High power umbilicals for subterranean electric drilling machines and remotely operated vehicles

The method of providing in excess of 60 kilowatts of electrical power to the electrical motor of a subterranean electric drilling machine through a substantially neutrally buoyant composite umbilical containing electrical conductors to reduce the frictional drag on the neutrally buoyant umbilical. Drilling and casing subterranean monobore wells are contemplated to distances of 20 miles from a wellsite. For drilling applications, the umbilical possesses a drilling fluid conduit. The umbilical also possesses high speed data communications such as a fiber optic cable or a coaxial cable that is used in the feedback control of the downhole electric drilling motor. Such umbilicals are also useful to provide power to remotely operated vehicles for subsea well servicing applications.

BACKGROUND OF THE INVENTION

1. Field of Invention

The fundamental field of the invention relates to methods and apparatus that may be used to drill and complete wells at great lateral distances from a drill site. The invention may be used to reach any lateral distance from the surface drill site, from close to the drill site, to a maximum radial distance of at least 20 miles from the surface drill site. This is accomplished by using a near neutrally buoyant umbilical that is attached to a subterranean electric drilling machine. The near neutrally buoyant umbilical is capable of providing up to 320 horsepower to do work at lateral distances of at least 20 miles. This drilling application requires near neutrally buoyant umbilicals capable of providing high power at great distances and high speed data communications to and from the surface. The near neutrally buoyant umbilical reduces the frictional drag of the umbilical within the wellbore. To convey drilling equipment to great distances also requires methods and apparatus to move heavy equipment through pipes at relatively high speeds. Similar high power umbilicals having high speed data communications to and from the surface are also useful for providing power and communications to remotely operated vehicles used for subsea service work in the oil and gas industry.

2. Description of the Related Art

The oil and gas industry does not now have the capability to drill horizontally extreme distances of approximately 20 miles to commercially meet some of the challenges that exist today. Industry extended reach-drilling capability is currently between 6 and 7 miles. Conventional drilling rigs using drill pipe and mud motors at shallow angles have established these conventional records. These wells have pushed conventional drilling technologies close to their practical limit and new methods are required for longer offsets.

The industry's lack of a 20 mile drilling capability reduces accessibility to oil and gas reserves. Many areas, both onshore and offshore, have no surface access for development drilling. Onshore, this may be due to urban development as is the case in Holland, national parks or other special areas such as the Arctic National Wildlife Refuge (ANWR), or other land uses that are sensitive to surface drilling operations. Offshore, the incentive is to maximize the use of existing structures and infrastructure by replacing expensive flowlines, manifold and trees. Near shore regions as found in the Santa Barbara Channel, and especially where ice may be present such as in the Arctic or near Sakhalin Island, or where migrating whales may limit seasonal operations provide significant incentives for this new 20 mile drilling capability.

The industry does not have an extreme reach lateral drilling system that is compatible with existing drilling and production infrastructure. If such a system were available, new roads, drill sites, pits, site remediation, permitting, etc. are all avoided in such onshore operations. Offshore, existing host structures will have greatly extended usefulness while reservoirs within 20-mile radii may be developed.

The industry does not have an extreme reach drilling capability that reduces the risk to the environment. If such a system were available, then operating from drilling and production centers would allow using subsurface access to the reservoirs. There would be no surface flowlines or facilities outside the regional drilling and production center. Extreme reach lateral drilling systems could eliminate the need for many of the flowlines on the ocean bottom in a regional development. However, centralized surface operations with fixed facilities require a paradigm shift in development drilling operations. The well drilling and maintenance equipment would not normally be mobile (except offshore on vessels) and it would normally spend its entire working life from one location.

Several references are cited below related to the topics of expandable casing, methods to expand tubulars and casings, fabricating composite umbilicals, and well management systems.

Relevant references to expandable casing includes U.S. Pat. No. 5,667,011, entitled “Method of Creating a Casing in a Borehole”, which issued on Sep. 16, 1997, that is assigned to Shell Oil Company of Houston, Tex., and the following U.S. Patents, entire copies of which are incorporated herein by reference:U.S. Pat. Nos. 5,366,012; 5,348,095; 5,240,074;4,716,965; 4,501,327; 4,495,997;3,958,637; 3,203,451; 3,172,618;3,052,298; 2,447,629; 2,207,478

Other relevant foreign patent documents related to expandable casing include the following, entire copies of which are incorporated herein by reference:S.U. 1,747,673; S.U. 1,051,222; W.O. 93/25799

Another relevant publication related to methods to expand tubulars and casings includes the following, an entire copy of which is incorporated herein by reference:Metcalfe, P. “Expandable Slotted Tubes Offer Well Design Benefits”, Petroleum Engineer International, vol. 69, No. 10 (October 1996), pp 60-63.

Other relevant foreign patent documents related to fabricating composite umbilicals include the following, entire copies of which are incorporated herein by reference:DE 4214383; EP 0024512; EP 352148; EP 505815; GB 553,110; GB 2255994; GB 2270099

Other relevant publications related to fabricating composite umbilicals include the following, entire copies of which are incorporated herein by reference:(a) Fowler Hampton et al.; “Advanced Composite Tubing Usable”, The American Oil & Gas Reporter, pp. 76-81 (September 1997).(b) Fowler Hampton et al.; “Development Update and Applications of an Advanced Composite Spoolable Tubing”, Offshore Technology Conference held in Houston Tex. from May 4th to 7th, 1998, pp. 157-162.(c) Hahan H. Thomas and Williams G. Jerry; “Compression Failure Mechanisms in Unidirectional Composites”, NASA Technical Memorandum pp 1-42 (August 1984).(d) Hansen et al.; “Qualification and Verification of Spoolable High Pressure Composite Service Lines for the Asgard Field Development Project”, paper presented at the 1997 Offshore Technology Conference held in Houston Tex. from May 5th to 8th, 1997, pp. 45-54.(e) Haug et al.,; “Dynamic Umbilical with Composite Tube (DUCT)”, Paper presented at the 1998 Offshore Technology Conference held in Houston Tex. from May 4th to 7th, 1998, pp.699-712.(f) Lundberg et al.; “Spin-off Technologies from Development of Continuous Composite Tubing Manufacturing Process”, Paper presented at the 1998 Offshore Technology Conference held in Houston, Tex. from May 4th to 7th, 1998, pp. 149-155.(g) Marker et al.; “Anaconda: Joint Development Project Leads to Digitally Controlled Composite Coiled Tubing Drilling System”, Paper presented at the SPEI/COTA, Coiled Tubing Roundtable held in Houston, Tex. from 5th to 6th of Apr., 2000, pp. 1-9.(h) Measures R. M.; “Smart Structures with Nerves of Glass”, Prog. Aerospace Sc. 26(4):289-351 (1989).(i) Measures et al.; “Fiber Optic Sensors for Smart Structures”, Optics and Lasers Engineering 16: 127-152 (1992)(j) Poper Peter; “Braiding”, International Encyclopedia of Composites, Published by VGH, Publishers, Inc., 220 English 23rd Street, Suite 909, New York, N.Y. 10010.(k) Quigley et al., “Development and Application of a Novel Coiled Tubing String for Concentric Workover Services”, Paper presented at the 1997 Offshore Technology Conference held in Houston, Tex. from 5th to 8th of May 1997, pp. 189-202.(l) Sas-Jaworsky II and Bell Steve “Innovative Applications Stimulated Coiled Tubing Development”, World Oil, 217(6): 61 (June 1996).(m) Sas-Jaworsky II and Mark Elliot Teel; “Coiled Tubing 1995 Update: Production Applications”, World Oil, 216 (6): 97 (June 1995).(n) Sas-Jaworsky, A. and J. G. Williams, “Advanced composites enhance coiled tubing capabilities”, World Oil, pp. 57-69 (April 1994).(o) Sas-Jaworsky, A. and J. G. Williams, “Development of a composite coiled tubing for oilfield services”, Society of Petroleum Engineers, SPE 26536, pp. 1-11 (1993).(p) Sas-Jaworsky, A. and J. G. Williams, “Enabling capabilities and potential application of composite coiled tubing”, Proceedings of World Oil's 2nd International Conference on Coiled Tubing Technology, pp. 2-9 (1994).(p) Sas-Jaworsky II Alex; “Developments Position CT for Future Prominence”, The American Oil & Gas Reporter, pp. 87-92 (March 1996).(r) Moe Wood T., et al.; “Spoolable, Composite Tubing for Chemical and Water Injection and Hydraulic Valve Operation”, Proceedings of the 11th International Conference on Offshore Mechanics and Arctic Engineering-1992, vol. III, Part A-Materials Engineering, pp. 199-207 (1992).(s) Shuart J. M. et al.; “Compression Behavior of 45°-Dominated Laminates with a Circular Hole of Impact Damage”, AIAA Journal 24(1): 115-122 (January 1986).(t) Silverman A. Seth, “Spoolable Composite Pipe for Offshore Applications”, Materials Selection & Design pp. 48-50 (January 1997).(u) Rispler K. et al.; “Composite Coiled Tubing in Harsh Completion/Workover Environments”, paper presented at the SPE Gas Technology Symposium and Exhibition held in Calgary, Alberta, Canada, on Mar. 15-18, 1998, pp. 405-410.(v) Williams G. J. et al.; “Composite Spoolable Pipe Development, Advancements, and Limitations”, Paper presented at the 2000 Offshore Technology Conference held in Houston Tex. from 1st to 4th of May 2000, pp. 1-16.

A relevant reference for well management systems includes U.S. Pat. No. 6,257,332, entitled “Well Management System”, which issued on Jul. 10, 2001, that is assigned to the Halliburton Energy Services, Inc., an entire copy of which incorporated herein by reference.

Typical procedures used in the oil and gas industries to drill and complete wells are well documented. For example, such procedures are documented in the entire “Rotary Drilling Series” published by the Petroleum Extension Service of The University of Texas at Austin, Austin, Tex. that is included herein by reference in its entirety comprised of the following:Unit I—“The Rig and Its Maintenance” (12 Lessons);Unit II—“Normal Drilling Operations” (5 Lessons);Unit III—Nonroutine Rig Operations (4 Lessons);Unit IV—Man Management and Rig Management (1 Lesson);and Unit V—Offshore Technology (9 Lessons). All of the individual Glossaries of all of the above Lessons in their entirety are also explicitly included herein, and all definitions in those Glossaries shall be considered to be explicitly referenced and/or defined herein.

Additional procedures used in the oil and gas industries to drill and complete wells are well documented in the series entitled “Lessons in Well Servicing and Workover” published by the Petroleum Extension Service of The University of Texas at Austin, Austin, Tex. that is included herein by reference in its entirety comprised of all 12 Lessons. All of the individual Glossaries of all of the above Lessons in their entirety are also explicitly included herein, and any and all definitions in those Glossaries shall be considered to be explicitly referenced and/or defined herein.

Entire copies of each and every reference explicitly cited above in this section entitled “Description of the Related Art” are incorporated herein by reference.

At the time of the filing of the application herein, the applicant is unaware of any additional art that is particularly relevant to the invention other than that cited in the above defined “related” U.S. Patents, the “related” co-pending U.S. Patent Applications, the “related” co-pending PCT Application, and the “related” U.S. Disclosure Documents that are specified in the first paragraphs of this application.

SUMMARY OF THE INVENTION

An object of the invention is to provide high power umbilicals for subterranean electric drilling.

Another object of the invention is to provide high power umbilicals that allow subterranean electric drilling machines to drill boreholes of up to 20 miles laterally from surface drill sites.

Another object of the invention is to provide high power umbilicals that allow the subterranean liner expansion tools to install casings within monobore wells to distances of up to 20 miles laterally from surface drill sites.

Another object of the invention is to provide high power near neutrally buoyant umbilicals for subterranean electric drilling to reduce the frictional drag on the umbilicals.

Yet another object of the invention is to provide a high power near neutrally buoyant umbilical that possesses high speed data communications and also provides a conduit for drilling mud.

Another object of the invention is to provide an umbilical that delivers in excess of 60 kilowatts to a downhole electric motor that is a portion of a subterranean electric drilling machine.

Yet another object of the invention is to provide a novel feedback control of a downhole electric motor that is a part of a subterranean electric drilling machine.

Yet another object of the invention is to provide high power umbilicals to operate subsea remotely operated vehicles.

Another object of the invention is to provide an umbilical to operate a subsea remotely operated vehicle that possesses high speed data communications and provides a conduit for fluids.

Yet another object of the invention is to provide a novel feedback control of a downhole electric motor that comprises a portion of a remotely operated vehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1shows a section view of a preferred embodiment of an umbilical2. In this preferred embodiment, substantial portions of the umbilical are fabricated from one or more composite materials. Consequently umbilical2is also called a composite umbilical. Composite umbilical2provides a connection between the surface and other downhole tools (such as a subterranean electric drilling machine to be described later) which is capable of performing useful work at great distances from a well site. In the preferred embodiment shown inFIG. 1, the umbilical is capable of performing useful work at the distance of 20 miles away from a surface drilling site. This statement means that the umbilical is capable of performing useful work at any distance between 0 miles to 20 miles away from a wellsite. This connection is called an umbilical and it does not rotate like drill pipe and its capabilities are different from those of coiled tubing used in drilling operations.

In particular,FIG. 1shows an umbilical that is substantially neutrally buoyant in any specific density of drilling mud4that is present in a wellbore. The drilling mud4may also be called the drilling fluid. The symbol for the density of drilling mud is ρ(drilling mud). In this particular example of a preferred embodiment, the density of drilling mud present in the wellbore is 12 lbs/gallon.

InFIG. 1, the composite umbilical is partially fabricated from inside pipe6. InFIG. 1, the umbilical has an inside diameter of ID1. In this particular embodiment, the inside diameter ID1 is equal to 4.5 inches. The inside diameter forms a hollow region through which fluids may be sent to, and from downhole. Put another way, the inside diameter forms a conduit through which fluids may be sent from the surface downhole, or from downhole to the surface. Therefore, the umbilical possesses a fluid conduit for conducting drilling fluids through the interior of the umbilical. The fluids present within the inside pipe are shown by element8in FIG.1. The density of the fluids8is defined to be the symbol ρ(umbilical fluid). For example, drilling mud may be sent downhole through the 4.5 inch ID pipe. The ID of this pipe is also called the interior of this pipe. The inside pipe6has wall thickness T1, but this legend is not shown inFIG. 1for brevity. In this preferred embodiment, the wall thickness of the inside pipe T1 is 0.25 inches. The wall of the inside pipe6is made from a composite material. This composite wall may have many layers of different composite materials made of different materials, each layer having a different specific gravity. As an example of one preferred embodiment, the composite material may be a carbon-based composite material. For reasons of simplicity, those layers are not shown in FIG.1. However, there will be an average specific gravity of the interior pipe that is defined to be SG(inside pipe). In this preferred embodiment, the specific gravity of the inside pipe is equal to 1.5.

InFIG. 1, the composite umbilical is partially fabricated from outside pipe10. InFIG. 1, the umbilical has an outside diameter of OD2 and this legend is shown in FIG.1. In this preferred embodiment, the outside diameter OD2 is equal to 6.00 inches O.D. Consequently, the external portion of the composite umbilical appears to be a pipe having the outside diameter of OD2. The outside pipe10has wall thickness T2, but this legend is not shown inFIG. 1for brevity. In this preferred embodiment, the wall thickness of the outside pipe T2 is 0.25 inches. The wall of the outside pipe10is made from a composite material. This composite wall may have many layers of different composite materials made of different materials, each layer having a different specific gravity. In one preferred embodiment, the composite material may be a carbon-based composite material. Those layers are not shown inFIG. 1for simplicity. For example, an outer layer of composite material may be chosen to be particularly abrasion resistant. As one example, the outer layer of composite material may be made of a carbon-based composite material. However, there will be an average specific gravity of the outside pipe that is defined to be SG(outside pipe). In this preferred embodiment, the specific gravity of the outside pipe is equal to 1.5.

As shown inFIG. 1, the interior pipe6is asymmetrical located within the exterior pipe10that forms an the asymmetric volume12between the two pipes. Within the asymmetric volume12between the two pipes are insulated current carrying electric wires designated by the legends A, B, C, D, E, and F in FIG.1. Also shown inFIG. 1is high speed data link14. This high speed data link provides high speed data communications from the surface to downhole equipment, and from the downhole equipment to the surface. High speed data link14is selected from a list including a fiber optic cable, a coaxial cable, and twisted wire cables. In the particular preferred embodiment of the invention shown inFIG. 1, the high speed data link is chosen to be a fiber optic cable. The asymmetric volume12between the two pipes that contains wires A, B, C, D, E, and F, and the fiber optic cable, is otherwise filled with syntactic foam material. This syntactic foam material is often made from silica microspheres that are embedded in a filler material, such as epoxy resin or other composite materials. The syntactic foam material has a specific gravity that is defined as SG(syntactic foam material). In this preferred embodiment of the invention, the specific gravity of the syntactic foam material is 0.825. In this preferred embodiment of the invention, syntactic foam material possessing silica microspheres is provided by the Cumming Corporation. The Cumming Corporation is located at 225 Bodwell Street, Avon, Mass. 02322. The Cumming Corporation can also be reached by telephone at (508) 580-2660 or by the internet at www.emersoncumming.com. The details on the syntactic foam material may be reviewed in detail in Attachment 28 to Provisional Patent Application No. 60/384,964, that has the Filing Date of Jun. 3, 2002, an entire copy of which is incorporated herein by reference. Using silica microspheres in a syntactic matrix provides the necessary buoyancy in high pressure wellbores. The high axial strength of the composite pipe construction compensates for variations in axial loads caused by mud weight and other density variations.

InFIG. 1, wires A, B, C, D, E, and F are 0.355 inches O.D. insulated No. 4 AWG Wire. The insulation is rated at 14,000 volts DC, or 0-peak AC. Wires A, B, and C comprise the first independent three phase delta circuit. Wires D, E, and F comprise the second independent three phase delta circuit. Each separate circuit is capable of providing 160 horsepower (119 kilowatts) over an umbilical length of 20 miles at the temperature of 150 degrees C. So, combined, the umbilical can deliver a total of 320 horsepower (238 kilowatts) at 20 miles to do work at that distance. At 320 horsepower, less than 1 watt per foot of power is dissipated in the form of heat, which makes this a practical design even if the umbilical is completely wound up on an umbilical carousel as shown in a later figure (FIG.4). In this preferred embodiment, wires A, B, C, D, E, and F are No. 4 AWG stranded silver plated copper wire which are covered with insulation rated to 14,000 VDC at 200 degrees C., where each wire has a DC resistance of 0.250 ohms per 1000 feet at the temperature of 20 degrees C., where the nominal outside diameter of each insulated wire is 0.355 inches, and where each wire weighs 180 lbs/1000 feet. Each wire is Part Number FEP4FLEXSC provided by Allied Wire & Cable, Inc. which is located at 401 East 4th Street, Bridgeport, Pa. 19405, which may be reached by telephone at (800) 828-9473. The details on Allied Part Number FEP4FLEXSC may be reviewed in Attachment 27 to Provisional Patent Application No. 60/384,964, that has the Filing Date of Jun. 3, 2002, an entire copy of which is incorporated herein by reference.

If the inside pipe6is carrying 12 lb per gallon mud, and if the exterior pipe is immersed in 12 lb per gallon mud in the well, then the upward buoyant force in the above preferred embodiment of the umbilical is plus 5.9 lbs per 1000 feet of this umbilical. Assuming a coefficient of friction of 0.2, the total frictional “pull-back” on 20 miles of this umbilical is only 124 lbs. This “pull-back” does not include any differential fluid drag forces. This umbilical was chosen to have an extreme length which shows that the essentially neutrally buoyant umbilical overcomes most friction problems associated with umbilicals disposed in wells. For the details of this calculation of a net upward force of 5.9 lbs as described above, please refer to “Case J” of Attachment 34 to Provisional Patent Application No. 60/384,964, that has the Filing Date of Jun. 3, 2002, an entire copy of which is incorporated herein by reference. Those particular calculations were performed on the date of Nov. 12, 2001. In these calculations, the density of water of 62.43 lbs/cubic foot was used to calculate the net forces acting on volumes having particular specific gravities. Please also see other relevant buoyancy calculations in Attachments 29 to 35 of Provisional Patent Application No 60/384,964.

The phrase “substantially neutrally buoyant”, “essentially neutrally buoyant”, “near neutral buoyant”, and “approximately neutrally buoyant” may be used interchangeably. For a substantially neutrally buoyant umbilical, or near neutrally buoyant umbilical, the downward force of gravity on a section of the umbilical of a given length is approximately balanced out by the upward buoyant force of well fluid acting on the umbilical of that given length. The density of mud in the well is strongly influenced by any cuttings from any drilling machine attached to the umbilical (to be described later). Similarly, the density of the fluids inside pipe6may also be strongly influenced by any cuttings from the drilling machine (if reverse flow is used). So, the density of the drilling mud4and the density of fluids present within the pipe8may vary with distance along the length of the umbilical. However, at any position along the length of the umbilical which is disposed in the well, the umbilical may be designed to be “substantially neutrally buoyant”, “essentially neutrally buoyant”, “near neutral buoyant” or “approximately neutrally buoyant”. In addition, using the design principles described herein, the entire length of the umbilical may be designed to be on average “substantially neutrally buoyant”, “essentially neutrally buoyant”, “near neutral buoyant”, or “approximately neutrally buoyant” over the entire length of the umbilical that is disposed within a wellbore.

An umbilical that is “substantially neutrally buoyant”, “essentially neutrally buoyant”, “near neutral buoyant”, or “approximately neutrally buoyant” greatly reduces the frictional drag on the umbilical as it moves in the wellbore. That statement is evident from the following. The net force on a length of umbilical from gravity and buoyant forces is F. The coefficient of sliding friction is k. Therefore, the net “pull back force” P for the given length of the umbilical is given by:
P=Fk  Equation 1.

The requirement of a near neutrally buoyant umbilical greatly reduces the frictional drag on the umbilical as it moves in the wellbore. This is a particularly important point. If an umbilical is “substantially neutrally buoyant”, “essentially neutrally buoyant”, “near neutral buoyant”, or “approximately neutrally buoyant” then the frictional drag on the umbilical is greatly reduced as it moves through the wellbore. There are other details to consider such as the starting friction, any sticky substances in the well, drag due to viscous forces, etc. However, Equation 1 forms the basis for providing high electrical power through umbilicals at great distances such as 20 miles from a drilling site. As stated before in relation to this preferred embodiment, with a net force on 1,000 feet of the umbilical being only plus 5.9 lbs (an upward force), assuming a coefficient of friction of 0.2, the total frictional “pull-back” on 20 miles of this umbilical is only 124 lbs.

The preferred embodiment also calls for other reasonable design requirements on the umbilical. The umbilical needs significant axial strength (to pull the drilling machine from the well in the event of equipment failure downhole as explained later) that would require a 160,000 lbs design load. The umbilical must provide an internal pressure capacity (shut-in pressure capacity of the well) of about 10,000 psi. The collapse resistance of the umbilical must exceed a 6,000 psi differential pressure. The umbilical must have the ability to work in at least 120 degrees C., and preferably, 150 degrees C. Composites are now routinely used at 120 degrees C., and experiments are now being conducted on composites at 150 degrees C. Hollow high-strength glass may replace carbon fiber composites for a cost savings, but there will be a weight penalty, thereby increasing frictional drag.

The umbilical may occasionally be damaged during its use and require field repairs. Repairs will be accomplished by cutting out the damaged part and using field installable end connections to rejoin the intact umbilical sections. The end connections will also join various sections of umbilical that may be stored separately at the surface. These couplings are expected to slightly reduce the ID and increase the umbilical OD.

The particular asymmetric design shown inFIG. 1was selected as a preferred embodiment in part because it illustrates the various considerations necessary to design and build such a high power umbilical that is neutrally buoyant in well fluids. Other more symmetric designs for such an umbilical are shown in another preferred embodiment shown inFIG. 20below. The references cited above in the section entitled “Description of the Related Art” provide the generally known methods used in the industry to construct composite umbilicals.

FIG. 2shows the uphole and downhole power management system for the composite umbilical shown in FIG.1. Wires A, B, and fiber optic cable14, which were identified inFIG. 1, are shown in FIG.2. InFIG. 2, the surface of the earth is shown figurative as element16. Any function shown above element16is identified as an “uphole function”, and any function shown below element16is identified as a “downhole function”.

InFIG. 2, only wires A and B of a first three phase delta circuit are shown. Three phase delta is an AC circuit having three wires (for example A, B, and C), each wire of which carries a an AC current, and there exists a voltage difference between each wire. There exists phase relationships between the current vs. time in each wire. There exits phase relationships between the voltage vs. time in each wire. However, inFIG. 2, wire C is not shown for simplicity. Electrical generator18provides three phase delta power through cable19to variable voltage and frequency converter20. The variable voltage and frequency converter possesses electronics that provides measurement of the voltages, currents and phases of the three phase delta circuit (although that electronics is not shown inFIG. 2for the purposes of simplicity). Electrical power is delivered by wires A and B to the downhole electrical load22. In one preferred embodiment, the electrical load is a downhole electric motor. The voltage, current, the relevant phases, and other parameters of the electrical load are measured with sensing unit24. Sensing unit24is marked with the legend “V” indicating that at least the voltage V is measured between wires A and B at electrical load22. Sensing unit24is attached to the electrical input terminals of the downhole electrical load. If this is a downhole electrical motor, the sensing unit24is attached to the electrical input terminals of the electric motor.

Sensing unit24also possesses suitable electronics that sends the measured downhole information to the surface through optical fiber14. The downhole information is sent by optical fiber14that provides the measured information to computer system26. The measured downhole information is digitized with related instrumentation (not shown for the purposes of simplicity in FIG.2), and the downhole information is forwarded uphole by light pulses sent through the optical fiber14.

InFIG. 2, the computer system26also possesses related electronics to implement the following. The computer system and related electronics provides commands to the variable voltage and frequency converter20by electronic feedback loop28to provide the necessary voltage, current, phases, and frequency as required by the downhole load22. Consequently,FIG. 2shows a closed-loop, dynamic feedback system, where downhole load parameters are measured, the information is sent uphole, and the uphole system is automatically adjusted to provide what is required to properly operate the electrical load. The point is that the feedback loop28from computer20is used to produce the required frequency, voltage, current and phases required by the downhole load22. This is an example of the feedback control of the downhole load22, which may be a downhole electric motor in several preferred embodiments.

In an alternative embodiment of feedback control, the feedback loop from computer26inFIG. 2is used to control the RPM of a motor generator whose 0-peak output voltage may be easily varied, which provides conveniently controlled frequency and voltage outputs, although that minor variation of the preferred embodiment is not shown in a separate figure for the purposes of brevity. In this case, the feedback loop from computer26is first used to control the RPM of the motor, and is also used for the second purpose to control the output voltage, frequency, and phase from the generator attached to the motor which makes the motor generator assembly.

Additional measured downhole load parameters are also sent uphole through the optical fiber. For example, in one preferred embodiment, element22inFIG. 2is an electrical motor, and as an example, the measured RPM, the current drawn by the motor through its input terminals, the voltage across its input terminals, and the phases of the voltages and current vs. time, the temperature, torque, etc. of that electrical motor can be sent uphole through the optical fiber14. In other preferred embodiments, the electrical load22is a submersible electric drilling machine, and in another embodiment, the electrical load is a remotely operated vehicle.

The system shown inFIG. 2controls a first three phase delta circuit that energizes wires A, B, and C inFIG. 1. Asecond similar system to that shown inFIG. 2controls the power derived to wires D, E and F from a second three phase delta circuit. For simplicity, the second three phase delta circuit is not shown in FIG.2. Such a system is capable of delivering 320 horsepower through an umbilical disposed in a wellbore shown inFIG. 1that has a length of up to 20 miles. This is important, because most of the available motors for downhole use are AC motors, and are not DC motors.

The AC power management system shown inFIG. 2has at least several advantages. First, DC voltages are not used which would generally require a “chopper” to convert DC to AC to operate most currently available downhole electric motors. Such high power choppers are complex, often large, and generate considerable heat. Second, no downhole transformer is necessary because of the active closed-loop feedback system shown in FIG.2.

However, the basic feedback control of downhole parameters as such as voltage and current are also useful for a DC power management system for DC electric motors that can be used in a subterranean electric drilling machine. Accordingly, another preferred embodiment of the invention is controlling DC voltages with an analogous system as outlined in FIG.2.

FIG. 3shows how three phase power of 160 horsepower (119 kilowatts) can be delivered through the electrical conductors inFIGS. 1 and 2to distances of 20 miles. This means that this power can be delivered from 0 miles to 20 miles away from a drill site for example. Two “legs” of the three phase delta circuit are shown inFIG. 3as wires A and B (wire C of the three phase delta circuit is not shown for simplicity). The resistances of a length of 20 miles of the wire is simulated with resistors having the magnitude of resistance in ohms of “R1”. The legend “R1” appears in FIG.3. These two resistors are also respectively labeled as elements30and32. In a preferred embodiment, the load at the end of the umbilical is simulated with a downhole electric motor34requiring 2,500 volts 0-peak at 45 amps 0-peak between any two wires of the three phase wiring system operating at 60 Hz. As a practical case, this “downhole motor” could in principle be comprised of two each REDA, 4 Pole Motors, each requiring 1250 volts 0-peak, at 45 amps 0-peak, having a nominal RPM of about 1700 RPM. The current flowing through wires A and B is represented by the legend I(t) in FIG.3. This required motor voltage is represented by the legend VM(t). The closed-loop, dynamic feedback system described inFIG. 2automatically and continuously adjusts the voltage provided downhole to the motor that is measured with sensing unit24in FIG.2. In this preferred embodiment, typically, the variable voltage and frequency converter20inFIG. 2provides 6,182 volts 0-peak and provides 45 amps 0-peak between any two legs of the three phase circuit. The supplied voltage is represented by element36in FIG.3. The voltage supplied by the voltage and frequency converter20is represented by the legend VS(t) in FIG.3. The point of this is that using the above described feedback system and reasonable gauge wiring, it is possible to actually deliver 160 horsepower (119 kilowatts) at a distance of 20 miles.

FIG. 3shows a first independent circuit that provides 2,500 volts 0-peak to a load, a motor in this preferred embodiment, at distances of up to 20 miles between wires A, B, and C respectively, and the motor may draw up to 45 amps 0-peak between any pairs of wires, A-B, B-C, or C-A. A second independent circuit, that is not shown for simplicity, also provides 2,500 volts 0-peak to another motor at distances to 20 miles between wires D, E, and F respectively, and that motor may also draw up to 45 amps 0-peak from any wire D,E, and F. Such voltages and currents are necessary for two series operated REDA 4 Pole Motors, each rated for 80 Horsepower (as shown in a later figure, FIG.8). REDA is a manufacturer called “Reda Div. Camco International, Inc.” that may be reached at 4th & Dewey, Bartlesville, Okla. 74005, having the telephone number of (918) 661-2000, that has a website that may be reached through www. schlumberger. com.

In summary, the umbilical2inFIG. 1must carry high power and high speed communications (320 hp—two circuits of 160 hp each—and fiber optic communications). An A.C. voltage, transformerless, downhole electrical power arrangement is used. The input power and voltage are managed topside to maintain constant downhole load voltage. In one preferred embodiment, one of the two circuits is dedicated to the downhole mud pump (or Smart Shuttle™) service, while the second circuit operates other Downhole Rig™ functions such as the rotation and weight loading of a drilling bit, which will be described in later figures. In various preferred embodiments, the various downhole motors feature soft start controls allowing the topside power supply to reliably track power demand.

In the above preferred embodiment, a three phase delta power circuit is used. In principle, any electrical power system may be used including 208 Y and related power systems, and ordinary single phase power systems.

FIG. 4shows an umbilical carousel in the process of being constructed. This equipment is similar to flexible pipe handling equipment now used in the industry. A first carousel flange38possesses interior spokes40that forms the inside diameter of the umbilical carousel. Wound on those interior spokes is the umbilical42. A second carousel flange (not shown) encloses the wound up umbilical, although it not shown in the interest of brevity. In one preferred embodiment, the umbilical42is the same umbilical as shown inFIG. 1that is 6 inches OD. The umbilical may be stored and operated as a single line. However, the umbilical is preferably divided into several smaller lengths, as an example 5 miles each, and stored on smaller carousals or drums to reduce the fluid friction losses as compared to one 20-mile continuous length. A level wind is provided on each carousel to correctly wrap the pipe as it is pulled from the well and returned to the carousel for storage.

Each carousel holding 5 miles of the 6 inch OD umbilical is approximately 8 ft tall with an outside diameter of 22 ft. The mud filled umbilical weighs approximately 234 tons. Unless this equipment is installed on offshore vessels, it is not easily moved. For this reason, drilling centers where the rig is assembled are expected to use the equipment over its useful life. Such carousals may be supplied by Coflexip Stena Offshore, Inc. located at 7660 Woodway, Suite 390, Houston, Tex. 77063, having the telephone number (713) 789-8540, which has its website at www.coflexip.com. Such carousals may also be supplied by Oceaneering International, Inc. located at 11911 FM 529, Houston, Tex. 77401, having telephone number (713) 329-4500, which has its website at www.oceaneering.com.

Much surface equipment is needed in support of handling the umbilical. This surface equipment is briefly described in the following. Much of this equipment may be supplied by a firm located in Holland called Huisman-Itrec, that may be located at Admiraal Trompstraat 2—3115 HH Schiedam, P.O. Box 150—3100 AD Schiedam, The Netherlands, Harbour No. 561, having the telephone number of 31(0) 10 245 22 22, that has its website at www.Huisman-Itrec.com.

Stripper heads and surface blow-out preventers (BOP's) provide an OD pressure seal to the umbilical, although no figures are provided to show this feature for simplicity. This equipment has a similar function to a coiled tubing stripper head, except it handles the larger umbilical OD sizes. In practice, the actual sealing element is expected to be dual 13 ⅝″ annular stripping BOPs with grease injection to lubricate the sealing elements as the umbilical moves through the sealing elements. This approach of dual stripping units allows the umbilical mechanical couplings to be transitioned into the well. The surface BOPs provide for surface well control in the event of a well kick. These (shear, pipe & blind ram) BOPs will be located between the wellhead and the stripping annular units.

An injector unit is required on the surface, although no figure is shown for simplicity. A 100-ton linear traction unit is preferred for this application. The injection unit provides drilling umbilical pushing and pulling loads at speeds to 10 feet per second. The maximum loads will be at low speeds. Speed will be limited by mudflows within the wellbore. This injector unit has a function similar to a coiled tubing injector but practically is closer in size and performance to a pipeline tensioner used to lay flexible pipe. Similar units are used for the handling and installation of flexible pipe by such firms as Coflexip Stena Offshore, Inc.; Wellstream, Inc.; and NKT Flexibles I/S. The address of Coflexip Stena Offshore, Inc. has been provided above. Wellstream, Inc. is a subsidiary of Halliburton Energy Services, and may be reached at 10200 Bellaire Boulevard, Houston, Tex. 77072-5299, having the telephone number of (281) 575-4033. NKT Flexibles I/S is a firm located in Denmark having the address of Priorparken 510, DK-2605 Broendby, Denmark, having the telephone of 45 43 48 30 00, that has its website at www.nktflexibles.com.

A surface mud system is required for the umbilical, although no figures showing this feature are provided for the sake of brevity. A large volume of working mud will be needed to manage the umbilical volume while tripping in the hole. For 20-mile offset operations, an active mud tank volume of 3,500 barrels may be required. This is similar to some large offshore drilling rigs in capacity. A minimum of two 750 hp surface mud pumps will be required for the preferred embodiment. The other details concerning the mud system will be presented in relation to a forthcoming figure (FIG.14).

A surface rig is needed to support umbilical and casing operations, although no figure is presented showing this detail in the interests of brevity. The surface rig handles and makes-up the casing as it is run into the hole. In many respects, it is similar to conventional coiled tubing drilling rigs, except it is much larger in size. During drilling operations, the best method for joining expandable casing is continuing to develop. Enventure Global Technology is developing an expandable threaded joint. Enventure also has commercially available various sizes of expandable pipes and can supply various means of joining lengths of the expandable pipe. Enventure Global Technology may be reached at 16200-A Park Row, Houston, Tex. 77084, having the telephone number of (281) 492-5000, that has its website at www.EnventureGT.com. Other alternatives of joining expandable is to weld long casing strings (similar to J-laying pipelines). The arrangement of surface rig equipment is compatible with both alternatives.

FIG. 5shows a computerized uphole management system for the umbilical. It is a portion of a preferred embodiment of an automated system to drill and complete oil and gas wells. It is also a portion of a preferred embodiment of a closed-loop system to drill and complete oil and gas wells.FIG. 5shows the computer control of the umbilical carousel in a preferred embodiment of the invention.

InFIG. 5, computer system26(previously described inFIG. 2) has typical components in the industry including one or more processors, one or more non-volatile memories, one or more volatile memories, many software programs that can run concurrently or alternatively as the situation requires, etc., and all other features as necessary to provide computer control of all of the uphole functions. In this preferred embodiment, this same computer system26also has the capability to acquire data from, send commands to, and otherwise properly operate and control all downhole functions. Therefore LWD and MWD data is acquired by this same computer system when appropriate. As a consequence, in one preferred embodiment, the computer system26has all necessary components to interact with a subterranean electric drilling machine. In a “closed-loop” operation of the system, information obtained downhole from the downhole system is sent to the computer system that is executing a series of programmed steps, whereby those steps may be changed or altered depending upon the information received from the downhole sensor located within the downhole system.

InFIG. 5, the computer system26has a cable44that connects it to display console46that has one or more display screens. The display console46displays data, program steps, and any information required to operate the entire uphole and downhole system. The display console is also connected via cable48to alarm and communications system50that provides proper notification to crews that servicing is required. Data entry and programming console52provides means to enter any required digital or manual data, commands, or software as needed by the computer system, and it is connected to the computer system via cable54.

InFIG. 5, computer system26provides commands over cable56to the electronics interfacing system58that has many functions. One function of the electronics interfacing system is to provide information to and from any downhole load through cabling60that is connected to the slip-ring62, as is typically used in the industry. Another function of the electronics interfacing system is to provide power to any downhole load through cabling60that is connected to the slip-ring62. The slip-ring62is suitably mounted on the side of the assembled umbilical carousel64in FIG.5. Information provided to slip-ring62then proceeds to wires A, B, C, D, E, F, and G within the umbilical wound up on the umbilical carousel. The umbilical66proceeds to an sheave and tensioner device68and then the umbilical proceeds downward at location70towards the injection unit and on to the stripper heads and surface blow-out preventers (BOP's). The sheave an tensioner device68may place appropriate tension on the umbilical as required.

InFIG. 5, electronics interfacing system58also provides power and electronic control of the hydraulic system72that controls the umbilical carousel through the connector at location74. Cabling76provides the electrical connection between the electronics interfacing system58and the hydraulic system72that controls the umbilical carousel. In addition, electronics interfacing system58has output cable78that provides commands and control to the drilling rig hardware control system80that controls various drilling rig functions and apparatus including the rotary drilling table motors, the mud pump motors, the pumps that control cement flow and other slurry materials as required, and all electronically controlled valves, and those functions are controlled through cable bundle82which has an arrow on it inFIG. 5to indicate that this cabling goes to these enumerated items.

In relation toFIG. 5, electronics interfacing system58also has cable output84to ancillary surface transducer and communications control system86that provides any required surface transducers and/or communications devices required for communications with the downhole equipment. In a preferred embodiment, ancillary surface and communications system86provides acoustic transmitters and acoustic receivers as may be required to communicate to and from certain downhole equipment. The ancillary surface and communications system86is connected to the required transducers, etc. by cabling88that has an arrow inFIG. 5designating that this cabling proceeds to those enumerated transducers and other devices as may be required. Electrical generator18provides three phase delta power to variable voltage and frequency converter20by cable90. The output from the voltage and frequency converter20is provided by cable92to the electronics interfacing system58. Power to wires A, B, C, D, E, F, and G, and signals to the fiber optic cable14(not shown inFIG. 5, but which are defined inFIG. 1) are provided from the electronics interfacing system58through cabling60that is connected to the slip-ring62. The cabling60and the slip-ring provide the suitable electrical and fiber optic connections. Cabling60possesses connection to wires A, B, C, D, E, F, and G, and to the fiber optic cable14. In certain preferred embodiments, there are two separated generators and voltage and frequency converters to independently control to first three phase delta system having wires A, B, and C, and the second thee phase delta system having wires D, E, and F.

With respect toFIG. 5, and to the closed-loop system to drill and complete oil and gas wells, standard electronic feedback control systems and designs are used to implement the entire system as described above, including those described in the book entitled “Theory and Problems of Feedback and Control Systems”, “Second Edition”, “Continuous(Analog) and Discrete(Digital)”, by J. J. DiStefano III, A. R. Stubberud, and I. J. Williams, Schaum's Outline Series, McGraw-Hill, Inc., New York, N.Y., 1990, 512 pages, an entire copy of which is incorporated herein by reference. Therefore, inFIG. 5, the computer system58has the ability to communicate with, and to control, all of the above enumerated devices and functions that have been described to this point.

To emphasize one major point inFIG. 5, computer system26has the ability to receive information from one or more downhole sensors for the closed-loop system to drill and complete oil and gas wells. This computer system executes a sequence of programmed steps, but those steps may depend upon information obtained from at least one sensor located within the downhole system. This computer system provides the automatic control of the umbilical and any uphole and downhole functions related to the deployment of that umbilical.

FIG. 6generally shows the subterranean electric drilling machine94that is disposed within a previously installed borehole casing96that is surrounded by existing downhole cement98. The previously installed casing ends at location100. The inside diameter of the previously installed casing is defined as “ID Casing”, but this legend is not shown onFIG. 6for simplicity. The outside diameter of the previously installed casing is defined as “OD Casing”, but this legend is not shown onFIG. 6for simplicity. The wall thickness of the previously installed casing is defined as “WT Casing”, but this legend is not shown inFIG. 6for simplicity. The previously installed casing is located within a geological formation102.

As shown inFIG. 6, the subterranean electric drilling machine is in the process of drilling a new borehole104into the geological formation. Pilot bit106is shown drilling the pilot hole108. The OD of the pilot bit is defined as “OD Pilot Bit”, but that legend is not shown inFIG. 6for brevity. The ID of the pilot hole is defined as “ID Pilot Hole”, but that legend is not shown inFIG. 6for brevity. Undercutters110and112expand the new borehole to full diameter. The OD of the undercutters110and112when in the fully extended position is defined as “OD Undercutters”, but that legend is not shown inFIG. 6for the purpose of brevity. The overall ID of the new borehole so drilled is defined to be “ID of New Hole”, but that legend is not shown inFIG. 6for the purposes of brevity. The pilot bit106and the undercutters110and112together form the entire “drill bit” of this assembly. This drill bit is an example of an “expandable drill bit”, also called a “retrievable drill bit”, that is also called a “retractable drill bit”. The following references describe such drill bits: U.S. Patents: U.S. Pat. No. 3,552,508, C. C. Brown, entitled “Apparatus for Rotary Drilling of Wells Using Casing as the Drill Pipe”, that issued on Jan. 5, 1971, an entire copy of which is incorporated herein by reference; U.S. Pat. No. 3,603,411, H. D. Link, entitled “Retractable Drill Bits”, that issued on Sep. 7, 1971, an entire copy of which is incorporated herein by reference; U.S. Pat. No. 4,651,837, W. G. Mayfield, entitled “Downhole Retrievable Drill Bit”, that issued on Mar. 24, 1987, an entire copy of which is incorporated herein by reference; U.S. Pat. No. 4,962,822, J. H. Pascale, entitled “Downhole Drill Bit and Bit Coupling”, that issued on Oct. 16, 1990, an entire copy of which is incorporated herein by reference; and U.S. Pat. No. 5,197,553, R. E. Leturno, entitled “Drilling with Casing and Retrievable Drill Bit”, that issued on Mar. 30, 1993, an entire copy of which is incorporated herein by reference. Some experts in the industry call this type of drilling technology to be “drilling with casing”. For the purposes herein, the terms “retrievable drill bit”, “retrievable drill bit means”, “retractable drill bit” and “retractable drill bit means” may be used interchangeably. The combination of the pilot bit and retractable drill bit may also be replaced under certain circumstances with a bicenter drill bit. The retrievable drill bits and the bicenter bits are rotary drill bits.

When the undercutters110and112are retracted into their closed positions, then they can be pulled through the unexpaded casing, and then the entire subterranean electric drilling machine can removed from the previously installed casing because in their retracted positions, the OD of the undercutters is less than the ID of the expandable casing and the ID of the previously installed casing. However, when the undercutters are in their extended position as shown inFIG. 6, the subterranean electric drilling machine is used to drill the new borehole.

The downhole electric motor114of the subterranean drilling machine obtains its electrical energy from umbilical116. The downhole electric motor114is a rotary motor. In one preferred embodiment, the umbilical is the lower end of the particular composite umbilical that is shown in FIG.1. Various electrical wires and connectors along the length of the subterranean electric drilling machine conduct electrical power from the umbilical to the downhole electric motor (which are designated figuratively by element118which is not shown inFIG. 6for the purposes of brevity). Downhole electric motor114also possesses internal sensors indicating the voltages between various inputs to the motor, the current drawn by various inputs to the motor, the power consumed by the motor, the temperature of the motor, the RPM of the motor, the torque delivered by the motor, etc. That information is digitized, sent thorough suitable electrical circuitry and connectors along the length of subterranean drilling machine (designated figuratively by element120which is not shown inFIG. 6for brevity), which digital information is then sent uphole through the fiber optical cable14within the umbilical in the form of suitable light pulses. Commands from the surface are also send downhole through the same bidirectional communications path. Such commands including changing RPM of the motor, etc.

The downhole electric motor has an output shaft which is figuratively designated by element122, which is not shown inFIG. 6for brevity. Electric motor output shaft122proceeds through the swivel and seal unit124to turn rotary shaft125which in turn rotates the undercutters110and112and the pilot bit106. Rotary shaft125is also called the “drilling work string” or simply the “drill pipe”. In this preferred embodiment, the undercutters110and112, and the pilot bit106comprise the “drill bit”. Therefore, in this preferred embodiment, electrical energy provided by umbilical116to downhole electric motor114rotates the drill bit and bores the new borehole104into the geological formation.

InFIG. 6, expandable casing126generally surrounds rotary shaft125. Expandable casing is described in various references in the above section entitled “Description of the Related Art”. The initial OD of the expandable casing (before expansion) is defined to be “Initial OD of Expandable Casing”, but that legend is not shown inFIG. 6for brevity. The initial ID of the expandable casing (before expansion) is defined to be “Initial ID of Expandable Casing”, but that legend is not shown inFIG. 6for brevity. The initial wall thickness of the expandable casing (before expansion) is defined to be the “Initial WT of Expandable Casing”, but that legend is not shown inFIG. 6for brevity. The length of the expandable casing126is defined to be “Length of Expandable Casing”, but that legend is not shown inFIG. 6for brevity. The Length of the Expandable Casing can be quite long, and in one preferred embodiment can be at least several thousand feet long. In such a situation, the length of the rotary shaft125would be approximately the same length.

InFIG. 6, the length of the submersible electric drilling machine is defined to be “Length of Submersible Electric Drilling Machine”, but that legend is not shown inFIG. 6for brevity. The Length of the Expandable Casing can be much longer than the Length of Submersible Electric Drilling Machine. The broken lines128inFIG. 6indicate that the Length of the Expandable Casing can be quite long compared to the Length of the Submersible Electric Drilling Machine. The various elements inFIG. 6are not in proportion.

InFIG. 6, the expandable casing126is attached to the casing hanger130. The casing hanger is shown inFIG. 7, and will be described in detail below. A portion of the casing hanger is surrounded by casing hanger seal132. The casing hanger setting tool134is located within the casing hanger130. When the new borehole104has been completed, the casing hanger setting tool134is used to expand the casing hanger so that it can make positive hydraulic and mechanical contact to the interior of the previously installed downhole casing that is adjacent to the casing hanger seal.FIG. 10below shows the casing hanger after it has been expanded with the casing hanger setting tool, but that will be described in detail in relation to that FIG.10.FIG. 12below also shows the casing hanger after it has been expanded with the casing hanger setting tool, but that will be described in detail in relation to that FIG.12.

Drilling operations typically require means to directionally drill, means to determine the location and direction of drilling, and means to perform measurements of geological formation properties during the drilling operations. Tool section136provides the rotary steering device for directional drilling and the LWD/MWD instrumentation packages. Here LWD means “Logging While Drilling” and “MWD” means “Measurement While Drilling”. Typically, MWD instrumentation provides at least the location and direction of drilling. The LWD instrumentation provides typical geophysical measurements which include induction measurements, laterolog measurements, resistivity measurements, dielectric measurements, magnetic resonance imaging measurements, neutron measurements, gamma ray measurements; acoustic measurements, etc. This information may be used to determine the amount of oil and gas within a geological formation. Power for this instrumentation is obtained from the umbilical116.

InFIG. 6, various electrical wires and connectors along the length of the subterranean electric drilling machine conduct electrical power from the umbilical to the rotary steering device and to the MWD/LWD instrumentation (which are designated figuratively by element138which are not shown inFIG. 6for the purposes of brevity). The sensors on the direction steering device and the MWD and LWD instrumentation provide information that is digitized, sent thorough suitable electrical circuitry and connectors along the length of subterranean drilling machine (designated figuratively by element139which is not shown inFIG. 6for brevity), which digital information is then sent uphole through the fiber optical cable14within the umbilical in the form of suitable light pulses. Commands from the surface are also send downhole through the same bidirectional communications path. For example, commands to change the direction of drilling may be sent downhole through this bidirectional communications path.

InFIG. 6, first anchor and weight on bit mechanism (AWOBM)140and second anchor and weight on bit mechanism (AWOBM)142selectively anchor the subterranean electric drilling machine and provide suitable weight on bit for drilling purposes. First AWOBM possesses anchor means144and146. Second AWOBM possesses anchor means148and150. This is an example of a tandem anchor system. In one preferred embodiment, the tandem anchor means144,146,148and150are comprised of inflatable packer-like elements.

InFIG. 6, first shaft152couples second AWOBM to the downhole electric motor114. In one preferred embodiment, the first shaft152is of fixed length. In another preferred embodiment, first shaft152is an extensible shaft. Mud flow channel154is shown inFIG. 6that will be more fully described later.

InFIG. 6, second shaft156couples the first AWOBM to the second AWOBM. Second shaft156is an extensible shaft. In one preferred embodiment, first AWOBM can move itself with respect to one end of the second shaft156, and second AWOBM can also move itself with respect to the opposite end of shaft156. In one embodiment, simple electric motor operated threaded screws and nuts suitably coupled to second shaft156are used to provide such motion. Those threaded screws, nuts, and electric motors are not shown inFIG. 6for the propose of simplicity. For other examples of related mechanisms, please refer to the following references: (a) Roy Marker, et al., in the paper entitled “Anaconda: Joint Development Project Leads to Digitally Controlled Composite Coiled Tubing Drilling System”, SPE 60750, presented at the SPE/ICoTA Coiled Tubing Roundtable, Houston, Tex., Apr. 5-6, 2000, and particularly inFIG. 8entitled “Tractor-driven BHA”, an entire copy of which is incorporated herein by reference; and (b) U.S. Pat. No. 5,794,703 that issued on Aug. 18, 1998 that is entitled “Wellbore Tractor and Method of Moving an Item Through a Wellbore”, an entire copy of which is incorporated herein by reference.

First anchor and weight on bit mechanism (AWOBM)140and second anchor and weight on bit mechanism (AWOBM)142provide extension mechanisms with electric powered assemblies that are used to advance the casing and provide bit weight during drilling operations. These mechanisms also resist the drilling torque of the bit by anchoring the rotary motor. In a preferred embodiment, the anchor packers are inflated and deflated with motor driven progressing cavity pumps. Using dedicated PCPs simplifies controls and valves to operate the mechanism.

First anchor and weight on bit mechanism (AWOBM)140and second anchor and weight on bit mechanism (AWOBM)142are high strength anchor assemblies which provide axial load capacity at a relative slow axial advance rate. Should the suspended casing weight (in the vertical wellbore) during casing running procedures exceed the umbilical strength rating, then this mechanism may be used to lower the casing into the near horizontal wellbore.

InFIG. 6, various electrical wires and connectors along the length of the subterranean electric drilling machine conduct electrical power from the umbilical to the first anchor and weight on bit mechanism (AWOBM)140and to the second anchor and weight on bit mechanism (AWOBM)142(which are designated figuratively by element160which are not shown inFIG. 6for the purposes of brevity). The first anchor and weight on bit mechanism (AWOBM)140and second anchor and weight on bit mechanism (AWOBM)142have many sensors including force sensors, torque sensors, position sensors, speed sensors, etc. Information from these sensors are sent thorough suitable electrical circuitry and connectors along the length of subterranean drilling machine (designated figuratively by element162which is not shown inFIG. 6for brevity), which digital information is then sent uphole through the fiber optical cable14within the umbilical in the form of suitable light pulses. Commands from the surface can also be sent downhole through this bidirectional communications path. For example, detailed commands can be sent to change the locations of first AWOBM140and second AWOBM142or to change the effective load placed on the drilling bit by these mechanisms.

InFIG. 6, first mud cuttings and bypass port (MCBP)164allows mud and drill cuttings to pass by the first AWOBM140. Second mud cutting and bypass port (MCBP)166allows mud and drill cutting to pass by the second AWOBM142. These are electrically operated ports. Various electrical wires and connectors along the length of the subterranean electric drilling machine conduct electrical power from the umbilical to the first MCBP and to the second MCBP (which are designated figuratively by element168which are not shown inFIG. 6for the purposes of brevity). The first MCBP and to the second MCBP have many sensors providing temperature, pressure, etc. The information from these sensors are sent through suitable electrical circuitry and connectors along the length of subterranean drilling machine (designated figuratively by element170which is not shown inFIG. 6for brevity), which digital information is then sent uphole through the fiber optical cable14within the umbilical in the form of suitable light pulses. Commands from the surface can also be sent downhole through this bidirectional communications path. For example, detailed commands can be sent to close first MCBP and to the second MCBP to prevent a well blow-out.

InFIG. 6, mud carrying shaft172is attached to the first AWOBM by housing174. The female side of universal mud and electrical connector176is attached to the male side of universal mud and electrical connector178. Progressing cavity pump180is driven by a downhole pump motor assembly generally designated by element182. A progressing cavity pump is abbreviated as a “PCP”. Progressing cavity pump180also includes an integral flexible shaft as is typical in the industry. In one preferred embodiment, the downhole pump motor assembly generally designated by element182is comprised of protector184; first 80 horsepower electric motor186requiring 1250 volts at 45 amps that runs at the nominal RPM of 1700 RPM; second 80 horsepower electric motor188requiring 1250 volts at 45 amps that also runs at the nominal RPM of 1700 RPM; universal motor base190; gearbox protector192; and gearbox194having a 4:1 reduction. The downhole pump motor assembly and a portion of the progressing cavity pump180is covered by shroud196.

Various electrical wires and connectors along the length of the subterranean electric drilling machine conduct electrical power from the umbilical to the downhole pump motor assembly (which are designated figuratively by element198which are not shown inFIG. 6for the purposes of brevity). The subterranean electric drilling machine has has many sensors including voltage sensors, current sensors, torque sensors, temperature sensors, RPM sensors, etc. The information from these sensors are sent thorough suitable electrical circuitry and connectors along the length of subterranean drilling machine (designated figuratively by element200which is not shown inFIG. 6for brevity), which digital information is then sent uphole through the fiber optical cable14within the umbilical in the form of suitable light pulses. Commands from the surface can also be sent downhole through this bidirectional communications path. For example, detailed commands can be sent to change the the RPM of first electric motor186and second electric motor188.

FIG. 6also shows three-way valve202. This three-way valve is used to change the direction of mud flow inside the subterranean electric drilling machine. The functions of the three way202valve will be described below.

FIG. 6also shows umbilical mud valve204. This mud valve is used to shut off mud flow, or otherwise prevent well blow-outs. The mud valve204has a total of three positions: (a) open, namely it allows mud to flow through as shown inFIG. 6; (b) stop (not allow any mud to flow straight through); and (c) vent to the annulus between the umbilical116and the ID of the previously installed casing212so that cement or cuttings can be cleaned from within the umbilical (which state is not shown inFIG. 6for simplicity).

Various electrical wires and connectors along the length of the subterranean electric drilling machine conduct electrical power from the umbilical to three-way valve202and to the umbilical mud valve204(which are designated figuratively by element206which are not shown inFIG. 6for the purposes of brevity). The three-way valve202and the umbilical mud valve204possess many sensors including pressure sensors, voltage sensors, current sensors, and temperature sensors, etc. The information from these sensors are sent thorough suitable electrical circuitry and connectors along the length of subterranean drilling machine (designated figuratively by element208which is not shown inFIG. 6for brevity), which digital information is then sent uphole through the fiber optical cable14within the umbilical in the form of suitable light pulses. Commands from the surface can also be sent downhole through this bidirectional communications path. For example, detailed commands can be sent to change set the three-way valve202into any position, or to close, or open, umbilical valve204.

In addition, Smart Shuttle™ seal210is shown in FIG.6. Smart Shuttle seal210is attached to a portion of shroud180. For the purposes of succinct reference within this disclosure, the above entire list of Provisional Patent Applications, the U.S. Patents that have issued, the Pending U.S. Patent Applications that appear under the title of “Cross-References to Related Applications”, the foreign pending Patent Applications under “Related PCT Applications”, and the above U.S. Disclosure Documents under of “Related U.S. Disclosure Documents”, all having William Banning Vail III as at least one of the inventors, is owned by the firm Smart Drilling and Completion, Inc. (“SDCI”), and therefore this intellectual property is defined herein to be the “SDCI Intellectual Property” or simply “SDCI IP” as an abbreviation. Smart Drilling and Completion, Inc. may be reached at 3123-198th Place S.E., Bothell, Wash. 98012, having the telephone number of (425) 486-8789, that has the website of www.Smart-Drilling-and-Completion.com. The Smart Shuttle is extensively described in the above defined “SDCI IP”. The principal of operation of the Smart Shuttle is also described below in relation to FIG.24. The shroud196extends to the left inFIG. 6so that the Smart Shuttle™ seal210is installed on a portion of that shroud.

In a preferred embodiment shown inFIG. 6. Areverse mud circulation system has been configured with the umbilical in the wellbore. Fresh mud travels from the surface down the annuli between the well casing and the umbilical designated by element212. The right-hand side ofFIG. 6is “down” in FIG.6. Fresh mud travels down from the surface as indicated by various arrows throughout the subterranean drilling machine. Clean mud then flows through the interior of the shroud214to the three-way valve202. In one preferred embodiment, the three-way valve directs mud into the input of the progressing cavity pump so that the pump boosts the pressure of the mud delivered to the drill bit. This is called “Position A” of the three-way mud valve. The detailed tubing and other hardware necessary to accomplish the details of “Position A” is not shown inFIG. 6for the purpose of simplicity. In “Position A”, clean mud then flows through the interior of the male side of universal mud and electrical connector178; then through the female side of universal mud and electrical connector176; then through mud carrying shaft172; then through mud flow channel158; then through the interior of second shaft156; then through mud flow channel154; then through the interior of first shaft152; then through the swivel and seal unit124; then through rotary shaft125; and then through the mud channels in pilot bit108.

InFIG. 6, cuttings laden mud then returns to the surface through the following path. The cuttings laden mud flows up between the outside diameter of the expandable casing126and the inside diameter of the new borehole104; then through the second mud cutting and bypass port (MCBP)166; then through the first mud cuttings and bypass port (MCBP)164; then through the volume between the exterior of the shroud196and the ID of the previously installed borehole casing96; then through cross-over system216; and then into umbilical116and through the umbilical mud valve204and then to the surface of the earth through the remainder of the umbilical disposed in the wellbore.

Cuttings laden mud returns to the surface flowing through the ID of the umbilical. The purpose is to keep the wellbore clean. The subterranean electric drilling machine94may be recovered to the surface while cuttings and mud fill the umbilical. Time to circulate the umbilical clean is not needed prior to tripping out of the hole.

In the preferred embodiment illustrated inFIG. 6, the clean mud is provided a booster pressure to improve bit hydraulics. If a bit is selected that produces fine cuttings, the PCP mud pump is compatible with pumping the cuttings filled mud. In an alternative design, the benefit for pumping the cuttings is a reduction in backpressure held on the geological formation.

InFIG. 6, there are two other positions of the three way-valve202, “Position B”, and “Position C”. In “Position B” of the three-way valve, the PCP pump180is not used to boost the mud pressure delivered through the mud channels of the pilot bit108. Here, clean mud flows through the interior of the shroud214to the three-way valve202, and then directly into the male side of universal mud and electrical connector178and through the remaining portions of the subterranean electric drilling machine to the mud channels of the pilot bit108. The detailed configuration of pipes and other related hardware to accomplish this mode of operation is not shown inFIG. 6for the purpose of brevity.

InFIG. 6, Position C of the three-way valve202allows the entire subterranean drilling machine to move within the previously installed borehole casing96. The fluid filled region defined between the subterranean drilling machine and the interior of the previously installed borehole casing is designated by element218in FIG.6. As previously stated, the fluid filled region defined between the inside of the previously installed casing and the outside diameter of the umbilical, which is the annuli between the well casing and the umbilical, is designated by element212. In “Position C” of the three-way valve202, fluids are pumped from the region218into region212. If there is a good seal between the exterior of the umbilical and the borehole at the surface produced by the stripper heads and surface blow-out preventers (BOP's), then the existence of the Smart Shuttle™ seal210causes the subterranean drilling machine to go down into the well. Reversing the PCP, causes the subterranean electric drilling machine to reverse direction. For a more detailed description of the operation of a Smart Shuttle, please refer to the above defined “SDCI IP”, entire copies of which are incorporated herein by reference. “Position C” of the three-way valve202provides an important function to rapidly trip the subterranean electric drilling machine to the surface and back should any drilling component need maintenance or replacement. This capability provides operational flexibility for the system. Based upon existing designs with currently available downhole electric motors and progressing cavity pumps, practical speeds of 10 feet per second can be anticipated while pulling a load of at least 4,000 lbs.

InFIG. 6, the fluid filled region between the casing hanger seal132and the pilot bit106is designated by element220. During drilling operations, the mud pressure in region212is defined to be P1; the mud pressure in the interior of the shroud defined by element214is P2; the mud pressure at the input to the three-way valve202is P3; the mud pressure within the male side of universal mud and electrical connector178is P4; the mud pressure inside the mud channels of the pilot bit108is P5; the pressure within region220is P5; the pressure within region218is P6; and the pressure within the umbilical116is P6.

The subterranean electric drilling machine inFIG. 6provides other benefits. Since the anchor points secure the drilling machine in the well's casing and mudflow paths must pass through valves within the machine, the entire unit serves the function of a downhole packer with safety valve and serves as a BOP located downhole, or Downhole BOP™. The BOP is comprised of first mud cuttings and bypass port (MCBP)164, second mud cutting and bypass port (MCBP)166, and the umbilical mud valve204provide the required functions of a BOP located downhole.

It is also worthwhile to make a few more comments about the downhole electric motor114. This electric motor rotates the drilling bit. This electric motor may possess a gearbox to match the bit's speed requirements. Monitoring the motor's power, RPM, torque, current drawn, voltage drawn etc., provides significant information about the condition of the bit and its drilling performance. As one particular example, the electric motor is chosen to be a REDA 4 pole, 80 horsepower, electric motor requiring 1250 volts at 45 amps that runs at the nominal RPM of 1700 RPM that is 5.4 inches OD and 31.5 inches long. The RPM of this motor may be conveniently varied by varying the frequency of the voltage applied to it as is indicated by FIG.2and the related description. In one preferred embodiment, the RPM of the electric motor in the subterranean electric drilling machine is varied between about 900 RPM to 2,500 RPM. In this one preferred embodiment, the particular REDA motor does not need a gearbox for this application. In another preferred embodiment, two such REDA motors are operated in series that provide a net downhole motor capable of providing 160 horsepower to a rotating drill bit at the rotation speed between 900 RPM and 2,500 RPM. The RPM and other parameters of the downhole motor are controlled by computer system26in FIG.5. Another preferred embodiment uses the electric motor described in U.S. Disclosure Document No. 498,720 filed on Aug. 17, 2001 that is entitled in part “Electric Motor Powered Rock Drill Bit Having Inner and Outer Counter-Rotating Cutters and Having Expandable/Retractable Outer Cutters to Drill Boreholes into Geological Formations”, an entire copy of which is incorporated herein by reference.

The drilling fluid transitions from a nonrotating element which is first shaft152, into a rotating pipe that is rotary shaft125. The swivel and seal unit124prevents fluid leaks in this area. Unlike a swivel-packing gland, this seal operates at a relative low differential pressure. Suitable rotating seal assemblies are commercially available for these conditions. Electric power and communications from the fixed (non-rotating) components to the rotating assembly is required. An inductive connection or a slip-ring assembly will provide the power, communication and control linkage through the swivel and seal unit124to the fiber optic communication system and the power available through the umbilical. However, the details for either the inductive connection or slip-ring assembly are not shown inFIG. 6in the interests of simplicity.

FIG. 6as described above drills the borehole with the long section of expandable casing126carried into the new hole104as the new hole is drilled. However, in an alternative preferred embodiment, a short section of expandable pipe126is used to drill the borehole, then the subterranean electric drilling machine is retrieved from the wellbore, and then that machine conveys into the well the long section of expandable casing126to be cemented and expanded into place within the new borehole104.

FIG. 6as described, uses the pilot bit106and the two undercutters110and112as the “drill bit” to drill the new borehole104. However, a bicenter bit as is used in the industry could also be used as the “drill bit” inFIG. 6, provided it had suitable dimensions to be withdrawn through the ID of the unexpanded state of the expandable casing126, and through the interior of the previously installed borehole casing96.

In relation toFIG. 1, wires A, B, and C comprise the first independent three phase delta circuit. Wires D, E, and F comprise the second independent three phase delta circuit. Each separate circuit is capable of providing 160 horsepower (119 kilowatts) over an umbilical length of 20 miles. In relation toFIG. 6, and in one preferred embodiment, the first independent three phase delta circuit provides up to 160 horsepower to the downhole electric motor114. In relation toFIG. 6, and in one preferred embodiment, the second independent three phase delta circuit provides up to 160 horsepower to the downhole pump motor assembly182in FIG.6. In one preferred embodiment, each first and second circuit are independently controlled. So, combined, the umbilical shown inFIG. 1can deliver a total of 320 horsepower (238 kilowatts) at 20 miles to do work at that distance.

FIG. 7shows the casing hanger130. The casing hanger was identified with element130inFIG. 6. Aportion of the casing hanger is surrounded by casing hanger seal132. The casing hanger seal was also previously identified with element132in FIG.6.

The expandable casing126shown inFIG. 6is attached to the casing hanger130. In one embodiment, the casing hanger is attached to the expandable casing by a threaded joint. In this embodiment, that threaded joint appears at end of casing hanger222, although the threads on the casing hanger are not shown inFIG. 7for simplicity. The opposite end of the casing hanger is shown as element223. In another preferred embodiment, the casing hanger can be manufactured integral with the expandable casing. A cement flowby port224is used during the cementing process as further explained in relation to FIG.10. The expandable hanger contact area is generally designated as element226in FIG.7. The length of the expandable hanger contact area is designated by the legend L1 in FIG.7.

FIG. 8shows more detail for the downhole pump motor assembly that is related to element182in FIG.6. Elements180,184,186,188,190,192and194were previously identified in FIG.6. Those same elements are related to the elements appearing in the following.

FIG. 8generally shows a downhole pump motor assembly identified as element228which is configured as a Smart Shuttle™. In one preferred embodiment, various parts from REDA are used to make a downhole pump motor assembly182. REDA may be located as defined above. In the embodiment, element230is a REDA protector for a bottom drive motor that is 5.4 inches OD, and 4.5 feet long. In this embodiment, element232is a first REDA 4 pole, 80 horsepower, electric motor requiring 1250 volts at 45 amps that runs at the nominal RPM of 1700 RPM that is 5.4 inches OD and 31.5 inches long. Element234is a power cable providing electrical power to the downhole pump motor assembly228. In this embodiment, element236is a second REDA 4 pole, 80 horsepower, electric motor requiring 1250 volts at 45 amps that runs at the nominal RPM of 1700 RPM that is 5.4 inches OD and 31.5 inches long. Element238is a REDA universal motor base part number UMB-B1 for a bottom drive motor that is 5.4 inches OD and 1.7 feet long. Element240is REDA gearbox protector part number BSBSB having 4 mechanical seals that is 5.4 inches OD and 10.6 feet long. Element242is a REDA gearbox having a 4:1 gear reduction that is 6.8 inches OD and 10.9 feet long. Element244is a Netzsch flexible shaft that is 7.87 inches OD and 10 feet long. Netzsch Oilfield Products is located at 119 Pickering Way, Exton, Pa. 19341, having the telephone number of (610) 363-8010, that has the website of www.netzchusa.com. Element248is a Netzsch progressing cavity pump part number NM090*3L (EX) that is 7.87 inches OD and 11.8 feet long. Element248is a crossover. Element250is 4 inch tubing. Element252is a Smart Shuttle seal. Element254is an intake port into the Netzsch progressing cavity pump. Element256is the discharge outlet from the Netzsch progressing cavity pump.

The downhole pump motor assembly identified as element228needs a cablehead, centralizers, bypass valves, sensors, and intelligent controls to make one embodiment of a Smart Shuttle™. Such a Smart Shuttle will have a minimum pulling force of 4400 lbs, a maximum transit speed of 11 feet per second, that operates within 9 ⅝ inch O.D., 53.5 lb/foot casing. It has variable speed, is reversible, and has high speed bidirctional communications with instrumentation on the surface of the earth.

FIG. 9shows a subterranean electric drilling machine boring a new borehole from an offshore platform.FIG. 9shows the subterranean electric drilling machine94deployed within a previously installed borehole casing96that is surrounded by existing downhole cement98that is in the process of drilling the new borehole104into geological formation102, which elements were previously defined in relation to FIG.6. Also shown inFIG. 9is the expandable casing126that was also defined in FIG.6. The subterranean electric drilling machine was thoroughly described in FIG.6.

InFIG. 9, an offshore platform258has a hoisting mechanism260that is surrounded by ocean262that is attached to the bottom of the ocean264. The ocean surface is shown by element265. Riser266is attached to blow-out preventer268. Surface casing270is cemented into place with cement272. A section of previously installed casing274extends from the lower portion of the surface casing270to the previously installed borehole casing96. The broken line276shows that the section of previously installed casing274can be many thousands of feet long. Previously installed casing274may actually be comprised of different lengths of casings having different inside diameters, outside diameters, and weights, but that detail is not shown inFIG. 9in the interest of simplicity. Other conductor pipes, surface casings, intermediate casings, liner strings, or other pipes may be present, but they are not shown for simplicity. The upper portion of the umbilical278proceeds to the stripper heads and surface blow-out preventers (BOP's), then proceeds to location70inFIG. 5, and is then wound up on the umbilical carousel64in FIG.5. In this preferred embodiment, the computerized uphole management system for the umbilical as shownFIG. 5is mounted on the offshore platform. InFIG. 9, other geological formations represented by element280are located above geological formation102. Other geological formations represented by element282are below geological formation102.

InFIG. 9, the directions of the arrows show the mud flow. Fresh mud travels from the surface down the annuli between the well casing and the umbilical designated by element212. Element212was previously defined in FIG.6. Cuttings laden mud returns to the offshore platform258on the interior of the umbilical283. The arrows show the mud flow pattern in the vicinity of the subterranean electric drilling machine94. This mud flow system is called a “reverse mud flow system”. This reverse mud flow system will keep the cuttings within the umbilical, therefore preventing any debris from accumulating in the annuli between the well casing and the umbilical that might prevent the subterranean electric drilling machine from returning to the offshore platform. In other preferred embodiments, the mud flow can be opposite—namely, clean mud flows down the interior of the umbilical, and cuttings laden mud flows up the annuli between the well casing and the umbilical.

For the purposes of this invention, the phrase “offshore platform” includes the following: (a) bottom anchored structures that include artificial islands, gravity based structures, piled truss structures (conventional platforms), and compliant towers; (b) mobile-bottom sitting structures that include submersible structures including submersible barges (in swampy and shallow water areas), mobile gravity base structures (like the concrete islands in the Arctic) and jackup platforms; (c) floating-permanently moored structures including the tension leg platforms (TLP), the SPAR and Semisubmersible, and the floating production, storage, and offloading structures (FPSO); and (d) floating-mobile structures such as shipshape-like drilling rigs, semisubmersibles that are catenary moored, and barges.

It is helpful to review howFIGS. 6,7,8, and9relate to the drilling process. As was shown inFIG. 6, the expandable casing126in its un-expanded state is carried into the hole as an outer sheath over rotary shaft125and associated components, which may also be called a “drilling work string”. At the lower end of that borehole assembly (“BHA”) is anchored into the casing. In one preferred embodiment, the string of expandable casing is 3,000 ft long.

Starting with the drilling machine out of the hole, the expandable casing is run in and suspended in the wellbore from the surface. The top of the casing has an expandable casing hanger installed.FIG. 7shows the expandable casing hanger. Next, the bottom hole assembly is run through the casing and secured into the bottom joint of the unexpanded suspended casing. The casing hanger setting tool134is secured into the casing hanger130together with the first and second anchor and weight on bit mechanisms140and142, the downhole electric motor114, and the remaining portions of the subterranean electric drilling machine94. The entire subterranean electric drilling machine and expandable casing is then tripped to the bottom of the well. Drilling the next section of the well continues until sufficient hole for the expandable casing has been drilled. With the expandable casing in place, the casing hanger setting tool expands and locks the unexpanded length of expandable casing in the hole. The subterranean electric drilling machine94then releases from the casing and is recovered from the well.

In one preferred embodiment, the casing hanger setting tool134is a packer-like assembly located beneath the downhole electric motor114. The casing hanger setting tool initially expands with sufficient pressure to secure the casing to the non-rotating housing that is connected to the swivel and seal unit124that centralizes the casing. Once the new hole has been drilled, and the casing hanger130is in proper setting position, much higher pressure is pumped into the casing hanger setting tool to plastically expand the hanger and cold forge the hanger into the previously installed borehole casing96. As an example of this process, various manufacturers connect pipeline repair tools to pipeline ends and connect wellheads to the top of casing strings with this type of “cold forge” process. The cement flowby ports of the casing hanger are left open for circulation of cement behind the casing. When the expandable casing is later expanded, these holes are sealed through contact with overlap in the previous casing string. The casing hanger seal and cement help ensure a leak tight seal.

In one preferred embodiment of the invention, the subterranean electric drilling machine is used to accomplish the many purposes including the following: (a) drill the new borehole104; (b) convey into the well the expandable casing126; and (c) then using the casing hanger setting tool134, the casing hanger is expanded into the previously installed borehole casing96. Thereafter, the subterranean electric drilling machine releases from the casing hanger, thereby leaving the casing hanger and the expandable casing126in its unexpanded state in the well, and the subterranean electric drilling machine is then removed from the well.

Thereafter, another tool called a subterranean liner expansion tool is conveyed into the wellbore. In one preferred embodiment, the subterranean liner expansion tool is labeled with element284in FIG.10.FIG. 10shows the previously installed borehole casing96, the existing downhole cement98, the new borehole104, a portion the casing hanger130after the above expansion steps have been performed in (c) above, one end222of the casing hanger shown inFIG. 7, and the other end223of the casing hanger shown in that figure. Cement flowby port224is also shown.

The subterranean liner expansion tool284is used in a two step process. First, the cement is injected behind the unexpanded expandable casing. That process is shown in FIG.10. Second, the expandable casing is expanded. That process is shown in FIG.11. Thereafter, the subterranean liner expansion tool is removed from the well, and the well is either completed, or the well is further extended using the methods and apparatus described above.

InFIG. 10, the subterranean liner expansion tool284is positioned within unexpanded casing286. Counter-rotating roller casing expander tool is generally shown as numeral288in FIG.10. In one preferred embodiment, clockwise rotating roller assembly290is on the uphole side of the counter-rotating roller casing expander tool. It has individual rollers292,294,296, and298. In this embodiment, counter-clockwise rotating roller assembly300is on the downhole side counter-rotating roller casing expander tool. It has individual rollers302,304,306and308. Electrically powered hydraulic systems within the counter-rotating roller casing expander tool are capable of loading the individual rollers against the interior of the expandable casing. In one preferred embodiment, several of the rollers, such as roller304, are canted through the angel θ. In one preferred embodiment, the rollers are hydraulically loaded and are canted to advance through the expandable casing as the rotating roller assembles290and300rotate in their respective directions. Electrically powered systems within the counter-rotating roller casing expander tool are then capable of rotating the appropriate elements of each rotating roller assembly. InFIG. 10, the rollers are in their fully retracted position. The electric motor and related hydraulics for the counter-rotating roller casing expander tool are located within housing310. That electric motor is labeled with legend312, and the related hydraulics is labeled with legend314, although those are not shown inFIG. 10for simplicity.

The torque resistance section316is a component of the counter-rotating roller casing expander. It has longitudinal rollers318and320. An electric motor322and associated hydraulics324are located within torque resistance section316to properly actuate the longitudinal rollers318and320. However, elements322and324are not shown inFIG. 10for the purposes of simplicity. The purpose of the torques resistance section316is to prevent any unbalanced torque resulting from the operation of the subterranean liner expansion tool that might cause the remainder of the downhole tool attached to the umbilical116to twist, thereby possibly breaking the umbilical. Breaking the umbilical downhole would be a catastrophic failure, although the tool can be retrieved using techniques to be described below.

Various electrical wires and connectors along the length of the subterranean liner expansion tool conduct electrical power from the umbilical116to the counter-rotating roller casing expander tool288(which are designated figuratively by element326which are not shown inFIG. 6for the purposes of brevity). Sensors within the counter-rotating roller casing expander tool provide measurements such as the force delivered by the rollers to the casing, the position of the rollers, etc., which measurements are suitably is digitized and sent thorough suitable electrical circuitry and connectors along the length of subterranean liner expansion tool (designated figuratively by element328which is not shown inFIG. 10for brevity), which digital information is then sent uphole through the fiber optical cable14within the umbilical116in the form of suitable light pulses. Commands from the surface are also send downhole through the same bidirectional communications path. For example, commands to change the contact of the rollers, or expand the rollers outward to expand the casing may be sent downhole through this bidirectional communications path.

FIG. 10further shows progressing cavity pump180that is driven by a downhole pump motor assembly182and shroud180, which were previously described in FIG.6. Inflatable cement seal330is inflated during cementing operations.

In the preferred embodiment shown inFIG. 10, cement from the surface proceeds through umbilical116; through umbilical mud valve204(which is used for both mud and cementing purposes); to the cross-over system216and into region332; through the cement flowby port224; through region334between the previously installed borehole casing96and the exterior of the unexpanded casing286; then into region336between the exterior of the unexpanded casing and the ID of the new borehole that labeled with element338. The mud valve204has a total of three positions: (a) open, namely it allows cement to flow through as shown inFIG. 10; (b) stop (not allow any cement to flow straight through); and (c) vent to the annulus between the umbilical116and the ID of the previously installed casing so that cement can be cleaned from within the umbilical (which state is not shown inFIG. 10for simplicity). The region between the umbilical116and the ID of the previously installed casing is shown a element212inFIG. 6, although that particular element is not shown inFIG. 10for simplicity (because of the large number of labeled elements in that vicinity of FIG.10).

InFIG. 10, the position of the “front” of the cement flow is shown by element340. Sufficient cement is introduced into region336so that when the unexpanded casing286is expanded in the next step (as explained below), then the well is properly cemented in place. Various sensors within the subterranean liner expansion tool provide data that allows the computer system26on the offshore platform in this embodiment to determine the proper amount of cement to be sent downhole that at least partially fills region342that is located between the exterior of the unexpanded casing286and OD of the new borehole338which is not filled with cement in FIG.10. The overlapping region between the old cement and the new cement that has not set up inFIG. 10is shown as element344. The new cement is now allowed to set up as shown in FIG.10. However, there is old cement that is hardened inFIG. 10such as the old cement behind the casing hanger130that is identified with numeral345.

The subterranean liner expansion tool284is comprised of a number of components including the counter-rotating roller casing expander tool284and the Smart Shuttle™. The subterranean liner expansion tool is transported downhole by the Smart Shuttle™ which is comprised of components including the Smart Shuttle™ seal210, the progressing cavity pump180, the downhole pump motor assembly182, and the shroud180which have been previously described in relation to FIG.6. The Smart Shuttle also returns the subterranean liner expansion tool to the offshore platform in this preferred embodiment.

In a preferred embodiment of the invention shown inFIG. 10, the unexpended casing286is 3,000 feet long, has a weight of approximately 40 lbs/foot, and has an unexpanded OD of approximately 8.0 inches OD. In a preferred embodiment shown inFIG. 10, the previously installed borehole casing96is a 9 ⅝ inch OD casing having a weight of approximately 40 lbs/foot.

FIG. 11shows the subterranean liner expansion tool284. Portions of the subterranean liner expansion tool are shown inFIG. 11including the counter-rotating roller casing expander tool288, the torque resistance section316, and the progressing cavity pump180that is attached to the downhole pump motor assembly182.

After cementing was completed inFIG. 10, the subterranean liner expansion tool is pulled up vertically above the casing hanger130. Then the rollers of the the clockwise rotating roller assembly290the counter-clockwise rotating roller assembly300are placed in their extended positions. Then counter-rotating roller casing expander tool288is suitably energized, and it begins to expand the expandable casing on its downward travel (to the right-hand side ofFIG. 11) within the well.FIG. 11shows the subterranean liner expansion tool in a location in the formation that is beyond the end of the previously installed casing100that is defined in FIG.10.

InFIG. 11, the expandable casing in its fully expandable form is shown at location348. InFIG. 11, the expandable casing in its unexpanded form is shown at location350. Cement surrounding the expandable casing in its fully expandable form is shown as element352in FIG.11. Cement surrounding the expandable casing in its unexpanded form is shown as element354in FIG.11. The counter-rotating roller casing expander tool288remains suitable energized, and it eventually completes the expansion of the expandable casing at some extreme distance in the well designed by element356in FIG.11. Thereafter, the liner expansion tool284is removed from the wellbore. Thereafter, the cement is allowed to cure. After the cement is cured, the well is completed to produce oil and gas using techniques and procedures typically used in the oil and gas industry or using those methods and apparatus described in the “SDCI IP”, entire copies of which are incorporated herein by reference.

InFIG. 11, the expandable casing in its fully expandable form as shown at location348can also be called equivalently a “liner” because of its attachment to the previously installed casing96in FIG.10. Hence, the name “subterranean liner expansion tool”.

FIG. 12shows the casing hanger130, a cement flowby port224, the previously installed borehole casing96, and expandable casing126in its unexpanded form that is attached to the casing hanger at casing hanger end222. These elements have been previously defined in FIG.6and in FIG.7.FIG. 12shows the casing hanger after a portion of it has been expanded with the casing hanger setting tool. The state of the casing hanger130inFIG. 12is similar to that shown in FIG.10. The inside diameter of the previously installed borehole casing96is shown inFIG. 12by the legend ID2. The wall thickness of the previously installed borehole casing is identified by the legend WT2. The inside diameter of the expandable casing126in its unexpanded form is identified by the legend ID3. The wall thickness of the previously installed borehole casing is identified by the legend WT3. This is the configuration before the passage of the subterranean liner expansion tool.

FIG. 13provides a section view of the configuration of components shown inFIG. 12after the passage by the subterranean liner expansion tool. Various elements onFIG. 13have been previously described. In addition, element358shows the expandable casing in its expanded state after the passage of the subterranean liner expansion tool. Various inside diameters are defined by legends ID2, ID4, and ID5. In general, ID2 will equal ID4 that will equal ID5. If this is the case, this is a true monobore well. However, there are limitations to the power of the subterranean liner expansion tool. So, if old hard cement is set up behind the overlapping portions of the previously installed casing in the location identified by element360, the subterranean liner expansion tool may not have sufficient power to crush old hard cement and rock behind that particular location. Such a location is identified by element345in FIG.10. In such event, ID4 would be less than ID2 by as much as 2 times the dimension of WT2 in FIG.12. This extra thickness may persist for the length of the casing hanger L1as shown in FIG.7. Therefore, the installation described inFIG. 13will provide either a monobore well, or a near-monobore well.

In the following, there are different topics of interest related to the above described preferred embodiment. Subsection titles will be used for the purposes of clarity.

FIG. 14shows relevant parameters related to fluid flow rates through the umbilical. Umbilical fluid flow rates are sufficient to support drilling as shown in FIG.9. One preferred embodiment uses a 4.5 inch ID pipe providing 173 gallons per minute (GPM) at a pressure of 1000 pounds per square inch (PSI) pressure loss over a 20 mile offset. Here, the “Pressure Loss” is 1000 PSI. Here, the “Flow Rate” is 173 gallons per minute. This was calculated using a Bingham Plastic mudflow model with 12 lb/gallon mud at a velocity of 3.5 feet per second (fps). This is a “Flow Velocity” of 3.5 feet per second. The umbilical geometry of 4.5 inches ID and 6.0 inches OD may be optimized under different situations as required. However, these particular dimensions are selected for a reverse flow mud system inside a 8.5 inch ID cased hole having a 20-mile offset. The Bingham Plastic mudflow model is described in detail in Section 8.2 entitled “Mathematical and Physical Models” of the book entitled “Petroleum Well Construction” by Michael J. Economides, Larry T. Watters, and Shari Dunn-Norman, John Wiley & Sons, New York, N.Y., 1998, an entire copy of which is incorporated herein by reference. An entire copy of the book referenced in the previous sentence is also incorporated herein by reference. In particular, please refer to Table 8-2 on page 222 of the book for detailed algebraic equations related to the Bingham Plastic Model.

Tripping into the Well

There are various constraints on how rapidly the subterranean electric drilling machine can enter the wellbore. Since the vertically suspended casing string and the subterranean electric drilling machine weight may be greater than can be safely run with the umbilical, the first anchor and weight on bit mechanism (AWOBM)140and second anchor and weight on bit mechanism (AWOBM)142as shown inFIG. 6provide an anchor mechanism that acts as a “downhole hoist” to “walk” the casing vertically downhole and eventually into any horizontal section of the well. This “downhole hoist” is also called herein an “anchor mechanism” when used for this particular purpose. The subterranean electric drilling machine and its related anchor mechanism can be fielded from within a lubricator as is standard practice in the industry to maintain well pressure control. Once the downhole weight is within the capacity of the umbilical, use of the anchor mechanism is stopped and the casing load is transferred to the umbilical. The anchor means144and146and anchor means148and150as shown inFIG. 6of the anchor mechanism are then collapsed for rapid transit to the bottom of the well. Further downhole travel of the casing and the subterranean electric drilling machine is accomplished by pumping mud into the annulus space between the well's installed casing and the umbilical. Pressure acting upon this annular piston area generates sufficient force to rapidly move the equipment downhole at about 2 fps in the 15 to 20 mile offset range. A 225,000 lb load with a 0.2 coefficient of friction requires approximately 1,600 psi differential pressure across Smart Shuttle seals (see element210in FIG.6). This pressure capability is obtained with multiple seals load-sharing the pressure. Motion cannot be accomplished without moving mud from below the drilling machine out of the well up through the umbilical ID. The pressure in the casing below the drilling machine (a sealed volume due to cementing) is approximately 3500 psi above static. The downhole mud pump may be used to assist in moving this required mudflow through the umbilical ID. For trip velocities in the range of 2 feet per second the surface mud pumps will need to provide 350 gallons per minute at 4600 pounds per square inch. At shorter distances with less pressure losses, the equipment may move faster (if surface mud pump volume capacity is available).

FIG. 15shows various parameters related to tripping the subterranean electric drilling machine and the expandable casing into the well. A 20 mile well is on the order of 100,000 feet. At this distance, and at 2 feet per second, the formation back pressure is 1000 PSI.

Tripping Out of the Well

The subterranean electric drilling machine94is tripped from the well with cuttings filled mud within the umbilical. Sufficient mudflow is pumped down the annulus between the umbilical and the uphole casing to fill the entire cased wellbore below the drilling machine. The maximum pressure the pump will provide this annulus is 5000 psi and at a 20 mile offset, the volume is limited to approximately 440 gallons per minute or a drilling machine trip speed of approximately 2.4 fps. Simultaneously, the surface linear umbilical traction unit pulls at approximately 12,500 lbs (to overcome the fluid flow drag upon the umbilical, the frictional umbilical drag and the frictional drag of the subterranean electric drilling machine and its seals).

As the subterranean electric drilling machine moves up the wellbore and the annular fluid pressure losses become less, the maximum mud pump pressure no longer limits the trip speed. The limiting factor then becomes the mud volumes, which the mud pumps may provide. For these tripping purposes, a third surface mud pump may be used in another preferred embodiment. It will support higher speed trips and provide redundancies during other operations.

Since all of the mud volumes pass through the downhole mud pump, an accurate metering of the mud volume and pressures is obtained throughout the trip. This keeps pressure off the open formation during trips out of the wellbore.

Surface Mud System

A large volume of working mud is needed to manage the umbilical volume while tripping in the hole. For 20-mile offset operations, an active mud tank volume of 3500 barrels may be required. This is similar in capacity to those used in some large offshore drilling rigs.

In one preferred embodiment, the installed casing is 8.5 inches ID, and the umbilical is a 6 inch OD umbilical with a 4.5 inch ID. During drilling operations, the maximum mud flow rate is 150 gallons per minute with a pressure drop of 825 pounds per square inch, which includes frictional losses only. During tripping out of the hole at 2.4 feet per second, the maximum mud flow rate is 422 gallons per minute with a pressure drop of 4,750 pounds per square inch. During running in the hole with casing at 2 feet per second, the maximum mud flow rate is 350 gallons per minute, with a pressure drop of 3600 pounds per square inch (with cement sealed on the bottom of the well).

Thus, for the tripping out of the well, a minimum of two 750 hp surface mud pumps would be required. One pump is adequate for routine drilling operations. When the subterranean electric drilling machine is at a distance of 20 miles, approximately 14 hours are required to run into the hole, 12 hours are required to come out of the hole, and 11 hours are required for cuttings to circulate from the bottom of the hole to the surface. Therefore, accurate monitoring and management of mudflow and quality into and out of the well and umbilical both at the surface and downhole at the drilling machine is important for reliable well control.

The Drilling Operation

When the subterranean drilling rig reaches the bottom of the hole, the high-speed bit may encounter cement within the bore of the cased hole. The anchor means144,146,148and150as shown inFIG. 6are engaged, mud circulation started and the bit is rotated. Notice that downhole sensors monitor mudflow composition parameters to minimize circulation time for conditioning the hole. Weight on bit is applied and drilling moves forward out of the previously cased hole. Traditional steering mechanisms and MWD tools are used to guide forward progress of the bit through the formation. Directly behind this BHA is the unexpanded casing.

The mudflow rates and the cutting solids this flow rate can transport out of the hole will limit drilling progress. For example, a drilled 12 ½ inch ID hole and a 4 ½ inch ID umbilical having an internal mud velocity of 3 feet per second carrying 6.5% solids will have a maximum penetration rate of 90 ft/hr.

Significant information will be monitored and communicated real time to the surface for control of the operations. Some of the information includes:(a) weight on bit(b) Penetration rate(c) Bit RPM(d) Bit power (determined from power consumed by the downhole electric motor114of the subterranean drilling machine)(e) Mud flow rate through bit (by monitoring throughput of the progressing cavity pump180)(f) Differential mud pressures across bit and to surface across umbilical(g) Mud quality sensors for entrained gas, cuttings loading, etc.(h) Mud temperatures(i) Basic operating parameters of the various subterranean electric drilling machine functions that include voltage, power, RPM, pressure, temperature, axial load in umbilical at the pump, etc. are all monitored in real time to verify equipment status.

This monitoring will provide for efficient control of the downhole drilling operation. If additional information is required, in one preferred embodiment additional instrumentation or tools may be included in the umbilical at the various connection points (approximately every 5 miles). In one preferred embodiment, it is preferable to have remotely operated downhole BOP's. These devices are packer-like assemblies, which when inflated, anchor to the inside of the casing. An internal valve provides a well fluid isolation point.

This extensive monitoring capability allows drilling operations to use under-balanced fluids, if beneficial to the well program. This equipment capability also allows for direct well control and production testing through the drilling machine.

When the well has drilled forward to the casing point, pressuring the setting tool included in the subterranean electric drilling machine sets the expandable casing hanger. The success of the hanger setting operation may be load tested with the downhole hoist (which when used in this application is also called a “weight on bit mechanism”). Upon verification of a successful operation, the subterranean electric drilling machine releases from the casing and starts its trip from the well. This will leave the well ready for casing cementing and casing expansion.

During all operations in a wellbore, the umbilical is maintained under tension between the downhole tools and the surface equipment. This permits rapid transit in the wellbore by preventing buckling. A constraint is that a minimum number of gentle bends should be included in the wellbore design. This constraint is similar to familiar drill pipe and coiled tubing operational constraints in current well operations. Selected means to provide such tension are shown in FIG.5. The tension is monitored with computer system26in FIG.5.

Several contingency operations are reviewed to illustrate the capabilities of the subterranean electric drilling system.

The subterranean electric drilling machine can control the well and can control a well “kick”, or well kicks. In one preferred embodiment, the well uses a reverse circulation system. The first mud cuttings and bypass port (MCBP)164and the second mud cutting and bypass port166in of the subterranean electric drilling machine act as a packer within the well directing all returns to the umbilical. The umbilical has sufficient pressure rating to contain any kick and allow it to be circulated from the well. Instrumentation monitoring mud conditions downhole should provide early indication of developing well control problems.

The subterranean electric drilling machine can survive n open hole collapse. The well is drilled with unexpanded casing over the drilling work string (that is element125in FIG.6). Should the formation collapse on the casing, the subterranean electric drilling machine is withdrawn through the unexpanded casing. The casing may subsequently be expanded and drilling operations resumed.

The subterranean electric drilling machine can survive a downhole blackout of power. Assume the failure is in the power transmission or control system during a tripping operation. The umbilical and surface traction winch have sufficient power to pull the dead equipment from the wellbore. Surface pumps would continue to provide mud for displacement replacement. With care, mud pressure below the subterranean electric drilling machine may be used to reduce the load required to pull the machine from the well.

If the failure occurs when the drilling machine is anchored and making hole, then a release between the downhole mud pump and the anchor means of the drilling machine is actuated. That disconnect occurs between the female side of universal mud and electrical connector176and the male side of universal mud and electrical connector178as shown in FIG.6. In one preferred embodiment, the release may be triggered with an “over-pull” or operation may be via pumping a dart or ball down the umbilical. Once the release is actuated, the drilling machine controls, and mud pump assembly may be pulled “dead” from the well. Once the fault is isolated and repaired, the recovered equipment is run back into the well where it connects with the drilling equipment left in the hole. The Smart Shuttle portion of the subterranean electric drilling makes this reconnection. Regaining control of the equipment allows either drilling operations to proceed or for the equipment to be recovered from the well.

The Well Construction Process

Drilling and casing operations in the preferred embodiment is a two-trip process. The drilling equipment defined above (the subterranean electric drilling machine) is used to drill the hole, position and anchor the casing (but not expand it) within the hole. The casing is left in position ready for cementing operations (if required) and casing expansion to its final installed dimension is accomplished with the use of a second tool system (the subterranean liner expansion tool).

In this preferred embodiment, the new expandable casing is 3,000 feet long, 54 lbs/ft, and has an unexpanded OD of 8.0 inches OD. The downhole casing hanger and the casing string are then suspended from the surface rig floor. The bottom hole assembly (BHA) is then made up and run into the casing string. In one preferred embodiment, the centralizing casing hanger setting tool is used to lock the casing and drilling equipment together. Next the rotary motor and the anchor mechanism are added to the assembly together with the downhole mud pump that may be used as a Smart Shuttle.

This described equipment is all long and heavy. It is handled as major assemblies with quick connection devices between each assembly. The estimated size and weight of various components appear below in the following.

The bit is about 2 feet long, and weighs 500 lbs in air. The MWD tools are 40 feet long and weigh about 1,200 lbs in air. The rotary steering tool is about 30 feet long, and weighs 1,500 lbs in air. The rotary shaft (element125inFIG. 6) also called the “drilling work string” or simply “drill pipe”, is about 3,000 feet long and weighs 28,500 lbs in air. The expandable casing has a weight of 54 lbs/ft, is about 3,000 feet long, and weighs 162,000 lbs in air. The rotary section and anchor section of the subterranean electric drilling machine (that includes elements114,140and142inFIG. 6) is about 120 feet long and weights 2,800 lbs. The downhole mud pump section of the subterranean electric drilling machine (including elements180,196, and214inFIG. 6) is about 122 feet long and weighs about 3,900 lbs in air. Any separate control module associated with the subterranean electric drilling machine is about 20 feet long and has a weight of 4,000 lbs. So, the total length of the assembly is about 3,334 feet long that weighs about 200,800 lbs in air.

Cementing and Expanding the Casing

In this preferred embodiment of the invention, subterranean liner expansion tool284inFIG. 10installs the cement and expands the monobore casing in the well. This approach was selected to simplify the subterranean electric drilling machine and to provide operational flexibility when performing these monobore well construction operations.

The subterranean liner expansion tool has two basic functions. The first is to cement the casing in the well (if required). In one embodiment, this is accomplished through a 2 inch cementing line in a 3 ½ inch OD umbilical. Unlike the subterranean electric drilling machine when attached to casing, the Smart Shuttle at speeds up to 10 feet per second pulls this umbilical into the well. The Smart Shuttle operation of the liner expansion tool requires that the inflatable cement seal330is collapsed, and then fluids are pumped from the downhole side of the Smart Shuttle™ seal210to the uphole side of that seal as has been previously described. To cement the well, inflatable cement seal330is inflated. This cement seal is also called a straddle seal (with one side being inflatable) on the tool's outside diameter that ensures the fluid connection between the umbilical and the cement ports in the casing hanger. Once the tool is in place, cement is circulated into the annulus space behind the unexpanded casing. Adequate instrumentation monitors cement placement, volume and Smart Shuttle location and reports all of these monitored parameters to the surface.

The second function of the subterranean liner expansion tool is to expand the casing to its final operating size. The roller mechanisms for this task have already been described in relation to FIG.10. Rollers provide power, control and reversibility. If the casing were expanded with internal pressure, it would lack any expansion control—for example, if the hole diameter were irregular, then the casing expansion would be irregular as well. Expansion dies have the problem of being a one shot, one size expansion process. Internal casing rollers have experience in buckled casing repair tools and in anchoring casing inside Unibore wellheads. Weatherford has developed a one step expansion tool for expanding casing that is featured on their website. Weatherford International, Inc. may be reached at 515 Post Oak Blvd, Suite 600, Houston, Tex. 77027, having the telephone number of (713) 693-4000, that has the website of www.weatherford.com. InFIG. 10, the counter-rotating roller casing expander tool288has contra-rotating rollers to minimize the tool's torque that has to be externally reacted while expanding the casing. The longitudinal rollers318and320inFIG. 10provide for this torque reaction. As previously described, a downhole motor powered with a separate electrical circuit from the surface provides the necessary rotary power.

In a preferred embodiment, the surface equipment is similar in arrangement to the drilling machine system. However, this equipment may be smaller as the umbilical OD may be chosen to be 3 ½ inches OD.

As described earlier, in one mode of operation of the, subterranean electric drilling machine, it acts like a Smart Shuttle. The Smart Shuttle will be used to pump the umbilical and the subterranean liner expansion tool to the downhole worksite. The Smart Shuttle works by pumping fluid from one side of the seals to the other with an electric powered progressive cavity pump (PCP) (or any positive displacement pump). At relative low differential pressures, large axial forces ( approximately 4,000 lbs net) are generated that are sufficient to pull the tool and umbilical into the hole. Top-hole speeds are the maximum design speed of 10 fps. At extreme offsets, the speed will be slower (2.5 feet per second) due to fluid drag force on the umbilical, which will be proportional to the transit speed.

The Smart Shuttle system is equipped with sensors to detect location and to easily position the tools straddle seals across the casing hanger of the last casing string. Once in position, the inflatable seal is inflated and circulation through the hole-casing annulus is confirmed. This may be accomplished by pumping from the surface or by using the Smart Shuttle pump to circulate the area. Cement will be spotted into the annulus and the casing will be expanded prior to the cement hardening.

FIG. 10illustrates the subterranean liner expansion tool with cement being injected from the surface through the umbilical. Approximately 69 gallons per minute will flow at 100,000 ft with a pressure loss of about 9,000 pounds per square inch. Thus, the cementing pump will have to deliver at 10,000 pounds per square inch at these rates. It will require 240 minutes for the cement to be delivered at 100,000 ft from the surface and then another 77 minutes to spot approximately 126 barrels of cement into the hole-casing annulus space. When operating at these large offsets, managing the setting time of the cement and the required volume of cement is important.

Tracers may be added to the fluid pads before and following the cement as it is pumped into the umbilical. Sensors located on the subterranean electric drilling machine will verify when the cement is passing these downhole sensor locations. This will help accurately spot cement into the well. Once the cement is out of the umbilical, a bypass valve is opened and mud is circulated through the annulus to clear the umbilical.

Some casing may not require to be cemented into the hole. It may be possible that the casing can be expanded into the wall of the hole with sufficient pressure that the residual contact stress between the rock and expanded casing are sufficient to form an axial fluid seal. This avoids the cementing step and simplifies operations. However, it places a significant load upon the casing expansion rollers.

Once the cement is in position within the hole-casing annulus, the inflatable cement seal330is deflated and the Smart Shuttle pulls the expansion tool back into the previously cased wellbore. The counter-rotating roller casing expander tool is energized, and its roller engage the casing ID by expanding until contact with the casing is established. Rotation of the rollers is begun and the tool slowly moves forward. Forward motion is provided by the slight canted angle of the rollers, which screw the expander into the casing hanger and pipe. This canted angle is shown as the angle θ in FIG.10. In one preferred embodiment, the counter-rotating roller casing expander tool has sufficient strength to expand the casing hanger and the previously set casing back into the formation to provide a smooth casing ID. This process is illustrated inFIGS. 12 and 13.FIG. 12shows the casing hanger area prior to tool's passage andFIG. 13illustrates this same region after the tool has passed. The subterranean liner expansion tool has to have sufficient strength to expand the two casing strings back into the formation rocks.

The subterranean liner expansion tool continues expanding the casing to the bottom of the string. The process of expanding the casing will reposition the cement that is in the annuli. It will be extruded along the reducing annuli until the cement reaches the end of the casing where excess will flow into the uncased hole below the expansion machine. Once the casing has been fully expanded, the rollers of the subterranean liner expansion tool are collapsed to their small transport size and the Smart Shuttle and surface traction winch are used to bring the tool to the surface. This leaves the hole ready for the next drilling cycle.

Drilling and monobore casing operations continue until the well reaches the target reservoir. It is then possible to drill lateral drainholes (using a similar process) or a single large bore completion may be made.

There are various methods to handle contingencies with the subterranean liner expansion tool. Similar to the subterranean electric drilling machine, considerable flexibility exists in the cementing and expansion tool concepts to handle most contingencies. A few of these contingencies illustrate this capability.

Suppose the power to the subterranean liner expansion tool is cut off during a tip into the well. A bypass valve around the Smart Shuttle pump will open and allow the tool to be pulled from the wellbore using the surface linear winch and the strength of the umbilical. Alternatively, in some wells, it may be possible to pump mud down the cement line in the umbilical and apply pressure below the Smart Shuttle to assist in its retrieval.

Suppose there is a loss of power with cement in the umbilical. Then, a downhole bypass valve will open connecting the umbilical bore with the cased well annulus. Mud pumps may then be used to flow the cement to the surface.

Suppose the subterranean liner expansion tool fails without expanding the entire casing string. The tool is then recovered and the cement in the well annulus is assumed to harden. The next drilling operation will be to mill out of the wellbore and sidetrack to resume drilling to target.

Suppose the expansion strength of the subterranean liner expansion tool is not sufficient to expand the casing hanger to a full bore ID. The subterranean liner expansion tool has the capability of operating at various diameters. It will expand the casing to gage diameter where ever possible. Some areas, (like the casing hanger area) may not achieve gage—especially if the formation is exceptionally hard/strong. The under gage diameter is not desirable, but not a significant problem as all of the tool systems should pass through this reduced diameter. Should it not be possible to achieve the minimum gage diameter, then a mill may be used to increase inside diameter as a last resort.

Casing Flotation Techniques

Casing flotation techniques may be used to dramatically reduce the well annuli pressure required to pump casing into the well or reduce the required downhole hoist capacity. Air or nitrogen may be enclosed within the casing at the surface to reduce its apparent weight in mud during running operations. Once on bottom, the near buoyant casing would be flooded and filled with mud so that operations as previously described would continue. This and other related weight saving concepts have the potential to reduce the well annuli running pressure or downhole hoist capacity by 90% as compared to the loads identified above in the section entitled “The Well Construction Process”. This capability allows much longer and/or heavier strings of casing to be optionally run.

Casing flotation techniques will not have an impact upon the umbilical's design criteria. The umbilical's internal working pressure defines its required axial strength. A 10,000 psi internal pressure for well control requires an umbilical axial load strength of approximately 160,000 lbs to resist the surface pressure effects.

Alternative Embodiments of Drilling Systems

InFIG. 6, first anchor and weight on bit mechanism (AWOBM)140and second anchor and weight on bit mechanism (AWOBM)142are an example of “anchors” or “anchor means”. In the following summary, the term “Anchor Means” may be capitalized.

InFIG. 6, the expandable casing126is being “pushed” deeper into the wellbore by the anchor means. Therefore, this configuration is called a “Drill & Push” configuration. In this situation, the anchor means are on the uphole side of the subterranean electric drilling machine. On the other-hand, if the anchor means were instead on the downhole side of the subterranean electric drilling machine, then this configuration would be called a “Drill & Drag” configuration.

InFIG. 6, the anchor means are located on the inside of the previously installed borehole casing96. In this configuration, the anchor means are located within the “Wellbore”. On the other-hand, if the anchor means are instead located within the new borehole104, then the anchor means are located in the “Open-Hole”.

InFIG. 6, the downhole electric motor114rotates the rotary shaft125that is also called the “drilling work string” or simply the “Drill Pipe”. InFIG. 6, the downhole electric motor rotates the Drill Pipe. Therefore, the “rotary means”, inFIG. 6is described by the following: “Rotates Drill Pipe”. InFIG. 6, the expandable pipe126is not rotated. However, there are other configurations of the rotary means including: “Rotates Drill Pipe and Casing”, and “In Open Hole Rotates Bit”. In the below defined list of different preferred embodiments, the term “rotary means” is capitalized as “Rotary Means”.

InFIG. 6, the expandable casing126is not rotated. Therefore, in this configuration, the expandable casing is “Non-Rotating”. In other preferred embodiments, the expandable casing can be rotated by the rotary means. In this configuration, the expandable pipe is “Rotated”.

InFIG. 6, the progressing cavity pump180is driven by a downhole pump motor assembly generally designated by element182that comprises the mud pump, or “Mud Pump” in FIG.6. In this preferred embodiment, the Mud Pump is located within the Wellbore.

Accordingly, another preferred embodiment of the invention may be succinctly described as follows (Preferred Embodiment “B”):Arrangement: Drill & PushAnchor Means: In WellboreMud Pump: In WellboreRotary Means: Rotates Drill Pipe and Expandable CasingExpandable Casing: RotatingComments: This requires higher rotary torque than Preferred Embodiment “A”.

Accordingly, another preferred embodiment of the invention may be succinctly described as follows (Preferred Embodiment “C”):Arrangement: Drill & DragAnchor Means: In Open HoleMud Pump: In WellboreRotary Means: In Open Hole, Rotates Drill BitExpandable Casing: Non-Rotating, Drags Behind Anchor MeansComments: This requires stable formations for Open Hole Anchor Means.

Accordingly, another preferred embodiment of the invention may be succinctly described as follows (Preferred Embodiment “D”):Arrangement: “Drainhole Drilling”Anchor Means: In WellboreMud Pump: In WellboreRotary Means: Rotates Drill PipeExpandable Casing: Non-RotatingComments: Similar to Preferred Embodiment “A”, except smaller diameters of expandable casing used.

In the above, Preferred Embodiment “C” is further described in the following document: U.S. Disclosure Document No. 494374 filed on May 26, 2001 that is entitled in part “Continuous Casting Boring Machine”, an entire copy of which is incorporated herein by reference.

In the above, Preferred Embodiment “D” is further described in the following document: U.S. Disclosure Document No. 495112 filed on Jun. 11, 2001 that is entitled in part “Liner/Drainhole Drilling Machine”, an entire copy of which is incorporated herein by reference.

The subterranean electric drilling machine has been illustrated performing hydrocarbon drilling applications. However, there are other preferred embodiments of the invention. The subterranean electric drilling machine has the capability of performing directional drilling over large distances both onshore and offshore. This includes drilling pipelines under large and deep rivers, across large topographical features like cliffs or subsea escarpments. Other applications for the subterranean electric drilling machine include near surface drilling in urban areas for installation or replacement of utilities like water lines, gas mains, sewers, storm drains, underground power lines, and communication lines, including broadband cables and fiber optic cables. The selected drill bit would be sized for the application. These preferred embodiments are not further described herein in the interests of brevity.

FIG. 16is similar toFIG. 9, except here the well is being drilled from an onshore wellsite. Subterranean electric drilling machine94is disposed within a previously installed borehole casing362that is surrounded by existing downhole cement364. The subterranean electric drilling machine94was described in relation to FIG.6. The subterranean electric drilling machine is in the process of drilling a new borehole366into geological formation368. Expandable casing370is carried into the new borehole by the subterranean electric drilling machine. Umbilical372connects the subterranean electric drilling machine to a land-based drill center374that has the hoist, the computer systems, the umbilical carousel, etc. Surface casing376is surrounded by cement378. The bottom of the surface casing is connected to previously installed casing362by casing string380. The ocean382has ocean surface384and ocean bottom386. Here, the new borehole is being drilled beneath the ocean from a land-based drill center. The land388joins the ocean at a beach390.

FIG. 17is similar to FIG.9andFIG. 16, except here the well is being drilled from a land based drill site. Subterranean electric drilling machine94is disposed within a previously installed borehole casing392that is surrounded by existing downhole cement394. The subterranean electric drilling machine94was described in relation to FIG.6. The subterranean electric drilling machine is in the process of drilling a new borehole396into geological formation398. Expandable casing400is carried into the new borehole by the subterranean electric drilling machine. Umbilical402connects the subterranean electric drilling machine to the land based drill site generally designated by element404. Shown figuratively are hoist406; the umbilical carousel, computers, etc.408; and another section of umbilical410. Element411figuratively shows a lubricator. Surface casing412is surrounded by cement414. The bottom of the surface casing is connected to previously installed casing392by casing string416. The surface of the earth is identified by element418.

FIG. 18shows a subterranean electric drilling machine420that is drilling an open borehole in the earth. Element420is called an open hole subterranean electric drilling machine. Electric motor422turns shaft424that rotates the rotary drill bit426that drills borehole428in geological formation430. First anchor and weight on bit mechanism (AWOBM)432is connected to second anchor and weight on bit mechanism (AWOBM)434by extensible shaft436, which elements comprise an anchor mechanism. Shaft438connects the female side of universal mud and electrical connector440to the male side of universal mud and electrical connector442. Progressing cavity pump444is driven by its pump motor446. Inflatable seal448surrounds the progressing cavity pump that makes a positive seal against the borehole wall of geological formation449. The progressing cavity pump has inlet450and outlet452. The inflatable seal448and the progressing cavity pump form a Smart Shuttle that can be used to move the open hole subterranean electric drilling machine shown inFIG. 18in and out of the hole. Centralizer454is attached to the portions of the tool body having electronics456and bidirectional communications458with the surface. Mud carrying umbilical460is connected to the cable head462that provides electrical power and mud to the open hole subterranean electric drilling machine. Mud from the surface through the umbilical proceeds down the interior of various elements of the drilling machine that are not shown for simplicity, and then mud laden cuttings return to the surface through the annulus464between the borehole wall and the outside diameter of the umbilical. The arrows inFIG. 18show the direction of mud flow. The inflatable seal448surrounding the progressing cavity pump is partially collapsed during actual drilling operations to allow the mud to pass. The inflatable seal448is inflated when quickly transporting the open hole subterranean electric drilling in and out of the well. In view of the detailed description provided in FIG.6and elsewhere, and in view of the description herein, it is now evident how the open hole subterranean electric drilling machine functions. Accordingly, no further detail will be presented here in the interests of brevity.

FIG. 19shows another subterranean electric drilling machine466that is drilling an open borehole in the earth. Element466is another embodiment of an open hole subterranean electric drilling machine called a “screw drive subterranean electric drilling machine”.FIG. 19is similar to FIG.18. Elements422,424,426,432,434,436,438,440and442have been defined in relation to FIG.18.

The fundamental change inFIG. 19is that the form of the Smart Shuttle shown inFIG. 18has been replaced by the screw translator device468. Element470has an electric motor472(not shown for simplicity), related electronics, and bidirectional communications electronics. When electric motor472rotates the screw blades474, then friction against the mud in the hole476causes the screw translation device468to translate within the hole (if the anchor means of elements432and434are in their retracted positions). Reversing the rotation of the screw blades reverses the direction of translation within the borehole. The female side of universal mud and electrical connector478is attached to the male side of universal mud and electrical connector480, that is in turn connected to umbilical482, however, elements480and482are not shown inFIG. 19for the purposes of simplicity. Centralizers484centralize element470within the wellbore486. The arrows show the path of the mud flow during drilling operations. In view of the previous disclosure, it is evident how the screw drive subterranean electric drilling machine is used to drill the new borehole488in the geological formation490.

In another preferred embodiment inFIG. 19, the screw blades474have a variable pitch, where the distance between successive blades is a smaller distance to the right-hand side ofFIG. 19than to the left-hand side of FIG.19. In yet another preferred embodiment, the pitch between the screw blades474is variable and controlled by the surface computer system26. Various embodiments of the “screw drive subterranean electric drilling machine” are further described in U.S. Disclosure Document No. 494374 filed on May 26, 2001, that is entitled in part “Continuous Casting Boring Machine”, an entire copy of which is incorporated herein by reference.

FIG. 20shows a cross section of another embodiment of an umbilical used for subterranean electric drilling machines and for open hole subterranean electric drilling machines. A version ofFIG. 20was originally filed in the U.S.P.T.O. on the date of Oct. 2, 2000 as a portion of U.S. Disclosure Document 480550. Umbilical492contains at least one insulated electrical conductor494. Each such conductor has electrical copper conductors496encapsulated by electrical insulation498. As shown inFIG. 20, there are a total of8such insulated electrical conductors. In one embodiment, the insulated electrical conductors may be chosen to be the same as shown in FIG.1. Also shown is high speed bidirectional data communications means500, which may be a fiber optic cable or a coaxial cable. The insulated electrical conductors and the high speed bidirctional data communication means is encapsulated by first composite material502. Second composite material504surrounds first composite material. As described above, the specific gravities of composite materials502and504may be engineered so that the umbilical492is substantially neutrally buoyant in wellbore fluids.

In one preferred embodiment of the invention inFIG. 20, the second composite material502is chosen for its good strength, durability against abrasion in the well, and perhaps for its electrical insulation properties. In one embodiment ofFIG. 20, the first composite material is chosen so with a particular specific gravity such that the overall umbilical is neutrally buoyant in typical well fluids (in 12 lb per gallon mud, for example, or in salt water, as another example). As previously discussed, syntactic foam materials having silica microspheres as provided by the Cumming Corporation (www.emersoncumming.com) for such purposes. The details on pressure balanced silica microspheres in syntactic foam may be reviewed in Attachment28to the Provisional Patent Application No. 60/384,964 filed on Jun. 3, 2002 that is entitled “Umbilicals for Well Conveyance Systems and Additional Smart Shuttles and Related Drilling Systems”, an entire copy of which is incorporated herein by reference.

The interior506of the umbilical is used to provide drilling fluids or cement downhole as required. Therefore, different embodiments of umbilicals provide electric power downhole, bidirectional communications, and provide the ability to conduct fluids to and from the borehole, which are neutrally buoyant in the fluids present. Umbilicals handling well fluids are also useful with a number of well services including the use with straddle packers, injection tools, oil gas separators, flow line cleaning tools, valves, etc. In another preferred embodiment, the interior506may be filled with composite materials to provide extra strength for certain applications that is also substantially neutrally buoyant.

FIG. 21shows yet another neutrally buoyant composite umbilical in 12 lb per gallon mud. Outer spoolable composite tubing508has an OD shown by legend OD6, and has an ID shown by legend ID6. In a preferred embodiment, OD6 is equal to 1.75 inches O.D., and ID6 is equal to 1.25 inches I.D. In one preferred embodiment, the composite tubing is chosen to have a specific gravity of 1.50.

Three each 0.355 inch O.D. insulated No. 4 AWG Wires510,512and514are disposed within the I.D. of the spoolable composite tubing. Optical fiber516is also disposed within the spoolable composite tubing. The remaining available volume within the spoolable composite518is then filled with pressure balanced silica microspheres in syntactic foam that has a specific gravity of 0.60. A calculation shows that this umbilical in 12 lbs/gallon mud weighs-50 lbs for every 1,000 feet. Assuming a coefficient of friction of 0.2, at 20 miles the umbilical could pull back with a frictional force of 1,056 lbs. So, this umbilical is substantially neutrally buoyant (or simply “neutrally buoyant” as defined below).

InFIG. 21, the insulated wire is rated at 14,000 volts. This particular wire is Part Number FEP4FLEXSC available through Allied Wire & Cable located in Bridgeport, Pa. This wire was previously described in relation to FIG.1. As is evident from the discussion involvingFIG. 1, the three power conductors can provide 160 horsepower (119 kilowatts) at 20 miles to do work at that distance. No fluids are conducted down the interior of this umbilical generally designated by element520in FIG.21. This umbilical is also useful for other applications to be discussed later.

Selecting different specific gravities for the pressure balanced silica microspheres in syntactic foam that fills the volume within the spoolable composite518allows different preferred embodiments to be designed to be neutrally buoyant within different well fluids having different densities. As a practical matter, an umbilical having a particular density will be used within a range of acceptable densities of well fluids.

FIG. 22is a schematic drawing that shows a ship performing subsea well servicing. Ship522in ocean524possesses an umbilical carousel526having umbilical528that proceeds through lubricator530that houses Smart Shuttle532. Subsea well534on the ocean bottom535has mating equipment536that mates to mating equipment538of the lubricator530. The lubricator is guided into place by remotely operated vehicle540obtaining its power and communications from umbilical542. The umbilical carousel for umbilical542is not shown for simplicity.

Upon entering the subsea well, the Smart Shuttle is to proceed through the base of the lubricator544and into the wellbore below (not shown in FIG.22). There, the Smart Shuttle is to perform a well workover that requires fluids to be injected into formation such as acids. Umbilical528may be selected to be a suitable umbilical including umbilical2inFIG. 1, and umbilical492in FIG.20. Equipment resembling what is shown inFIG. 5is on board the ship so that a computer system can control the workover operations.

In this case, umbilical542need not provide fluids to the remotely operated vehicle540. Therefore, umbilical542may be chosen from umbilicals that includes umbilical520in FIG.21. Equipment resembling what is shown inFIG. 5is also onboard ship so that a computer system can control the remotely operated vehicle540. The upper end of umbilical542proceeding to its carousel is not shown on the left-hand side ofFIG. 22for simplicity. In this case, the umbilical542is designed to have any desired buoyancy in sea water, that specifically includes densities greater than sea water, as is conventional in the industry. The apparatus and methods to control the power and communications is similar to that shown inFIGS. 2,3,4and5and will not be repeated here for the purpose of brevity. In one preferred embodiment, over 60 kilowatts of power is provided by umbilical542to remotely operated vehicle540. This power is provided to the load of the remotely operated vehicle, which in several preferred embodiments, is an electric motor that drives a propeller that provides thrust for the remotely operated vehicle. For simplicity,FIG. 22does not show a free floating remotely operated vehicle (ROV) tethered to the ship by a free floating umbilical.

FIG. 23is a schematic drawing similar to FIG.22.FIG. 23also shows a ship performing subsea well servicing. Ship546in ocean548possesses a first umbilical carousel550(not shown inFIG. 23for simplicity) having umbilical552that proceeds through lubricator554that houses Smart Shuttle556. Subsea well558on the ocean bottom560has mating equipment562that mates to mating equipment564of the lubricator554. The lubricator is guided into place by first remotely operated vehicle566that obtains its power and communications from umbilical568that is deployed from second umbilical carousel570(not shown inFIG. 23for simplicity). In this case, the umbilical568is designed to have any desired buoyancy in sea water, that specifically includes densities greater than sea water as is conventional in the industry. The upper end of umbilical568proceeding to carousel570near the top of the crane on the right-hand side ofFIG. 23is not shown for simplicity.

Upon entering the subsea well, the Smart Shuttle is to proceed through the base of the lubricator572and into the wellbore below (not shown in FIG.22). There, the Smart Shuttle is to perform a well workover that does not necessarily require fluids to be injected into formation. Therefore, umbilical552may be selected to be a suitable umbilical including umbilical520in FIG.21. Equipment resembling what is shown inFIG. 5is on board the ship so that a computer system can control the Smart Shuttle, and any equipment attached to the Smart Shuttle, during workover operations.

In this case, umbilical568need not provide fluids to first remotely operated vehicle566. Therefore, umbilical568may be chosen from umbilicals that includes umbilical520in FIG.21. Equipment resembling what is shown inFIG. 5is also onboard ship so that a computer system can control first remotely operated vehicle566. In this case, the umbilical568is designed to have any desired buoyancy in sea water, that specifically includes densities greater than sea water as is conventional in the industry. The apparatus and methods to control the power and communications to first remotely operated vehicle are similar to that shown inFIGS. 2,3,4and5and will not be repeated here for the purpose of brevity.

FIG. 23shows second remotely operated vehicle574that obtains its power and communications from umbilical576that is deployed from third umbilical carousel578(not shown inFIG. 23for simplicity). Second remotely operated vehicle574is to suitably attach to the subsea well558and is to remove fluids from the wellbore. Therefore, umbilical576may be selected to be a suitable umbilical including umbilical2in FIG.1and umbilical492in FIG.20. The upper end of umbilical576proceeding to carousel578near the top of the crane on the left-hand side ofFIG. 23is not shown for simplicity. Equipment resembling what is shown inFIG. 5is on board the ship so that a computer system can control the operation of second remotely operated vehicle574. In this case, the umbilical576is designed to have any desired buoyancy in sea water, that specifically includes densities greater than sea water as is conventional in the industry. In one preferred embodiment, over 60 kilowatts of power is provided by umbilical576to remotely operated vehicle574. This power is provided to the load of the remotely operated vehicle, which in several preferred embodiments, is an electric motor that drives a propeller that provides thrust for the remotely operated vehicle. In other embodiments, this power is provided to an electric motor that drives a downhole pump. For simplicity,FIG. 23does not show a free floating remotely operated vehicle (ROV) tethered to the ship by a free floating umbilical.

InFIGS. 22 and 23, the feedback control of the voltage, RPM, current, and other parameters of an electric motor within an remotely operated vehicle is accomplished by analogy to that disclosed in relation to the electric motor of the subterranean electric drilling machine. In the interests of brevity, this feedback control of remotely operated vehicles will not be further discussed.

FIG. 24shows one embodiment of the Smart Shuttle™ generally designated with the numeral580that is located within a “pipe means”582that includes a casing, drill pipe, tubing, etc. The Smart Shuttle is comprised of a progressive cavity pump584that has a rotor586and stator588as is typical of such pumps. The progressive cavity pump is coupled to gear box590that is in turn coupled to the electrical submersible motor592, which in turn is connected to electronics assembly594having any downhole computer, the downhole sensors, and communications system, which in turn is connected by the quick change collar596to the umbilical head598that is connected the umbilical600.

The lower wiper plug assembly602has sealing lobe604and this assembly is firmly attached to the body of the progressive cavity pump at the location shown in FIG.24. Lower wiper plug assembly has lower bypass passage606which has electrically operated valves608and610. The upper wiper plug assembly612has sealing lobe614and this assembly is firmly attached to the sections of the apparatus having the gear box and the electrical submersible motor at the location shown in FIG.24. The upper wiper assembly also has permanently open upper bypass port616in the embodiment shown in FIG.24.

In terms ofFIG. 24, and when the electrical submersible motor is suitably turning the rotor of the progressive cavity pump (PCP), a volume of fluid ΔV2 per unit time in the wellbore is pumped into the lower side port618of the PCP and out of the upper side port620of the PCP. With valves608and610closed, the fluid ΔV2 is then forced through the upper bypass port616into the portion of the well above the upper surface of the upper wiper plug assembly. In this manner, the Smart Shuttle is then forced downward into the wellbore. The Retrieval Sub620is attached to the body of the Smart Shuttle by quick change collar622that in turn is connected to the lower body of the progressive cavity pump. This, and related embodiments of the Smart Shuttle is used to transport equipment attached to the Retrieval Sub into wells and out of wells. The Smart Shuttle is an example of a “well conveyance means”, or simply, a “conveyance means”. Fluid conduction means624is able to conduct any fluids available from umbilical600through the Retrieval Sub620, although that fluid conduction means624is not shown inFIG. 24for simplicity. Fluid conduction means624is fabricated using tubing and technology currently available in the oil and gas industry.

FIG. 25shows another well conveyance means. Umbilical626possesses one or more electrical conductors. In several preferred embodiments, umbilical626possesses one or more high power electrical conductors. Umbilical head628connects the umbilical to tractor conveyor630. The tractor conveyor has at least one friction wheel632which engages the interior of pipe634. The tractor conveyor has four friction wheels as shown in FIG.25. Quick change collar assembly635connects the tractor conveyor to the Retrieval Sub636.

The tractor conveyor630with its Retrieval Sub636installed inFIG. 25is an example of a “tractor conveyance means”, a “tractor deployer”, or a “downhole tractor deployment device”. Electrical energy delivered via the umbilical to the tractor conveyor is used to drive electrical motors and/or electro-hydraulic systems637to provide rotational energy to the friction wheels (although the details of element637are not shown inFIG. 25for simplicity). That rotational energy causes the tractor conveyor to move within the well.

The tractor conveyance means inFIG. 25provides similar operational features as different embodiments previously described heretofore as Smart Shuttles. Fluid conduction means638is able to conduct any fluids available from umbilical626through the Retrieval Sub636, although that fluid conduction means638is not shown inFIG. 24for simplicity. Fluid conduction means638is fabricated using tubing and technology currently available in the oil and gas industry.

By analogy with the Smart Shuttle, one embodiment of the tractor conveyance means may be used as a portion of an “automated well drilling and completion system”. As described herein, this automated system is called the “tractor conveyance system” or the “automated tractor conveyance system”. The tractor conveyance means is substantially under the control of a computer system that executes a sequence of programmed steps that has at least one computer system located on the surface of the earth and has means to convey at least one completion device attached to the Retrieval Sub into the wellbore under the automated control of the computer system. The automated system has at least one sensor means located within the tractor conveyance means, has first communications means that provides commands from the computer system to the tractor conveyance means, has second communications means that provides information from the sensor means to the computer system, where the execution of the programmed steps of the computer system to control the tractor conveyance means takes into account information received from the sensor means to optimize the steps executed by the computer system to drill and complete the well.

The Retrieval Sub can be attached to a number of the devices shown in FIG.26. Those devices include any commercial tool or device640; any logging tool642; any torque reaction centralizer644; any scraper646; any perforating tool648; any flow meter650; any Downhole Rig with rotary bit652; any Universal Completion Device™654; any straddle packer656; any injection tool658; any oil/gas separator660; any flow line cleaning tool662; any casing expanding tool664; any plug666; any valve668; and any locking mechanism670. These different tools are either defined in applicant's applications or are tools used in the oil and gas industry. The point is that any of these devices can be attached to the Retrieval Sub of the Cased Hole Smart Shuttle672or to the Retrieval Sub of the Open Hole Smart Shuttle674. These devices may similarly be attached to the Retrieval Sub of the tractor conveyance means. Each such device in this paragraph may be called a “completion device” and collectively, these may be referenced as “completion devices”.

These devices specified in the previous paragraph may be used for a variety of different purposes in the oil and gas industry. Many of those tools can be used to serve wells. Please refer toFIG. 27that shows a diagrammatic representation of functions that may be performed with the Smart Shuttle or the Well Locomotive.FIG. 27shows that the Smart Shuttle or the Well Locomotive shown diagrammatically as element676may be used for the purposes of completion678(ie., to perform completion services on a well); production & maintenance680(ie., to perform production and maintenance services on a well); enhanced recovery682(ie., to perform enhanced recovery services on a well); and for drilling684. Under completion functions, or “completion services”, the Smart Shuttle and Well Locomotive may be used for the completion of extended reach lateral wells686; for logging and perforating688; for stimulation and fluid services690; may be used to install the Universal Completion Device™692; and may be used to install completion hardware such as plugs, valves, gages, etc.694. Under production and maintenance functions, or “production and maintenance services”, the Smart Shuttle and Well Locomotive may be used for flow assurance services696; for maintenance and repair698; for workovers, that include logging, perforating, etc.,700; and for reservoir monitoring and control702. Under enhanced recovery functions, or “enhanced recovery services”, the Smart Shuttle and Well Locomotive may be used for recompletions, well extensions, and laterals704; to install downhole separators706; to perform artificial lift708; to facilitate downhole injection710; and for fluid services712. Under drilling functions, or under “drilling services”, the Smart Shuttle and the Well Locomotive may be used for casing drilling purposes714; for liner drainhole drilling purposes716; for coiled tubing drilling718; and for extended reach lateral drilling720. Extensive details are provided in about each of these functions in the related U.S. Disclosure Documents and in the related Provisional Patent Applications cited above.

Any one or more of the functions provided in the previous paragraph is called a “well service”. Two or more of such functions are called “well services”. The execution of the programmed steps of the automated computer system to control the Smart Shuttle™, or tractor conveyance means, takes into account information received from the sensor means within the tractor conveyance means to optimize the steps executed by the computer system to service the well.

The above umbilicals have stated calculations pertaining to lengths of 20 miles. However, the umbilicals can be any length from 100's of feet to 20 miles. The extreme distance of 20 miles was chosen to show neutrally buoyant umbilicals can provide high power and high speed data communications at great distances that has heretofore not been recognized in the oil and gas industry.

As stated previously, the phrase “substantially neutrally buoyant”, “essentially neutrally buoyant”, “near neutral buoyant”, and “approximately neutrally buoyant” may be used interchangeably. In several preferred embodiments of the invention, the meaning of these terms is that in the presence of the well fluids, that the buoyancy of the umbilical causes the typical friction of the umbilical against the well to be substantially reduced.

As stated earlier, the tractor conveyor tractor conveyor630with its Retrieval Sub636inFIG. 25is an example of a “conveyance means”, a “tractor conveyance means”, a “tractor deployer”, or a “downhole tractor deployment device”. There are many “well tractors”, or devices related to well tractors, a selection of which are described in the following documents: U.S. Pat. Nos. 6,347,674; 6,345,669; 6,318,470; 6,296,066; 6,273,189; 6,257,332; 6,241,031; 6,241,028; 6,225,719; 6,179,058; 6,179,055; 6,173,787; 6,089,323; 6,082,461; 5,954,131; 5,794,703; 5,547,314; 5,375,668; 5,209,304; 5,184,676; 5,121,694; 5,018,451; 5,040,619; 4,960,173; 4,686,653; 4,643,377; 4,624,306; 4,570,709; 4,463,814; 4,243,099; 4,192,380; 4,085,808; 4,071,086; 4,031,750; 3,969,950; 3,890,905; 3,888,319; 3,827,512; in EP0564500B1; and in WO9806927; WO9521987; WO9318277; and WO9116520; entire copies of which are incorporated herein by reference. Entire copies of the 39 cited references in this paragraph are incorporated herein by reference. Many of these devices are means to cause or generate movement within wellbores. Such “movement means” may be attached to a device similar to the Retrieval Sub636. Devices similar to Retrieval Sub636are called “retrieval means”. So, movement means may be coupled to retrieval means to make a “tractor conveyance means”, or tractor deployers, or downhole tractor deployment devices.

In view of the above, several embodiments of this invention use a closed-loop system to service a well for producing hydrocarbons from a borehole in the earth having at least one computer system located on the surface of the earth, which possess at least one conveyance means to convey at least one completion device into the borehole under the automated control of the computer system that executes a series of programmed steps, which possess at least one sensor means located within the conveyance means, which have first communications means that provides commands from the computer system to the conveyance means and possessing second communications means that provides information from the sensor means to the computer system, whereby the execution of the programmed steps by the computer system to control the conveyance means takes into account information received from the sensor means to optimize the steps executed by the computer to service the well. Such system is called a “closed-loop tractor conveyance system”. The closed-loop system may also be used to monitor and control production of hydrocarbons from the wellbore.

The above described umbilicals, and other variations of such umbilicals that meet the above defined operational specifications, could be manufactured on a contractual basis by a firm called ABB Offshore Systems that is located in Stavanger, Norway, that has its U.S.A. office that may be reached through ABB Offshore Systems, Inc., having the address of 8909 Jackrabbit Road, Houston, Tex. 77095, having the telephone number of (281) 855-3200, that has its website that can be reached through www.abb.com. The above described umbilicals, and other variations of such umbilicals that meet the above defined operational specifications, might be manufactured on a contractual basis by a firm called the Fiberspar Corporation that may be reached at 28 Patterson Brook Road, West Warehan, Mass. 02576, having the telephone number (508) 291-9000, which has its website at www.fiberspar.com. This firm is capable of supplying various spoolable composite tubes capable of being spooled onto a reel having relevant anisotropic characteristic, a specified burst pressure, a specified collapse pressure, a specified tensile strength, a specified compression strength, a specified load carrying capacity, which is also bendable. Some of these tubes include an inner liner material, an interface layer, fiber composite layers, a pressure barrier layer, and an outer protective layer. The fiber composite layers can have triaxial braid structure. The composites may be fabricated from carbon-based composites.

In the above, syntactic foam materials were described in various preferred embodiments to change the apparent buoyancy of an umbilical in the presence of other surrounding fluids. However, any material of a different density may be used for this purpose.

A preferred embodiment above has described an apparatus to drill oil and gas wells having subterranean electric drilling machine disposed in a wellbore such as that shown as element94FIG.6. The subterranean electric drilling machine possesses at least one downhole electric motor that is shown as element114in FIG.6. This electric motor rotates a rotary drill bit identified as elements106,110and112in FIG.6. This electric motor rotates the drill bit at a selected RPM determined by the frequency, current and voltage applied to input terminals of the electric motor as shown in FIG.2and in FIG.3. One advantage of such an electrically operated drill bit operating at relatively high RPM is that it produces very fine rock cuttings that are easily transported to the surface by mud flow. The input terminals of the electric motor are identified as the inputs to the downhole electrical load22inFIG. 2, which in several embodiments is an electric motor, which are also attached to the sensing unit24. The input terminals of the electric motor are shown a the leads attached to either side of element34in FIG.2. The electric motor operates properly with a particular voltage level applied to its electrical input. Please refer to the preferred embodiment discussed in relation to electric motor34in FIG.3. It is important to note that in several preferred embodiments, the electrical motor34inFIG. 3is dissipating 160 horsepower (119 kilowatts). A surface power supply means located on the surface of the earth provides a voltage output that is identified with element20in FIG.2. An umbilical means disposed in the wellbore surrounded by well fluids connecting the surface power supply means to the subterranean electric drilling machine provides electrical power to the electrical input of the electric motor. For example, such an umbilical means is shown as element116in FIG.6and in FIG.9. The umbilical means possesses insulated electric wires as shown inFIGS. 1, and20. The umbilical means possess high speed data communications means such as high speed data link14in FIG.1. The umbilical means possesses a fluid conduit for conveying drilling fluids through the interior of the umbilical means such as element8inFIG. 1 and 506in FIG.20. The preferred embodiment has means to measure first voltage applied to the first electrical input of the electrical motor as shown by element24in FIG.2. The preferred embodiment possesses means to transmit information related to the measured first voltage through a high speed data communications means within the umbilical to a computer located on the surface of the earth by using the high speed data link14in FIG.1. The embodiment further possesses computer controlled means to adjust the first voltage output as shown by element28in FIG.2. The computer system26inFIG. 2is used to maintain first voltage input at a particular voltage level to provide proper operation of the electric motor within the subterranean electric drilling machine.

In several preferred embodiments, the electric motor34inFIG. 3dissipates in excess of 60 kilowatts. This is important because it is the recollection of the inventors that several scientists and senior managers of a major oil services company stated their opinions that it would be impossible to provide over 60 kilowatts to an electric motor, or any other electrical load, at distances of up to 20 miles from a wellsite through any type of reasonably sized umbilical that would be practical to use within wellbores. According to the recollection of the inventors, these senior managers and scientists clearly stated their opinions before the invention herein was disclosed to those particular individuals. Yet further from this recollection, it apparently never occurred to these same scientists and senior managers that any such umbilical delivering in excess of 60 kilowatts could also be neutrally buoyant. However, only after disclosure of the invention herein to those scientists and senior managers, did they apparently accept that such umbilicals could be designed and built. Accordingly, because the individuals involved are well known in the oil and gas industry, and are experts in fields directly pertaining to the invention, the preferred embodiment described herein is not obvious to one having ordinary skill in the art.

Therefore, a preferred embodiment is an apparatus to drill oil and gas wells comprising:(a) a subterranean electric drilling machine disposed in a wellbore that possesses at least one electric motor that rotates a rotary drill bit at a selected RPM, whereby the electric motor possesses first electrical input, whereby the electric motor properly operates with a particular voltage level applied to first electrical input, and whereby the electric motor dissipates in excess of 60 kilowatts with the particular voltage level applied to the first electrical input;(b) surface power supply means located on the surface of the earth providing first voltage output;(c) umbilical means disposed in the wellbore surrounded by well fluids connecting the surface power supply means to the subterranean electric drilling machine that provides electrical power to the first electrical input of the electric motor, whereby the umbilical means possesses insulated electric wires, whereby the umbilical means possesses high speed data communications means, and whereby the umbilical possesses a fluid conduit for conveying drilling fluids through the interior of the umbilical means;(d) means to measure first voltage applied to the first electrical input of the electrical motor;(e) means to transmit information related to the measured first voltage through the high speed data communications means within the umbilical to a computer located on the surface of the earth;(f) computer controlled means to adjust the first voltage output so as to maintain first voltage input at the particular voltage level to provide proper operation of the electric motor within the subterranean electric drilling machine.

Another preferred embodiment of the invention described in the previous paragraph provides an umbilical means that a approximately neutrally buoyant within the well fluids to reduce the frictional drag on the neutrally buoyant umbilical.

In view of the above disclosure, yet another preferred embodiment is the method of feed-back control of an electric motor having at least one voltage input located within a subterranean electric drilling machine located in a borehole that dissipates at least 60 kilowatts that receives power from a surface power supply through an umbilical surrounded by well fluids that possesses at least two insulated electric wires, whereby the umbilical also possesses high speed data link for data communications, comprising the steps of:(a) measuring the voltage input to the electric motor;(b) sending information related to the measured voltage input through the high speed data link to a computer located on the surface of the earth; and(c) using the computer to adjust the voltage output of the surface power supply that is used to control the voltage input to the electrical motor.

Another preferred embodiment of the invention described in the previous paragraph provides an umbilical that is a approximately neutrally buoyant within the well fluids to reduce the frictional drag on the umbilical.

In view of the above disclosure, yet another preferred embodiment is the method of providing in excess of 60 kilowatts of electrical power to the electrical motor of a subterranean electric drilling machine through a substantially neutrally buoyant composite umbilical containing electrical conductors to reduce the frictional drag on the neutrally buoyant umbilical.

In view of the disclosure related toFIGS. 22 and 23, it is evident that the invention may be used to provide electrical power to an electric motor located within a remotely operated vehicle. Accordingly, a preferred embodiment of the invention provides a method of feed-back control of an electric motor having at least one voltage input located within a remotely operated vehicle that dissipates at least 60 kilowatts that receives power from a power supply located on a ship through an umbilical surrounded by sea water that possesses at least two insulated electric wires, whereby the umbilical also possesses high speed data link for data communications, comprising the steps of:(a) measuring the voltage input to the electric motor;(b) sending information related to the measured voltage input through the high speed data link to a computer located on the ship; and(c) using the computer to adjust the voltage output of the power supply located on the ship that is used to control the voltage input to the electrical motor.

Accordingly, yet another preferred embodiment of the invention is the method of providing in excess of 60 kilowatts of electrical power to the electric motor of a remotely operated vehicle through an umbilical containing electrical conductors and at least one high speed data communications means.

Several of the above preferred embodiments describe the Subterranean Electric Drilling Machine™, or simply the Subterranean Drilling Machine™ (SDM™), that performs Subterranean Electric Drilling™ (SED™) that is used to construct a Subterranean Electric Drilled Monobore Well™ or an SED Monobore Well™. Several of the above preferred embodiments also describe the Subterranean Liner Expansion Tool™ (SLET™) otherwise called the Casing Expansion Tool™ (CET™).

While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as exemplification of preferred embodiments thereto. As have been briefly described, there are many possible variations. Accordingly, the scope of the invention should be determined not only by the embodiments illustrated, but by the appended claims and their legal equivalents.