Abstract:
A chemical injection system includes a TRSV; a communication nipple in operable communication with the TRSV and positioned relative to the TRSV to be downhole of a flapper closure mechanism thereof when installed in a wellbore; a chemical injection line in fluid communication with the communication nipple; and a capillary sleeve receivable at the communication nipple and configured to sealingly convey fluid from the communication nipple to a remote location without affecting operation of the TRSV and method.

Description:
BACKGROUND 
   In the hydrocarbon recovery industry, it is often desirable to chemically treat specific portions of well systems to, for example, enhance production, reduce corrosion of production components, reduce or avoid the buildup of problematic substances such as scale, paraffin, hydrates, etc. In some well systems, the application of chemicals to a target area can be a relatively straightforward process with little obstructive conditions or componentry to cause concern or consternation. In other well systems, however, chemical injection, as it is vernacularly termed, is less selectively achieved. In one example, well systems that are legally required to employ Surface Controlled Subsurface Safety Valves (SCSSV) present a difficult obstacle to chemical injection. The operator is faced with either having a fixed location for chemical injection, installed at the time that the TRSV is installed or a system that impacts functionality of the TRSV. Since running a tool through the SCSSV would create a safety issue by holding its closure mechanism open, considerable modification and complexity will be required to maintain a failsafe operation and protection of the well, in order to maintain compliance with applicable law. Since increased cost and complexity are always parameters of well operation to be avoided, the art is always receptive to alternative methods and apparatus that eschew such parameters. 
   SUMMARY 
   A chemical injection system includes a TRSV; a communication nipple in operable communication with the TRSV and positioned relative to the TRSV to be downhole of a flapper closure mechanism thereof when installed in a wellbore; a chemical injection line in fluid communication with the communication nipple; and a capillary sleeve receivable at the communication nipple and configured to sealingly convey fluid from the communication nipple to a remote location without affecting operation of the TRSV. 
   A method for injecting a chemical to an area of a wellbore downhole of a TRSV includes running a PCT to a preinstalled communication nipple downhole of the flapper closure mechanism of the TRSV; creating an opening in the communication nipple with the PCT thereby fluidly communicating a chemical injection line with an inside dimension of the communication nipple; and sealing a capillary sleeve with the inside dimension of the communication nipple at the opening. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
       FIG. 1  is a schematic quarter-sectional view of a Tubing Retrievable Surface Controlled Subsurface Safety Valve (TRSCSSV or TRSV) and a communication nipple in accordance with an embodiment of the invention; 
       FIG. 2  is a quarter-section view of a Puncture Communication Tool (PCT) of the prior art; 
       FIG. 3  is a quarter section view of a capillary sleeve in accordance with an embodiment of the invention; and 
       FIG. 4  is an enlarged view of the communication nipple of  FIG. 1  with the capillary sleeve illustrated in place within the punctured communication nipple. 
   

   DETAILED DESCRIPTION 
   Referring to  FIGS. 1 ,  2 , and  3 , a system  10  is illustrated that together facilitates chemical injection downhole of an SCSSV while retaining full function of the SCSSV. In one embodiment, the SCSSV is a TRSV as illustrated. Referring to  FIG. 1 , a TRSV  12  is illustrated connected to a communication nipple  14 . The TRSV is commercially available, for example, from Baker Oil Tools, Houston, Tex. under Product Number H825603800 and therefore requires no specific discussion of its components or operation. It is to be appreciated that the chemical injection line is most commonly run at the outside dimension of the TRSV and is fixed there by known methods. 
   The TRSV is threadedly connected at thread  20  to a tubing spaceout string (not shown) or directly to the communication nipple  14 . Communication nipple  14  may be of a commercially available type sold, for example, by Baker Oil Tools, Houston Tex. under the product number H824063810, for example. It is to be appreciated that the chemical injection line  16  is fluidly connected to the nipple  14  at connection site  22  and in one embodiment, as illustrated, only after passing through a Chemical Injection Valve  24  (CIV), which is a check valve configuration. An appropriate CIV is, for example, commercially available from Baker Oil Tools Houston Tex. under product number H861039996. Connection site  22  is fluidly connected to a thin walled portion  26  of the nipple  14  that is intended to receive a puncture device from a subsequently run PCT  28  (for example, commercially available from Baker Oil Tools Houston Tex. under product number H822813815), see  FIG. 3 . It is to be appreciated that several types of puncture devices  30  are available each being contemplated for use in this system. 
   Once the PCT  28  is run to position and operated, the chemical injection line is open at opening  27  and will flow chemical into the communication nipple  14  (the flow path of the produced hydrocarbons). As the provision of chemical at this location does not necessarily improve the production process, it is desirable to quickly trip the PCT  28  out of the hole and run in with a capillary sleeve  32  as disclosed herein. 
   Referring to  FIGS. 3 and 4 , capillary sleeve  32  is a completely self-contained component that is run in the hole on a running tool (not shown) and then released after engagement with a profile  34  at an inside dimension of communication nipple  14  (see  FIGS. 1 and 4 ). Profile  34  is engaged by one or more dogs  36  illustrated herein as four dogs, but other numbers are clearly substitutable. Dogs  36  and profile  34  are, in one embodiment, a snap-in/snap-out arrangement so that they are sufficiently engaged to support both the capillary sleeve  32  and a capillary tube  38  depending therefrom without further engagement to any structure extending through the TRSV and yet may be relatively easily disengaged by a retrieval tool (not shown) in the event that there is reason to remove the capillary sleeve  32  and dependent capillary tube  38 . It is important to note here that because of the configuration of the capillary sleeve  32  that makes it wireline retrievable, any malfunction of the system (CIV, Capillary tube, etc.) can be repaired easily by retrieving it to the surface. It is also possible of course to simply replace these components of the system rather than repair them when pulled. The dogs  34  may also be configured to respond to a retrieval tool such that a snap out is not necessary but rather engagement of a retrieval tool causes the dogs to retract. 
   The capillary sleeve  32  further includes, an arrangement configured to seal the opened communication nipple to contain the chemical injection fluid. In the illustrated example, the capillary sleeve includes a pair of seals  40  and  42  supported on an outside dimension of the capillary sleeve  32  at positions calculated to create a seal with the inside dimension  44  of the communication nipple  14  while straddling the opening in the nipple  14 . This configuration creates an annular sealed flow area for chemical injection fluid and thus a sealed pathway between the chemical injection line  16  and the capillary tube  38 . Between the seals  40  and  42  is a recessed area  46  of the sleeve  32  that enlarges the annular flow area for enhanced flow characteristics to for example avoid a flow restriction in this area. Within the recessed area  46  is an inlet  48  to receive the chemical injection fluid and a conduit  50  within the sleeve  32  that is fluidly connected with the inlet  48  and to the capillary tube  38  to convey fluid thereto for subsequent transport to a remote location such as a perforation area of the wellbore (not shown). Capillary tube  38  is fluidly connected to the conduit  50  through a suitable connection such as a threaded connection  52  as illustrated in  FIG. 4 . In one embodiment, a redundant CIV  54  is included at a distal end  56  of capillary tube  38  to prevent wellbore fluid entering the capillary tube  38 . Each of the CIVs illustrated in this system provide a fail safe operation as they will automatically shut if sufficient hydraulic pressure is not maintained upon them from the surface. In addition to the foregoing, the capillary sleeve is configured to provide the largest inside dimension practicable to improve the flow cross section of the tool. Because the componentry (cross section) of the capillary sleeve is kept to a minimum, the patency (flow area for recovery of hydrocarbons through the capillary sleeve) can be maximized. 
   In one embodiment, referring to  FIG. 1 , a Y-block  60  is employed so that the control line  62  for the TRSV can be used for the chemical injection as well. The line is split and thereafter runs both to the TRSV and to the communication nipple. This is an optional configuration however, and a dedicated line for the chemical injection will be employed in some applications. In an application where a Y-block is used, one configuration will have the TRSV open at about 7,000 psi and the CIVs at 10,000 psi. This will ensure that the TRSV will reliably open before and independently of the chemical injection valves. 
   It is to be understood that the distance between the location of the TRSV  12  and the communication nipple  14 , and the distance between the nipple  14  and the capillary end  56  is largely limitless other than as practically limited simply by hydraulic friction. Each of these components may be spaced out as desired to ensure that chemical injection fluid is distributed as intended by the well operator. It is also possible to place multiple communication nipples  14  downhole that can individually be accessed to shorten the length of capillary tube  38  necessary to reach a target area with the chemical injection fluid. 
   A benefit of the system as disclosed herein is that the TRSV function is completely preserved using the disclosed configuration thereby not requiring a Wireline Retrievable Safety Valve (WRSV) or any other component extending through the TRSV. This of course reduces costs and maintains patency (flow area for recovery of hydrocarbons) in the flow area of the tubing string. Another benefit of this system is that there is no risk of producing hydrocarbons up the chemical injection prior to running a PCT and the capillary sleeve, which may not be necessary until later in the life of the well. The feature also provides benefits in thru tubing cement applications where cement is pumped through the ID of the tubing. During the initial completion of the well cement can be safely pumped through the ID of the communication nipple. The PCT will be able to punch through any cement (also scale and other solids that may deposit on the communication nipple) that remains on the wall of the communication nipple. 
   While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.