Patent Publication Number: US-9903181-B2

Title: Communication and lock open safety valve system and method

Description:
BACKGROUND 
     In the drilling and completion industry, the formation of boreholes for the purpose of production or injection of fluid is common. The boreholes are used for exploration or extraction of natural resources such as hydrocarbons, oil, gas, water, and alternatively for CO2 sequestration. A production tubing string is typically run thousands of feet into a well bore. Generally, when running a tubing string downhole, it is desirable, and in some cases required, to include a safety valve on the tubing string. The safety valve typically has a fail safe design whereby the valve will automatically close to prevent production fluid from flowing through the tubing, should, for example, the surface production equipment be damaged or malfunction. 
     Should the safety valve become inoperable, the safety valve may be retrieved to surface. The tubing retrievable surface controlled subsurface safety valve (“TRSV”) is attachable to production tubing string and includes a flapper pivotally mountable on the lower end of the safety valve assembly by a flapper pin. A torsion spring is provided to bias the flapper in the closed position to prevent fluid flow through the tubing string. When fully closed the flapper seals off the inner diameter of the safety valve assembly preventing fluid flow therethrough. A flow tube is provided above the flapper to open and close the flapper. The flow tube is adapted to be movable axially within the safety valve assembly. When the flapper is closed, the flow tube is in its uppermost position; when the flow tube is in its lowermost position, the lower end of the flow tube operates to extend through and pivotally open the flapper. When the flow tube is in its lowermost position and the flapper is open, fluid communication through the safety valve assembly is allowed. A rod piston contacts the flow tube to move the flow tube. The rod piston is located in a hydraulic piston chamber within the TRSV. The upper end of the chamber is in fluid communication, via a control line, with a hydraulic fluid source and pump at the surface. Seals are provided such that when sufficient control fluid (e.g. hydraulic fluid) pressure is supplied from surface, the rod piston moves downwardly in the chamber, thus forcing the flow tube downwardly towards the flapper to open the valve. When the control fluid pressure is removed, the rod piston and flow tube move upwardly allowing the biasing spring to move the flapper and thus the valve, to the closed position. 
     If the TRSV becomes inoperable or malfunctions due to the buildup of materials such as paraffin, fines, and the like on the components downhole, e.g., such that the flapper does not fully close or does not fully open, it is known to replace the TRSV by retrieving the safety valve assembly to surface by pulling the entire tubing string from the well and replacing the safety valve assembly with a new assembly, and then rerunning the safety valve and the tubing string back into the well. Because of the length of time and expense required for such a procedure, it is known to run a replacement safety valve downhole within the TRSV. These replacement safety valves are run downhole via a wireline, and thus often referred to as wireline insertable safety valves (“WISV”). Before inserting the WISV into the TRSV assembly, however, two operations are performed. First, the TRSV is locked in its open position (i.e., the flapper must be maintained in the open position); and second, fluid communication is established from the existing control fluid line to the interior of the TRSV, thus providing control fluid (e.g. hydraulic fluid) to the WISV. Lockout tools perform the former function; communication tools perform the latter. When it is desired to lock the safety valve assembly in its open position, the lockout tool is lowered through the tubing string and into the TRSV. The lockout tool is then actuated to lock the valve mechanism (e.g. the flapper) of the TRSV in the open position. 
     Before inserting the WISV, communication is established between the hydraulic chamber of the TRSV and the internal diameter of the TRSV. A cutter of the communication tool is utilized to provide fluid communication between the inner diameter of the TRSV and the hydraulic chamber, so that the hydraulic control line from surface can be utilized to operate the WISV. Once communication has been established with the hydraulic chamber, the WISV is subsequently run downhole. The WISV may resemble a miniature version of the TRSV assembly. The WISV is placed within the inner diameter of the TRSV assembly. The WISV includes an upper seal above the communication flow passageway and a lower seal below the flapper and at a bottom sub, and the control line to the TRSV is used to actuate the valve mechanism of the WISV. More specifically, the upper and lower seals allow control fluid from the control line to communicate with the hydraulic chamber and piston of the WISV in order to actuate the valve of the WISV between the open and closed positions. Once the WISV is in place, the wireline is removed and the tubing string placed on production. 
     The art would be receptive to alternative devices and for downhole systems incorporating TRSV and WISV, and improved methods for operating such systems. 
     BRIEF DESCRIPTION 
     A downhole system includes a safety valve system. The safety valve system includes a tubular housing having a hydraulic control chamber, and a lock-open communication sleeve within the tubular housing. The sleeve is longitudinally movable with respect to the tubular housing. The sleeve has a downhole end portion configured to abut and enact downhole movement of a flow tube. The sleeve further has a radial communication port alignable with the hydraulic control chamber. 
     A method of communicating and locking open a tubing retrievable safety valve (“TRSV”) includes engaging a lock-open communication sleeve within a tubular housing, the sleeve having a radial communication port, longitudinally moving the sleeve within the housing to align the radial communication port with a hydraulic control chamber in the housing, and abutting a flow tube with a downhole end portion of the sleeve and longitudinally moving the flow tube to open the valve. 
     A downhole system includes a safety valve system. The safety valve system includes a tubular housing having a hydraulic control chamber and a rotatable sleeve within the tubular housing. The sleeve is longitudinally movable with respect to the tubular housing when rotated. The sleeve includes at least one of a downhole end portion, configured to abut and enact downhole movement of a flow tube to lock open a flapper valve, and a radial communication port, alignable with the hydraulic control chamber upon rotation of the sleeve, the radial communication port configured to communicate an interior of the tubular housing and sleeve with the hydraulic control chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  depicts a partial side cross-sectional view of an exemplary embodiment of a tubing retrievable safety valve (“TRSV”) and a partial side cross-sectional view of an exemplary embodiment of a lock-open/communication (“LOC”) sleeve in an uphole position; 
         FIG. 2  depicts a partial cross-sectional view of an exemplary embodiment of a TRSV with the LOC sleeve of  FIG. 1  moved to a downhole position; 
         FIG. 3  depicts a cross-sectional view of a downhole portion of the exemplary TRSV of  FIGS. 1 and 2 ; 
         FIG. 4  depicts a perspective and partial cross-sectional view of the TRSV and LOC sleeve of  FIG. 1 ; and, 
         FIG. 5  depicts a partial side view of an exemplary embodiment of an actuating tool for rotating the LOC sleeve. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     An exemplary embodiment of a downhole system  10  having a tubing retrievable safety valve (“TRSV”)  12  including a lock/open communication (“LOC”) sleeve  14  is shown in  FIGS. 1, 2 and 4  with a downhole portion of the TRSV  12  shown in  FIG. 3 . The TRSV  12  may be just one part of the downhole system  10 , which may further include, but not limited to, many sections of tubing, joints, and other downhole tools. As will be further described below, the LOC sleeve  14  is configured to establish communication between the hydraulic control chamber  16  of the TRSV  12  and the interior/flowpath  18  of the TRSV  12  when needed for a wireline insertable safety valve (“WISV”) (not shown). The LOC sleeve  14  is additionally configured to lock the flapper  20  of the TRSV  12  ( FIG. 3 ) into the open position at substantially the same time that the communication is established. An exemplary embodiment of a WISV is shown in U.S. Pat. No. 6,260,850, herein incorporated by reference in its entirety, however it should be understood that various embodiments of a WISV may be utilized once the TRSV  12  is communicated and locked open. 
     The illustrated TRSV  12  is a tubular device having a longitudinal axis  22 . For illustrative purposes, a cutaway view of LOC sleeve  14  is shown in  FIG. 1 . The interior  18  of the TRSV  12  provides a flow path for passing production fluids in an uphole direction  24  or injection fluids in a downhole direction  26 . With reference to  FIG. 3 , when the flapper  20  of the TRSV  12  is in an open position, the flapper  20  is secured between flow tube  28  and housing  30  of the TRSV  12 . The flapper  20  is pivotally mountable on the downhole portion of the TRSV  12 , such as by a flapper pin  32 . A biasing member  34 , such as a torsion spring, is provided to bias the flapper  20  in the closed position (shown by dotted lines) to prevent and block, or at least substantially prevent and block, flow through the flow path of the interior  18  of the TRSV  12  and downhole system  10 . The flow tube  28  is provided uphole of the flapper  20  to open and close the flapper  20 . The flow tube  28  is positioned radially inward of the housing  30  of the TRSV  12  and is adapted to be movable longitudinally within the TRSV  12 . The flow tube  28  is positioned downhole of the LOC sleeve  14 . When the flapper  20  is in the closed position blocking the flow through the flow path of the interior  18  as shown by the dashed lines in  FIG. 3 , the flow tube  28  is in its uphole position allowing the biasing member  34  to bias the flapper  20  to the closed position. When the flow tube  28  is in its downhole position, the downhole end portion  36  of the flow tube  28  operates to extend downhole through the interior  18  and pivotally open the flapper  20 . When the flow tube  28  is in its downhole position and the flapper  20  is open, fluid communication through the flowpath  18  of the TRSV  12  is allowed. 
     A piston  38 , such as a rod piston, is operatively connected to the flow tube  28  to move the flow tube  28 . The piston  38  may be rod shaped, and the piston chamber  40  may be sized to accommodate any exterior shape of the piston  38 . Movement of the piston  38  translates to movement of the flow tube  28 , and likewise movement of the flow tube  28  translates to movement of the piston  38 . The piston  38  is located in the piston chamber  40  within the housing  30  of the TRSV  12 . The piston chamber  40  is in fluid communication with the hydraulic chamber  16 . A portion, such as an uphole portion, of the hydraulic chamber  16  is in fluid communication, via a control line  42  (a partial portion of which is illustrated), with a hydraulic fluid source and pump at the surface (not shown). The control line  42  may be secured to the housing  30  via a hydraulic fitting  44  at a hydraulic port  45  of the housing  30 , the hydraulic port  45  in communication with the hydraulic control chamber  16 . Seals  46  may be provided about the piston  38  such that when sufficient control fluid (e.g. hydraulic fluid) pressure is supplied from surface, the piston  38  moves in downhole direction  26  in the piston chamber  40 , compressing a power spring  80  ( FIG. 3 ) at a downhole end of the piston  38 , and forcing the flow tube  28  towards the flapper  20  to move the flapper  20  to the open position, opening the TRSV  12 . When the control fluid pressure is removed, the piston  38  and flow tube  28  move back in uphole direction  24  allowing the biasing member  34  to move the flapper  20  and thus the TRSV  12 , to the closed position. 
     The housing  30  of the TRSV  12  may include a nipple adapter  48  attached to a top sub  50 , the top sub  50  connected to a cylinder sub  52 , and the cylinder sub  52  connected to a bottom sub  54 . Together, the nipple adapter  48 , top sub  50 , cylinder sub  52 , and bottom sub  54  are referred to as the housing  30  of the TRSV  12 , however the housing  30  may take on various shapes and differing subs as needed. The housing  30 , or in particular the top sub  50 , includes a helical groove or female/internal thread  56  on an interior surface  58  of the housing  30  configured to receive a helical or male/external thread  60  on a threaded portion  62  of an exterior surface  64  of the LOC sleeve  14 . The hydraulic control chamber  16  may be formed in the top sub  50  between the top sub  50  and the cylinder sub  52  as shown in  FIGS. 1 and 4 , although in alternate embodiments the hydraulic control chamber  16  may be formed in the cylinder sub  52 , such as shown in  FIG. 2 . The hydraulic control chamber  16  is thus formed in the housing  30 . The hydraulic control chamber  16  may either be annular or simply a section of the top sub  50 /cylinder sub  52 /housing  30 . That is, an annular hydraulic chamber  16  may be replaced by a non-annular hydraulic chamber as long as the geometry of the piston chamber  40  is appropriately modified to allow communication with the non-annular hydraulic chamber. 
     Without the LOC sleeve  14  in place, the hydraulic control chamber  16  would be open to the interior  18  of the TRSV  12 . However, in normal operation of the TRSV  12  (prior to necessitating the need for communicating the hydraulic chamber  16  to operate a WISV), the hydraulic control chamber  16  is covered by the LOC sleeve  14 , such as by a non-threaded portion  66  of the LOC sleeve  14 , and sealed from the interior  18  of the TRSV  12  by a first (uphole) seal  68  and a second (downhole) seal  70  between the LOC sleeve  14  and the housing  30 . The LOC Sleeve  14  creates an inner surface of the hydraulic chamber  16  by radially interiorly covering the two seals  68 ,  70  in the top sub  50  and the cylinder sub  52 , and spanning the inner exposed surface area of the hydraulic control chamber  16 . Under normal operation of the TRSV  12 , the LOC sleeve  14  forms a surface of the hydraulic control chamber  16 . The first and second seals  68 ,  70  may be cylindrical type seals, and although only two seals  68 ,  70  are shown in particular locations it should be understood that a variety of seal types may be used to create the seal between the LOC Sleeve  14  and the hydraulic chamber  16 . The LOC sleeve  14  is positioned within the housing  30  to cover and seal a radially interior portion of the hydraulic control chamber  16  from the interior  18  of the TRSV  12  in normal operation of the TRSV  12 . Normal operation of the TRSV  12  involves utilizing the hydraulic control line  42  to pressurize the hydraulic chamber  16  to move the piston  38  in the downhole direction  26  and open the flapper  20  by moving the flow tube  28  with the piston  38  to push the flapper  20  to the open condition. Also, when the flapper  20  needs to close, or when the flapper  20  is closed due to a fail-safe condition, the hydraulic pressure in the chamber  16  will be reduced such that the piston  38  and flow tube  28  move back towards an uphole position in the uphole direction  24 , allowing the flapper  20  to move to its biased closed position. 
     When the TRSV  12  is operable, the flow tube  28  is movable in both uphole and downhole directions  24 ,  26  while the LOC sleeve  14  remains in the position shown in  FIG. 1 , covering the hydraulic control chamber  16 . However, if the TRSV  12  becomes inoperable, and a WISV is to be run downhole as a replacement, the LOC sleeve  14  can be longitudinally moved from the position shown in  FIG. 1  in the downhole direction  26  to the position shown in  FIG. 2 , such as by rotation of the LOC sleeve  14  within the housing  30 . The LOC sleeve  14  includes at least one radial communication port  72  or slot in the non-threaded portion  66 , such that moving the LOC sleeve  14  downhole aligns the radial port  72  or slot with the hydraulic control chamber  16  between the first and second seals  68 ,  70  to provide a path for control fluid from the port  45  to reach the interior  18  of the TRSV  12  for the purpose of operating the WISV in the event that the TRSV  12  becomes inoperable. Further, movement of the LOC sleeve  14  in the downhole direction  26  moves the flow tube  28  of the TRSV  12  in the downhole direction  26 , locking the flapper  20  into the open position shown in  FIG. 3 . To move the flow tube  28  in the downhole direction  26 , the downhole end  74  of the LOC sleeve  14  abuts with an uphole end  76  of the flow tube  28 . The downhole movement of the LOC sleeve  14  may be stopped by a shoulder  78 , or final interior thread, on the interior surface  58  of the housing  30 . That is, when the downholemost portion of the threaded portion  62  engages with the shoulder  78  as shown in  FIGS. 1 and 4 , further downhole movement of the LOC sleeve  14  will be prevented. This stop also coincides with alignment of the communication port  72  with the hydraulic chamber  16 , and with an open (trapped/locked) position of the flapper  20 . 
     The downhole movement of the LOC sleeve  14  thus establishes both hydraulic communication between the interior  18  and the hydraulic chamber  16  and lock-open of the flapper  20 . One tool (the LOC sleeve  14 ) and one downhole trip is required to perform both the communication or communication and lock-open operations. Flow through is then allowed through the flowpath  18  because of the locked-open flapper  20 , and a WISV may be subsequently inserted in the TRSV  12 . Also, the LOC sleeve  14  enables the ability to return the flow tube  28  and compressed power spring  80  back to the normal operation position for redress, eliminating at least some of the safety risks of working with a compressed power spring  80 . 
     As described above, the exterior surface  64  of the LOC Sleeve has a threaded portion  62  having external thread  60  that produces movement in the downhole direction when the LOC sleeve  14  is rotated, via rotary to linear motion. In one exemplary embodiment, the direction of the threads  56 ,  60  would be for downhole movement during left-hand rotation (counter-clockwise rotation) to prevent movement of the sleeve  14  during operations using the more common right-hand rotation. The housing  30  includes matching threads or groove/pin for rotation purposes. In the event of failure of the TRSV  12  or planned use of a WISV, an actuation tool  100  ( FIG. 5 ) could be deployed to rotate the LOC sleeve  14 . In an exemplary embodiment, the LOC sleeve  14  may have slots  82  in an uphole end  84  or portion of the LOC sleeve  14  to accept a latching feature  102  of the actuation tool  100 . The latching feature  102  may include fingers  104  sized for receipt within the slots  82 . This allows rotation to be applied to the LOC sleeve  14 . Rotation of the actuation tool  100  could be created by using downhole jarring and a J-slot mechanism (not shown) or by rotating the tool  100  itself using coiled tubing. 
     Rotation of the LOC sleeve  14  moves the port  72  located in the sleeve  14  from a position uphole of the first seal  68  and longitudinally distanced from the hydraulic control chamber  16 , to a position downhole of the first seal  68  (but still uphole of the second seal  70 ), establishing hydraulic control fluid communication between the hydraulic control chamber  16  with the interior  18  of the TRSV  12  as described above. Furthermore, the rotation of the LOC sleeve  14  also pushes the flow tube  28  in the downhole direction  26 , compressing the power spring  80  and opening the flapper  20 . This will leave the flapper  20  locked in the open position where, unlike some other systems, it cannot be closed by flow or wireline operations. Advantageously, this method provides the ability to return the power spring  80  to the pre-compressed position, eliminating or at least potentially substantially reducing safety risks involved with disassembling a fully compressed power spring  80 . While the ability to perform both communication and lock open operations provides the system  10  and TRSV  12  with significant advantages, the ability to either lock open the flapper  20  by rotating the sleeve  14  or communicate the hydraulic chamber  16  by rotating the sleeve  14  would also provide advantages to a system  10 , if both actions are not required. 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.