Disconnect assembly for cylindrical members

An assembly for disconnecting portions of a downhole tubular string, such as a drill stem or drill string, and removing an upper portion of the tubular string from the lower stuck portion in a well, includes a connection between joints of two portions of the tubular string. The assembly includes two tubular members and an inner sleeve having two splines each with different angular pitches or teeth counts. The assembly may include a rotary shouldered threaded connection, wherein the two tubular portions are disconnectable at the rotary shouldered threaded connection in the assembly. The assembly may include a sleeve lock, a selective no-go for landing in a profile, and a selectively deployable unlocking and unblocking tool for activating the assembly. The assembly may include connectable cylindrical members other than downhole tubulars.

BACKGROUND

This disclosure relates to releasable connections between cylindrical members or bodies. In some aspects, this disclosure relates to connections between downhole tubulars, such as drill pipe tool joints, as are employed in the rotary system of drilling. More particularly, the downhole tubular connections or drill pipe tool joints include connections configured to be selectively disconnectable within the well bore, such that upper and lower portions of the downhole tubular string can be separated.

In drilling by the rotary method, a drill bit is attached to the lower end of a drill stem composed of lengths of tubular drill pipe and other components joined together by tool joints with rotary shouldered threaded connections. In this disclosure, “drill stem” is intended to include other forms of downhole tubular strings such as drill strings and work strings. A rotary shouldered threaded connection may also be referred to as a RSTC. Furthermore, the tubular members that make up a drill stem may also be substituted with other rods, shafts, or other cylindrical members that may be used at the surface and which may require a releasable connection.

The drill stem may include threads that are engaged by right hand and/or left hand rotation. The threaded connections must sustain the weight of the drill stem, withstand the strain of repeated make-up and break-out, resist fatigue, resist additional make-up during drilling, provide a leak proof seal, and not loosen during normal operations.

The rotary drilling process subjects the drill stem to tremendous dynamic tensile stresses, dynamic bending stresses and dynamic rotational stresses that can result in premature drill stem failure due to fatigue. The accepted design of drill stem connections is to incorporate coarse tapered threads and metal to metal sealing shoulders. Proper design is a balance of strength between the internal and external threaded connection. Some of the variables include outside diameter, inside diameters, thread pitch, thread form, sealing shoulder area, metal selection, grease friction factor and assembly torque. Those skilled in the art are aware of the interrelationships of these variables and the severity of the stresses placed on a drill stem.

The tool joints or pipe connections in the drill stem must have appropriate shoulder area, thread pitch, shear area and friction to transmit the required drilling torque. In use, all threads in the drill string must be assembled with a torque exceeding the required drilling torque as a minimum, or more to handle tensile and bending loads without shoulder separation because shoulder separation causes leaks and fretting wear.

Drill stem and tool joints with rotary shouldered threaded connections are addressed by industry accepted standards such as, but not limited to: International Industry Standard (ISO), ISO 10424-1:2004 (modified)—Part 1 and Part 2; Petroleum and natural gas industries-Rotary drilling equipment—Part 1: Rotary drill stem elements; American Petroleum Institute (API), API 7-1 Specification for Rotary Drill Stem Elements; API 7G Recommended Practice for Drill Stem Design and Operating Limits; and others. These standards address design, manufacture, use and maintenance of drill stem thread joints.

Offshore drilling, for example, is performed in progressively deeper water, with deeper penetration of the earth and possibly having higher deviations from a vertical bore hole. Further, many wells now have sections of horizontal bore hole. The temperatures are high, the friction between drill stem and borehole is high, the hanging weight is extreme and the well bores may not be straight. Consequently, a portion of the drill stem often becomes stuck at a great distance from the surface, preventing its movement and recovery. Further causes of stuck drill pipe include accumulation of cuttings falling out of circulated fluids, unconsolidated earth caving in the borehole, low pressure strata capturing the drill stem due to differential pressure, and the like.

In rotary drilling, to remove stuck drill stem from the well, typically the first remedial action is to identify the point at which the drill stem is stuck. A decision is then often made to either explosively loosen a thread joint or sever the drill stem with highly reactive explosive or chemical tools.

Highly specialized crews, equipment and tools must be mobilized and transported to the well location. The transportation of explosive or highly reactive chemical tools is subject to tight governmental regulation. The use of such explosive or highly reactive chemical tools presents a risk to the well operation in that the possibility exists that accidental discharge on the surface can cause property damage and injury or death to personnel. Mobilization and transportation can consume a significant amount of expensive, non-productive time.

Current tubing disconnects designed for within-the-well-bore activation are lacking. In the discussion below, tubing disconnects are disposed in work strings or pipe strings used for coiled tubing drilling, well completion, workover, and other services less demanding than rotary drilling. Consequently, current tubing disconnects do not meet the requirements of the ISO and/or API specifications for rotary drilling equipment. They incorporate non-shouldered connections and/or connections that do not establish a stress pattern within the connection to prevent shoulders from separation under extreme tension and/or bending loads.

Further, current tubing disconnects employ non-metal seals. Failure of one of these seals may result in a washout or total joint failure. The sliding fit of the seals facilitates fretting and wear as the tubing is flexed in response to axial, bending and rotational forces. Some tubing disconnects make use of springs or washers that restrict the inside diameter of the tubing string, or leave a connection in the well that cannot be easily reconnected without special tools. Some tubing disconnects leave a ball or other activation device in the well that can inhibit additional work that may be required after recovery of the upper unstuck tubing section.

Various current tubing disconnects are intended for very specific applications. Often, the environment in which these tubing disconnects are operated is relatively stable and predictable. For example, such tubing disconnects are intended for releasing perforating guns after firing, sub-sea risers, or coiled tubing drilling bits. However, such tubing disconnects do not have the ruggedness and are not designed to operate in the extremes of rotary drilling. Such tubing disconnects often include mechanical features that a driller would recognize as a weak link in a rotary drill stem.

Some current tubing disconnects include pressure activation, requiring the ability to circulate fluids within the well tubing. Pressure activated tubing disconnects are typically activated by dropping or pumping a ball or like device to engage a seat, so that pressure may be applied down the tubing to initiate disconnection. Without circulation, differential pressure cannot be reliably established to disconnect the tubing. The seat is a restriction to and subject to damage by the passage of instruments such as measurement while drilling tools and the like. Accidental impact of tools passing the seat may initiate inadvertent and unwanted disconnection. If the well tubing is plugged, a circulation port must be opened before disconnection is possible. A circulation port degrades the reliability and pressure integrity of the tubing.

In the process of drilling a well, a drill bit and drill stem may drill a significant distance into the earth without requiring removal and refitting of a new drill bit. It is problematic to determine where to install a disconnect within the drill stem. Deciding the optimum location of a disconnect requires an accurate estimation of the probable depth of the portion of the drill stem that has become stuck. This problem is compounded because a disconnect is lowered progressively deeper as the well is drilled. The tubing or drill stem may become stuck due to solids, such as sand, falling out of well fluid suspension at any depth within a well.

The several embodiments described herein overcome these and other limitations in the art. By way of example, and in no way limiting the scope of this disclosure, a downhole tubular string disconnect mechanism in accordance with the principles disclosed herein may be configured for selective activation within the well bore, meet industry standards and/or expectations of ruggedness for rotary drilling and other downhole applications, be insensitive to the passage of instruments and tools, not require well fluid circulation, not require pressure application to the drill stem, not leave an obstructed well bore after disconnection, and allow disconnection of a drill stem at selectable, multiple locations by installing multiple disconnects along the length of the drill stem and providing the ability to disconnect the lowest one in the unstuck portion of the drill stem. Other limitations are also overcome, including for cylindrical member couplings such as for drive shafts.

NOMENCLATURE

The words up, upper, upward or upwardly refer to a direction, portion, motion or action that is closer to the surface of the earth and/or closer to the surface of the water and/or that which is further from the bottom of the well.

The words down, lower, downward or downwardly refer to a direction, portion, motion or action that is further from the surface of the earth and/or further from the surface of the water and/or that which is closer to the bottom of the well.

“Rotary shouldered threaded connection” (RSTC) is a tubular connection with rotationally engaged threads and one or more contacting shoulders to limit engagement and relative movement between two tubulars or pipes.

“Tool joint” is a heavy coupling element utilizing a rotary shouldered connection. A tool joint in a drill stem typically has coarse tapered threads and sealing shoulders designed to sustain the weight of the drill stem, withstand the strain of repeated make-up and break-out, resist fatigue, resist additional make up during drilling and provide a leak proof seal. API specifications include a series of numbered tool joint designs; however, proprietary tool joint designs exist that are different from the numbered tool joints of API that include rotary shouldered connections.

“Drill stem” is an assembly of components joined by tool joints for use in a well for rotary drilling. Components such as a drill bit, a bit sub, drill collars, crossover subs, drill pipe, kelley valves, a swivel sub, a swivel and the like are included. “Drill string” is a length of connected drill pipes used for drilling. As previously described, “tubing” refers to those conveyances used for coiled tubing drilling, well completion, workover, and other services less demanding than rotary drilling. The terms “tubular member” or “tubular string” refer to all of the various pipes and strings mentioned above regardless of their specific application in the well.

“Minimum make-up torque” is the minimum amount of torque necessary to develop an arbitrary derived tensile stress in the external thread or compressive stress in the internal thread of a tool joint. This arbitrary derived stress level is perceived as being sufficient in most conditions to prevent downhole make-up and to prevent shoulder separation from bending loads.

“Friction factor” is a value that represents the coefficient of friction of mating surfaces within a threaded connection and the relative magnitude of assembly torque required to achieve a recommended stress level in an assembled connection, as specified by the API.

“Torque turn” is a technique of recording assembly torque and rotation as a thread connection is assembled or disassembled. The collected data is usually analyzed on a computer with specialized software.

“Washout” is a portion of borehole enlarged by erosion of high velocity fluid flow or leakage.

SUMMARY

An assembly for disconnecting and removing an upper portion of a drill stem or tubular string from a well is represented by the various embodiments herein. The drill stem or tubular string may become stuck in the well, and the disconnect assembly may be used to separate an upper portion of the drill stem from a lower, stuck portion of the drill stem. In one embodiment, the disconnect assembly (also referred to as a drill stem disconnect or DSD) comprises an upper body and a lower body connected by a rotary shouldered threaded connection (RSTC), wherein the assembly is adapted to be installed as part of a rotary drill stem. It is understood that the drill stem may be other various kinds of tubular strings, and the RSTC may be other kinds of joints such as non-shouldered joints and joints not meeting specific API standards, without affecting the principles disclosed herein.

The RSTC may be configured to assemble at a lower torque than other connections within the drill stem and meet the requirements of accepted drilling industry standards. The RSTC may be configured to assemble with rotation in either direction. The DSD may be configured to withstand the fatigue caused by dynamic tensile, compressive and rotational loads experienced within a rotary drill stem. The upper and lower bodies, when in a locked position, may be blocked from relative rotation by a third body engaging the upper and lower bodies after proper torque has been applied, thereby assuring retention of proper assembly torque and allowing the transmission of torque equal to the other connections of the drill stem. The third body may be locked in place and may be selectively released and moved from blocking engagement of the upper and lower bodies.

An activation tool, or unlocking and unblocking tool (UUT), may selectively unlock and move the third body out of blocking engagement with at least one of the upper or lower bodies, to allow rotation for disengaging the upper and lower bodies. The tool may be powered by hydrostatic pressure within the well bore. Circulation of well fluids may not be required and pressure need not be applied to the well. An embodiment of the tool may include a selective anchor allowing any one of multiple identical drill stem disconnects installed in the drill stem to be unlocked and unblocked. The UUT may be configured such that it is retained and removed with the upper body and the upper disconnected portion of the drill stem. After removal of the upper disconnected portion of the drill stem, the upward facing connection of the lower body, remaining in the well, is unobstructed, facilitating re-attachment of a later deployed string or tool.

A drill stem tool joint depends on proper assembly torque to achieve optimum performance. If all tool joints in a drill stem similarly configured, then they are typically assembled with the same torque. If the tool joints within a drill stem vary in size, proprietary design, material properties and the like, then they must be assembled with a minimum make up torque value that exceeds the torque value required to be transmitted during drilling operations. If a joint cannot withstand this level of assembly or make up torque, then the joints are sometimes bonded using epoxy compounds. Assembly torque may need to be greater and vary along the length of drill stem to prevent tensile and bending loads from separating the rotary shoulders within a tool joint.

The torque required to disassemble a particular tool joint is a function of assembly torque. More assembly torque results in more disassembly torque necessitated to disassemble the tool joint. Furthermore, tool joints may tighten when in use because of jarring and/or impact of the working drill bit, temperature effects on thread lubricants, and time of use.

When a drill stem becomes stuck within the well bore, it is problematic to determine where along the length of drill stem that reverse torque will disengage a tool joint.

It is possible, within the parameters and equations specified within API 7G, to have tool joints of equal strength that require different minimum assembly torque. For instance, differing friction factors and other variables within the equations specified within API 7G can individually or in combination provide similar variations of required minimum assembly torque. If the equal strength, but lower assembly torque tool joint is rotationally blocked from further assembly or disassembly, it can be used in a drill stem at higher torque levels.

An example of this concept is to assemble identical tool joints with lubricants of different friction factors, the high torque tool joints assembled with high friction factor grease and the low assembly torque joints assembled with low friction factor grease and subsequently disposed to be rotationally blocked from further assembly or disassembly. However, a tool joint assembled with low torque and not rotationally blocked will disassemble with low torque. Thus a stuck drill string will disassemble, through reverse rotation of the upper un-stuck drill string, at an unblocked low assembly torque tool joint location. A rotationally blocked, low assembly torque tool joint that facilitates selective, within-the-well-bore un-blocking, can facilitate the removal of the upper unstuck drill stem and yet satisfy industry standards, such as API 7G, when rotationally blocked.

It is common to utilize so called “Torque Turn” techniques to assure proper assembly of tool joints. This technique accurately measures the torque as a tool joint is rotated during assembly. Those with ordinary skill in the art are aware that, during assembly, there is very little rotation after the rotary shoulders achieve minimum torque as contact is made, and there is little additional rotation to achieve maximum torque.

Those with ordinary skill in the art understand that each time a tool joint is assembled, disassembled and reassembled that variations in angular position between the halves of the tool joint are common due to wear, variations of lubricant thickness and the like.

In some embodiments, a disconnect assembly includes an upper body and a lower body connected by a rotary shouldered threaded connection, adapted to be installed as part of a rotary drill stem. The rotary shouldered threaded connection is adapted to assemble at a lower torque than other connections within the drill stem and meet the requirements of accepted drilling industry standards. The rotary shouldered threaded connection may be configured to assemble with rotation in either direction. The assembly is designed to withstand the fatigue caused by dynamic tensile, compressive and rotational loads experienced within a rotary drill stem. The upper and lower bodies are blocked from further rotation by a third body, or rotational blocking sleeve, engaging the upper and lower bodies after proper torque has been applied, thereby assuring retention of proper assembly torque and allowing the transmission of torque equal to the other connections of the drill stem. The third body is locked in place and may be selectively released and moved from blocking engagement. A locking assembly has a bore larger than surrounding bores and is thus protected from accidental engagement when well bore instruments or tools are passed therethrough.

The rotational blocking sleeve or member provides accurate rotational positioning between the upper and lower bodies for proper torque retention. The blocking sleeve accommodates variations of angular alignment when the upper and lower bodies are properly assembled. In some embodiments, the blocking member is a serrated or splined blocking sleeve that facilitates selective blocking and unblocking of the upper and lower bodies, wherein the upper and lower bodies are joined by a low assembly torque rotary shouldered threaded connection.

In the embodiments disclosed herein, a method is presented that addresses one or more of the limitations noted above. The blocking sleeve is moveable to and from blocking engagement with the upper and lower bodies using a sliding fit including a small amount of angular clearance. The splines or first serration of the upper body include a different number of teeth, or a different angular pitch, than the splines or second serration of the lower body. The blocking sleeve includes accommodating or mating splines or serrations. The blocking sleeve serrations have a progressive, incremental angle between the individual features or teeth forming the serrations because of the differing number of teeth or angular pitch. In one embodiment, the incremental pitch between upper and lower serrations on the blocking sleeve is smaller than the total of the angular clearance between the upper body serration and the upper serration of the blocking sleeve plus the angular clearance between the lower body serration and the lower serration of the blocking sleeve. Thus, no matter how the upper and lower bodies angularly align, the blocking sleeve may be rotated and moved into blocking engagement therebetween.

By way of example, if the blocking sleeve has a 50-tooth serration on one axial end and a 51-tooth serration on the other axial end, the incremental angle will be

Thus, if the total angular clearance is 0.2 degrees, the blocking sleeve may be installed for any angular orientation of the upper and lower splines and the maximum angular deviation from nominal is 0.2 degrees. It is noted that other angular clearances, both less than and greater than 0.2 degrees can be used.

The compressive stress retained in the rotationally blocked rotary shouldered connection of the assembly embodiments described herein is retained between a minimum and maximum allowed value. So when configured, the upper and lower bodies or subs of the disconnect assembly disclosed herein may be torqued to a specific or predetermined value and, without rotational adjustment, the blocking sleeve may be engaged.

In some embodiments, the blocking sleeve is retained in the engaged position by a locking mechanism that transfers impact and vibration forces directly from the blocking sleeve to the upper and lower bodies of the assembly. The locking mechanism is held and selectively released in response to forces applied by the unlocking and unblocking tool disclosed herein.

In some embodiments, an unlocking and unblocking tool selectively unlocks and moves the sleeve out of blocking engagement between the upper or lower bodies, to allow rotation to disengage the upper and lower bodies of the drill stem disconnect assembly. The UUT is powered by hydrostatic pressure within the well bore. Circulation of well fluids is not required and pressure need not be applied to the well. The UUT includes a selective anchor allowing any one of multiple identical drill stem disconnects installed in the drill stem to be unlocked and unblocked. The activating UUT is configured such that it is retained and removed with the upper body and the upper disconnected portion of the drill stem. After removal of the upper disconnected portion of the drill stem, the upward connection of the lower body, remaining in the well, is unobstructed, facilitating re-attachment.

In some embodiments, a disconnect assembly includes a first body including a first serration, a second body including a second serration, and a third body including a third serration to be engaged with the first serration using a first number of teeth, and the third body include a fourth serration to be engaged with the second serration using a second number of teeth to lock the first body relative to the second body. In an embodiment, the third body is free to rotate to align the first and third serrations and the second and further serrations prior to movement of the third body to a locking position.

In some embodiments, a disconnect assembly includes a first tubular member including a first inner serration, a second tubular member including a second inner serration, wherein the first tubular member is coupled to the second tubular member, and an inner sleeve including an upper serration engaged with the first inner serration with a first angular pitch, and a lower serration engaged with the second inner serration with a second angular pitch. In an embodiment, the upper serration and the first inner serration each have the same number of teeth, and the lower serration and the second inner serration each have the same number of teeth that is different than the number of upper serration teeth. In an embodiment, the engaged upper serration and first inner serration has a first clearance, the engaged lower serration and second inner serration has a second clearance, and the upper and lower serrations have an incremental pitch less than the sum of the first and second clearances.

In some embodiments, a disconnect assembly includes a first tubular member including a first inner serration, a second tubular member including a second inner serration, an inner sleeve including an upper serration engaged with the first inner serration and a lower serration engaged with the second inner serration, and a rotary shouldered and threaded connection coupling the first and second tubular members. In an embodiment, the upper and lower serrations are axially engageable with the first and second serrations for any rotational position of the inner sleeve using a first angular pitch for the upper engaged serration and a second angular pitch for the lower engaged serration.

In some embodiments, a disconnect assembly includes a first tubular member including a first inner spline, a second tubular member including a second inner spline, and an inner sleeve including an upper spline engaged with the first inner spline and a lower spline engaged with the second inner spline, wherein the inner sleeve is held into engagement with the first and second tubular members by a lock.

In some embodiments, a disconnect assembly for a downhole tubular string includes a first body connected to a second body with a threaded connection, a first serration in the first body, a second serration in the second body, a third body including upper and lower serrations for mating engagement with the first and second serrations, the third body, in a first position, prevents rotation between the first and second bodies, and in a second position allows relative rotation between the first and second bodies, and the upper and lower serrations are aligned with the first and second serrations for movement of the third body between the first and second positions after an assembly torque is applied to develop a predetermined amount of axial load between the first and second bodies. In an embodiment, the third body is free to rotate between the first and second positions to align the upper and lower serrations with the first and second serrations for movement of the third body into a locking position.

These and other features will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments and by referring to the accompanying drawings.

DETAILED DESCRIPTION

Referring collectively toFIGS. 1, 2A-2F, 3-8, 22 and 22A-22D, an embodiment of a drill stem disconnect assembly50and a blocking sleeve3are illustrated. The drill stem disconnect assembly50(FIG. 2B) includes a generally tubular shape with an outer surface51. An upper body or sub1is connected to a lower body or sub2(FIG. 2C) by a tool joint15. Tool joint15is a heavy coupling element utilizing a rotary shouldered and threaded connection.

Referring toFIG. 2A, upper body1includes an internal upper thread1c, often called a female thread or a box thread, which is half of a tool joint for connection within a drill stem. The axial lower end of lower body2(FIG. 2F) includes an external lower thread2c, often called a male thread or pin thread, which is the other half of a tool joint for connection within a drill stem.

Referring toFIGS. 2A-2F, upper body1has an upper shoulder1f(FIG. 2A) displaced from lower shoulder1b(FIG. 2B) by an internal recess1hwhich is axially above internal diameter1a; forming landing profile1l. To allow passage for an unlocking and unblocking tool (UUT), internal diameter1ais smaller than tool joint internal diameter1k(FIG. 2A), internal diameter of the passage of the drill stem above upper body1, internal diameter3a(FIG. 2C) of blocking sleeve3, internal diameter2gof lower body2and the internal diameter of the passage of the drill stem below lower body2. are larger than internal diameter1a, to allow passage of an unlocking and unblocking tool (UUT) and will be addressed during the discussion of the operation of the assembly below. Axially opposing shoulders1iand3kform a recess1j. Internal recess1jand internal diameter1gare important to the function of the UUT, as will be described.

Tool joint15may be designed or specially lubricated such that it is properly assembled at a lower torque than other tool joints in a drill stem. Upper thread1c(FIG. 2A) and lower thread2c(FIG. 2F) are part of tool joints and form tool joints of a drill stem (not shown). These tool joints and others of the drill stem may be designed or lubricated to properly assemble at a higher assembly torque than that required to assemble tool joint15.

Serration or splines1d(FIGS. 2C and 3) within upper body1and serrations or splines2d(FIGS. 2C and 5) within lower body2may be formed in different manners such as, but not limited to, milling, shaping, electro discharge machining and the like. Internal diameter1ais smaller than serration1d, and internal diameter2gis smaller than serration2d; it may be practical to form serration1dand serration2din upper body1, while forming lower body2individually when not assembled at tool joint15. As previously described, alignment of serration1dand serration2dwhen tool joint15is properly assembled may vary because of manufacturing tolerances, wear, thickness of lubrication and the like.

Referring toFIGS. 2C, 3, and 5, blocking sleeve3(FIG. 2C) is disposed radially within upper body1and lower body2. Blocking sleeve3has upper serration or splines3bradially engaged with compatible or mating serration1dof upper body1and lower serration or splines3c(FIG. 2C) engaged with compatible or mating serration2dof lower body2. Upper serration3bof blocking sleeve3and serration1dof upper body1are complementary and have angular clearance13(FIG. 3) configured for sliding engagement; accordingly, they may have the same number or angular pitch serration. Lower serration3cof blocking sleeve3and serration2dof lower body2are complementary and have angular clearance13a(FIG. 5) configured for sliding engagement; accordingly, they may have the same number or angular pitch serration.

Upper serration3bof blocking sleeve3and serration1dof upper body1have a different number or angular pitch than lower serration3cof blocking sleeve3and serration2dof lower body2. Angular clearance13(FIG. 3) added with angular clearance13a(FIG. 5) results in a clearance that is greater than incremental pitch14(FIG. 22D) between lower serration3cand upper serration3b.

Referring toFIGS. 22 and 22A-22D, the incremental pitch14(FIG. 22D) between serration3band serration3cof blocking sleeve3is shown adjacent to aligned set of teeth14a(though alignment is not necessary for the pitch increment).FIGS. 22C and 22Billustrate serration3cand serration3brespectively, whileFIG. 22Aillustrates both serration3band serration3cas viewed from the axial end ofFIG. 22. In this particular embodiment, serration3bincludes 50 teeth while serration3cincludes 51 teeth. Serration3band serration3cinclude a set of aligned teeth14a. Due to the difference in the number of teeth between serration3band serration3c, the set of teeth14b(FIG. 22D) circumferentially adjacent to aligned set14aare not angularly aligned like the aligned set of teeth14a, but instead are out of phase by the amount of incremental pitch14. Additional sets of teeth along the circumference of serrations3band3cwill be further out of phase, with the next additional set circumferentially adjacent to set14bout of phase by twice the incremental pitch, the next circumferentially adjacent set out of phase by triple the incremental pitch, etc., until serration13band serration13care completely out of phase at a point along the circumference of serrations3band3cdiametrically opposed to aligned set of teeth14a. In this embodiment, serration1d(FIG. 3) includes 50 teeth (matching serration3b) and serration2d(FIG. 5) of lower body2includes 51 teeth (matching serration3c), mirroring the incremental pitch14aof serration3band3cof blocking sleeve3.

Having the same incremental pitch, serration1dand serration2d, regardless of angular alignment, will include sets of teeth in phase and sets of teeth incrementally out of phase, with the incremental shift into and out of phase by each set of teeth governed by the incremental pitch. Thus, aligning the in phase sets of teeth of serrations3band3cwith the corresponding in phase sets of teeth of serrations1dand2dallows upper serration3bto engage serration1dsimultaneously with the engagement between lower serration3cand serration2d, regardless of the rotational alignment of serration1dand serration2dwhen tool joint15is properly assembled. Thus, it may not be necessary to compromise desired assembly torque to adjust the angular alignment of upper body1and lower body2for engagement with blocking sleeve3, nor are match-fit parts required.

Blocking sleeve3, so engaged, prevents relative rotation between upper body1and lower body2. Referring toFIGS. 2C and 2D, blocking sleeve3includes an upper seal surface3e, lower seal surface3f, intermediate gap3d, internal diameter3a, upper end3gof upper serration3b, lower end3hof lower serration3c, upper end3j, and lower end3i. Blocking sleeve3may be prevented from axial upward movement by engagement between upper end3jof blocking sleeve3and shoulder1eof upper body1. Blocking sleeve3is prevented from being displaced axially lower by lower end3iengaging “c” ring5, which may be disposed axially below blocking sleeve3.

Tool joint15is sealed by the contact of the rotary shoulders incorporated therein, while upper seal10within groove1mand lower seal12within groove2jfunction as debris barriers and maintain lubrication of serrations1d,3b,2dand3c. Upper seal surface3emay be the same or very nearly the same diameter as lower seal surface3fto assure ease of movement in a high hydrostatic pressure fluid environment.

Now referring toFIG. 2D, “c” ring5is held in a radially expanded condition within groove2aof lower body2by support surface4cof lock sleeve4. Filler “c” ring9, which serves to assist in assembly, is configured to be inserted within groove2ein order to trap and transfer loads from retaining ring8and lower body2. Ring7and shock absorber6, which is possibly made of elastomeric material, secure lock sleeve4in position for lock sleeve4to axially support “c” ring5and transfer loads axially from lock sleeve4to retaining ring8. Retaining ring8is robust and may require a force to shear. In an exemplary embodiment, tens of thousands of pounds of force may shear the retaining ring8. Lock sleeve4is lighter than blocking sleeve3and thus will create proportionately smaller inertial forces when subjected to the forces of rotary drilling. Shock absorber6protects retaining ring8from the affects of vibration and impact shock that take place during rotary drilling.

Axial gap16between “c” ring5and the axial upper end of lock sleeve4assures that forces acting to move blocking sleeve3downward are transferred from blocking sleeve3, through “c” ring5, to the shoulder2bof groove2aof lower body2. Internal diameter3aof blocking sleeve3may be smaller than internal diameter4aof lock sleeve4, thereby providing protection from forces associated with lowering service tools through the drill stem, such as measurement while drilling tools and the like. Internal diameter3amay be larger than internal diameter1a, which may provide clearance to internal surfaces during the functioning of a UUT, which will be addressed during the discussion of the operation of the assembly below.

As will be discussed below, blocking sleeve3may be unlocked by displacing lock sleeve4axially downward. A UUT engages shoulder4bof lock sleeve4, forcibly compelling shoulder4dto axially compress shock absorber6and force ring7to shear retaining ring8. After retaining ring8is sheared, forming an outer portion8awhich remains in groove2eand an inner portion8bwhich moves downwardly ahead of lock sleeve4, the UUT displaces lock sleeve4downwardly into a position where support surface4cis no longer in position to axially support “c” ring5in the radially expanded position within groove2aof lower body2.

Blocking sleeve3, upon being fully displaced axially downward, serration1dof upper body1is disengaged from upper serration3b(FIG. 2C) of blocking sleeve3and lower serration3cis disengaged from serration2dof lower body2. Accordingly, upper end3gof upper serration3bis now disposed axially below “c” ring11, preventing upper serration3bof blocking sleeve3from returning to engagement with serration1dof upper body1. Torque applied in the opposite rotational direction from torque applied during assembly will cause rotation between upper body1and lower body2, assuming the portion of drill stem below lower body2is stabilized, such as by being stuck in the well bore, and thus will be prevented from rotation in either direction. Continued rotation in the rotational direction opposite of that used in the assembly of tool joint15and lifting of the upper unstuck drill stem will disconnect the drill stem at tool joint15.

Filler ring9(FIG. 2D) may aid in assembly. Initially filler ring9is disposed within bore2i(FIG. 2E). Retaining ring8, ring7, shock absorber6, lock sleeve4, “c” ring5and blocking sleeve3are displaced downward by a UUT until retaining ring8engages shoulder2fof lower body2. In this configuration, lower serration3cof blocking sleeve3and serration2dof lower body2are disengaged and upper body1may be properly assembled to lower body2. After proper torque is applied at tool joint15, blocking sleeve3may be rotated for spline engagement, as discussed more fully above, and displaced upwardly until upper end3jengages shoulder1eof upper body1. Subsequently, “c” ring5, forcibly compelled by lock sleeve4, is displaced upwardly and when it reaches groove2a(FIG. 2D) “c” ring5radially expands and allows lock sleeve4to pass underneath “c” ring5and radially support “c” ring5with support surface4c. Thereafter, filler ring9is displaced axially upward to engage shock absorber6and retaining ring8with shoulder4dof lock sleeve4. In this position, filler “c” ring9may radially expand and engage shoulder2fof lower body2.

Alternative embodiments of a drill stem disconnect assembly including a blocking sleeve are illustrated with reference toFIGS. 9, 10A-10F, 11-21, 23, and 23A-23D. The alternative embodiments described below include some differences from the embodiments described above with reference toFIGS. 1, 2A-2F, 3-8, 22, and 22A-22D.

It may be desirable, for certain sizes and tool joint designs, to form the internal body serrations with a broach. Referring toFIGS. 10A-10E, internal diameters18b,18e,18fand18gand internal diameters27g(FIG. 10C),27i,27m(FIG. 10D),27n,27o,27p,27q(FIG. 27E) and27rare sufficiently diametrically large to allow the forming of serration18a(FIG. 10C) and serration27dby displacing a broach with progressively larger teeth axially through an upper sub18(FIG. 10B) and a lower sub27(FIG. 10C). Serration18adisposed within upper sub18and serration27ddisposed within lower sub27may be formed in different manners such as, but not limited to, broaching, milling, shaping, electro discharge machining and the like.

A lower body26(FIG. 10E) may also be assembled as a sub-assembly. Lower sub27includes: “c” ring45disposed within groove27j, removable shoulder29(FIG. 10D) including first arc piece29a, short arc piece29band second arc piece29c, installed in groove27l, removable shoulder28(FIG. 17) including first arc piece28a(FIG. 18), short arc piece28band second arc piece28c, installed in groove27k(FIG. 10D), collectively form lower body26, which may be interchangeable with lower body2ofFIGS. 2C-2F.

Upper sub18is shown to have an internal upper thread18c(FIG. 10A) often called a female thread or a box thread, which is half of a tool joint for connection within a drill stem (not shown). The lower end of lower sub27is shown to have an external lower thread27c(FIG. 10F) often called male thread or pin thread, which is the other half of a tool joint for connection within a drill stem (not shown).

Referring toFIGS. 10C and 10D, blocking sleeve41(FIG. 10C) is disposed within upper sub18and lower sub27. Blocking sleeve41includes upper serration41bengaged with compatible or mating serration18aof upper sub18and lower serration41cengaged with compatible or mating serration27dof lower sub27. Upper serration18aand serration41bare complementary and have angular clearance42(FIG. 13) for sliding engagement; accordingly, upper serration18aand serration41bmay have the same number or angular pitch serration. Lower serration41cand serration27dare complementary and have angular clearance42a(FIG. 15) for sliding engagement; accordingly, lower serration41cand serration27dmay have the same number or angular pitch serration.

Upper serration41band serration18aof upper sub18have a different number or angular pitch than lower serration41cand serration27dof lower sub27. The summation of angular clearance42(FIG. 13) and angular clearance42a(FIG. 15) is greater than the incremental pitch43(FIG. 23D) between lower serration41cand upper serration41b(FIG. 10C). As best seen inFIGS. 23 and 23A-23D, incremental pitch43(FIG. 23D) between serration41band41cof blocking sleeve41(FIG. 10C) is shown adjacent to aligned teeth43a(FIG. 23D) (though alignment is not necessary for the pitch increment). Blocking sleeve41may be rotated such that engagement between upper serration41band serration18aof upper sub18occurs simultaneously with engagement between lower serration41cand serration27dof lower sub27, regardless of the rotational alignment of serration18aand serration27dwhen tool joint33is properly assembled. Thus, it may not be necessary to compromise desired assembly torque to adjust the angular alignment of upper sub18and lower sub27for engagement with blocking sleeve41, nor are match-fit parts required.

Bushing20(FIG. 10B) includes an upper shoulder20c(FIG. 10A) axially displaced from lower shoulder20b(FIG. 10B) by an internal recess20ewhich is disposed axially above internal diameter20a; thus, a landing profile20his formed for landing and anchoring a UUT. Internal diameter18b(FIG. 10A), which is the internal diameter of the passage of the drill stem axially above upper sub18, internal diameter41a(FIG. 10C) of blocking sleeve41, and internal diameter of the drill stem axially below may all be greater in diameter than internal diameter20a, in order to allow for the passage of a UUT. Shoulder20f(FIG. 10B) and shoulder41k(FIG. 10C) form recess22b. Recess22band diameter20dprovide radial clearance for the functioning of a UUT. These features and their relationship with the UUT will be addressed during the discussion of the operation of the assembly below.

Tool joint33may be configured or specially lubricated such that it is properly assembled at a lower applied torque than other tool joints in a drill stem. Upper thread18cof upper sub18and lower thread27cof lower sub27are part of and form tool joints of a drill stem (not shown). These tool joints and others of the drill stem are configured or lubricated to properly assemble at a higher applied assembly torque than tool joint33.

Blocking sleeve41is disposed within upper sub18and lower sub27. Blocking sleeve41includes upper serration41bthat may be configured to engage compatible or mating serration18aof upper sub18, and lower serration41cthat may be configured to engage compatible or mating serration27dof lower sub27. Blocking sleeve41, when engaged, may prevent relative rotation between upper sub18and lower sub27. Blocking sleeve41also includes upper seal surface41e, lower seal surface41f(FIG. 10D), intermediate gap41d(FIG. 10C), internal diameter41a, upper end41gof upper serration41b, lower end41hof lower serration41c, upper end41jand lower end41i(FIG. 10D). Blocking sleeve41is prevented from upward axial displacement by upper end41jengaging shoulder22aof spacer22. Internal recess22b(FIG. 10C) is disposed axially above shoulder22a. Blocking sleeve41is prevented from downward axial displacement by engagement between lower end41iand “c” ring36(FIG. 10D).

Tool joint33is sealed by the contact of the rotary shoulders incorporated therein, while upper seal23and lower seal32function as debris barriers and maintain lubrication of serrations18a,41b,27dand41c. Upper seal surface41emay be the same or very nearly the same diameter as lower seal surface41fto assure ease of movement in a high hydrostatic pressure fluid environment.

Referring toFIG. 10D, “c” ring36is held in a radially expanded condition within groove27aof lower sub27by support surface35cof lock sleeve35. Filler “c” ring40may be configured to be inserted within groove27ein order to trap and transfer loads from retaining ring39and lower sub27. Ring38and shock absorber37, which is possibly made of elastomeric material, secure lock sleeve35in position for lock sleeve35to axially support “c” ring36and transfer loads axially from shoulder35dof lock sleeve35to retaining ring39. Retaining ring39is robust and may require a force to shear. In exemplary embodiments, the force may be tens of thousands of pounds. Lock sleeve35is lighter than blocking sleeve41and thus will create proportionately smaller inertial forces when subjected to the forces of rotary drilling. Shock absorber37protects retaining ring39from the affects of vibration and impact shock that take place during rotary drilling.

Axial gap44between “c” ring36and the axial upper end of lock sleeve35assures that forces acting to move blocking sleeve41downward are transferred from blocking sleeve41, through “c” ring36, to the shoulder27bof groove27aof lower sub27. Internal diameter41aof blocking sleeve41may be smaller than internal diameter35aof lock sleeve35, thereby providing protection from forces associated with lowering service tools through the drill stem, such as measurement while drilling tools and the like. Internal diameter20amay be smaller than internal diameter41aof blocking sleeve41.

Blocking sleeve41may be unlocked by displacing lock sleeve35axially downward. A UUT engages shoulder35bof lock sleeve35, forcibly compelling shoulder35dto axially compress shock absorber37and force ring38to shear retaining ring39. After retaining ring39is sheared, forming an outer portion39awhich remains in groove27eand an inner portion39bwhich moves downwardly ahead of lock sleeve35, the UUT displaces lock sleeve35downwardly into a position where support surface35cis no longer in position to axially support “c” ring36in the radially expanded position within groove27aof lower sub27.

Blocking sleeve41, upon being fully displaced axially downward, serration18aof upper sub18is disengaged from upper serration41bof blocking sleeve41and lower serration41cis disengaged from serration27dof lower sub27. Accordingly, upper end41gof upper serration41bis now disposed axially below “c” ring34, preventing upper serration41bof blocking sleeve41from returning to engagement with serration18aof upper sub18. Torque applied in the opposite rotational direction from the torque applied during assembly will cause rotation between upper sub18and lower sub27, as long as the portion of drill stem below lower body26is stuck or otherwise stabilized such that it will not rotate or move axially up or down. Continued rotation in the rotational direction opposite of that used in the assembly of tool joint33and lifting of the upper unstuck drill stem will disconnect the drill stem at tool joint33.

Filler ring40(FIG. 2D) may aid in assembly. Initially filler ring40is disposed within internal diameter27q(FIG. 2E). Retaining ring39, ring38, shock absorber37, lock sleeve35, “c” ring36and blocking sleeve41are displaced downward by a UUT until retaining ring39engages shoulder45aof “c” ring45. In this configuration, lower serration41cof blocking sleeve41and18aof upper sub18are disengaged and upper sub18may be properly assembled to lower sub27. After proper torque is applied at tool joint33, blocking sleeve41may be rotated for spline engagement, as discussed more fully above, and displaced upwardly until upper end41jengages shoulder22aof spacer22. Subsequently, “c” ring36, forcibly compelled by lock sleeve35, is displaced upwardly. When “c” ring36reaches groove27ait radially expands and allows lock sleeve35to pass underneath and radially support “c” ring36with support surface35c. Thereafter, filler ring40is displaced axially upward to engage shock absorber37and retaining ring39with shoulder35dof lock sleeve35. In this position, filler “c” ring40may radially expand and engage shoulder27fof lower sub27.

In further embodiments, it is also possible to assemble upper sub18and lower sub27with the proper assembly torque and requisite lubricant, then using a broaching process, to configure serration18aand serration27dto achieve aligned angular registry therebetween. In this instance, blocking sleeve41may be manufactured with upper serration41band lower serration41caligned and matching. The installation of all other components may be made without disassembling tool joint33.

Referring collectively toFIGS. 25A-25H and 26-46, embodiments of an activation tool, unlocking and unblocking tool, or UUT90are illustrated. Referring initially toFIGS. 25A-25H, an upper end includes a fishing neck100(FIG. 25A) connected to a mandrel101by threads102. Mandrel101is connected to upper control tube103(FIG. 25B) by threads104, which is connected to intermediate control tube105(FIG. 25F) by threads106(FIG. 25E), which is connected to lower control tube107(FIG. 25G) with threads108. A body109(FIG. 25A) is connected to core110(FIG. 25B) by threads111, which is connected to upper core extension112(FIG. 25F) by threads135(FIG. 25E), which is connected to core adapter113(FIG. 25F) by threads114, which is connected to intermediate core extension115(FIG. 25G) by threads116(FIG. 25F), which is connected to lower core adapter117(FIG. 25G) by threads118, which is connected to lower core extension119(FIG. 25H) by threads120.

The interaction of shoulder101g(FIG. 25A) with shoulder109sprovide an up stop, and the interaction of end surface101h(FIG. 25B) with end surface110aprovide a down stop, respectively, limiting the relative motion between the mandrel101and body109during the functioning of the UUT, and will be further addressed during the discussion of the operation of the assembly below.

Referring toFIGS. 25A and 28, key136(FIG. 25A) is radially movable in window109aof body109. Radial outward motion of key136is limited by shoulder136a, shoulder136band bore109d. Radial inward movement of key136is limited by surface136ccontacting diameter101a. Key137, key138and key139(FIG. 28) are functionally identical and fitted for movement within body109the same as key136. The interaction of key136with shoulder101fand diameter101ewill be addressed further during the discussion of the operation of the assembly below.

Referring toFIGS. 25A and 27, “c” ring140is in groove101b, contacting shoulder109eand limiting upward movement of mandrel101with respect to body109. “C” ring140is biased radially outward but restrained from expansion by bore109f. The function of groove109gwill be addressed during the discussion of the operation of the assembly below. Hole140aand hole140bfacilitate assembly and disassembly.

Referring toFIGS. 25B and 29, a bore sensor142is disposed in the body109. Bore sensor142is radially movable in hole1091. “C” ring141is within groove101cand groove109hpreventing mandrel101from moving down with respect to body109. “C” ring141is biased radially outward, pushing sensor142outward. Radial outward motion of bore sensor142is stopped by flange142acontacting groove109h. Bore sensors143,144,145,146and147(FIG. 29) are functionally similar and fitted for movement within body109the same as bore sensor142.

Referring toFIG. 25B, spring151forcibly compels collet131, shear pin132and lower ring133downwardly. The limit of downward motion is lower ring133contacting core110. Spring151is sufficiently forceful to overcome friction between “c” ring148and bore131a. Lower ring133is free to move upwardly against spring151along diameter109n. Spring151also urges upper ring134upwardly. Upper ring134is prevented from upward movement along diameter109nby shoulder109o.

Collet131has finger131dwith lower external shoulder131e, lower internal shoulder131f, upper external shoulder131g, upper internal shoulder131h, internal surface131iand external surface131j. The functional interface of lower internal shoulder131fof collet finger131dwith diameter109pand shoulder109qof body109will be addressed during the discussion of the operation of the assembly below. InFIG. 25B, finger131dis not biased inwardly for contact between internal surface131iand diameter109p. Collet131has fingers131k,131l,131m,131nand131o(FIG. 29) that are similar and functionally the same as finger131d.

Referring toFIGS. 25C, 33 and 25D, 34, upper finger121a(FIGS. 25C and 33) may be relaxed and in the inward position shown inFIG. 25C, with internal surface121eadjacent diameter110b. Lower finger121f(FIGS. 25D and 34) may be relaxed and in the inward position shown inFIG. 25D, with internal surface121jadjacent diameter110f. Upper finger121n, upper finger121o, upper finger121p, upper finger121qand upper finger121r(FIG. 33) are similar and functionally the same as upper finger121a. Lower finger121s, lower finger121t, lower finger121u, lower finger121vand lower finger121w(FIG. 34) are similar and functionally the same as lower finger121f.

Referring toFIG. 25E, fluid passage121l,103aand110kassure fluid communication and equal pressure between the radially outer and inner cylindrical surfaces of grapple121. Shear screw159is secured within threaded hole121mand within groove110j, locating grapple121axially along core110.

The interrelationship of external shoulder121b, external surface121d, external surface121i, external shoulder121g, lower external shoulder131e, external surface131jand shoulder136dwith the DSD50ofFIGS. 1, 2A-2F, 3-8, 22, and 22A-22Dwill be addressed during the discussion of the operation of the assembly below.

Seal bore119b(FIG. 25H), seal bore117b(FIG. 25G), seal bore115b, seal bore113b(FIG. 25F) and seal bore112b, are substantially the same. There is no or very little force caused by high hydrostatically pressurized fluid184, as would exist deep within a fluid filled well, to move the fishing neck100up or down.

As assembled, chamber179, chamber180, chamber181and chamber182contain air at or near the atmospheric pressure in which they were assembled. Seal surface112a(FIG. 25F) and seal surface119a(FIG. 25H) are the same or very nearly the same diameter; thus, there is a balancing upward force acting on lower connector130against a downward force acting on connector124(FIG. 24E).

Referring toFIG. 25E, grapple121and core110are designed such that high pressure fluid184surrounding the UUT may not result in the severing of shear screw159.

Referring toFIGS. 25A-25H, as will be more fully described in the discussion of operation of the assembly below, the net result of allowing hydrostatically pressurized fluid184into chamber180and182would be to urge grapple121downward and to equally urge body109upward.

Allowing hydrostatically pressurized fluid184within chamber180(FIG. 25F) creates a downward force on intermediate connector127and an upward force on core adapter113. Allowing hydrostatically pressurized fluid184within chamber182(FIG. 25H) eliminates the upward force upon lower connector130that acted to balance the downward force upon core adapter124(FIG. 25E), which creates an upward force on lower core adapter117(FIG. 25G).

The functional interrelationship of the relative longitudinal position of the fishing neck100with respect to body109and the affected fluid passages113a,105a,113c,105b,117a,107aand117cand related chambers179,180,181, and182will be addressed during the discussion of the operation of the assembly below.

The interrelationship and operation of UUT90shown inFIGS. 25A-25H and 26-46with the DSD50shown inFIGS. 1, 2A-2F, 3-8, 22 and 22A-22Dis discussed below as if being used in a hypothetical well.

Functionally identical items disclosed inFIGS. 25A, 25B, 28-30 and 32will not be mentioned below for brevity. In the following discussion, key136will be inclusive of functionally identical key137(FIGS. 25A and 28), key138, and key139. Bore sensor142(FIGS. 25B and 29) will be inclusive of functionally identical bore sensor143, bore sensor144, bore sensor145, bore sensor146and bore sensor147. Ball150(FIGS. 25B and 30) will be inclusive of functionally identical ball154, ball155, ball156, ball157and ball158. Shear pin152(FIGS. 25B and 32) will be inclusive of functionally identical shear pin153.

In an exemplary embodiment, a well includes multiple DSD's installed at intervals along the length of a rotary drill stem. The spacing, number and location Of the DSD's is based on a risk analysis by those responsible for the drilling program. For example, one DSD may be connected between every nine joints of drill pipe, starting at two thousand feet above the drill bit and continuing to the surface. Thus, there would be twelve disconnects in the well. Further, the drill pipe could be stuck such that the drill pipe will not move up or down, cannot be rotated and circulation of drill fluids is not possible. The pipe could then be stretched and relaxed to hypothetically determine that the pipe is stuck below the eighth DSD.

In such an exemplary situation, a UUT90would be connected to a conventional wireline unit, with appropriate weight bar, jars, running tool and the like (not shown), via the fishing neck100.

Referring toFIGS. 2A-2C, 25A, 25B, 47A-47G, the UUT90is lowered, then raised and lowered again within the well drill stem. “C” ring140(FIG. 25A) is within groove101band shoulder109ereceives the weight of the UUT90and transmits upward forces from the wireline (not shown) in all of the motions. During the movements of the UUT90, mandrel101and body109do not move relative to one another and thus the lower portions of the UUT90are inactive.

FIG. 47Ashows the portion of the UUT90described previously inFIG. 25B, as it is received within the first DSD50of the twelve identical DSD's of this exemplary situation. Arrow186indicates the direction of the axial motion of UUT90. Outer diameter110mof core110slides axially through internal diameter1aof upper body1, with a clearance existing between the two diameters. The external surface131jpasses through internal diameter1gwith a clearance existing between the two diameters. Bore131aprevents the radially outward biased “c” ring148from expanding outwardly, and because of ball150, radially outward biased “c” ring149is prevented from expanding outwardly. “C” ring149is within groove101dand groove109m, preventing relative movement between mandrel101and body109. Bore sensor142is radially displaced outward by “c” ring141and is disposed within groove101cand109h, preventing relative movement between mandrel101and body109. Shear pin132remains unsevered and spring151forcibly urges collet131downward.

FIG. 47Bshows the portion of the UUT90described previously inFIG. 25B, as it is lowered further into the DSD50and downwardly displaced from its position illustrated inFIG. 47A, but still within the first of the twelve identical DSD's of this exemplary situation. Arrow186indicates the direction of motion of the UUT90. As UUT90is displaced downward from the position inFIG. 47Ato the position inFIG. 47B, lower exterior shoulder131econtacts lower shoulder1b, forcibly preventing collet131from further travelling downward. As the UUT90is lowered further through the drill stem, diameter109pslides under internal surface131icompressing spring151until finger131dis no longer supported by diameter109p. Subsequent downward lowering of body109further compresses spring151and causes finger131dto radially deflect inward, sliding radially down shoulder109qand subsequently move axially downward, sliding along internal diameter1a. Bore sensor142is displaced radially inward by lower shoulder1b, displacing “c” ring141radially deeper within groove101cand out of engagement with groove109h. Bore131aprevents “c” ring148from expanding radially outward, and because of ball150, “c” ring149is prevented from expanding radially outward. “C” ring149is within groove101dand groove109m, preventing relative axial movement between mandrel101and body109. Shear pin132remains unsevered and spring151forcibly urges collet131downward.

FIG. 47Cshows continued downward movement of the UUT90through the DSD50. As UUT90is displaced downward from the position ofFIG. 47Bto the position ofFIG. 47C, upper external shoulder131gslides axially downward and radially outwards along shoulder1iand external surface131jmoves axially out of internal diameter1a. Shear pin132is remains unsevered and spring151forcibly moves collet131downward to a position of lower ring133, causing collet131to contact core110. Finger131dmoves radially outward to a relaxed position with internal surface131iradially adjacent diameter109p. Bore sensor142returns to the radial outward position by the outward urging of radially biased “c” ring141as “c” ring141returns to its initial position within groove101cand groove109h, preventing relative axial movement between mandrel101and body109. Bore131aprevents “c” ring148from radially expanding outward, and because of ball150, “c” ring149is prevented from radially expanding outward. “C” ring149is disposed within groove101dand groove109m, preventing relative axial movement between mandrel101and body109. The UUT90has now returned to the condition as shown inFIG. 47A; however, now in the position shown inFIG. 47C, instead of the outer diameter110mof core110being within internal diameter1aof upper body1, outer diameter110mof core110is now within internal diameter3aof blocking sleeve3with clearance, existing between the two diameters.

As the UUT90is moved further down the drill stem it will repeat the above positioning of components illustrated inFIGS. 47A-47Cas it passes through the internal diameter1aof each DSD50encountered. The UUT90is thus capable of passing downward through any number of DSD's.

In this exemplary situation, after passing the eighth DSD50, known to the wireline operator by a depth indicator at the surface of the well, the UUT90is slowly elevated until upper external shoulder131gof collet131contacts shoulder1iof the eighth DSD, known to the wireline operator by a weight indicator at the surface of the well.

After confirming the downhole depth, the UUT90is lowered downward at a high enough acceleration to create sufficient velocity for the momentum of the weight bar, jars, running tool and UUT to sever shear pin152ofFIG. 25B.

FIG. 47Dshows the portion of the UUT90previously described inFIG. 25B, as it is raised upward through, but still within, the eighth of twelve identical DSD's in this exemplary situation. Arrow188indicates the direction of the upward motion of UUT90. As UUT90is displaced from the position ofFIG. 47Cto the position ofFIG. 47D, external surface131jpasses through blocking sleeve3with a clearance between the two surfaces, and upper external shoulder131gcontacts shoulder1i, forcibly preventing collet131from any further upward movement. Initially, momentum of UUT90carries core110upward, which in turn forcibly compels lower ring133upward, severing shear pin132. Further, the lower end of spring151no longer pushes collet131downward, as shear pin132is now severed and lower ring133is no longer connected to collet131. Spring151now acts to radially expand collet131as end surface134aof upper ring134contacts shoulder131b. Body109then begins moving upward within collet131, with diameter109pmoving upward and sliding under internal surface131iof collet131. Core110moves upward and forcibly compels lower ring133to compress spring151.

As body109moves upward in relation to collet131, “c” ring148slides axially upward and along bore131aand radially outwards into groove131q, with ball150and “c” ring149moving radially outward disengaging “c” ring149from groove101din mandrel101. However, because bore sensor142remains disposed radially outward due to the force acting on it from outwardly biased “c” ring141which resides in groove109hand groove101c, axial motion remains inhibited between mandrel101and body109. Core110continues to move upward, forcibly compelling lower ring133to further compress spring151.

Continued upward movement of body109further compresses spring151, as diameter109pcontinues to slide upward and along internal surface131iuntil upper internal shoulder131hslides downward along shoulder109rand deflects finger131dradially inward, resulting with external surface131jsliding into internal diameter1a. Once external surface131jof collet131slides upward into internal diameter1a, lower ring133, forcibly acted upon by core110, does not compress spring151any further.

FIG. 47Eshows the position of UUT90as it is displaced upward from the position shown inFIG. 47D, while still within the eighth of twelve identical DSD's in this exemplary situation. Arrow188indicates the direction of motion of the UUT90. In this position, outer diameter110mof core110is disposed within internal diameter3aof blocking sleeve3. Bore sensor142, having been displaced further upward, has entered internal diameter1aand is now displaced radially inward by shoulder1i, in turn displacing “c” ring141radially inward, deeper within groove101cand out of engagement with groove109h; however, “c” ring149is disposed within groove101dand109m, preventing relative axial motion between mandrel101and body109. Spring151now urges collet131upward. Continued upward motion of UUT90axially displaces external surface131jof collet131upward, within internal diameter1a. Body109and mandrel101may be further displaced upward with external surface131jmoving axially within internal diameter1a.

FIG. 47Fshows a portion of UUT90as it is displaced upward, above the eighth of the twelve identical DSD's in this exemplary situation. Arrow188indicates motion of the UUT in either direction. Bore sensor142, upon exiting internal diameter1adue to its upward displacement, is radially displaced outward by “c” ring141, disposing it within groove101cand109h, preventing relative axial movement between mandrel101and body109. During the transition from the position ofFIG. 47Eto the position ofFIG. 47F, external surface131jof collet131is displaced upward through internal diameter1a, and bore sensor142exits internal diameter1abefore external surface131jbecause while external surface131jis in sliding contact with internal diameter1a, bore sensor142is disposed above the lowermost edge of external surface131j, where external surface131jmeets lower external shoulder131e. Thus, as bore sensor142displaces radially outward, “c” ring141engages groove101cand groove109hbefore external surface131jof collet131axially exits internal diameter1a, preventing relative axial motion between mandrel101and body109.

As collet131is displaced upward to exit internal diameter1a, lower external shoulder131eslides axially along lower shoulder1b, allowing finger131dto displace radially outward as upper internal shoulder131his displaced radially outwardly as it slides along shoulder109runtil internal surface131islides axially along diameter109p. As collet131moves upward relative to body109, bore131tslides upward in relation to “c” ring148, allowing “c” ring148to radially expand into groove131qand ultimately engage shoulder131rof collet131. “C” ring149radially expands out of groove101das ball150follows the radial expansion of “c” ring148. However, because bore sensor142remains radially outward from the urging of radially biased “c” ring141, which is disposed in groove109hand groove101c, relative axial motion is prevented between mandrel101and body109.

If UUT90is displaced axially upward through another DSD in the drill stem, collet131will frictionally engage internal diameter1awhile body109continues to travel upward, allowing finger131dof collet131to radially collapse along shoulder109rand pass through internal diameter1aof the DS, at which time finger131dmay radially expand again to engage diameter109pand return to the condition ofFIG. 47F. In this manner, the UUT may be raised and removed from the well, passing thru any number of DSDs in the drill stem.

FIG. 47Gshows a portion of the UUT90as it is axially displaced downward into the eighth of the twelve identical DSD's in the hypothetical drill stem of this exemplary situation. Arrow190indicates axial motion of UUT90. Finger131dis disposed in the relaxed position with internal surface131isupported on diameter109p. Lower external shoulder131eof collet131engages lower shoulder1band axial downward movement of the body109is prevented by the engagement of “c” ring148, which is radially disposed within both groove109kand shoulder131r. While “c” ring149is radially disposed outside of groove101d, Bore sensor142is radially disposed within internal diameter1aand has radially displaced “c” ring141outwards so that it is no longer disposed within groove109h; thus, for the first time in the sequence of movements of UUT90of this exemplary situation, relative axial movement between mandrel101and body109is possible.

As described in the exemplary situation above, an embodiment of UUT90may be selectively landed in any one of multiple DSD's and be retrieved from the well at any time. In the following description, the functioning of an embodiment of the UUT to unlock and unblock a DSD will be explained. The following actions performed by an embodiment of the UUT are initiated by relative axial movement of fishing neck100with respect to body109.

Hydrostatically pressurized fluid184is located within fluid passage183, completely surrounding UUT90, within the drill stem connected axially upward of body1, within DSD50, and in the stuck drill stem connected axially downward of lower body2.

Referring toFIGS. 48A-48E, collet131has landed on and engaged shoulder1b, preventing axial downward movement of body109, as shown inFIG. 48A. Body109is connected to grapple121, by shear screw159(FIG. 48C).

The weight of the wireline tools has resulted in the axial movement of fishing neck100(FIG. 48A) downward such that “c” ring140is no longer engaging shoulder109eof body109. Shoulder101fof mandrel101has moved axially downward within landing profile11of upper body1and is now disposed radially inwards of radially outwards displaced key136. Diameter101eradially engages key136within window109aof body109with shoulder136din proximity of shoulder1f. Body109is axially anchored within landing profile11of upper body1, as are all parts connected to it, including, through shear screw159, grapple121(FIG. 48C) and all parts connected to it. Although fishing neck100has been axially displaced in relation to body109, flow passages113a,113c,105a,105b,117a,117cand107aare all blocked, as shown inFIG. 48D. Chambers179(FIG. 48C),180,181and182(FIG. 48D) may be preassembled and thus contain air at or near atmospheric pressure. Seal surface112a(FIG. 49C) and seal surface119a(FIG. 49D) may be structurally similar. Thus, high hydrostatically pressurized fluid184surrounding DSD50and within passage183, as is present deep within a fluid filled well, will not result in the application of forces or relative motion between grapple121and core110that would sever shear screw159.

All components of the embodiment of DSD50are as shown inFIGS. 1, 2A-2F, 3-8, 22 and 22A-22D. Referring toFIGS. 48A-48E, diameter110bof core110(FIG. 48B) is disposed radially adjacent of internal surface121eof upper finger121a. External surface121dof upper finger121ais displaced axially downward from internal diameter1aof upper body1, where internal diameter1ais smaller than internal diameter3aof blocking sleeve3, which in turn is smaller than internal diameter4aof lock sleeve4. Diameter110fof core110is disposed radially adjacent of internal surface121jof lower finger121f. External surface121iof lower finger121fis displaced downward from internal diameter1a.

Referring toFIGS. 49A-49E, the weight of the wireline tools results in the downward axial displacement of fishing neck100(FIG. 49A) until end surface101hof mandrel101engages end surface110aof core110. Due to this axial displacement, “c” ring140has radially expanded within groove109gof body109and is no longer radially disposed within groove101bof mandrel101. Flow passages113a,105band117a(FIG. 49D) remain blocked. Thus, chambers179(FIG. 49C) and181(FIG. 49D) continue to contain air at or near atmospheric pressure. However, passages113c,105a,117cand107aare now in fluid communication with hydrostatically pressurized fluid184via passage183(FIG. 49E). Chamber180and chamber182now begin to rapidly fill with hydrostatically pressurized fluid184. As chamber180fills with pressurized fluid184, chamber180applies an axial downward force on intermediate connector127(FIG. 49D) and an axial upward force on core adapter113. As chamber182fills with pressurized fluid184, chamber182applies an axial downward force on lower connector130, effectively removing the axial upward force of lower connector130acting to balance the axial downward force of core adapter124; chamber182also applies an axial upward force on lower core adapter117. As explained above, filling chamber180and chamber182with pressurized fluid184forcibly compels grapple121axially downward and, with equal and opposite magnitude, forcibly compels body109axially upward.

Further, the compulsion of grapple121downward and body109upward results in shear screw159being severed, grapple121and connected parts being displaced axially downward, and lower finger121fexpanding radially outward as internal shoulder121htraverses shoulder110gof core110. Internal surface121jis radially supported by diameter110hand shoulder121gengages shoulder4bof lock sleeve4. Grapple121is temporarily prevented from further axial displacement as retaining ring8is not yet severed. As internal shoulder121c(FIG. 49B) of upper finger121atraverses shoulder110cof core110, internal surface121eis radially supported by diameter110d; thus, external surface121dis radially expanded outward and exterior shoulder121bis radially positioned to contact upper shoulder3kof blocking sleeve3, but spaced axially away for later engagement. This axial spacing assures that the forces generated within UUT90are not diminished by friction about the blocking sleeve3and are retained for severing retaining ring8.

The equal and opposite forces generated as pressure rapidly builds within chamber180and chamber182displaces body109axially upward until window109aengages key136, and shoulder136dengages upper shoulder if of landing profile11within upper body1. Body109is prevented from further upward axial displacement by key136and shoulder if of upper body1. Collet131does not contact shoulder1b. Downward axial displacement of grapple121is briefly restrained by retainer8while pressure rapidly builds within chamber180and182.

Referring toFIGS. 50A-50E, pressure within chamber180and chamber182(FIG. 50D) has, at this point, increased sufficiently to sever retaining ring8into outer portion8aand inner portion8b(FIG. 50C). Due to the severing of retaining ring8, grapple121and connected parts have displaced axially downward. Surface121jof lower finger121f, radially supported by surface110hwith external shoulder121gengaging shoulder4b, has axially displaced lock sleeve4downward such that support surface4cis no longer axially disposed within “c” ring5. Internal surface121e(FIG. 50B) of upper finger121a, radially supported by diameter110d, has been displaced axially downward such that external shoulder121bengages upper shoulder3kof blocking sleeve3. Blocking sleeve3has started displacing downward and lower end3i(FIG. 50C) has forcibly compelled “c” ring5axially downward, as shoulder2bof lower body2radially displaces “c” ring5inward to reside axially within bore2k.

Referring toFIGS. 51A-51E, after a brief period of time, grapple121(FIG. 51C) has been further axially displaced downward, such that finger121fhas been radially displaced inward with internal surface121jand is now disposed radially adjacent diameter110nof core110. Thus, locking sleeve4is no longer engaging grapple121. Finger121a(FIG. 51B), with internal surface121eradially supported by diameter110d, has forcibly compelled blocking sleeve3axially downward such that upper seal10no longer engages upper seal surface3e.

Referring toFIGS. 52A-52E, after another brief period of time, grapple121(FIG. 52B) has been further axially displaced downward. Blocking sleeve3has been fully displaced downward such that serration1dof upper body1is no longer engaging upper serration3bof blocking sleeve3. Further, “c” ring11, radially adjacent upper seal surface3eand axially upward from upper end3gof upper serration3b, prevents upper serration3bfrom re-engaging serration1d. Finger121ahas been radially displaced inward with internal surface121enow disposed adjacent diameter110fof core110. Thus, blocking sleeve3is no longer in engagement with grapple121. Also, shoulder136d(FIG. 52A) no longer engages shoulder1f. Collet131is again in engagement with shoulder1b, preventing downward axial displacement of UUT90.

Referring toFIGS. 53A-53E, after a brief period of time, grapple121(FIG. 53C), no longer engaged with either locking sleeve4or blocking sleeve3, has been fully displaced axially downward. Within chambers179and181(FIG. 53D), minor pressure and temperature changes have occurred during this process to the atmospheric air trapped during assembly of the UUT90. The pressure changes within these two chambers are insignificant in relation to the high hydrostatic pressures that exist deep within a fluid filled well, and thus the trapped air within chambers179and181is considered near atmospheric pressure. Meanwhile, chambers180and182are filled with hydrostatically pressurized fluid184.

Referring toFIGS. 54A-54E, for the culmination of this process, the drill stem situated axially upward from upper body1, as shown inFIG. 54A, and lower body2, as shown inFIG. 54B, are both rotated in the opposite direction from the rotational position used to assemble the rotary shouldered and threaded connection of tool joint15, as shown inFIG. 2C, and then lifted upward such as to disconnect an upper half15aof upper body1from a lower half15bof lower body2, as shown inFIG. 54B. Collet131engages lower shoulder1band elevates UUT90with the upper unstuck portion of the drill stem. UUT90may be upwardly removed with the upper drill stem. The wireline unit may be disconnected and fishing neck100left down or up. Passage183is open to drain fluids as the drill stem is elevated.

Alternately, as shown inFIGS. 54A-54E, fishing neck100may be displaced upwardly such that groove101baxially passes “c” ring140, shoulder101gof mandrel101engages shoulder109sof body109, key136is radially displaced outward, surface136cis radially adjacent diameter101a, and flow passages113a,105b,117a,113c,105a,117cand107a(FIG. 54D) are now all open to hydrostatically pressurized fluid184via passage183(FIG. 54E). Chambers179,180,181and182are filled with pressurized fluid184and are at similar pressures. As such there will be no forces or trapped pressures as the UUT is elevated by wireline to the surface.

Referring toFIGS. 25A-25H and 26-46, UUT90may be broken apart at threads123,135and106(FIG. 25E) and axially lengthened by adding: an additional intermediate control tube105(FIG. 25F) with seals160,161,162and163, an additional upper core extension112, an additional upper barrel122(FIG. 25E), an additional intermediate connector127(FIG. 25F) with seals174,175and163, and an additional core adapter113with seal173. Reassembly of UUT90with this additional segment will add another atmospheric chamber and another pressurized chamber. This addition may be repeated as many times as desired to allow UUT90to be used shallower in a well that cannot be pressurized from the surface.

A DSD and UUT may also include alternative embodiments. For instance, referring toFIGS. 55-57, a DSD200includes an axially inverted block and lock sleeve mechanism including a block sleeve203and a lock sleeve204. The positions of block sleeve203and lock sleeve204are reversed or inverted compared to the similar structures of the DSD50shown inFIGS. 2A-2F. Also axially inverted compared to similar components of DSD50are the first mating serrations206and the second mating serrations208between block sleeve203and body202. DSD200also includes a first tool joint215and a second tool joint214. The other features of inverted DSD200may be substantially the same as those shown and described with reference to DSD50ofFIGS. 2A-2F.

Referring toFIGS. 58-64, to activate DSD200, an alternative UUT250may be used. UUT250includes an upper end similar to the same portion of UUT90inFIGS. 25A and 25B. UUT250also includes an inner core252and a grapple254similar to grapple121but with some differences. Grapple254includes an upper collet mechanism with a plurality of collets fingers256(FIG. 58), a lower collet mechanism with a plurality of collets fingers260(FIG. 60) and a shear member253. However, grapple254of UUT250is inverted such that engagement members258,262of the collet fingers256and260are directed in the opposite axial direction relative to the similar members of grapple121of UUT90. Thus, the axially inverted collets of UUT250are adapted for operational interaction with the appropriate portions of the axially inverted DSD200described above, in a manner similar to that described above with respect to UUT90and DSD50.

Furthermore, UUT250also includes an axially inverted lower hydraulic and atmospheric chamber portion as compared to UUT90. A detailed description of the lower chamber portion of UUT90, including chambers179,180,181and182, is provided with reference toFIGS. 25E-25H.

Referring toFIGS. 61-64, the lower hydraulic and atmospheric chamber portion of UUT250is axially inverted such that a connector270(FIG. 61) is disposed at an upper end of this portion of UUT250radially inside outer barrel264, forming a chamber282. Axially below this location is a chamber281(FIG. 62) formed between radially outer barrel264and radially inner core266. As shown inFIGS. 63 and 64, an intermediate connector268partially defines a chamber280; also, a chamber279is disposed within this portion of UUT250and is partially defined by lower connector272, outer barrel264and inner core266. UUT250also includes lower end fluid passage283. The operation of the inverted lower hydraulic and atmospheric chamber portion of UUT250is similar in manner as compared to the corresponding chamber portion of UUT90. However, unlike UUT90and DSD50, block sleeve203of DSD200shifts axially upward upon activation of the assembly and the disconnection is made in a manner similar as previously described with regard to UUT90and DSD50, at the lower tool joint215shown inFIG. 57.

In further alternative embodiments of the DSD and UUT, other changes may be made to these assemblies to provide additional functionality and flexibility to the overall system of disconnecting portions of pipe strings. Referring toFIGS. 65 and 66, another alternative DSD300is illustrated which is axially inverted and includes a shear or frangible release in place of the lock sleeve. DSD300comprises a body302(FIG. 65) with no tool joint axially adjacent to the upper end of a block sleeve303. Instead a tool joint315is disposed toward the axially lower portion of block sleeve303(FIG. 66). Disposed axially between body302and block sleeve303are first mating serrations306and second mating serrations308, which are axially displaceable to engage or disengage the upper and lower bodies on either side of the tool joint315as described herein. Block sleeve303includes an axially upper portion303aand an axially lower portion303bcoupled by a threaded connection303c. A lower shearable or frangible release mechanism310radially engages both block sleeve303and body302until activation of the assembly occurs in response to a UUT as described herein. Upon the application of an upward force by a UUT, mechanism310shears or releases to allow the upper end312of block sleeve303to move axially upward into a bore space314of body302(FIG. 65), thereby axially disengaging mating serrations306,308, and allowing the upper and lower tubular strings to be disconnected at the tool joint315. Other features of DSD300not specifically described herein are consistent with corresponding features of the DSD's described elsewhere in this description.

Referring toFIGS. 67 and 68, in a further alternative embodiment of DSD300, a DSD400is also axially inverted as compared to DSD50, but also includes a lower lock mechanism409(FIG. 68) rather than the shear mechanism310of DSD300. Upon activation of the assembly in response to a UUT as described herein, an upward force is applied to a lock sleeve414(FIG. 68) and a collet mechanism410of the lower lock mechanism409, releasing a block sleeve403. Lower lock mechanism409comprises an axial lower portion403band an axial upper portion403aof block sleeve403, coupled by a threaded connection403c. The released block sleeve403is displaced axially upward such that an upper end412of block sleeve403is displaced axially into a bore space414of a body402(FIG. 67), thereby axially disengaging mating serrations406,408, and allowing the upper and lower tubular strings to be disconnected at the tool joint415. Other features of DSD400not specifically described herein are consistent with corresponding features of the DSD's contained elsewhere in this description.

The DSD's300,400, include only one rotary shouldered and threaded tool joint and one lock or release mechanism, thus only requiring one collet mechanism in the respective activating UUT. An alternative embodiment of a UUT is illustrated inFIGS. 69-71. UUT450is designed to activate inverted DSD's300,400, and thus it shares many of the same features and characteristics of the previously described UUT250. For example, the upper fishing neck and collet portion of UUT450corresponds to the fishing neck and collet portion of UUT's50,250, ofFIGS. 25A and 25B. Also, the lower chamber portion of UUT450corresponds to the lower chamber portion of UUT250, shown inFIGS. 61-64. However, UUT450includes a grapple454(FIG. 70) with only a single collet mechanism including a plurality of collets fingers456and a shear member453. The axially inverted collet mechanism includes engagement members458of the collet fingers directed in the axially opposed direction of the engagement members of the grapple121of UUT90. The collet mechanism of the UUT450is configured for operational interaction with the single, lower release or lock mechanism of the inverted DSD's300,400, described above.

Another embodiment of a disconnect assembly relates to the use of serrations to rotationally couple two bodies of a disconnect assembly using a third body with a varying number of serrations on each body, and is shown inFIGS. 72-77. First body500(FIG. 72) may be a solid or hollow object of any shape fitted with a generally cylindrical end with serrations500adisposed radially about an outer circumference of first body500. Second body501may be a solid or hollow object of any shape fitted with a generally cylindrical end with serrations501adisposed radially about an outer circumference of second body501. Serrations500aof first body500and serrations501aof second body501are of different count or pitch. A third body502is fitted with serrations502adisposed radially about an inner circumference of third body502for companion engagement with serrations500aof first body500, and serrations502bdisposed radially about the inner circumference of third body502but axially displaced from serrations502afor companion engagement with serrations501aof second body501.

Sufficient axial clearance must be provided such that serrations502aand502bof third body502may disengage from their respective mating serrations500aand501a, to allow third body502to be rotated independently of first body500and second body501. Axial gap503disposed axially upward from serration500amust be of sufficient width to allow the third body502to be axially displaced upward to disengage serration502afrom serration500aof first body500and, assuming serration502bwould interfere by engaging serration500a, axial gap504between serrations500aand501amust be sufficient to allow the third body502to be axially displaced upward to disengage serration502bfrom serration501aof second body501.

Screws505aand505bretained by nuts506aand506bextend radially through second body502, holding third body502in the engaged position as shown inFIG. 72.

If first body500and second body501are immovable or positioned in a desired rotational position with respect to one another, the third body502, axially positioned such that serration502ais aligned in gap503and serration502bis aligned in gap504, may be rotated into a particular position and axially engaged with the serrations of the first body500and the second body501by axially displacing third body502such that serration502aengages serration500aand serration502bengages serration501a, to prevent rotation between first body500and second body501.

The accuracy of alignment between third body502and first and second bodies500and501is dependent on the clearance between the bodies and number of or pitch of the serrations as previously described.

While keeping with the principles of this disclosure, the first body500and the second body501may be shaft couplings within a machine or a sign post and a ground fitting. In further embodiments, the bodies500,501include not just downhole tubulars, but tubular or cylindrical members in fields outside of hydrocarbon exploration and production.

Also keeping with the principles of this disclosure, if serrations502bof third body502and501aof second body501are sufficiently diametrically larger than serrations500aof first body500and502aof third body502, gap504may be eliminated as larger diameter serration502bmay be disposed radially over serration500awithout engaging smaller diameter serration500a. Additionally, if first body500may be displaced axially upward and away from second body501far enough to disengage third body502from both the first body500and the second body501, as in the situation of bolted down machine components, gaps503and504would not be required and screws505a,505b, and nuts506aand506bmay also not be required.

Yet another embodiment of a disconnect assembly using serrations to rotationally couple two bodies using a third body, with a different number of serrations on each body is shown inFIGS. 78-88. The first body507(FIG. 78) is in the form of a shaft including a key slot507b(FIG. 83) disposed axially along the circumference of a central bore507cand a threaded set screw hole507d(FIG. 80) extending radially away from first body507for mounting on a shaft510disposed concentrically within first body507using a circumferentially disposed key511. First body507has a serrated face507a(FIGS. 82, 83). The second body508is in the form of a shaft including a key slot508b(FIG. 84) disposed axially along the circumference of a central bore508cand a threaded set screw hole508d(FIG. 508D) extending radially away from second body508for mounting on a shaft512disposed concentrically within second body508using a circumferentially disposed key513. Second body508has a serrated face508a(FIGS. 84, 85). Serrations507aof first body507and serrations508aof second body508are of different count or pitch. A third body509(FIG. 80) is fitted with serrations509a(FIG. 87) disposed on a face of third body508for companion engagement with serrations507aof first body507, and serrations509bdisposed on an opposite face of third body508for companion engagement with serrations508aof second body508.

Circumferentially disposed about the axial engagement between first body507, second body508, and third body509are semi-cylindrical retainers514and515(FIG. 78). Retainer515and retainer514surround and act to hold first body507, second body508and third body509in companion serration engagement. Retainer515and retainer514are secured in engagement about first body507, second body508and third body509by studs516a,516b, nuts517a,517b,517cand517d(FIG. 81).

With the retainer514and retainer515removed serrations507aof first body507and serrations508aof second body508may be disengaged from the companion serrations509aand509bof third body509and first body507and second body508may be rotated in relation to one another to form a new angular relationship. Retainers514and515may then be reinstalled as previously described depending on clearances and number of or angular pitch of the pairs of serrations.

Keeping with the principles of this disclosure, first body507and second body508may be formed integrally with shafts510and512so long as freedom exists to move the shaft mountings axially apart to position and engage the serration pairs509aand509bformed with third body509.

It will be understood that all tool joints of the drill stem including tool joint15ofFIG. 2Cmay be identical but assembled with different lubricants, or they may be of different design but assembled with the same lubricant, or a mixture of different designs and lubricants and not deviate from the scope and spirit of the principles disclosed herein.

The exemplary situation given above is by way of example only, and other embodiments may include one DSD or any number of DSD's used at any depth, at regular or random spacing intervals so long as adequate hydrostatic or applied pressure is available. Wireline was used in the exemplary situation to lower and raise the UUT within the drill stem, though other common methods may be used with this description such as coiled tubing, pump down, macaroni tubing, sand line and the like. Circulation was not possible in the exemplary situation described above to display the versatility of the embodiments disclosed herein, though circulation is often desirable and would aid, not inhibit, the function of the described UUTs.

It will be understood that the lower thread of upper body1(FIG. 2A) and the upper thread of lower body2(FIG. 2F) could be reversed or interchanged such that upper body1could have an external thread and the upper end of lower body2could have an external thread, and the functioning of the tool described herein would not change. Likewise the threads connecting upper body1and lower body2could be configured to engage by clockwise or counterclockwise rotation, depending on location and need of a particular use without deviating from the spirit of the principles described herein. Further, the upper thread and lower thread could be any type or kind of drill stem connection to accommodate any particular drill stem.

It will thus be seen, that the disconnect for a well drill stem as well as the selective anchoring and functioning of the unlocking and unblocking tool of the present description may be adapted to carry out the ends and advantages mentioned as well as those inherent therein. While some embodiments of the apparatus have been shown for the purposes of this disclosure, numerous changes in the arrangement and construction of parts may be made by those skilled in the art. All such changes are encompassed within the scope and spirit of the appended claims.

It should be understood by those skilled in the art that the disclosure herein is by way of example only, and even though specific examples are drawn and described, many variations, modifications and changes are possible without limiting the scope, intent or spirit of the claims listed below.