Patent Application
20060266530
The present invention relates in general to well completion systems, and more particularly to a system and method for fluid control in expandable tubing.
Numerous operations are performed during the drilling and maintenance of subterranean wells that require the introduction of various fluids into the well for specific purposes. For example, fluids may be introduced into the well for the performance of gravel packing operations, sand treatment operations, or other completion or service operations. Such fluids as acids, cements, polymers, and sand-filled liquids may be injected into the formation or into the outer annulus between a sand screen and a perforated well casing. After the various operations are performed, completion fluids are introduced into the well to displace the service fluids that were used to perform the various operations.
Once the completion fluid introduction operation is complete, the apparatus used for the operation must be removed along with the tubular work string carrying the apparatus. As the apparatus is removed, however, quantities of completion fluid contained within the apparatus and work string may be lost. For example, the completion fluid may be spilt into the formation as the apparatus and work string is removed. The loss of completion fluid is undesirable since completion fluid is costly and will contaminate the formation if it is not contained.
Several methods have been developed for preventing completion fluid from being spilt into the formation. Those methods include introducing viscous pills, loss circulating material and/or gel material in the bore as the work string is withdrawn in order to protect the formation from the completion fluid. Such materials may be used to seal leak paths.
Still another method used for containing completion fluids is that of an automatically operating flapper valve. Such valves have been conventionally mounted on a screen support sub between the screen and a packer for pivotal movement from an upright, open bore position, to a horizontal, closed bore position. The flapper valve is propped open in the upright position during the various completion and service operations. When the work string and the apparatus are pulled out, the flapper valve is moved into the horizontal position against a valve seat, usually by a biasing mechanism. The closed valve keeps the completion fluid contained above the valve until another tubing string is inserted into the well.
Conventional flapper valves are generally not compatible, however, with expandable tubing, which is of a reduced diameter during installation and is expanded to an increased diameter after the tubing is in place within the borehole. In its unexpanded state, expandable tubing facilitates installation in offset, slanted, or horizontal boreholes. Upon expansion, solid or perforated tubing and screens provide support for uncased borehole walls while screening and filtering out sand and other produced solid materials which can damage the tubing. After expansion, the internal diameter of the tubing is increased, thereby improving the flow of fluids through the tubing. Because a flapper valve is typically not moved into the horizontal, or closed, position until after the tubing is expanded to the increased diameter, however, the flapper valve may not form a sufficient seal with the valve seat. As a result, a flapper valve incorporated into expandable tubing may not be effective to inhibit the loss of completion fluid.
The teachings of the present invention provide a system and method for forming a seal in a portion of expandable tubing. In accordance with a particular embodiment, the system includes a section of generally cylindrical expandable tubing. An inflatable element is disposed along an inner surface of the expandable tubing, and a tool is disposed within the expandable tubing. The inflatable element is predisposed to expand inwardly when fluid pressure is applied to the inflatable element using the tool. The inflatable element forms a seal within the expandable completion.
In accordance with another embodiment, a method for forming a seal within expandable tubing includes installing a section of expandable tubing in a borehole. The expandable tubing has an inflatable element disposed along an inner surface of the expandable tubing. The inflatable element is predisposed to expand inwardly under fluid pressure. Fluid pressure is applied to the inflatable element using a tool within the expandable tubing, and the inflatable element is expanded to form a seal within the expandable tubing.
In accordance with another embodiment, a system for removing a seal within expandable tubing is provided. The system includes a wireline operable to puncture an inflatable element when the inflatable element is in an inflated state within a section of generally cylindrical expandable tubing. The system also includes a grapple that is operable to remove the inflatable element from the expandable tubing.
Depending on the specific features implemented, particular embodiments of the present invention may exhibit some, none, or all of the following technical advantages. A technical advantage may be that a fluid-tight seal may be formed in a portion of expandable tubing. Accordingly, fluid flow within the expandable tubing may be restricted. As a result, the spillage of completion fluids and other service fluids may be reduced, and the contamination of the formation substantially prevented.
Another advantage may be that the seal may be formed from an inflatable bladder housed within the expandable tubing. Because the inflatable bladder may be selectively inflated, the fluid path in the expandable tubing may remain open during operations such as switching fluids in the open hole. When such completion operations are finished, however, the inflatable bladder may then be inflated to seal the tubing until production operations are initiated or until it is otherwise desired that the fluid flow in the expandable tubing be restored.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some or none of the enumerated advantages.
In
Tubing 12 has been placed to run from the lower end of casing 16 down through open hole portion 20 of the well. Within open hole portion 20, tubing 12 has an expandable section 22. Expandable section 22 may be a perforated liner and may typically carry sand screens or filters about its outer circumference. Expandable section 22 is illustrated as having two perforated sections 24 and 26. Although only two perforated sections 24 and 26 are illustrated, it is generally recognized that tubing 12 may extend for thousands of feet within borehole 10 and may include numerous perforated sections for controlled production from one or more zones within a formation. The term “perforated” as used in this document (e.g., perforated tubing or perforated liner) means that the member has holes or openings through it. The holes may be round, rectangular, slotted, or of any other suitable shape. “Perforated” is not intended to limit the manner in which the holes are made. For example, “perforated” does not require that the holes be made by perforating and does not limit the arrangement of the holes.
In particular embodiments, both the solid sections and perforated sections 24 and 26 of expandable section 22 may be expanded to increase the overall diameter of the section. Depending on the types of expansion required, a fixed expansion cone and/or a variable diameter expansion cone may be used to expand expandable section 22. The fixed expansion cone may be carried on an expansion tool string. Expansion may be initiated from a cone launcher 28 that is disposed up hole from expansion section 22. The fixed expansion cone may be used to expand the entire tubing string down hole of expansion launcher 28 as the tool is run down borehole 10. Where additional expansion is desired at particular locations in tubing 32, an adjustable cone may be carried on the expansion tool string in addition to the fixed cone. Alternatively, an adjustable cone may be carried down hole with tubing 32 as tubing 32 is installed and picked up by the expansion tool when the cone reaches the end of tubing 12.
The use of expandable tubing 12 provides numerous advantages. For example, expandable tubing 12 is of a reduced diameter during installation, which facilitates installation through relatively small diameter sections uphole from the desired location of the expandable tubing, and in offset, slanted, or horizontal boreholes. Upon expansion, expansion sections 22 and screens disposed on the outer diameter of expansion sections 22 provide support for uncased borehole walls while screening and filtering out sand and other produced solid materials which can damage expandable tubing 12. After expansion, the internal diameter of expansion sections 22 is increased improving the flow of fluids through expandable tubing 12.
It is desirable for expandable tubing 12 to reduce the annulus between expandable tubing 12 and the borehole wall as much as possible. Expandable tubing 12 may be expanded only a limited amount, however, without rupturing. It is therefore desirable for expandable tubing 12 to have the largest possible diameter in its unexpanded condition as expandable tubing 12 is run into the borehole. That is, the larger expandable tubing 12 is before expansion, the larger expandable tubing 12 may be after expansion. Elements carried on the outer surface of expandable tubing 12 as it is run into borehole 10 increase the outer diameter of the string. The total outer diameter must be sized to allow the string to be run into borehole 10. The total diameter is the sum of the diameter of the actual tubing 12 plus the thickness or radial dimension of any external elements. Thus, external elements effectively reduce the allowable diameter of the expandable tubing 12 itself.
In the illustrated embodiment, spacer pipe 202 comprises a wall that has an inner surface 208, which defines the inner diameter of spacer pipe 202, and an outer surface 210, which defines the outer diameter of spacer pipe 202. Inner surface 208 includes a recess 212 formed around at least a portion of the circumference of inner surface 208. Recess 212 is configured to house inflatable element 204. Accordingly, recess 212 may be configured to accommodate any appropriate size and shape for housing inflatable element 204. In particular embodiments, recess 212 is sized such that an inner surface 214 of inflatable element 204 is substantially flush with inner surface 208 of spacer pipe 202 when inflatable element 204 is in a non-inflated state.
In particular embodiments, inflatable element 204 comprises an elongate, longitudinal bladder that is installed within recess 212. Inflatable element 204 forms a fluid chamber that may be selectively actuated, or inflated, to form a fluid-tight seal between an up hole portion of the tubing and a down hole portion of the tubing (illustrated in
For receiving the completion or other fluids in inflatable element 204 and for actuating inflatable element 204, spacer pipe 202 is configured to include a control line 216 disposed within the wall of spacer pipe 202. Stated differently, fluid is received in inflatable element 204 from control line 216 located between inner surface 208 and outer surface 210. Accordingly, a first down hole end of control line 216 is in fluid communication with inflatable element 204 and provides a conduit through which completion fluid or another service fluid may be passed from control line 216 and into inflatable element 204.
For receiving fluid to be transferred to inflatable element 204, a second end of control line 216 includes a fluid port 218. Fluid enters control line 216 through fluid port 218 and is then transported through control line 216 to inflatable element 204. For the selective control of fluid, however, control line 216 may include a check valve 220 in particular embodiments. Thus, fluid may pass freely through check valve 220 in a downhole direction. However, check valve 220 prevents passing of fluid through control line 216 in an uphole direction to prevent backflow of the fluid contained in inflatable element 204. Accordingly, check valve 220 may be used to maintain the pressure of fluid within inflatable element 204. In particular embodiments, check valve 220 may not only help to contain the fluid or other material within the fluid chamber defined by inflatable element 204, but also allow for the selective and partial release of fluid from inflatable element 204, to alleviate excessive pressure therein.
As described above, expansion tool 206 operates as the source of fluid or other material for actuating inflatable element 204. Accordingly, expansion tool 206 cooperates with fluid port 218 to provide fluid to control line 216. As described above, expansion tool 206 is backed up the borehole after the expansion process until expansion tool 206 is properly positioned within spacer pipe 202. In particular embodiments, expansion tool 206 may be properly positioned relative to spacer pipe 202 when an outer fluid port 222 of expansion tool 206 substantially aligns with fluid port 218 of spacer pipe 202. As will be described in more detail below, outer fluid port 222 provides a portion of the conduit through which fluid may be transferred from expansion tool 206 to control line 216.
For the proper alignment of expansion tool 206 and spacer pipe 202, spacer pipe 202 includes a latch-type mechanism 223 of the type that are commonly known in the art for locking two tool components together. In the illustrated embodiment, latch-type mechanism 223 includes a locating profile 224 on the inner surface 208 of spacer pipe 202. Locating profile 224 cooperates with a corresponding key 226 on the outer surface of expansion tool 206 to lock expansion tool 206 to spacer pipe 202 in the desired position. For example, locating profile 224 of spacer pipe 202 may include a series of notches and projections, which are generally opposite to a series of notches and projections on key 226 of expansion tool 206. In particular embodiments, latch-type mechanism 223 may be spring loaded such that when the corresponding notches and projections are engaged, a force is applied by latch-type mechanism 223 to hold the corresponding notches and projections in their cooperative position.
As described above, when expansion tool 206 is locked into the proper position relative to spacer pipe 202, outer fluid port 222 of expansion tool 206 may be substantially aligned with fluid port 218 of spacer pipe 202. In the initial locked-in position of expansion tool 206, however, fluid may be prevented from being transferred from expansion tool 206 to control line 216 by a misaligned inner fluid port 228 of expansion tool 206. Thus, the fluid passage formed by inner fluid port 228 and outer fluid port 222 may be said to be “closed” in the initial locked-in position of expansion tool 206.
After the performance of gravel packing, sand treatment, or other completion operations, it may be desirable to seal off spacer pipe 202 to maintain the pressure of fluid in the spacer pipe 202. Accordingly, fluid passage 300 may be “opened.”
After the blockage of interior passage 304, additional fluid that is pumped through the up hole portion of interior passage 304 causes a buildup in pressure in the portion of interior passage 304 that is up hole of ball 302. When the pressure reaches a predetermined level, a shear pin 308 may react to the pressure by shearing. The shearing of shear pin 308 may release a portion of expansion tool 206 from a fixed position. As a result, a portion of expansion tool 206 that includes inner passage 228 may movably slide or otherwise be displaced relative to a portion of expansion tool 206 that includes outer passage 222. The movement of the portion of expansion tool 206 that includes inner passage 228 may result in the alignment of inner passage 228 with outer passage 222 and, thus, the “opening” of fluid passage 300. Fluid within the portion of interior passage 304 may then pass through fluid passage 300 and port 218 and into control line 216, which feeds into inflatable element 204. In this manner, inflatable element 204 may be inflated with fluid to form a fluid-tight seal between an up hole portion of the tubing (illustrated in
To prevent fluid loss into the space between expansion tool 206 and spacer pipe 202, expansion tool 206 includes a pair of seals 310. A seal 310 is disposed on both sides (up hole and down hole) of fluid passage 310 on the exterior of expansion tool 206. In particular embodiments, seals 310 may be configured like and operate similar to baffle cups. When expansion tool 206 is in the locked in position relative to spacer pipe 202, seals 310 may form a fluid-tight seal between expansion tool 206 and spacer pipe 202. As a result, when fluid passes from fluid passage 300 of expansion tool 206 to fluid port 218 of spacer pipe 202, fluid may be prevented from spilling into the space between expansion tool 206 and spacer pipe 202.
Various systems and methods may be used to inflate the inflatable elements illustrated and described within this specification. For example, in lieu of the tool described above, the inflatable element(s) may be inflated remotely via annular pressure, or a control line, for example. It should be recognized by those of ordinary skill in the art that many methods, systems and configurations may be employed to introduce sufficient pressure to the inflatable element, to cause expansion of the inflatable element.
As illustrated in
The expandable element described herein may be used to form a complete or partial seal in almost any configuration of tubing or other components of a well bore. In accordance with an alternative embodiment of the present invention, an expandable element of the type illustrated herein may be used to form an annular seal between two sections of tubing of the well bore. For example, in accordance with one embodiment, a second section of tubing may be disposed within a larger section of tubing, creating a flow path between the two sections of tubing. In this embodiment, the expandable element may be disposed between the two sections of tubing, to form a seal between the two sections of tubing when the expandable element is expanded.
In the non-inflated state, first and second portions 402 and 404 form a substantially continuous inflatable liner within a spacer pipe 406. In particular embodiments, spacer pipe 406 may be configured similar to and operate like spacer pipe 202 of
First and second portions 402 and 404 may each be coupled to a control line that is substantially similar to control line 216 of
To prevent fluid loss, first and second portions 402 and 404 are configured in a manner that forms a fluid-tight seal when inflated. In the illustrated embodiment, each of first and second portions 402 and 404 are in the shape of a half circle. Thus, each of first and second portions 402 and 404 include a substantially spherical surface 410 and a substantially planar surface 412. When inflated, substantially planar surface 412 of first portion 402 contacts substantially planar surface 412 of second portion 404 to form a fluid-tight seal with one another. Because first and second portions 402 and 404 cooperate to form a fluid-tight seal, inflatable element 400 forms a fluid tight seal within spacer pipe 406 and the flow of fluid up hole and down hole of spacer pipe 406 is prevented.
Specifically, it may be desirable to remove inflatable element 502 to clear the interior passage 510 defined by spacer pipe 504 for the performance of production operations. Accordingly, prior to the commencement of production operations, retrieval system 500 may be ran down spacer pipe 504 within the borehole until retrieval system 500 is properly positioned within spacer pipe 504. In particular embodiments, retrieval system 500 may be locked to spacer pipe 504 using a latch-type mechanism of the type that is commonly known in the art for locking two elements together. In particular embodiments, the latch-type mechanism may be configured like and operate similar to the latch-type mechanism described above with regard to
After retrieval system 500 is properly positioned in and locked to spacer pipe 504, grapple 508 may be ran through inflatable element 502 from an up hole end of inflatable element 502 to a down hole end of inflatable element 502. When run through inflatable element 502, grapple 508 may pierce inflatable element 502 and release fluid contained within the fluid chamber defined by inflatable element 502 into interior passage 510. As a result, inflatable element 502 may be returned to an non-inflated state. To remove inflatable element 502 from spacer pipe 504, the latch-type mechanism locking retrieval system 500 to spacer pipe 504 may be disengaged. Retrieval system 500 may be backed-up the borehole and removed from spacer pipe 504. As retrieval system 500 is backed up the borehole, inflatable element 502 may be caught on grapple 508 and carried on retrieval system 500. In this manner, inflatable element 502 may be removed from spacer pipe 504 such that interior passage 510 is substantially cleared for production and other operations.
Although retrieval system 500 is described as including a wireline and grapple configuration, it is generally recognized that other configurations of retrieval system 500 and/or methods may be used to remove inflatable element 502. For example, in lieu of the wireline and grapple configuration, a chemical cut tool on an electric line may be used to pierce inflatable element 502. In particular embodiments, the chemical cut tool may be positioned in spacer pipe 504 similar to the positioning of the wireline and grapple configuration. An electric current may then be provided to activate chemicals inside the chemical cut tool. The chemicals may result in the at least partial dissolution of inflatable element 502. Where desired, a grapple might then be used to remove any remaining bits of inflatable element 502. Various other methods, systems and tool configurations are also available for the removal of the inflatable element, in accordance with the teachings of the present invention.
Returning generally to
Another advantage may be that the seal may be formed from an inflatable bladder housed within the expandable tubing. Because the inflatable bladder may be selectively inflated, the fluid path in the expandable tubing may remain open during sand treatment, gravel packing, and other completion operations. When such completion operations are finished, however, the inflatable bladder may then be inflated to seal the tubing until production operations are initiated or until it is otherwise desired that the fluid flow in the expandable tubing be restored.
Although the present invention has been described in several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, variations, alterations, transformations, and modifications as falling within the spirit and scope of the appended claims. For example, many of the above-described embodiments include the use of an expansion cone type of device for expansion of the tubing. However, one of skill in the art will recognize that many of the same advantages may be gained by using other types of expansion tools such as fluid powered expandable bladders or packers.
As another example, although many of the embodiments illustrated and described herein include expandable completion systems, the teachings of the present invention are also applicable to non-expandable completion systems, for example, sand control completions with non-expanded screens.
As yet another example, although many of the embodiments illustrated and described herein include the inflatable element embedded in the wall of a spacer pipe, the inflatable element could also be embedded in a well casing. In this embodiment, the inflatable element could be activated during a separate trip of the work string.
As another example, in many of the above described embodiments, the system is illustrated using an expansion tool which travels down hole as it expands expandable tubing and then is partially retracted to deploy a fluid control system. Each of these systems may operate equally well with an expansion tool which travels up hole during the tubing expansion process. In some embodiments, the locations of various latch-type mechanisms, seals, ports, drag blocks, and check valves may be changed if the direction of travel of the expansion tool is changed. For horizontal boreholes, the term up hole means in the direction of the surface location of a well.
Similarly, while many of the specific preferred embodiments herein have been described with reference to use in open boreholes, similar advantages may be obtained by using the methods and structures described herein to form annular isolators between tubing and casing in cased boreholes. Many of the same methods and approaches may also be used to advantage with production tubing which is not expanded after installation in a borehole, especially in cased wells.
