Abstract:
Methods and devices for utilizing an electrically-actuated wireline insert safety valve (WLSV) and for delivering power to an electrically actuated WLSV via inductive charging and without the use of wired contact.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates generally to safety valves and devices used within a wellbore. 
         [0003]    2. Description of the Related Art 
         [0004]    In the oil and gas industry, subsurface safety valves are used as a means of stopping the production of hydrocarbons in the event of an unexpected catastrophe or a planned shut down of a well. Most subsurface safety valves are hydraulically controlled from the surface facility by connecting a hydraulic control line to surface pumping equipment. Application of pressure at the surface is transmitted to the safety valve to open the device. Subsurface safety valves are typically installed into the well as a part of the production tubing string. Accordingly, these safety valves are typically referred to as tubing retrievable safety valves (TRSVs). In the event that the TRSV fails or stops functioning properly, it is possible to install a smaller safety valve into the interior diameter of the existing TRSV by running the smaller valve into the production tubing on wireline. The smaller installed valve is referred to as a wireline insert safety valve (WLSV). The WLSV operates off of the hydraulic pressure of the TRSV. Before running the WLSV into the TRSV, it is necessary to create a communication chamber between the TRSV and the wellbore. Several tools or methods can be used to accomplish fluid communication with the hydraulic chamber of the TRSV. Once communication is established, the WLSV is landed into the TRSV. A set of seals located on the upper portion and the lower portion of the WLSV land above and below the TRSV. The seals prevent the hydraulic fluid from escaping into the wellbore and allow the WLSV to operate off of the hydraulic control line of the TRSV. 
         [0005]    It is problematic to utilize a wireline insert safety valve where the TRSV uses electrical power rather than hydraulic power to be actuated. There is no mechanism for transmitting hydraulic power to the wireline insert valve. In addition, if the WLSV is electrically powered, it is difficult to transmit electrical power to the WLSV in a reliable manner. Downhole environments are filled with debris and are extremely corrosive environments. Solids can build up on exposed areas of a downhole valve, including electrical contacts. An electrical plug or port for electrically mating the TRSV and WLSV would likely become exposed and filled with debris to make an electrical connection difficult, if not impossible. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention provides methods and devices for utilizing an electrically-actuated wireline insert safety valve and for delivering power to an electrically actuated WLSV without the use of wired contact. In a preferred embodiment, inductive charging is used to deliver actuating power from a TRSV to a WLSV. There are preferably no exposed metallic contacts to corrode, and the electronic compartments are preferably sealed to prevent water corrosion or physical damage from debris within the wellbore. 
         [0007]    In a described embodiment, an electrically-powered tubing-run safety valve is provided with an induction charging coil that is sealed within the valve housing. A wireline-run insert safety valve is also provided with an induction charging coil that is operably interconnected with a valve actuator assembly that is operable to cause a safety valve member, such as a flapper member, to be operated within the safety valve. 
         [0008]    In an aspect of the present invention, the WLSV may be selectively inserted into the production tubing string which carries the TRSV. The WLSV is preferably landed within a landing profile associated with the TRSV. When landed, the induction charging coils of the TRSV and WLSV become substantially aligned to form an inductive coupling. Energizing the induction charging coil of the TRSV will transmit electrical energy to the coil of the WLSV. The transmitted electrical energy is used to actuate the WLSV valve actuator assembly and safety valve. In an alternative embodiment, the transmitted electrical energy is preferably stored within a charge storage device in the WLSV, and the stored electrical energy is thereafter used to actuate the WLSV valve actuator assembly and safety valve. 
         [0009]    In certain embodiments, the WLSV may be actuated from the surface by a wireless signal to a wireless receiver that is operably interconnected with the WLSV valve actuator assembly. In this instance, the wireless transmitted will command the WLSV to remain in the open position, and the WLSV valve member will move from the closed position to the open position. Thereafter, current supplied to the WLSV from the induction charging coil in the TRSV will retain the WLSV in the open position. The WLSV can be closed by deenergizing the induction charging coil in the TRSV. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The advantages and further aspects of the invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawing and wherein: 
           [0011]      FIG. 1  is a side, partial cross-sectional view of an exemplary wellbore containing a production string with subsurface safety valves constructed in accordance with the present invention. 
           [0012]      FIG. 2  is a side, cross-sectional view of an exemplary tubing-retrievable safety valve, in accordance with the present invention, with the valve in an open configuration. 
           [0013]      FIG. 3  is a side, cross-sectional view of the tubing-retrievable safety valve shown in  FIG. 2 , now in a closed configuration. 
           [0014]      FIG. 4  is a side, cross-sectional view of an exemplary wireline insert safety valve constructed in accordance with the present invention. 
           [0015]      FIG. 4   a  is an enlarged side cross-sectional view of portions of the wireline insert safety valve shown in  FIG. 4 . 
           [0016]      FIG. 5  is a side, cross-sectional view of the wireline insert safety valve inserted within the tubing-retrievable safety valve. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]      FIG. 1  illustrates an exemplary wellbore  10  that has been disposed within the earth  12  from the surface  14  and down to a hydrocarbon-bearing formation  16  from which it is desired to obtain hydrocarbon production fluid. The wellbore  10  is lined with metallic casing  18  in a manner known in the art. Perforations  20  are formed through the casing  18  and into the formation  16 . 
         [0018]    A production tubing string  22  is disposed within the wellbore  10 , and an annulus  24  is formed between the production tubing string  22  and the casing  18 . A central axial flowbore  23  is defined along the length of the production tubing string  22  for flow of fluids therethrough. The production tubing string  22  may be made up of a number of threaded production tubing string segments, in a manner known in the art. Alternatively, the production tubing string  22  may be formed of coiled tubing. The production tubing string  22  includes a ported production nipple  26 , of a type known in the art, which is located within the wellbore  10  proximate the perforations  20 . Packers  28  isolate the production nipple  26  within the wellbore  10 . 
         [0019]    The production tubing string  22  also includes an electrically-powered tubing-retrievable safety valve assembly (TRSV)  30  above the production nipple  26 . An electrical power supply cable  32  extends from the valve assembly  30  to the surface  14  wherein it is operably associated with a power source  34 . The safety valve assembly  30  is preferably a flapper-type safety valve which is operable between open and closed positions to selectively block fluid flow through the production tubing string  22 . The TRSV  30  includes a tubular outer housing  36  which defines a central axial valve bore  38  which is aligned with the flowbore  23  of the production tubing string  22 . The valve bore  38  contains a landing profile  40 . In addition, seal bores  42 ,  44  are located within the valve bore  38 . The seal bores  42 ,  44  are smooth bore portions that for packing stacks of seals on a component disposed inside the valve bore  38  to seal against the seal bores  42 ,  44 . 
         [0020]    The housing  36  of the valve assembly  30  includes an induction charging coil  46  which is preferably fully enclosed within the housing  36  and separated from the valve bore  38 . The induction charging coil  46  is operably associated with the power supply cable  32  so that the coil  46  may be energized from the surface  14 . The power supply cable  32  is also operably associated with a flapper valve actuator, which is depicted schematically at  48 . The valve actuator  48  is interconnected with valve piston assembly  50 . The valve piston assembly  50  includes a piston cylinder  52  and a piston member  54  that is movably disposed within the cylinder  52 . The piston member  54  is interconnected with a flow tube  56  which controls the position of pivotable flapper member  58 , in a manner known in the art. The flapper member  58  is a known device which is moveable about pivot point  59  between an open position, illustrated in  FIG. 2 , wherein fluid may pass through the valve bore  38 , and a closed position, illustrated in  FIG. 3 , wherein fluid flow through the valve bore  38  is blocked by the flapper member  58 . As is known, the flapper member  58  is biased by a torsional spring toward the closed position. The flow tube  56  is moveably disposed within a radially enlarged bore portion  60  of the valve bore  38 . The flow tube  56  is biased toward the closed position by a compressible power spring  61 , of a type known in the art. This spring bias provides for the valve assembly  30  to have a fail-safe mode such that, in the event of loss of a control signal from the surface (e.g., an electrical signal via cable  32 ), the power spring  61  will lift the flow tube  56  (see  FIG. 3 ) and allow the flapper member  58  to rotate to its closed position. When the flow tube  56  is in a lowered position within the bore portion  60 , as depicted in  FIG. 2 , the flow tube  56  retains the flapper member  58  in the open position. When the flow tube  56  is moved to an upper position within the bore portion  60 , the flapper member  58  moves to its closed position against valve member seat  62 , as depicted in  FIG. 3 . The flapper valve actuator  48  may be a fluid pump, a motor, an electromagnetic solenoid, or an-electro-hydraulic actuator device which is operable to cause movement of the piston member  54  within the piston cylinder  52 . One suitable electro-hydraulic valve actuator is described in U.S. Pat. No. 6,269,874 issued to Rawson et al. U.S. Pat. No. 6,269,874 is owned by the assignee of the present invention and is hereby incorporated in its entirety by reference. 
         [0021]      FIG. 4  illustrates an exemplary wireline insert safety valve  70  which is insertable into the production tubing string  22  and securable within the tubing run safety valve  30  in the event that the tubing-run safety valve  30  fails to operate. The wireline insert safety valve  70  includes a tubular valve housing  72  which is shaped and sized to fit within the valve bore  38  of the tubing run safety valve  30 . An axial flowbore  74  is defined along the length of the valve housing  72 . The valve housing  72  is secured by release pins  76  to a wireline running tool  78 . The housing  72  carries a plurality of latching keys  80  which are biased radially outwardly by compression-springs  82 . A flapper member  84  is also located within the flowbore  74  and is pivotable about pivot point  86  between open and closed positions within the flowbore  74 . As with the flapper member  58 , the flapper member  84  is biased toward a closed position by a torsional hinge spring. An axially moveable flow tube  88  is retained within a radially enlarged portion  90  of the flowbore  74 . The flow tube  88  is spring-biased by an axially compressible power spring  91  (see  FIG. 4   a ) toward a position that would lift the flow tube  88  and allow the flapper member  84  to be closed. The flow tube  88  serves the same purpose in controlling the flapper member  84  as the flow tube  56  does in controlling the configuration of the flapper member  58 . A pair of external fluid seals  93  radially surrounds the valve housing  72  (see  FIG. 4 ). 
         [0022]    An electric flapper member actuating assembly, generally indicated at  92 , is preferably housed within the housing  72  of the valve  70 . The flapper member actuating assembly  92  includes an induction charging coil  94  which is preferably sealed within the housing  72  so as to not be in contact with either the flowbore  74  or the radial outer surface of the tool  70 . The induction charging coil  94  is operably interconnected with a charge storage device  96 , such as a rechargeable battery. The charge storage device  96  is operably interconnected with a valve actuator, shown schematically at  98 . In an alternative embodiment, the coil  94  is directly connected with the valve actuator  98  such that energizing the coil  94  will cause the valve actuator  98  to be operated. In one preferred embodiment, the valve actuator  98  also includes a wireless receiver that is operable to receive a wireless signal from a surface-based wireless transmitter  99  and, in response to receipt of such a signal, will generate a command to actuate the associated valve piston assembly  100 . The valve actuator  98  is interconnected with valve piston assembly  100 . The valve piston assembly  100  includes a piston cylinder  102  and a piston member  104  that is movably disposed within the cylinder  102 . The piston member  104  is interconnected with the flow tube  88  which controls the position of pivotable flapper member  84 . When the valve actuator  98  is actuated, the spring bias provided by the power spring  91  is overcome by the actuator  98 . The valve actuator  98  may be a fluid pump, a motor, an electromechanical solenoid, or an electro-hydraulic actuator device which is operable to cause movement of the piston member  104  within the piston cylinder  102 . Upon loss of power to the valve actuator  98 , the valve member  84  will be closed due to the fail-safe spring bias of the power spring  91 . 
         [0023]      FIG. 5  depicts the WLSV  70  landed securely within the valve bore  38  of the TRSV  30  so that the keys  80  of the WLSV  70  are latched into the landing profile  40  of the radially surrounding TRSV  30 . When the keys  80  are latched into the landing profile  40 , the induction charging coil  94  of the WLSV  70  is in proximity to the induction charging coil  46  of the TRSV  30  such that electrical energy can be effectively transferred from the coil  46  to the coil  94  via induction charging. It can be seen from  FIG. 5  that, when the wireline insert valve  70  is landed within the landing profile  40 , the induction charging coil  94  of the WLSV  70  is preferably generally aligned with the induction charging coil  46  of the TRSV  30  to form an inductive coupling. Energizing the coil  46  of the TRSV  30  will cause the coil  94  to be energized via inductive charging. When the WLSV  70  is landed within the landing profile  40 , the fluid seals  93  on the outer radial surface of the WLSV valve housing  72  form a seal against the seal bores  42 ,  44  of the TRSV  30 . 
         [0024]    In operation, the WLSV  70  may be used as a back-up valve in the event that the TRSV  30  fails to operate. When the TRSV  30  fails, the WLSV  70  is affixed to the wireline running tool  78  and is run into the tubing string  22 . The WLSV  70  is lowered through the production tubing string  22  until the keys  80  of the WLSV  70  become latched into the landing profile  40 . Following landing, electrical power is transmitted from the surface through the cable  32  to the induction coil  46  of the TRSV  30  to energize the coil  46 . Via induction charging, electric charge is transmitted from the outer coil  46  to the induction charging coil  94  of the WLSV  70 . The transmitted electrical charge is stored in the storage device  96  or, alternatively, used to directly retain the flapper member in the open position. 
         [0025]    When a sufficient amount of electrical charge has been transmitted to the WLSV  70 , the WLSV  70  may be selectively actuated to move the flapper member  84  between its open and closed positions. In one preferred embodiment, the WLSV  70  is run into the production tubing string  22  in the closed position. Once sufficient electrical charge has been transmitted to the induction charging coil  94 , the valve actuator  98  causes the piston member  104  to be moved axially within the cylinder  102  so that the flow tube  88  is moved axially downwardly within the housing  72 , resulting in the flapper member  84  being moved to the open position. In the event of a loss of power to the charging coil  94 , the flapper member  84  would rotate to the closed position as the power spring  91  moves the flow tube  88  upwardly. 
         [0026]    Use of the wireless transmitter  99  to operate the WLSV  70  is preferred when used in connection with a charge storage device  96 . In this instance, the WLSV  70  would be again run into the production tubing string  22  in the closed position. Transmission of power from the surface to induction charging coil  94  will then store electrical charge within the storage device  96 . When it is desired to open the WLSV  70 , a wireless command is transmitted from the transmitter  99  to the valve actuator  98 . 
         [0027]    The WLSV  70  may alternatively be actuated to close the flapper member  84  by transmitting a wireless signal from the transmitter  99  to the valve actuator  98 . The valve actuator  98  causes the piston member  104  to be moved axially within the cylinder  102 . As the piston member  104  is moved within the cylinder  102 , the flow tube  88  is moved axially upwardly with respect to the surrounding housing  72  to allow the flapper member  84  to rotate to its closed position, thereby blocking fluid flow through the flowbore  74  of the housing  72 . Due to the seal formed between the seals  42 ,  44  of the TRSV  30  and the housing  72  of the WLSV  70 , any fluid flow through the flowbore  38  of the TRSV  30  and production tubing string  22  is thereby blocked by the flapper member  84 . 
         [0028]    The TRSV  30  and WLSV  70  collectively form a safety valve arrangement that will allow the flowbore  23  of the production tubing string  22  to be selectively closed off to fluid flow even in the event that the TRSV  30  becomes inoperable and is no longer able to close off fluid flow through the flowbore  23 . 
         [0029]    The foregoing description is directed to particular embodiments of the present invention for the purpose of illustration and explanation. It will be apparent, however, to those skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope and the spirit of the invention.