the reservoir by injecting fluids into a first lateral borehole in a first direction, and then performing acid-fracturing through a second lateral borehole in a second direction offset from the first direction. The acid fractures are in the form of wormholes in a direction that does not intersect the pressure boundary. 
     The downhole hydraulic jetting assembly  50  and the methods herein also permit the operator to pre-determine a path for the jetting of lateral boreholes. Such boreholes may be controlled in terms of length, direction or even shape. For example, a curved borehole or each “cluster” of curved boreholes may be intentionally formed to further increase SRV exposure of the formation  3  to the wellbore  4   c . Wellbores may optionally be formed in corkscrew patterns to further expose the formation  3  to the wellbore  4   c.    
     The downhole hydraulic jetting assembly  50  and the methods herein also permit the operator to re-enter an existing wellbore that has been completed in an unconventional formation, and “re-frac” the wellbore by forming one or more lateral boreholes using hydraulic jetting technology. The hydraulic jetting process would use the hydraulic jetting assembly  50  of the present invention in any of its embodiments. There will be no need for a workover rig, a ball dropper/ball catcher, drillable seats or sliding sleeve assemblies. 
     The downhole hydraulic jetting assembly  50  and the methods herein also permit the operator to create a network of lateral boreholes that includes side mini-lateral boreholes formed off of newly-created boreholes. Such a method may include the steps of:
         (a) partially withdrawing the jetting hose and connected nozzle from the first lateral borehole;   (b) identifying a location of the jetting nozzle within the rock matrix;   (c) re-orienting the jetting nozzle; and   (d) injecting hydraulic jetting fluid through the jetting hose and connected jetting nozzle, thereby excavating a first side mini-lateral borehole within the rock matrix in the pay zone off of the first lateral borehole.       

     The method may further comprise:
         (e) withdrawing the jetting hose and connected nozzle from the first side mini-lateral borehole;   (f) repeating steps (a) through (c); and   (g) injecting hydraulic jetting fluid through the jetting hose and connected jetting nozzle, thereby excavating a second side mini-lateral borehole within the rock matrix in the pay zone off of the first mini-lateral borehole.       

     The method may further comprise (h) repeating steps (a) through (g) at least once to form a network of side mini-lateral boreholes, the network being configured to optimize a Stimulated Reservoir Volume (SRV) (i) from a subsequent hydraulic fracturing treatment, (ii) from a subsequent acid treatment, or (iii) both. Alternatively, the method may further comprise:
         (i) repeating steps (a) through (g) at least once to form a network of side mini-lateral boreholes;   (j) injecting fracturing fluids through an annulus formed between the external conduit and the surrounding production casing;   (k) further injecting the fracturing fluids into the network of side mini-lateral boreholes at an injection pressure sufficient to part the rock matrix in the pay zone to form a network of hydraulic fractures; and   (l) monitoring the growth of the network of hydraulic fracture and Stimulated Reservoir Volume (SRV) emanating from the network of mini-lateral boreholes in real time using (i) tiltmeters, (ii) micro-seismic surveys, (iii) ambient micro-seismic surveys, (iv) microphones, or combinations thereof.       

     The method may then include producing hydrocarbon fluids from the network of side mini-lateral boreholes. 
     Based on the downhole hydraulic jetting assembly  50  described above, a unique method of forming a wellbore may be conducted. The method, in one embodiment, includes:
         running a jetting hose into a horizontal section of a parent wellbore using a conveyance medium, the jetting hose having a nozzle at a distal end;   injecting a jetting fluid through the jetting hose and connected nozzle while advancing the jetting hose and connected nozzle into a surrounding formation, thereby forming a first lateral borehole off of the horizontal section from a first wellbore exit location;   withdrawing the jetting hose and connected nozzle from the first lateral borehole at the first wellbore exit location, and re-locating the nozzle to a second wellbore exit location (either by placing a whipstock at a different depth, or by placing the whipstock at the same depth but at a different angular orientation) in the same trip; and   injecting a jetting fluid through the jetting hose and connected nozzle while advancing the jetting hose and connected nozzle into the surrounding formation, thereby forming a second lateral borehole off of the horizontal section from the second wellbore exit location.       

     In this method, advancing the jetting hose into each of the lateral boreholes is done at least in part through a hydraulic force acting on a sealing assembly along (such as at an upstream end of) the jetting hose. Further, the jetting hose is advanced and subsequently withdrawn without coiling or uncoiling the jetting hose in the wellbore. 
     In one embodiment, advancing the jetting hose into each of the lateral boreholes is further done through a mechanical force applied by rotating grippers of a mechanical tractor assembly located within the wellbore, wherein the grippers frictionally engage an outer surface of the jetting hose. 
     In another embodiment, advancing the jetting hose into each of the lateral boreholes is accomplished by forward thrust forces generated from flowing jetting fluid through rearward thrust jets located in the jetting assembly. These rearward thrust jets are specifically located in the jetting nozzle, or in a combination of the nozzle and one or more in-line jetting collars strategically located along the jetting hose. Preferably, the nozzle permits a flow of the jetting fluid through rearward thrust jets in response to a designated hydraulic pressure level. In this instance, the flowing of fluid through the rearward thrust jets is only activated after the jetting hose has advanced into each borehole at least 5 feet from the parent wellbore. The additional rearward thrust jets located in the in-line jetting collar(s) are then activated at incrementally higher operating pressures, typically when the jetting hose has been extended such a significant length from the parent wellbore that the rearward thrust jets within the nozzle alone can no longer generate significant pull force to continue dragging the full length of jetting hose along the lateral borehole. 
     In a related aspect, the method may include monitoring tensiometer readings at a surface. The tensiometer readings are indicative of drag experienced by the jetting hose as lateral boreholes are formed. In this instance, the flowing of fluid through the rearward thrust jets is activated in each of the plurality of boreholes in response to a designated tensiometer reading.