Downhole casing patch

An apparatus for bridging a section of ruptured casing within an oil well comprising a length of bridging pipe extending between first and second ends sized to be located within the casing so as to span the section of ruptured casing, a first seal located around the bridging pipe proximate to the first end thereof, a second seal located around the bridging pipe proximate to the second end thereof, an installation assembly extending through the bridging pipe operably engaged with the first and second ends of the bridging pipe, wherein the installation assembly is operable to extend each of the first and second seals into engagement with the oil well and wherein the installation assembly is further operable to selectably disengage from the bridging pipe.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to a method and apparatus for bridging and sealing a compromised downhole casing.

2. Description of Related Art

In hydrocarbon production, many casings or production tubes may be prone to fatigue and/or wear. These stresses on the casing may cause such casing to crack or rupture leading to loss of integrity of the well bore. Such operations may occur in the case of steam assisted gravity drainage or SAGD operations or primary operations.

One method of repairing such a rupture is to provide a bridging pipe or liner inside of the ruptured casing with seals on each end. However present methods of installing and activating such bridges are time consuming and difficult to install. Such conventional bridging pipes have also suffered from short service lives and have been unable to be retrieved from the well.

SUMMARY OF THE INVENTION

According to a first embodiment of the present invention, there is disclosed an apparatus for bridging a section of ruptured casing within an oil well comprising a length of bridging pipe extending between first and second ends sized to be located within the casing so as to span the section of ruptured casing, a first seal located around the bridging pipe proximate to the first end thereof, a second seal located around the bridging pipe proximate to the second end thereof, an installation assembly extending through the bridging pipe operably engaged with the first and second ends of the bridging pipe, wherein the installation assembly is operable to extend each of the first and second seals into engagement with the oil well and wherein the installation assembly is further operable to selectably disengage from the bridging pipe.

The first seal may comprise top and bottom first seal collet arms extending away from a first seal retaining ring disposed around the bridging pipe, each of the top and bottom first seal collet arms extending to distal ends having outwardly oriented pipe engagement surfaces, top and bottom first seal cones positioned adjacent to the distal ends of the top and bottom first seal collet arms around the bridging pipe, first seal engagement sleeve surrounding the bridging pipe proximate to the first end thereof and a first seal element extending around the bridging pipe between the top first seal cone and the first seal engagement sleeve

The first seal retaining ring, the top first seal cones and the first seal engagement sleeve may be temporarily secured to the bridging pipe with shear pins. The shear pins securing the first seal retaining ring, the top first seal cones and the first seal engagement sleeve may be sheared in order from top to bottom as the bridging pipe moves therethrough. The first seal retaining ring, the top first seal cones and the first seal engagement sleeve may be removed from engagement with the oil well by retrieval rings adapted to engage thereupon. The first seal retaining ring, the top first seal cones and the first seal engagement sleeve may be engaged upon in order from top to bottom by the retrieval rings.

The second seal may comprise top second seal collet arms extending downwardly from a top collet retaining ring disposed around the bridging pipe, the top second seal collet arms extending to distal ends having outwardly oriented pipe engagement surfaces, top and bottom second seal cones positioned below the top second seal collet arms around the bridging pipe, a second seal element extending around the bridging pipe between the top and bottom second seal cones, bottom second seal collet arms extending upwardly from a bottom collet retaining ring disposed around the bridging pipe, the bottom second seal collet arms extending to distal ends having outwardly oriented pipe engagement surfaces, second seal engagement sleeve surrounding the bridging pipe proximate to the second end thereof and The top collet retaining ring, the top and bottom second seal cones, the bottom retaining ring and the second seal engagement sleeve are temporarily secured to the bridging pipe with shear pins.

The shear pins securing the top collet retaining ring, the top and bottom second seal cones, the bottom retaining ring and the second seal engagement sleeve may be sheared in order from bottom to top as the bridging pipe moves therethrough. The top collet retaining ring, the top and bottom second seal cones, the bottom retaining ring and the second seal engagement sleeve may be removed from engagement with the oil well by retrieval rings adapted to engage thereupon. The top collet retaining ring, the top and bottom second seal cones, the bottom retaining ring and the second seal engagement sleeve may be engaged upon in order from top to bottom by the retrieval rings. The shear pin securing the top collet retaining ring is sized larger than the shear pins securing the top and bottom second seal cones, the bottom retaining ring and the second seal engagement sleeve may be temporarily secured to the bridging pipe with shear pins. The apparatus may further comprise a selectably compressible sleeve between the top second seal cone and the second seal element.

The selectably compressible sleeve may comprises a plurality of release arms extending from a sleeve adjacent to the second seal element, the plurality of release arms having end surfaces selectably engageable with a corresponding receptacle sleeve extending from the top second seal cone, wherein the end surfaces of the release arms are maintained in engagement with the receptacle sleeve by the bridging pipe, wherein the recess is located at a position along the bridging pipe corresponding to a position at which the release arms are desired to be released from engagement with the receptacle sleeve.

The bridging pipe may include a plurality of longitudinal slots extending therealong and further including a carriage within each slot in engagement with the second seal engagement sleeve so as to transmit longitudinal movement of a tool inside the bridging pipe to the second seal engagement sleeve.

According to a further embodiment of the present invention, there is disclosed a method for bridging a section of pipe having a compromised section comprising providing a length of bridging pipe extending between first and second ends located within the casing so as to span the section of ruptured casing, locating an installation assembly within the bridging pipe, positioning the bridging pipe within the pipe so as to span the section of ruptured casing, with the installation assembly, longitudinally compressing the first end of the bridging pipe so as to extend a first seal therearound located proximate to the first end of the bridging pipe, releasing the installation assembly from the first end of the bridging pipe, with the installation assembly, longitudinally compressing the second end of the bridging pipe so as to extend a second seal therearound located proximate to the second end of the bridging pipe, releasing the installation assembly from the second end of the bridging pipe, removing the installation assembly from the bridging pipe.

According to a further embodiment of the present invention, there is disclosed an apparatus for selectively decoupling a setting tool from a pipe comprising an inner tubular body locatable within the pipe, an outer tubular body located annularly between the pipe and the inner tubular body, a plurality of collet arms extending from the outer tubular body, the plurality of collet arms having an exterior gripping surface engagable upon the pipe and a catch extending between the inner tubular body and the outer tubular body so as to selectably lock the inner and outer tubular bodies together.

The catch may comprise at least one radially movable pin extending between aid inner and outer tubular bodies wherein the at least one pin engages the inner and outer tubular body at a first radially extended position and disengages from the outer tubular body at a second radially compressed position. The apparatus may further comprise a sleeve longitudinally displaceable within a central bore of the inner tubular body so as to retain the at least one pin at the first position. The sleeve is longitudinally displaceable to permit the at least one pin to move to the second position.

The inner tubular body includes a cone at a position to bias the plurality of collet arms into engagement with the pipe at an initial position.

According to a further embodiment of the present invention, there is disclosed a method for selectively decoupling a setting tool from a pipe comprising locating an inner tubular body within the pipe, locating an outer tubular body annularly between the pipe and the inner tubular body, biasing a plurality of collet arms extending from the outer tubular body into engagement with the pipe and selectably longitudinally retaining inner and outer tubular bodies relative to each other with a catch extending between the inner tubular body and the outer tubular body so as to selectably.

According to a further embodiment of the present invention, there is disclosed a n apparatus for selectively retaining and releasing a dropped ball within a down hole tool comprising a body locatable within the down hole tool having a central passage therethrough, the central passage having an enlarged cavity section, a slidably tubular member having a central passage therethrough located within the cavity section, a plurality of collet arms longitudinally extending upwardly from the tubular member, each collet arm extending to a free distal end wherein the free distal arms define a ball seat and a retaining ring positioned to surround the free distal ends of the collet arms to as to retain the free distal ends at a radially compressed configuration, wherein the slidably tubular member is slidable between a first position wherein the retaining ring compresses the free distal ends of the plurality of collet arms and second position wherein the collet arms are disengaged from the retaining ring so as to be permitted to radially expand.

The apparatus may further comprise at least one shear pin adapted to selectably retain the slidable tubular member at the first position.

According to a further embodiment of the present invention, there is disclosed a method for selectively retaining and releasing a dropped ball within a down hole tool comprising providing a body within the down hole tool having a central passage therethrough, the central passage having an enlarged cavity section, locating a slidably tubular member having a central passage therethrough within the cavity section, providing a plurality of collet arms longitudinally extending upwardly from the tubular member, each collet arm extending to a free distal end wherein the free distal arms define a ball seat and locating a retaining ring around the free distal ends of the collet arms to as to retain the free distal ends at a radially compressed configuration, slidably displacing the tubular member from a first position wherein the retaining ring compresses the free distal ends of the plurality of collet arms and second position wherein the collet arms are disengaged from the retaining ring so as to be permitted to radially expand thereby permitting the ball to pass therethrough.

According to a further embodiment of the present invention, there is disclosed a packer setting tool comprising an inner cylinder having an inner passage extending therethrough, the inner cylinder being securable to an inner housing of the packer, an outer cylinder annularly surrounding the inner cylinder, the outer cylinder being slidably relative to the inner cylinder and having a diameter selected to longitudinally engage an outer longitudinally movable sleeve of the packer, at least one annular piston located within an annular cavity between the inner and outer cylinders, the at least one annular piston connected to the outer cylinder, at least one port extending between the inner passage and the annular cavity so as to transmit a pressure within the inner passage to the annular cavity thereby displacing the at least one annular piston and the outer cylinder in a direction towards the packer so as to bear thereupon.

According to a further embodiment of the present invention, there is disclosed a method for setting a packer comprising securing an inner cylinder having an inner passage extending therethrough, the inner cylinder being to an inner housing of the packer, slidably locating an outer cylinder annularly around the inner cylinder, the outer cylinder having a diameter selected to longitudinally engage an outer longitudinally movable sleeve of the packer, transmitting a pressurized fluid within the inner passage through the inner cylinder to an annular cavity between the inner and outer cylinders thereby displacing at least one annular piston located within the annular cavity, wherein the at least one annular piston are connected to the outer cylinder thereby displacing the at least one annular piston and the outer cylinder in a direction towards the packer so as to bear thereupon.

According to a further embodiment of the present invention, there is disclosed an apparatus for coupling a top down hole assembly to a bottom down hole assembly for removal from a well bore comprising a first pipe extending longitudinally upward from the bottom down hole assembly, a second pipe extending longitudinally downwards from the top down hole assembly sized to be received within the first pipe, an end assembly on a distal end of the first pipe assembly and a tag ring located within the first pipe coupled to the end assembly, the tag ring sized to longitudinally abut the second pipe to as to prevent the second pipe from passing therethrough.

The second pipe may includes a stinger tube extending from a bottom end thereof sized to pass through the tag ring. The tag ring may be releasably secured to the end assembly by at least one radial pin extending from the tag ring engagable within a j-shaped slot within the end assembly. The tag ring and a distal end of the second pipe may include castellations adapted to engage upon each other permitting the second pipe to rotate the tag ring out of engagement with the end assembly. The second pie may include a plurality of angularly oriented rings therearound wherein the end assembly includes a corresponding angularly oriented ring so as to permit the second pipe to be passed therethrough in a direction towards the bottom down hole assembly and prevent movement of the second pipe away from the bottom down hole assembly.

According to a further embodiment of the present invention, there is disclosed a method for coupling a top down hole assembly to a bottom down hole assembly for removal from a well bore comprising providing a first pipe extending longitudinally upward from the bottom down hole assembly, providing an end assembly on a distal end of the first pipe assembly and slidably inserting a second pipe extending longitudinally downwards from the top down hole assembly within the first pipe, abutting a distal end of the second pipe against a tag ring located within the first pipe coupled to the end assembly and rotating the second pipe relative to the first pipe so as to engage castellations on each of the distal end of the second pipe and the tag ring and disengage at least one pin from the tag ring from j-shaped slots in the end assembly.

DETAILED DESCRIPTION

Referring toFIG. 1, an assembly for bridging a compromised section of a down-well casing according to a first embodiment of the invention is shown generally at10. The assembly10extends between first and second ends,12and14, respectively and includes a central bridging pipe16adapted to be located within the compromised section of casing and sealed therein as will be more fully described below. The bridging pipe16of the apparatus10includes a first seal18and first pair of gripping collet arms20located proximate to a first end22thereof and a second seal24and a second pair of gripping collet arms26located proximate to a second end28thereof. In operation, the first and second collet arms and seals are extended into engagement with the casing after the bridging pipe portion is located in the desired location so as to seal the compromised portion of the pipe and repair any perforations or ruptures therein.

Turning now toFIGS. 2 through 20, a cross sectional view of the assembly ofFIG. 1is shown. The assembly includes a bridging pipe16having an inner pipe assembly80extending through in interior thereof. As illustrated in greater detail inFIG. 3, the assembly includes a setting tool40at the first end thereof. The setting tool40includes the first end12of the assembly which may include an internal threading for connection to a tool string as is commonly known. The setting tool is adapted to utilize pressure within the tool string or the annulus between the tool string and the casing to extend the seals into engagement with the casing.

As shown inFIGS. 3 and 10, the setting tool40comprises an outer tubular portion42and an inner tubular portion44forming an annular chamber46therebetween. The annular chamber46is sealed at the leading edge by an end body48of the setting tool and includes an annular piston50therein. The annular piston50is operably connected to the outer tubular portion42and slidably sealed to the inner tubular portion44. A passage52extends between the interior of the inner tubular portion44and a boundary between the annular piston50and the end body48so as to convey pressure within the interior of the tool string therebetween. In operation when a user desires to extend the seals, an increasing pressure is applied to the interior of the tool string so as to pressurize the location between the annular piston50and the end body48so as to move the annular piston50and thereby the outer tubular portion42in a direction towards the second end14of the assembly. Details of the extension of such seals will be provided further below. As illustrated inFIG. 3, the setting tool40may include a second set of pistons generally indicated at53secured to each of the inner tubular portion44and outer tubular portion42so as to increase the force which the setting tool may apply. As illustrated inFIG. 3, the setting tool includes a transfer sleeve43sized to correspond to the matching first end sleeve17of the bridging pipe16.

Turning now toFIGS. 4 and 11, a detailed view of an auto tripping ball seat60for forming the desired pressure within the setting tool40is illustrated. The auto tripping ball seat60is secured to the inner tubular portion44of the setting tool so as to be run into and retrieved from the well as a single component. In particular, the auto tripping ball seat60may comprise an upper slidable tubular member62located within a ball seat body64. The upper slidable tubular member62includes a plurality of collet arms66at a leading edge thereof forming a ball seat67at a leading edge of the slidable tubular member62. The upper slidable tubular member62is sealably secured within a cavity68in the ball seat body64by set screws or the like and the collet arms66are adapted to be retained in the reduced orientation as shown to retain a dropped ball by engagement upon the cavity68as illustrated inFIG. 12. The cavity68includes an expanded portion70downstream of the initial position of the collet arms66such that at a sufficiently high enough pressure, the set screws69will be broken and the upper slidable tubular member62is permitted to shift in a direction towards the second end14of the assembly thereby also permitting the collet arms to expand and release the ball to pass therethrough as illustrated inFIG. 13. The upper slidable tubular member62also includes an annular recess72in an exterior thereof wherein the ball seat body64include a plurality of keys74extending therethrough into engagement with an upper collet sleeve73inside the first end sleeve17and engages upon the first end22of the bridging pipe16. As the upper slidable tubular member62shifts toward the second end14of the assembly10, the keys74are permitted to retract into the annular recess72and out of engagement with the upper collet sleeve73thereby decoupling the ball seat body from the upper collet sleeve73and bridging pipe16. As a safety precaution if sufficient pressure does not shift the ball seat downwardly, the setting tool may be rotated to shear release pins200thereby releasing collet arms120. As illustrated inFIGS. 21 and 22, the shear release pins200pass through bores202in the ball seat body64and bores204in the upper collet sleeve73. The shear release pins200prevent rotation between the ball seat body64and the upper collet sleeve73thereby retaining the keys74within notches206in the upper collet sleeve73. Upon shearing of the shear release pins200, the keys74may be rotated into enlarged portions208in the bore of the upper collet sleeve73thereby permitting longitudinal movement therebetween. As illustrated inFIG. 27, the release collet arms120may have a dovetailed profile received within corresponding dovetail slots on the cone so as to retract the release collet arms120as the cone is moved down hole.

As illustrated inFIGS. 4 and 5, the assembly includes an inner pipe assembly80extending between the ball seat body64and the release apparatus90as will be more fully described below. The inner pipe assembly80ensures that the entire contents of the interior of the bridging pipe16may be removed after setting the bridging pipe. With reference toFIG. 6, the release apparatus90is illustrated which includes the second end14of the assembly. The release apparatus90includes a release body92extending from and connected to the inner pipe assembly80. The release body forms an inner passage having a bottom cavity94adapted to sealably receive a lower tubular sliding member96therein. The lower tubular sliding member96includes a ball catch surface97at a leading edge thereof adapted to receive and retain a dropped ball thereon. The lower tubular sliding member96is secured to the release body92through the use of shear pins99.

As illustrated inFIG. 6the release apparatus90further includes a plurality of retaining arms98extending from the release body92into engagement with the interior of the bridging pipe16which are retained in engagement therewith by a backing body100. The backing body100is slidably located around the release body92and secured thereto with a plurality of lower keys102or the like. The lower keys102are retained in such engagement by the lower tubular sliding member. As illustrated inFIG. 6, the lower tubular sliding member96includes an annular recess104therein adapted to release the lower keys102from engagement with the backing body100. In operation, a sufficiently high enough pressure applied to a ball on the lower tubular sliding member96will rupture or shear the shear pins99thereby allowing the lower tubular sliding member96to shift towards the second end14of the assembly. If the ball cannot seat on the bottom seat due to damage from the first seat or any other reason, then a second larger ball can be dropped to land in ball catch surface97. At such position, the lower keys102will be permitted to retract into the annular recess104thereby disengaging the release body92from the backing body100and thereby permitting any movement of the inner pipe assembly80and therefore the release body92in a direction towards the first end12of the assembly to disengage the retaining arms98from the bridging pipe16. After such disengagement, the release apparatus90may be removed from the interior of the bridging pipe16along with the inner pipe assembly80. If pressure cannot shear pins99and the release apparatus90then an over pull condition may be applied to shear a weakened location on the collet arms98that will allow the inner pipe assembly80and release apparatus90to be pulled out of the hole.

Turning now toFIGS. 7 through 9, a sequence of operation for utilizing the assembly is illustrated. In operation, the assembly10may be located within a ruptured casing with the first and second seals18and24to either side thereof. To extend the seals, a ball may be dropped down the tool string to engage upon the ball seat67on the first slidable tubular member62. Applying pressure to the tool string will urge the annular piston50and the end body48apart until the transfer sleeve43engages the bridging pipe16. As the inner pipe assembly80and thereby the release apparatus are connected to the second end28of the bridging pipe16, such engagement and further movement will urge the top edge of the bridging pipe16in a direction towards the second end14of the assembly and extend the first seal18and gripping collet arms20.

After the first seal18has been set, further increasing the pressure within the tool string will thereafter shear the set screws between the first slidable tubular member62and the ball seat body64thereby permitting the first slidable tubular member to shift as set out above which will release the ball to pass therethrough to the lower tubular sliding tubular member96.

Furthermore, a downward force upon the setting tool40towards the second end14of the apparatus will further cause the collets arms120to retract from engagement with the bridging pipe16.

As illustrated inFIG. 17, a bottom seal activation assembly400may include a release mechanism in an alternative embodiment to the release mechanism90shown inFIG. 6. The bottom seal activation assembly400may include a further auto tripping ball seat60as set out above for providing a second extending force to the setting tool. It will be appreciated that the second auto tripping ball seat60may be located at any location within the assembly so as to provide a pressure increase thereto. Additionally, it will be appreciated that at such time, the retrieval collet arms120will have been disengaged from the bridging pipe16so as to permit inner pipe assembly80to move relative to the bridging pipe16. Accordingly pressuring the annular chamber46will pull upward on the inner pipe assembly80relative to the bridging pipe16which is secured at the first seal18to the well bore.

As illustrated inFIG. 18, the bottom seal activation assembly400is included proximate to the second end14of the bridging pipe16. The bottom seal activation assembly400includes a plurality of carriages402located within slots404through a bottom pipe extension19, extending from the second end28of the bridging pipe16. The inner pipe assembly80includes a plurality of pulling arms406extending therefrom which are spaced annularly around the inner pipe assembly80with splines408therebetween. The pulling arms406are secured to a pulling sleeve410with shear pins412. As the inner pipe assembly80pulls upwardly in a direction generally indicated at420, the pulling arms406pull upwardly on the pulling sleeve410to engage upon the carriages402which are then moved through the slots404to extend the second seal24and second pair of gripping collet arms26as set out below.

Thereafter further increasing the pressure through the tool string will again urge the annular piston50(as shown inFIGS. 3 and 10) and the end body48apart so as to pull upward on the inner tubular portion44against the first pair of collet arms20. Such movement of the inner tubular portion44will act through the inner pipe assembly80so at to pull upward on the second end28of the bridging pipe16. Such upward movement of the second end28of the bridging pipe16will compress the bridging pipe16so as to extend the second seal24and second pair of gripping collet arms26into engagement with the casing. At such time a test pressure may be applied to the annulus between the tool string and the casing to test the integrity of the seals. As illustrated inFIG. 17, the bottom portion of the assembly may include inner packer cups450and outer packer cups542adapted to seal the annulus of the well bore to the assembly10as well as seal the bridging pipe16to the inner pipe assembly80thereby permitting such pressure test.

After the seals have been verified, the pressure within the annulus may be reduced and the pressure within the tool string again increased to shear the shear pins of the lower tubular sliding member96. After such shear pins have been sheared, the release apparatus and therefore the inner pipe and setting tool may be removed from the bridging pipe.

In operation, the first and second pairs of gripping collet arms20and26are extended by cones25which are urged under the ends of the pairs of gripping collet arms20and26. Each of the cones, and collet arms are initially secured to the bridging pipe by set screws which are sheared as the bridging pipe is compressed by the setting tool. The first end of the bridging pipe16is indexed to the first pair of gripping collet arms20by a ratchet30therebetween to permit movement therebetween caused by the shifting tool, but not thereafter whereas the bottom most cone is secured to the bridging pipe16by a larger set screw34selected to remain in place after setting of the collet arms. Furthermore, the second pair of gripping collet arms26are retained in position by a larger set screw32as illustrated inFIG. 5which will maintain the second pair of gripping collet arms26at a position along the bridging pipe16until a sufficiently large enough thermal expansion force is applied to the bridging pipe whereafter they will be sheared permitting the second pair of gripping collet arms26and second seal to float along the bridging pipe so as to permit thermal expansion of the bridging pipe16.

After being set in place the setting tool40and release apparatus90can be removed from the bridging pipe16to permit operation of the well again as set out above. When the bridging pipe16is desired to be removed, the setting tool including the auto tripping ball seat60can again be run into the well bore to engage and release the collet arms. The setting tool40includes a downwardly oriented a retrieval ring125at a position adapted to engage upon retrieval grips127on the release collet arms120as illustrated inFIGS. 11 and 14. After the top seal has been set, upward motion of the inner pipe assembly80as set out above will pull the release collet arms120out of the bridging pipe as well wherein the retrieval ring125prevents the release collet arms120from moving relative to the cone122so as to prevent them from re-engaging upon the bridging pipe16.

After being located within the bridging pipe16, a ball may again be dropped to be located on the ball seat67so as to cause the inner tubular portion44to be moved upward relative to the outer tubular portion42as set out above. In order to remove the bridging pipe, the auto tripping ball seat60with release collet arms120at the initial position may be inserted into the well bore so as to engage the release collet arms120upon the bridging pipe as illustrated in inFIG. 11. Thereafter an upward force may be applied to the auto tripping ball seat60so as to pull upwardly on the bridging pipe16.

Thereafter, this movement caused by the pressurized working string along with an upward force applied to the top end of the work string will further engage the retrieval collet arms120in the bridging pipe and pull it upwardly out of the well bore. The upward motion of the bridging pipe16will initially shear the larger set screw34securing the bottom cone on bridging pipe to release this cone therefrom. The bridging pipe includes first second and third retrieval rings124,126and128, respectively each adapted to engage and pull upwardly on the topmost cone, the top collet arm and bottom collet arm, respectively. The upward motion of the bridging pipe thereafter will engage the first second and third retrieval rings124,126and128in order thereby removing the cones25and collet arms20in sequence. Advantageously, the first second and third retrieval rings124,126and128are positioned around the bridging pipe so as to engage the top cone first, the top collet second and the bottom collet third so as to space such components along the bridging pipe as they are pulled out of the well.

After the top collets and seal have been released, the bottom collets and seals may then also be released. If the larger set screw32has not yet been sheared by thermal cycling of the upward motion of the bridging pipe16will then shear such set screw. Optionally the larger set screw32may be received within a slot130in the bridging pipe so as to permit the larger set screw32to be sheared at a different time than the larger set screw34above so as to reduce the total force required. Similar to the top collets and seal above, the bridging pipe16includes first and second retrieval rings132and134respectively for pulling upwardly on the topmost collet arms as well as upwardly on the bottom most cone. The bridging pipe also includes a compression sleeve140between the topmost cone and the seal24. The compression sleeve140comprises inner and outer arms144and142, respectively interlocked with each other. The bridging pipe16includes a recess146just below the interlock such that upward movement of the bridging pipe permits the inner arms to radially move inward and therefore out of engagement with the outer arms. This will then permit the compression sleeve140to compress and therefore permit the topmost cone to slip downwardly out from under the collet arms thereby disengaging them from the well bore. As set out above, the first and second retrieval arms132and134are spaced apart by a distance to space all components along the bridging pipe.

As illustrated inFIG. 2and described above, the inner pipe assembly80bridges the bottom portion of the present apparatus to the top portion so as to transmit movement therebetween as set out above. The inner pipe assembly80comprises a first pipe500extending from a bottom pipe base502adapted to form an inner base for the release apparatus90. The first pipe500extends to a distal end having an end assembly502thereon. The end assembly comprises and end collar504and a selectably releasable tag ring506releasably secured to said end assembly within the first pipe500. As illustrated inFIG. 26, the tag ring506includes a plurality of radially extending pins508therefrom which are adapted to be engaged within j-shaped slots509in the end collar504and rotated therein so as to secure the tag ring therein.

The inner pipe assembly80also includes a second pipe510extending from the auto tripping ball seat60. As illustrated inFIG. 4, the second pipe510is secured to the auto tripping ball seat60by top and bottom connectors512and514respectively. In operation the top and bottom connectors may have one or more pipe sections therein so as to space the second pipe away from the auto tripping ball seat60by a distance required to bridge the compromised well casing section. The second pipe510includes a plurality of grooves516around an exterior surface thereof stepped so as to permit movement of the end collar504in a direction towards the first end12of the assembly10only. As illustrated inFIG. 25, the end collar504includes a corresponding indexed ring520therein adapted to engage upon the grooves516so as to permit such movement only. As illustrated inFIG. 25, the tag ring506includes an entrance end having a profile defined by a series of rectangular blocks or castellations530therearound. The distal end of the second pipe532includes a corresponding end surface so as to be engageable therein.

In operation, as illustrated inFIG. 23, the bottom assembly comprising the bottom seal, bottom seal activation assembly400and first pipe500along with the end assembly502is located within a well bore. Thereafter, a plurality of pipes are secured thereto to form the bridging pipe16of a desired length. The second pipe510along with the stinger tube540may be introduced into the bore and inserted until the distal end532of the second pipe510engages upon the tag ring506to confirm matching lengths of the inner pipe assembly80and bridging pipe16. It will be appreciated that a number of pipes may be located between the top and bottom connectors512and514to provide the desired length. Thereafter, the top assembly may be completed as illustrated inFIG. 24, comprising the setting tool40, auto tripping ball seat60and second pipe510along with the stinger tube540and reinserted into the well until the distal end532of the second pipe510encounters the tag ring506. Thereafter the top assembly may be rotated to engage the castellations in the second pipe with the corresponding castellations in the tag ring and thereafter rotating the tag ring506such that the pins508out of the j-shaped slots509so as to permit the second pipe510to pass therethrough. The top assembly may then be further inserted thereinto to complete the bridging pipe16at which point the completed assembly10may be inserted in to the well bore to the desired location. As illustrated inFIG. 17, the slidable member60and collet arms66may be positioned to cover a release hole440. When the slidable member60is shifted downwards as set out above, the release hole440may be positioned to be uncovered so as to fluidically connect the interior of the assembly with the annulus thereby preventing pressure build up from removing the assembly from the well bore.

As utilized herein “pipe” shall be defined to include at least one pipe section which may be connected to additional pipe sections of commonly provided lengths which may be joined in any conventional means such as, by way of non-limiting example, welding, couplers or pipe joints as are commonly known. As utilized herein castellation shall be used to describe an end surface of a pipe or other body having a series of rectangular notched indented portions.