Abstract:
A communication tool apparatus is described which is adapted to provide selective communication of control fluid through a downhole device such as a safety valve. The downhole safety valve is a tubing retrievable subsurface safety valve (“TRSSSV”). The communication tool may be run downhole and within the TRSSSV. Once within the TRSSSV, the communication tool apparatus activates a cutting device within the TRSSSV such that communication of control fluid through the TRSSSV is possible. A replacement safety valve run on a wireline may then be inserted into the TRSSSV and be operated via the control fluid line, as a new communication path created by the communication tool described herein. A method of using the communication tool apparatus is also described.

Description:
PRIORITY 
   This application claims the benefit of U.S. Provisional Application No. 60/901,187, filed on Feb. 13, 2007, entitled “COMMUNICATION TOOL FOR SUBSURFACE SAFETY VALVE WITH COMMUNICATION DEVICE,” which is hereby incorporated by reference in its entirety. 

   FIELD OF THE INVENTION 
   The present invention relates to the drilling and completion of well bores in the field of oil and gas recovery. More particularly, this invention relates to an apparatus to provide selective communication of control fluid through a downhole tool, such as a safety valve. A method of using the communication tool apparatus is also described. 
   DESCRIPTION OF THE RELATED ART 
   In the oil and gas industry, 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 by removing the tubing string, as described hereinafter. The tubing retrievable subsurface safety valve (“TRSSSV”) may be a flapper-type safety valve, a ball-seat type of valve, or other types of valves known in the art. The TRSSSV is attachable to production tubing string and generally comprises a flapper pivotally mountable on the lower end of the safety valve assembly by a flapper pin, for example. A torsion spring is typically 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 typically 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 typically located in a hydraulic piston chamber within the TRSSSV. 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 through 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. 
   On relatively rare occasions, the safety valve assembly may become inoperable or malfunction due to the buildup of materials such as paraffin, fines, and the like on the components downhole, e.g., such that the flapper may not fully close or may not fully open. Regardless, it is known to replace the TRSSSV 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 tubing retrievable safety valve as described hereinafter. These replacement safety valves typically are run downhole via a wireline. Thus, these replacement safety valves are often referred to as wireline retrievable sub-surface safety valves (“WRSSSV”). Before inserting the wireline safety valve into the TRSSSV assembly, however, two operations are performed. First, the TRSSSV 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 TRSSSV, thus providing control fluid (e.g. hydraulic fluid) to the replacement wireline safety valve. Lockout tools perform the former function; communication tools perform the latter. 
   Various lockout tools are commercially available, and will not be further discussed herein. 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 safety valve. The lockout tool is then actuated to lock the valve mechanism (e.g. the flapper) of the TRSSSV in the open position. 
   Before inserting the replacement safety valve or WRSSSV, communication is established between the hydraulic chamber of the TRSSSV and the internal diameter of the TRSSSV. The communication tool disclosed herein may be utilized to provide fluid communication between the inner diameter of the safety valve and the hydraulic chamber, so that the hydraulic control line from surface can be utilized to operate the replacement wireline safety valve. 
   Once communication has been established with the hydraulic line, the WRSSSV may be run downhole. The WRSSSV may resemble a miniature version of the TRSSSV assembly described above. The WRSSSV is adapted to be run downhole and placed within the inner diameter of the TRSSSV assembly described above. The WRSSSV typically includes an upper and lower set of seals that will straddle the communication flow passageway established by the communication tool so that the control line to the TRSSSV may be used to actuate the valve mechanism of the WRSSSV. 
   More specifically, the seal assemblies allow control fluid from the control line to communicate with the hydraulic chamber and piston of the WRSSSV in order to actuate the valve of the WRSSSV between the open and closed positions. Once the WRSSSV is in place, the wireline may be removed and the tubing string placed on production. 
   There are various methods of establishing communication used today. One such method involves inserting a communication tool downhole which must be radially aligned just right in order for the cutter to cut the required communication point. Some of these tools require special sleeves which precisely position the communication tool in exact alignment. 
   There are disadvantages to these designs. If the alignment is off, the cutter will miss the intended communication point and communication will not be established. This may also lead to costly damage to the interior of the tool. Also, designing and installing the sleeves used to align the tools is costly and may introduce unnecessary leak paths in the tubing. 
   In view of the foregoing, there is a need in the art for, among others, a cost effective communication tool which establishes fluid communication without the need for alignment of the tool or the costly components associated therewith. 
   SUMMARY OF THE INVENTION 
   According to one embodiment, the invention relates to an apparatus for establishing communication between a control fluid line from surface to the inner diameter of a downhole tool such as a safety valve. In a preferred embodiment, a communication device is provided to establish fluid communication between the control line and the inner diameter of a safety valve. Should a need arise where it is necessary to establish fluid communication between the control line and the interior of the safety valve (e.g., if the TRSSSV is no longer operable), an embodiment of a communication tool may be run into the safety valve. At a predetermined point, a cutter extends from the tool and will ultimately penetrate through a communication component in the TRSSSV. The communication component is installed in, and extends from, the non-annular hydraulic piston chamber of the TRSSSV. When the cutter is above the communication component, application of a downward force causes the cutter to axially penetrate the communication component, thereby establishing communication between the control line and the inner diameter of the safety valve. A wireline replacement valve may then be run downhole, and operated utilizing the control line to surface. 
   According to a preferred embodiment, the cutter of the communication tool does not have to be axially aligned with the communication component of the TRSSSV prior to actuating the communication tool. The cutter is extended from the communication tool once the tool has been locked into position inside the TRSSSV. The cutter extends into an internal recess on the inner diameter of the TRSSSV. With the cutter in the extended position, downward jarring on the central prong of the tool causes downward displacement of the cutter. A return spring and indexing spring combine to cause the cutter to rotate a pre-selected amount when the jarring weight is removed from the central prong. Following rotation, jarring is commenced again. The cutter will rotate through 360 degrees with continued jarring and rotating steps. The cutter will contact the communication component at least once per complete revolution. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a communication tool in the running mode according to an exemplary embodiment of the present invention; 
       FIG. 2  shows the communication tool of  FIG. 1  in the jarring mode; 
       FIGS. 3A-3H  show the communication tool of  FIG. 1  in various modes, including the first 90 degrees of the available 360 degrees of rotation of the tool; 
       FIGS. 4A and 4B  are enlarged views of the cutter, cutter housing, and return spring for the communication tool of  FIG. 1 ; 
       FIGS. 5A and 5B  show a partial cutaway view of the ratchet springs and index springs of the communication tool of  FIG. 1 ; 
       FIG. 6  shows an embodiment of the communication tool with the ratchet sleeve removed; 
       FIG. 6A  shows a section view taken along the line A-A in  FIG. 6 ; 
       FIG. 6B  is a section view taken along the line B-B in  FIG. 6 ; 
       FIGS. 7A-7D  show a sectional view of a communication tool in the running position after it has landed in a TRSSSV according to an exemplary embodiment of the present invention; 
       FIGS. 8A-8D  show the communication tool of  FIGS. 7A-7D  in the pre-jarring position; 
       FIGS. 9A-9D  show the communication tool of  FIGS. 7A-7D  in the jarring position; 
       FIGS. 10A-10C  show one embodiment of the communication component of the TRSSSV; and 
       FIG. 11  illustrates the indexing profile on the central prong according to an exemplary embodiment of the present invention. 
   

   While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Illustrative embodiments and related methods of the invention are described below as they might be employed in the oil and gas well. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. Further aspects and advantages of the various embodiments and methods of the invention will become apparent from consideration of the following description and drawings. 
   Embodiments of the invention will now be described with reference to the accompanying figures. Like numbers refer to like elements throughout. 
     FIG. 1  illustrates the communication tool  10  in the running mode according to an exemplary embodiment of the present invention. In this position, the central prong  15  is secured from axial movement by one or more shear pins  42  (shown in  FIG. 7B ). In this mode, the cutter  55  is retracted and the lock dogs  40  can radially seek the appropriate lock profile in the tubing retrievable subsurface safety valve. As shown in  FIG. 1 , the communication tool according to one embodiment comprises an upper housing  20 , ratchet sleeve  25 , indexing body  30 , lock body  35 , return spring adapter  45 , cutter housing  50  and nose  60 . Ratchet springs  75  (shown in  FIG. 5A ) are mounted inside ratchet sleeve  25 . Indexing body  30  houses indexing springs  65  and ratchet springs  75 , the operations of the indexing springs and ratchet springs being more fully described below. Extending from the indexing body  30  is lock body  35  which houses lock dogs  40  for locking the communication tool in a mating lock profile in the TRSSSV. A return spring adapter  45  extends from the lock body  35  and contains return spring  70  (shown in  FIGS. 4A &amp; 4B ). A cutter housing  50  is connected to the lower end of return spring adapter  45  and contains cutter  55 . The communication tool  10  may include a nose  60  connected to the lower end of cutter housing  50 , wherein the nose includes a tapered profile for guiding the tool through a production tubing and the TRSSSV. 
     FIG. 2  illustrates an exemplary embodiment of the communication tool in the jarring mode. In the jarring mode, central prong  15  has been forced down, axially extending the cutter housing  50  and the cutter  55  in order to cut into an exposed communication component in the TRSSSV. When the weight bar (not shown) is picked up again, an internal return spring  70  returns the central prong  15 , cutter housing  50 , cutter  55 , and nose  60  to a pre-jarred state (as shown in  FIG. 1 ). During the return, an integral indexing system rotates the central prong  15 , cutter housing  50 , cutter  55  and nose  60  45 degrees counterclockwise for another jarring hit. For purposes of this disclosure, the terms indexing and rotating are used interchangeably to denote rotating the cutter  55  a fixed amount around the axis of the communication tool  10 . One of skill in the art having the benefit of this disclosure will recognize that the indexing system could rotate the central prong  15 , cutter housing  50 , cutter  55  and nose  60  any desired amount, either clockwise or counterclockwise as may be desired. 
     FIGS. 3A-3H  illustrate the first 90 degrees of the available 360 degrees of possible rotation for the cutter of communication tool  10 .  FIG. 3A  illustrates the communication tool  10  while running in the well.  FIG. 3H  illustrates the communication tool  10  being pulled out of the well after establishing communications with the locking dogs and cutter retracted.  FIG. 3B  illustrates the lock dogs  40  being extended radially to lock communication tool  10  relative to the TRSSSV and to extend the cutter  55  for establishing communications.  FIGS. 3C-3G  illustrate the jarring/rotating steps. More particularly,  FIGS. 3C ,  3 E and  3 G illustrate the communication tool  10  being jarred downwardly, each figure showing cutter  55  rotated 45 degrees from the previous jarring position.  FIGS. 3D and 3F  show the cutter rotated 45 degrees from its prior position. In a preferred embodiment, the cutter  55  is extended throughout the jarring phase of operation. The return spring and indexer rotate the cutter relative to the safety valve. In the illustrated embodiment, the lower portion of the communication tool  10  will rotate through 360 degrees with continued jarring. The cutter  55  will contact the communication component of the TRSSSV at least once per complete revolution (or, for example, 8 jarring licks in the illustrated embodiment). 
   Prior to jarring, the return spring  70  holds a preload that is, for example, two times greater than the weight of the cutter  55 , cutter housing  50 , nose  60 , central prong  15  and the jar weight. The preloaded return spring  70  is illustrated in  FIG. 4A . Once jarred, the return spring  70  compresses as illustrated in  FIG. 4B . When the impact is complete, the return spring  70  brings the cutter  55 , cutter housing  50 , nose  60  and central prong  15  back to the starting position. During the recovery, the indexing mechanism rotates the lower end of the communication tool  10  by 45 degrees for another jarring hit. In essence, the communication tool  10  works as an axial jackhammer that is designed to compromise the hydraulic integrity of the communication component of the TRSSSV. 
   As illustrated in  FIGS. 5A-5B  and  FIGS. 6 ,  6 A and  6 B, when central prong  15  is driven back up from the return spring  70 , the index springs  65  force the central prong  15  to rotate while the ratchet springs  75  prevent any counter rotation. The indexing profiles  85  cut on the outer diameter of the central prong  15  allows each of the indexing pins  64  on the plurality of index springs  65  to track in a mating groove, the shapes of which force the central prong  15  to rotate, for example, 45 degrees with each return. Indexing springs  65  are biased radially inwardly.  FIG. 11  illustrates one exemplary embodiment of indexing pin  64  and indexing profile  85 . Ramps  78  and ledges  88  are formed in the indexing profile and cause the inner prong to turn relative to the rest of the tool as pin  64  tracks through the indexing profile  85 . Please note, however, those ordinarily skilled in the art having the benefit of this disclosure realize there are any number of ways to accomplish the indexing function of the present invention. 
   The ratchet springs  75 , as shown in  FIG. 6A , keep the central prong  15  from rotating in the wrong direction. In the embodiment shown in  FIG. 6A , two ratchet springs  75  are circumferentially located about central prong  15 . The ratchet springs  75  are mounted to a indexing body  30  located between ratchet sleeve  25  and central prong  15 . The ratchet springs  75  are biased radially inwardly. As the central prong  15  is rotated, the tip  79  of a ratchet spring will ride up the ramp of the ratchet profile  80  of the central prong  15  until it snaps over a shoulder  82  on the ratchet profile  80 . The interaction of shoulders  82  and tips  79  of the ratchet spring  75  prevent clockwise rotation of central prong  15 . Ratchet profile  80  includes eight profile surfaces, each one representing 45 degrees of rotation. One skilled in the art having the benefit of this disclosure will recognize that the number of surfaces will correlate to the amount of rotation desired per return (e.g., the larger the rotation the fewer the surfaces). 
     FIGS. 7A-7D  illustrate the communication tool  10  in the running position inside of the tubing retrievable subsurface safety valve (TRSSSV)  100  according to an exemplary embodiment of the present invention. Central prong  15  extends longitudinally through the outer assembly of communication tool  10 , the outer assembly including the upper housing  20 , ratchet sleeve  25 , lock body  35 , return spring adapter  45 , cutter housing  50  and nose  60 . According to one exemplary embodiment, indexing body  30  is mounted inside of the lower end of upper housing  20 , ratchet sleeve  25  and the upper end of lock body  35 . Indexing body  30  includes indexing pins  64  on springs  65  which travel in indexing profiles  85  on the central prong. 
   Communication tool  10  is run inside of the production tubing and into the top of TRSSSV  100  until the lock dogs  40  are positioned adjacent to a mating profile in the safety valve hydraulic chamber housing  105 . In this position, cutter  55  is in the retracted position as illustrated in  FIG. 7C . Cutter  55  is adjacent hydraulic chamber housing internal relief  108  which provides access to the upper end of communication component  110 . The communication component  110  is in communication with piston bore  120  of the safety valve via communication retention ball  115 . Retention ball  115  is press fitted inside of communication component  110 , thereby retaining the component in the safety valve. Retention ball  115  includes an internal passageway which provides communication between communication component  110  and piston bore  120 . Further discussion of communications component  110  will follow in conjunction with the description of  FIGS. 10A-10C . 
   Hydraulic piston  125  is mounted inside non-annular piston bore  120  and connects to flow tube  135 . Flow tube  135  may be shifted via hydraulic pressure acting on piston  125  to extend through flapper  145  to open TRSSSV  100 . If hydraulic pressure is lost, power spring  140  will force flow tube  135  upwardly above flapper  145 , thereby allowing flapper  145  to pivot to the closed position and to prevent flow of well bore fluids up through the safety valve. Although not shown in detail, it is understood that flow tube  135  is locked in the open position prior to the insertion of communication tool  10 . Various methods of locking open the TRSSSV  100  are known. 
   To set lock dogs  40 , weight is applied to central prong  15  causing shear pins  42  to be severed thereby allowing the central prong  15  to move downwardly until an enlarged section of the central prong moves behind locking dogs  40  causing the dogs to radially extend into the mating profile in the hydraulic chamber housing  105 . In this position, locking dogs  40  are set thereby locking the communication tool to the TRSSSV  100 . The downward movement of a central prong  15  also causes an internal profile in the central prong  15  to move downwardly relative to cutter extension pin  57 . As shown in  FIG. 8C , the movement of extension pin  57  relative to the internal profile causes cutter  55  to extend into the internal recess  108  in the hydraulic chamber housing. Once locked in place, the communication tool  10  is ready for jarring to establish communications through communication component  110 . 
     FIGS. 9A-9D  illustrate the communication tool in the jarring position according to an exemplary embodiment of the present invention. Jarring on the central prong  15  will cause the prong  15  to move downwardly relative to the outer assembly of the communication tool  10  thereby causing cutter  55  to move downwardly relative to the safety valve. Should the cutter extend over the top of the communication component  110 , the movement of the prong  15  downwardly will cause the cutter to compromise the integrity of the communication component  110  as shown in  FIG. 9C . Once compromised, communication will be established through the communication component  110  and into the internal bore of the TRSSSV  100 . Since piston bore  120  is in fluid communication with a control line that extends to the surface (not shown) the control line may be used to control a wire line subsurface safety valve subsequently installed within the internal bore of the TRSSSV  100 . 
   The downward movement of the central prong  15  during the jarring mode, causes return spring  70  to be compressed. More particularly, extension mandrel  71  (shown in FIG.  7 B) connected about the lower end of prong  15  compresses spring  70 . The downward movement of prong  15  also causes the indexing springs  65  to snap over the index profile ramps  80  as shown in  FIGS. 6A and 6B . When the weight on the prong  15  is removed, the compression spring  70  pushes the central prong  15  back up and the lower portion of the tool  10  rotates 45 degrees which will allow for another jarring hit. In this way, cutter  55  will rotate 45 degrees about the radially enlarged recess  108  prior to the subsequent hit. The jarring/rotating steps will be repeated as many times as necessary until the cutter eventually extends over the communication component and it is jarred downwardly through the component. The ratchet springs  75  keep the central prong  15  from rotating in the wrong direction. Once the communication component  110  is severed, pulling up on the central prong  15  will retract the cutter and the lock dogs allowing for the communication tool  10  to be withdrawn from the TRSSSV  100  and pulled out of the hole. 
     FIGS. 10A-10C  show one exemplary embodiment of the communication component  110  according to the present invention. Communication component  110  comprises body  112  and communication retention ball  115 . The communication component body  112  is first installed into the hydraulic conduit within the TRSSSV hydraulic chamber housing. Sealing grooves  114  are provided on the lower end of body  112 . When the retention ball  115  is pressed into the communication component body, a high contact pressure, metal-to-metal seal between sealing groves  114  of body  112  and the hydraulic conduit wall is established, effectively isolating the hydraulics from the inside of the TRSSSV  100 . Once the communication component is broken, the hydraulic fluid will be able to communicate through the fluid bypass passage  118  extending through retention ball  115  into the bore of the TRSSSV  100 . The communication component  110  is made of a frangible material that may be cut, pierced, sheared, punctured, or the like. During normal operations of the TRSSSV  100 , the communication component is protected in the sidewall of the hydraulic chamber housing. In a preferred embodiment, body  112  is made of 718 Inconel or 625 stainless steel and ball  115  is made of 316 or 625 stainless steel. Please note, however, that one ordinarily skilled in the art having the benefit of this disclosure would realize any variety of communications components, chambers, etc. could be utilized within the scope of this invention. 
   Although various embodiments have been shown and described, the invention is not so limited and will be understood to include all such modifications and variations as would be apparent to one skilled in the art. For example, the communication tool could be used to establish communication with other types of downhole devices (i.e., devices other than a TRSSSV). Such tools may, or may not, include a communication component through which fluid communication is established with the communication tool. Thus, the present invention is not limited to establishing communication with a TRSSSV but may be used to establish communication with other types of downhole devices. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.