Patent Publication Number: US-2020291750-A1

Title: Method of intervention in a failed deep-set subsurface safety valve in a deepwater or ultra-deepwater subsea well using a light intervention vessel

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 16/378,740, filed on Apr. 9, 2019, which claims the benefit of, or priority to, U.S. Provisional Patent Application Ser. No. 62/779,121, filed on Dec. 13, 2018, both of which are hereby incorporated by reference in their entirety. 
     This application is a continuation-in-part of U.S. patent application Ser. No. 16/386,624, filed on Apr. 17, 2019, which claims the benefit of, or priority to, U.S. Provisional Patent Application Ser. No. 62/718,737, filed on Aug. 14, 2018, both of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     While the oil and gas industry has drilled more than 14,000 deepwater subsea wells, in the aftermath of the Macondo incident in the Gulf of Mexico off the southeastern coast of Louisiana and the Montara incident in the Timor Sea off the northern coast of Australia, the International Association of Oil and Gas Producers (“OGP”) formed the Global Industry Response Group (“GIRG”) to investigate these and other incidents around the world and develop recommendations to the industry. In 2011, the GIRG published their recommendations in a report entitled  Deepwater Wells: Global Industry Response Group Recommendations  (“Report No. 463”). In Report No. 463, the GIRG recommends that “operators maintain a permanently applied minimum of two well barriers when the well is capable of discharging hydrocarbons or other fluids to the surface or external environment. . . . During drilling, completion, and abandonment phases of a well we regard a [blowout preventer] BOP as a barrier for the purposes of such a policy even when operated in the open position—if the BOP and associated procedures meet the operator&#39;s policy in . . . configuration and certification; redundancy for the operations being undertaken; function and pressure testing; and operational controls to use the BOP to shut in the well.” See Section 1.1 of Report No. 463. As such, operators consider the subsea blowout preventer (“SSBOP”) one of the permanently applied well barriers and typically install a surface-controlled tubing-retrievable subsurface safety valve as the second permanently applied well barrier. 
     A subsurface safety valve is a failsafe device deployed downhole to prevent catastrophic failure by shutting-in a well when other means of control are compromised or lost. During initial completion operations, while the drilling rig is still on the well site, a tubing-retrievable type of subsurface safety valve is run into the well as part of the production tubing. The term tubing-retrievable means the subsurface safety valve is deployed as an integrated part of, and is only retrievable by pulling, the production tubing. During production operations, typically after the drilling rig has left the well site, the tubing-retrievable subsurface safety valve is hydraulically actuated into the open, or producing, state permitting production flow towards the surface. When the operator wants to halt production, the hydraulic pressure in the control line is sufficiently reduced or removed and the bias spring automatically closes the tubing-retrievable subsurface safety valve, preventing further production flow. In the event of a failure or other contingency, tubing-retrievable subsurface safety valves are designed to fail safely in the closed position to prevent further production flow. To that end, subsurface safety valves require the affirmative application of hydraulic pressure in the control line that is sufficient to overcome the bias spring, influenced by pressure at the setting depth, to open a unidirectional flapper or valve and controllably permit the flow of production fluids toward the surface. When the hydraulic pressure in the control line is sufficiently reduced or removed, intentionally or otherwise, the bias spring causes the flapper or valve to automatically close, thereby safely preventing any further production flow. 
     As tubing-retrievable subsurface safety valves were being set deeper in the well due to their use in deeper water, the valves had difficulty operating due to the hydrostatic head in the control line, which eviscerated the failsafe protection they were intended to provide. As such, tubing-retrievable subsurface safety valves were modified to provide additional biasing force to balance the increased hydrostatic head in the control line. These deep-set tubing-retrievable subsurface safety valves include additional biasing means, such as, gas-charged chambers described in, for example, U.S. Pat. Nos. 4,252,197, 4,660,646, 4,976,317, and 5,310,004, or balance lines described in, for example, U.S. Pat. Nos. 6,003,605 and 7,392,849 that provide additional biasing force to the biasing spring. In general, the additional biasing means are designed to offset the hydrostatic head in the control line so that the operating pressures within the control line remain relatively low, such that the subsurface safety valve may be actuated at depth and fully close as intended when the hydraulic pressure in the control line is sufficiently reduced or removed. 
     BRIEF SUMMARY OF THE INVENTION 
     According to one aspect of one or more embodiments of the present invention, a method of intervention in a failed deep-set tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well includes cutting or grinding a radial port in an interior facing portion of the failed deep-set tubing retrievable subsurface safety valve with an e-line wireline-deployable communication tool to communicate a hydraulic chamber housing of the failed deep-set tubing-retrievable subsurface safety valve. The method further includes running in a deep-set wireline-retrievable subsurface safety valve into a central lumen of the failed tubing-retrievable subsurface safety valve. The deep-set wireline-retrievable subsurface safety valve includes a closure actuation mechanism disposed below a closure device. The actuation mechanism includes a pressure-balanced piston exposed to wellbore fluids on both distal ends of the piston. 
     Other aspects of the present invention will be apparent from the following description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows the deployment of a conventional deep-set tubing-retrievable subsurface safety valve in a deepwater or ultra-deepwater subsea well. 
         FIG. 2  shows a conventional deep-set tubing-retrievable subsurface safety valve. 
         FIG. 3  shows a light intervention vessel disposed on a well site of a failed tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well in accordance with one or more embodiments of the present invention. 
         FIG. 4A  shows communication of the failed deep-set tubing-retrievable subsurface safety valve in accordance with one or more embodiments of the present invention. 
         FIG. 4B  shows a radial cutout formed in an interior facing surface of the failed deep-set tubing-retrievable subsurface safety valve providing access to the hydraulic chamber (not independently shown) in accordance with one or more embodiments of the present invention. 
         FIG. 5  shows a block diagram of a deep-set wireline retrievable subsurface safety valve for a failed deep-set tubing-retrievable subsurface safety valve in accordance with one or more embodiments of the present invention. 
         FIG. 6  shows a bottom facing perspective view of a portion of a deep-set wireline-retrievable subsurface safety valve in accordance with one or more embodiments of the present invention. 
         FIG. 7  shows an exploded view of a portion of a deep-set wireline-retrievable subsurface safety valve in accordance with one or more embodiments of the present invention. 
         FIG. 8A  shows a cross-sectional view of a portion of a deep-set wireline-retrievable subsurface safety valve in accordance with one or more embodiments of the present invention. 
         FIG. 8B  shows a cross-sectional view of a portion of deep-set wireline-retrievable subsurface safety valve disposed within a failed deep-set tubing-retrievable safety valve with a ball valve in a closed state preventing flow in accordance with one or more embodiments of the present invention. 
         FIG. 8C  shows a cross-sectional view of a portion of a deep-set wireline-retrievable subsurface safety valve disposed within a failed deep-set tubing-retrievable subsurface safety valve with a ball valve in an opened state permitting production flow in accordance with one or more embodiments of the present invention. 
         FIG. 8D  shows a detailed portion of a cross-sectional view of a portion of a deep-set wireline-retrievable subsurface safety valve disposed within a failed deep-set tubing-retrievable subsurface safety valve with a ball valve in an opened state permitting flow in accordance with one or more embodiments of the present invention. 
         FIG. 9A  shows a detailed portion of a perspective view of a ball valve of a deep-set wireline-retrievable subsurface safety valve on seat in accordance with one or more embodiments of the present invention. 
         FIG. 9B  shows a detailed portion of a perspective view of a ball valve of a deep-set wireline-retrievable subsurface safety valve off seat under actuation pressure in accordance with one or more embodiments of the present invention. 
         FIG. 10A  shows a cross-sectional view of a closure device, such as, for example, ball of a deep-set wireline-retrievable subsurface safety valve in a closed state in accordance with one or more embodiments of the present invention. 
         FIG. 10B  shows a cross-sectional view of a closure device, such as, for example, ball of a deep-set wireline-retrievable subsurface safety valve in an open state in accordance with one or more embodiments of the present invention. 
         FIG. 11  shows a light intervention vessel performing a method of intervention in a failed deep-set tubing-retrievable subsurface safety valve in a deepwater or ultra-deepwater subsea well in accordance with one or more embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     One or more embodiments of the present invention are described in detail with reference to the accompanying figures. For consistency, like elements in the various figures are denoted by like reference numerals. In the following detailed description of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention. In other instances, well-known features to one of ordinary skill in the art are not described to avoid obscuring the description of the present invention. For purposes of clarity, as used herein, top, upper, or above refer to a portion or side that is closer, whether directly or in reference to another component, to the surface above a wellbore and bottom, lower, or below refer to a portion or side that is closer, whether directly or in reference to another component, to the bottom of the wellbore. 
       FIG. 1  shows the deployment  100  of a conventional deep-set tubing-retrievable subsurface safety valve  105  in a deepwater or ultra-deepwater subsea well  110 . In offshore operations, a bottom founded, semi-submersible, drillship, or other floating drilling rig  115  is floated onto the well site to drill a subsea well  110  to recover oil or gas reserves disposed below the seafloor  120 . In deepwater applications, the water depth, W Depth , may be in a range between 3,500 and 5,000 feet. In ultra-deepwater applications, the water depth, W Depth , may be greater than 5,000 feet. The total vertical depth of the wellbore  110  may extend many thousands of feet below the seafloor  120 . 
     During drilling and pre-production operations, a marine riser system  125  facilitates fluid communication between drilling rig  115  and subsea well  110 . An SSBOP  135  is disposed above a subsea wellhead, or wet tree,  130  disposed above subsea well  110 . The wellhead  130  is in fluid communication with production tubing  140  disposed within the interior of wellbore  110 . In this way, a central lumen is formed that fluidly connects drilling rig  115  to the interior of wellbore  110  for the deployment of drilling equipment and other tools (not shown). During initial completion operations, deep-set tubing-retrievable subsurface safety valve  105  is deployed as an integrated part of production tubing  140 , typically disposed within 200 feet of the hanger (not independently illustrated) of the wet tree  130 . After completion, drilling rig  115  is moved off the well site and a Floating Production and Storage Offloading (“FPSO”) vessel (not shown) is typically brought in to fluidly connect to the wet tree  130  to facilitate production activities. The FPSO (not shown) typically includes a surface-based control system (not shown) that communicates hydraulic actuation fluid through the wet tree  130  to the deep-set tubing-retrievable subsurface safety valve  105  via the control line (not shown). When the operator wishes to start production, the surface-based control system (not shown) provides hydraulic pressure in the control line (not shown) that overcomes the resistance of the biasing means (not shown), causing the flapper (not shown) or valve (not shown) to open, permitting production flow towards the surface. The production fluids may be directed from the wet tree  130  to a storage tank (not shown) on the FPSO (not shown) for storage and delivery. 
       FIG. 2  shows a conventional deep-set tubing-retrievable subsurface safety valve  105  well-known in the art. A conventional deep-set tubing-retrievable subsurface safety valve  105  such as, for example, the valve shown and described in U.S. Pat. No. 5,310,004, may be deployed as part of the production tubing (e.g.,  140  of  FIG. 1 ) and disposed in a subsea well (e.g.,  110  of  FIG. 1 ). The valve  105  is typically set at a depth within the valve&#39;s fail-safe setting depth. The fail-safe setting depth is the maximum true vertical depth at which the valve may be set and expected to properly close under worst-case hydrostatic conditions. 
     As described in U.S. Pat. No. 5,310,004, valve  105  includes a central lumen  202  that extends from distal end to distal end and a flapper  204  connected to a lower portion of a housing  206  by a pivot pin  208 . Valve  105  allows end-to-end communication through the central lumen  202  when flapper  204  is in the open position and prevents flow when flapper vale  204  is in the default closed position. Valve  105  includes a piston  210  and a cylinder  212  that are connected to a flow tube  214 . To open valve  105 , the application of hydraulic pressure, via the control line (not shown), to the top side of piston and cylinder assembly  216  causes flow tube  214  to move downward, forcing flapper  204  off of valve seat  218 , opening valve  105  to production flow therethrough. In the absence of sufficient hydraulic pressure, biasing means, such as biasing spring  220  and a pressurized gas chamber  222 , are biased to push flow tube  214  in an upward direction, thereby releasing flapper  204  to close valve  105 . Spring  220  acts between a shoulder  224  on housing  206  and a shoulder  226  on flow tube  214 . Pressurized gas chamber  222  includes a plurality of tubing coils  228  containing pressurized nitrogen. 
     As a failsafe, piston  210  includes a second piston  232  that is telescopically positioned in an end of first piston  210 . The second piston  232  includes a first end  234  and a second end  236 , where the second end  236  has a larger cross-sectional area than the first end  234 . The first end  234  and second end  236  each sealably engage first piston  210  by seals  238  (not shown) and  240  (not shown). Seal  238  seals a smaller cross-sectional area than larger seal  240 . The first piston  210  includes a hydraulic fluid passageway  242  that extends from a first side of the hydraulic piston and cylinder assembly  216  to the first end  234  of the second piston  232  and acts against seal  240 . The second end  236  of second piston  232  is exposed to the gas pressure in chamber  222 . Because the cross-sectional area of the second end  236  of second piston  232  has a larger seal area  240  than seal area  238  of first end  234 , second piston  232  will remain in engagement in the end of first piston  210  with a lower gas pressure acting on second end  236  compared with hydraulic actuation fluid acting on first end  234 . However, if gas pressure is lost, and unable to overcome the hydrostatic head of the hydraulic actuation fluid in the control line (not shown), the force of the gas pressure acting on second end  236  of the second piston  232  decreases allowing the hydrostatic pressure of the hydraulic fluid acting on the first end  234  to push the second piston  232  out of piston  210 , thereby balancing the hydrostatic actuation fluid forces on piston  210 , such that biasing spring  220  may close valve  105  safely. One of ordinary skill in the art will appreciate that the conventional deep-set tubing-retrievable subsurface safety valve described herein is merely exemplary and there are other designs, however, each of which relies on additional biasing means to assist in closing the valve against the increased hydrostatic head encountered in deep-set applications. 
     In the aftermath of the Deepwater Horizon incident, the use of deep-set tubing retrievable subsurface safety valves increased dramatically. While various original equipment manufacturers claim that deep-set tubing-retrievable subsurface safety valves are capable of reliable operation at substantial depth, until recently, their actual performance in deepwater and ultra-deepwater wells was not well characterized. Unfortunately, data from the field suggests that deep-set tubing retrievable subsurface safety valves have a substantially higher failure rate than that of conventional tubing-retrievable subsurface safety valves, resulting in non-commanded closures and other critical failure modes. Specifically, high-profile failures have shed light on the substantial risk these deep-set valves pose in deepwater and ultra-deepwater applications. In a litigation matter filed in the United States District Court for the Southern District of Texas, styled Hess Corporation® v. Schlumberger Technology Corporation® (case 4:16-CV-03415), Hess filed suit against Schlumberger for damages resulting from the alleged failure of Schlumberger&#39;s deep-set tubing retrievable subsurface safety valves deployed offshore. Hess purchased five (5) deep-set tubing-retrievable subsurface safety valves from Schlumberger for use in subsea wells in the Outer Continental Shelf of the Gulf of Mexico. As of the date of the complaint, three (3) of the five (5) deep-set tubing-retrievable subsurface safety valves deployed in deepwater subsea wells failed. According to Hess, this has resulted in significant production losses, costs associated with pulling and replacing the failed valves, costs associated with restoring production capabilities, property loss and damage, and deferred production costs associated with schedule delays on subsequent producer and injector wells. The subsea wells at issue were drilled in approximately 4,300 feet of water, with the wells themselves having an approximate total vertical depth of approximately 25,000 feet. These wells produced between 2,000 and 16,500 barrels of oil per day, before being shut-in by non-commanded valve closure and potentially other failure modes. In quantifying the substantial costs incurred due to these failures, Hess complained that, with respect to a single subsea well, it took 64 days and cost approximately $60 million dollars to restore production operations, exclusive of lost profits. 
     The issues complained of in the above-noted litigation highlight a longstanding problem in the industry that threatens the financial viability and overall feasibility of deepwater and ultra-deepwater plays. While tubing-retrievable subsurface safety valves are required in deepwater and ultra-deepwater applications, unfortunately, when they fail, the well must be re-completed in a time-consuming and expensive process that requires floating a drilling rig back onto the well site, pulling the production tubing, replacing the failed tubing-retrievable subsurface safety valve, and re-deploying the production tubing with the replaced tubing-retrievable subsurface safety valve. In addition to the substantial costs associated with the above-noted re-completion activities, profits lost for the duration of these operations are substantial. As noted in the real-world example, the frequency of failure of deep-set tubing-retrievable subsurface safety valves and the substantial time and cost required to re-complete a well jeopardize the safety of operations and many operators are shying away from such deepwater and ultra-deepwater plays, where a significant amount of oil and gas reserves are known to exist. 
     In a failed conventional, not deep-set, tubing-retrievable subsurface safety valve set at a shallower depth, typically less than 3,500 feet, one avenue for proceeding is to deploy a conventional wireline-retrievable subsurface safety valve within the failed tubing-retrievable subsurface safety valve. The wireline-retrievable subsurface safety valve may be run into the well on a lock that locates the wireline-retrievable subsurface safety valve within a desired location of the failed tubing-retrievable subsurface safety valve. The wireline-retrievable subsurface safety valve typically includes packing elements that isolate the hydraulic chamber that was previously used to control the now failed tubing-retrievable subsurface safety valve. The process of opening up the original hydraulic actuation pathway of the failed tubing-retrievable subsurface safety valve for use with the wireline-retrievable subsurface safety valve is referred to as communication. Once communication has been achieved, a surface-controlled pump system may pump hydraulic actuation fluid through the hydraulic chamber of the failed tubing-retrievable subsurface safety valve to the hydraulic chamber of the wireline-retrievable subsurface safety valve to hydraulically actuate the wireline-retrievable subsurface safety valve in a similar manner to that of the failed tubing-retrievable subsurface safety valve. 
     While the wireline-retrievable subsurface safety valve potentially reduces the flow rate of production fluids, it allows such wells to continue to produce after failure of the tubing-retrievable subsurface safety valve without the attendant costs of recompleting the well. Similar to the tubing-retrievable subsurface safety valve, the conventional wireline-retrievable subsurface safety valve is a failsafe device that fails in the closed state such that production flow is halted whenever hydraulic actuation pressure is sufficiently reduced or removed. As such, the conventional wireline-retrievable subsurface safety valve requires the positive application of hydraulic actuation pressure to open a flapper or valve to permit production flow through the subsurface safety valve. In the event of a failure or catastrophic event, once the hydraulic actuation is lost, the energy stored in a power spring disposed above the flapper of the wireline-retrievable subsurface safety valve causes the subsurface safety valve to close, thereby safely halting production flow. 
     Notwithstanding, conventional wireline-retrievable subsurface safety valves cannot be used in deepwater and ultra-deepwater subsea wells. The depth at which conventional wireline-retrievable subsurface safety valves may be deployed is constrained by the ability to provide sufficient hydraulic activation pressure at the setting depth. Conventional wireline-retrievable subsurface safety valves require the application of hydraulic actuation pressure to compress a bias spring disposed above the flapper or valve to controllably open the valve when production flow towards the surface is desired. If the conventional wireline-retrievable subsurface safety valve is deployed at a depth that exceeds the ability of the hydraulic actuation to overcome the hydrostatic head in the control line, the conventional wireline-retrievable subsurface safety valve cannot be opened, thereby preventing production flow. 
     Further, conventional wireline-retrievable subsurface safety valves require a bias spring disposed above the flapper or valve that is capable of storing sufficient energy to offset the increased hydrostatic head in the control line, at the setting depth, such that it can reliably fail in the closed state. However, this is not feasible because the size of the bias spring disposed above the flapper or valve is physically constrained by the inner diameter of the wireline-retrievable subsurface safety valve itself. Since the conventional wireline-retrievable subsurface safety valves require an inner diameter capable of fluidly communicating production flow, the amount of space above the flapper or valve is physically constrained, thereby limiting the amount of energy capable of being stored in the bias spring and, as a consequence, substantially limiting the depth at which the conventional wireline-retrievable subsurface safety valve may be set, typically much shallower than 3,500 feet. 
     As such, the current state of the art in the industry is to deploy a SSBOP and deep-set tubing-retrievable subsurface safety valve as a permanently installed two barrier system for deepwater and ultra-deepwater subsea wells. When the tubing-retrievable subsurface safety valve fails, for whatever reason, the operator must undertake a complex, time-consuming, and expensive process to re-complete the well in an attempt to resume production operations. As noted above, a drilling rig must be brought onto the well site, the production tubing must be pulled, the failed deep-set tubing-retrievable subsurface safety valve must be replaced, the production tubing must be run back into the well, and the well must be completed with a wellhead or wet tree. 
     Accordingly, in one or more embodiments of the present invention, a method of intervention in a failed deep-set tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well does not require re-completion of the well and substantially reduces non-productive down-time, lost profits, and costs associated with resuming production. Advantageously, the production tubing, including the failed deep-set tubing-retrievable subsurface safety valve do not have to be pulled, dramatically simplifying operations and reducing costs. A light intervention vessel may be used as the platform for performing the intervention, rather than a conventional drilling rig or platform, substantially expediting operations and reducing costs typically associated with floating a large drilling rig back onto the well site. A deep-set wireline-retrievable subsurface safety valve may be deployed via wireline into the failed deep-set tubing-retrievable subsurface safety valve, where the deep-set wireline-retrievable subsurface safety valve has a closure actuation mechanism that is disposed below the closure device. In addition, the closure actuation mechanism includes a pressure-balanced piston that is exposed to wellbore fluids on both distal ends of the piston, thereby allowing the piston to actuate the closure device in deepwater and ultra-deepwater wells with significant hydrostatic head in the control line. 
       FIG. 3  shows a light intervention vessel  305  disposed on a well site  310  of a failed tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ) disposed in a deepwater or ultra-deepwater subsea well (e.g.,  110  of  FIG. 1 ) in accordance with one or more embodiments of the present invention. While the use of light intervention vessels for different reasons is well-known in the art, such vessels  305  may be used with one or more methods of the claimed invention to facilitate deepwater or ultra-deepwater intervention in failed tubing-retrievable subsurface safety valves. Light intervention vessels  305  are small, dynamically positioned, and monohulled vessels that are capable of being disposed on the wellsite  310  much faster than large semi-submersible, drillship, or other large drilling rigs or platforms (e.g.,  115  of  FIG. 1 ). Once disposed on the wellsite  310 , light intervention vessel  305  facilitates wireline access to the subsea well (e.g.,  110  of  FIG. 1 ) where the failed tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ) is disposed. In certain embodiments, wireline access may be provided by a riser-based system (not shown). In other embodiments, wireline access may be provided by a coiled-tubing-based  315  system. In still other embodiments, wireline access may be provided by a slickline-based  315  system. In still other embodiments, wireline access may be provided by wireline-based  315  system. One of ordinary skill in the art will recognize that any system that provides wireline access such that communication tools may be deployable, and a deep-set wireline retrievable subsurface safety valve (not shown) may be landed, within the failed deep-set tubing retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ) may be used in accordance with one or more embodiments of the present invention. 
     In certain embodiments, a robotically operated vehicle (“ROV”)  320  may be tethered to an ROV umbilical  325  to observe and assist in the intervention operations taking place at or near the seafloor  120 . After wellbore access is achieved, a wireline-deployable lockout tool (not shown) is run into the wellbore (e.g.,  110  of  FIG. 1 ) to lock out the failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ). In certain embodiments, a deformation type of lockout tool (not shown) may be used. Deformation-type lockout tools locate a positive shoulder of a known-location, such as, for example, a no-go shoulder or profile, often located in the top sub of the tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ). Downward jarring on the tool engages the flowtube (e.g.,  214  of  FIG. 2 ) of the failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ), causing the flowtube (e.g.,  214  of  FIG. 2 ) to shift downward causing the flapper (e.g.,  204  of  FIG. 2 ) or valve (not shown) to open. Simultaneously, prongs or specially adapted hammers (not shown) protrude from the deformation-type lockout tool (not shown) and deform the flowtube (e.g.,  214  of  FIG. 2 ) permanently opening the flapper (e.g.,  204  of  FIG. 2 ). In some applications, the flowtube (e.g.,  214  of  FIG. 2 ) may be stuck such that it cannot be moved. In such circumstances, a cylindrical metal coil (not shown) may be deployed with the lockout tool and deposited in or near the flapper (e.g.,  204  of  FIG. 2 ) housing to permanently open the flapper (e.g.,  204  of  FIG. 2 ). Once locked out, the failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ) is locked into the open state, such that fluids are freely communicated through the tubing-retrievable subsurface safety valve. 
       FIG. 4A  shows communication of the failed deep-set tubing-retrievable subsurface safety valve  105  in accordance with one or more embodiments of the present invention. It is well-known in the art that you must communicate a failed subsurface safety valve in order to operate the insertable valve. However, a deep-set wireline-retrievable subsurface safety valve deployed in deepwater and ultra-deepwater subsea wells present special challenges because communication of failed deep-set tubing-retrievable subsurface safety valves (e.g.,  105 ) has never been attempted or accomplished to date. The objective here is the same as that used in non-deepwater subsea wells, namely, to locate within the failed deep-set tubing retrievable subsurface safety valve  105  a location (e.g.,  410 ) where a communication pathway may be opened with the hydraulic chamber (not shown) of the failed tubing-retrievable subsurface safety valve  105  such that hydraulic actuation fluids (not shown) may flow from the hydraulic chamber (not shown) of the failed tubing-retrievable subsurface safety valve  105  into to the hydraulic pathway of the deep-set wireline retrievable subsurface safety valve (not shown). A wireline-deployable communication tool  405  may be run into an interior diameter of the failed deep-set tubing-retrievable subsurface safety valve  105  and powered by an electric or e-line (not shown). As shown in the figure, the communication tool  405  may be lowered into the failed deep-set tubing-retrievable subsurface safety  105  and precisely located by locating off of a lock profile or no-go shoulder or a distance from a closed flapper (not shown). 
     Once properly located, the communication tool  405  may be turned on to remove material and form a radial cutout  410  that intersects at least one piston hole in the hydraulic chamber (not shown) of the failed deep-set tubing-retrievable subsurface safety valve  105 , thereby establishing communication to enable operation of an insert valve, such as a deep-set wireline-retrievable subsurface safety valve (not shown). Continuing,  FIG. 4B  shows a radial cutout  410  formed in an interior facing surface of the failed deep-set tubing-retrievable subsurface safety valve  105  providing access to the hydraulic chamber (not independently shown) in accordance with one or more embodiments of the present invention. In certain embodiments, the method of intervention further includes cutting or grinding a radial port in an interior facing portion of the failed deep-set tubing-retrievable subsurface safety valve with a wireline-deployable communication tool to communicate a hydraulic chamber (not independently illustrated) of the failed deep-set tubing-retrievable subsurface safety valve. Prior to running in the deep-set wireline-retrievable subsurface safety valve, other tools may be used to clear obstructions, polish the surfaces, or take other actions to facilitate landing the deep-set wireline-retrievable subsurface safety valve in a manner that minimizes damage and increases the likelihood of success. 
       FIG. 5  shows a block diagram of a deep-set wireline retrievable subsurface safety valve  500  for a failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ) in accordance with one or more embodiments of the present invention. A deep-set wireline retrievable subsurface safety valve  500  must be capable of being deployed in failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ) in a deepwater or ultra-deepwater subsea well and provide failsafe protection like any other subsurface safety valve. Specifically, the deep-set wireline retrievable subsurface safety valve must be capable of opening the flapper, valve, or closure device  510  upon application of hydraulic actuation pressure from the surface and fully closing when the hydraulic actuation pressure is sufficiently reduced or removed or other contingency arises. In order to achieve this functionality in deepwater and ultra-deepwater subsea wells, where existing wireline-retrievable subsurface safety valves are not capable of operating, the closure actuation mechanism  520  is disposed below the closure device  510  and the closure device  510  includes a pressure equalization feature. 
     Once communication is complete, a deep-set wireline-retrievable subsurface safety valve  500  is run into a central lumen of the failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105  of  FIG. 1  and  FIG. 2 ). The closure actuation mechanism  520  of the deep-set wireline retrievable subsurface safety valve  500  may be disposed below the closure device  510 . In certain embodiments, the closure actuation mechanism  520  comprises a pressure-balanced piston (not shown) that is exposed to wellbore fluids on both sides, or exposed distal ends, of the piston. Because closure actuation mechanism  520  is pressure-balanced and the energy to close the valve  500  is stored below the closure device  510 , the closing ability of valve  500  is tubing pressure insensitive, and capable of reliable operation at depth. In addition, closure device  510  comprises an equalization feature that equalizes pressure across the closure device to facilitate opening the valve  500  regardless of the hydrostatic head at the setting depth in deepwater or ultra-deepwater. 
     For purposes of illustration, an embodiment of a deep-set wireline-retrievable subsurface safety valve  500  is described herein. However, one of ordinary skill in the art, having the benefit of this disclosure, will appreciate that other designs that meet the above-noted requirements may be used in accordance with one or more embodiments of the present invention and their usage is contemplated by one or more methods of the claimed invention.  FIG. 6  shows a bottom facing perspective view of a portion of a deep-set wireline-retrievable subsurface safety valve  500  in accordance with one or more embodiments of the present invention. In one or more embodiments of the present invention, a deep-set wireline-retrievable subsurface safety valve  500  may include a locking mechanism (not shown) to secure deep-set wireline-retrievable subsurface safety valve  500  within an inner diameter of a failed deep-set tubing retrievable subsurface safety valve (e.g.,  105 ), an upper packing housing (not shown), an upper packing element (not shown) that may create an upper hydraulic seal on an annulus between the deep-set wireline-retrievable subsurface safety valve  500  above a hydraulic fluid intake port  608 , and a spacer  604 . One of ordinary skill in the art will recognize that the upper packing housing (not shown) and the upper packing element (not shown) may be substantially similar to that of lower packing housing  624  and lower packing element  620  described in more detail herein. Spacer  604  may include the hydraulic fluid intake port  608  that connects an exterior of spacer  604  to a central lumen, or passageway, disposed therein and have a length to dispose the hydraulic fluid intake port  608  below a flapper or valve (not shown) of the failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105 ) in which the deep-set wireline-retrievable subsurface safety valve  500  is disposed. The hydraulic fluid intake port  608  receives surface-injected hydraulic actuation fluid (not shown) from the annulus surrounding the safety valve  500  when deployed within the failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105 ). Deep-set wireline-retrievable subsurface safety valve  500  may also include lower packing element  620  to create a lower hydraulic seal on the annulus between deep-set wireline-retrievable subsurface safety valve  500  and the failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105 ) below hydraulic fluid intake port  608  and the flapper or valve (not shown) of the failed deep-set tubing-retrievable subsurface safety valve (e.g.,  105 ), a lower packing housing  624 , a seat housing  644 , a plurality of flow ports  648  disposed about the seat housing  644 , a hydraulic chamber housing  630 , a spring housing  690 , and a nose cap  698 . 
       FIG. 7  shows an exploded view of a portion of a deep-set wireline-retrievable subsurface safety valve  500  in accordance with one or more embodiments of the present invention. In one or more embodiments of the present invention, deep-set wireline-retrievable subsurface safety valve  500  may include a spacer  604  having a hydraulic fluid intake port  608  and a plurality of O-rings  612  and  616  that seal the connection between a lower packing housing  624  and spacer  604 . A lower packing element  620  covers a portion of lower packing housing  624  and a plurality of double O-rings  628  and  632  seal the connection interface between the lower packing housing  624  and seat housing  644 . A hard seat  636  and a soft seat  640  partially receive a ball  652 , which is one type of closure device (e.g.,  510  of  FIG. 5 ) contemplated herein. Seat housing  644  may include a plurality of flow ports  648 . One or more setting screws  654  may be disposed within ball  652 . Deep-set wireline-retrievable subsurface safety valve  500  may also include an upper retention screw  656 , an upper power seal  660 , a plurality of double O-rings  664  and  668  that seal the connection interface between hydraulic chamber housing  672  and seat housing  644 , a double O-ring  676  that seals the connection interface between hydraulic chamber housing  672  and spring housing  690 , a power piston  680 , an intermediate power seal  684 , an intermediate retention screw  686 , a spring ring  687 , a power spring  689 , a lower retention screw  692 , a lower power seal  694 , a double O-ring  696  that seals the connection interface between spring housing  690  and nose cap housing  698 , and a nose cap plug  699 , discussed in more detail herein. 
       FIG. 8A  shows a cross-sectional view of a portion of a deep-set wireline-retrievable subsurface safety valve  500  in accordance with one or more embodiments of the present invention. Spacer  604  may include a central lumen through which wellbore fluids (not shown) may flow when ball  652  valve is moved off soft seat  640 . A lower packing housing  625  may connect to spacer  604  and may include a first hydraulic fluid passage  610  to align with hydraulic fluid intake port  608  of spacer  604 . When hydraulic actuation fluid (not shown) is injected from the surface (not shown), hydraulic actuation fluid (not shown) may flow into the hydraulic fluid intake port  608 , through first hydraulic fluid passage  610  that traverses the hydraulic seal formed by the upper packing element (not shown) and lower packing element  620  into a second hydraulic fluid passage  611  and a third hydraulic fluid passage  613 . If sufficient hydraulic actuation pressure is provided, the hydraulic fluid exerts a downward force on a piston shoulder chamber  681  that causes power piston  680  to move down and compress power spring  689 , thereby moving ball  652  off soft seat  640  (not shown). 
     Continuing,  FIG. 8B  shows a cross-sectional view of a portion of deep-set wireline-retrievable subsurface safety valve  500  disposed within a failed deep-set tubing-retrievable safety valve  105  with a ball  652  valve in a closed state preventing flow in accordance with one or more embodiments of the present invention. In one or more embodiments of the present invention, deep-set wireline-retrievable subsurface safety valve  500  may be landed within a no-go shoulder profile of failed deep-set tubing-retrievable safety valve  105  (which is locked open and communicated prior to landing). A locking mechanism (not shown) may be used to secure deep-set wireline-retrievable subsurface safety valve  500  to failed deep-set tubing-retrievable subsurface safety valve  105 . An upper packing (not shown) and lower packing  620  may create a hydraulic seal in an annulus surrounding a portion of the deep-set wireline-retrievable subsurface safety valve  500 . A hydraulic fluid intake port  608  may receive hydraulic fluid in the annulus surrounding the deep-set wireline-retrievable subsurface safety valve  500  within the hydraulic seal from an FPSO disposed on a surface (not shown) of a body of water (not shown). The hydraulic actuation fluid (not shown) may be communicated via first hydraulic fluid passage  610 , second hydraulic fluid passage  611 , and third hydraulic fluid passage  613  disposed below the hydraulic seal to a piston shoulder chamber  681  and, if sufficient hydraulic actuation pressure is provided, may exert a downward force on piston shoulder chamber  681  that causes power piston  680  to move down and compress a power spring  689  disposed within an a gas chamber. A ball  652  valve may be disposed above the hydraulic chamber and may be connected to power piston  680 . Absent sufficient hydraulic actuation pressure, power spring  689  uncompresses and ball  652  is moved fully on soft seat  640  and hard seat  636 , thereby preventing formation fluids (not shown) from flowing toward the surface (not shown) through deep-set wireline-retrievable subsurface safety valve  500 . 
     Power spring  689  may be disposed within a gas chamber formed by spring housing  690 , intermediate power seal  684 , hydraulic chamber housing  672 , lower power seal  684 , and nose cap housing  698 . The gas chamber may be voided, filled with air, or charged with one or more gases, including potentially, nitrogen, although nitrogen charging is not required to uncompress power spring  689  at deepwater or ultra-deepwater depths. While upper power seal  660  and lower power seal  694  are in communication with production tubing pressure, both seals have the same diameter and are disposed on opposing ends of power piston  680 . As such, their pressure areas are the same and the forces acting on the power piston  680  effectively cancel each other out, thus power piston  680  is said to be pressure balanced. As such, power spring  689  may not be sensitive to production tubing pressure. Thus, the hydraulic actuation pressure required to compress power spring  689  may be substantially less than the production tubing pressure and when that actuation pressure is sufficiently reduced or removed, power spring  689  does not require nitrogen charging to uncompress and fully close deep-set wireline-retrievable subsurface safety valve  500  at a deepwater or ultra-deepwater depths. 
     Continuing,  FIG. 8C  shows a cross-sectional view of a portion of a deep-set wireline-retrievable subsurface safety valve  500  disposed within a failed deep-set tubing-retrievable subsurface safety valve  105  with a ball  652  valve in an opened state permitting production flow in accordance with one or more embodiments of the present invention. As previously discussed, failed deep-set tubing-retrievable subsurface safety valve  105  has been communicated (not shown) and flapper  204  is locked open. Deep-set wireline-retrievable subsurface safety valve  500  has been landed within a no-go shoulder or internal landing profile (not shown) of failed deep-set tubing-retrievable subsurface safety valve  105  and locked (not shown) or otherwise secured to failed deep-set tubing-retrievable subsurface safety valve  105 . An upper packing (not shown) element forms an upper hydraulic seal in the annulus between deep-set wireline-retrievable subsurface safety valve  500  and failed deep-set tubing-retrievable subsurface safety valve  105 . Lower packing element  620  forms a lower hydraulic seal in the annulus between deep-set wireline-retrievable subsurface safety valve  500  and failed deep-set tubing-retrievable subsurface safety valve  105 . The upper and lower hydraulic seals form a hydraulic seal. Hydraulic fluid (not shown) may be injected from the surface (not shown) via the puncture (not shown) into the annulus surrounding the deep-set wireline-retrievable subsurface safety valve  500  disposed between the upper and lower hydraulic seals. The injected hydraulic fluid (not shown) in the annulus enters the hydraulic fluid intake port  608  and flows through first hydraulic fluid passage  610 , second hydraulic fluid passage  611 , and third hydraulic fluid passage  613  to a piston shoulder chamber  681 . 
     Continuing,  FIG. 8D  shows a detailed portion of a cross-sectional view of a portion of a deep-set wireline-retrievable subsurface safety valve  500  disposed within a failed deep-set tubing-retrievable subsurface safety valve  105  with a ball  652  valve in an opened state permitting flow in accordance with one or more embodiments of the present invention. As shown in the detailed view, power piston  680  may be connected on a first distal end to ball  652  by one or more set screws  653  and on a second distal end to a nose cap housing (e.g.,  698  of  FIG. 8C ). Power piston  680  may extend through hydraulic chamber housing  672 . Spring ring  687  may be disposed on a top distal end of power spring  689 . Upper power seal  660  may seal an annulus surrounding power piston  680  and an upper portion of hydraulic chamber housing  672 . Upper power seal retainer  656  may retain upper power seal  660  in place. Intermediate power seal  684  may seal an annulus surrounding power piston  680  and a lower portion of hydraulic chamber housing  672 . Intermediate power seal retainer  686  may retain intermediate power seal  684  in place. As such, any pressure trapped between upper power seal  660  and intermediate power seal  684  forces power piston  680  down. If the hydraulic actuation fluid (not shown) is provided at the actuation pressure or higher, hydraulic fluid enters third hydraulic fluid passage  613  and piston shoulder chamber  681 , forcing power piston  680  down, compressing power spring  689 , and moving ball  652  off soft seat  640  and hard seat  636 . When ball  652  is off soft seat  640 , formation fluids in the annulus between spring housing  690  and production tubing  691  enter deep-set wireline-retrievable subsurface safety valve  500 . A plurality of flow ports  648  may allow fluid communication from the annulus surrounding the deep-set wireline-retrievable subsurface safety valve  500  below the hydraulic seal into a central lumen of the deep-set wireline-retrievable subsurface safety valve  500  that is exposed when ball  652  is moved off soft seat  640 . 
       FIG. 9A  shows a detailed portion of a perspective view of a ball  652  valve of a deep-set wireline-retrievable subsurface safety valve  500  on seat  640  in accordance with one or more embodiments of the present invention. Absent sufficient hydraulic actuation pressure, first hydraulic fluid passage (not shown), second hydraulic fluid passage  611 , third hydraulic fluid passage  613 , and piston shoulder chamber  681  may be voided. Continuing,  FIG. 9B  shows a detailed portion of a perspective view of a ball  652  valve of a deep-set wireline-retrievable subsurface safety valve  500  off seat  640  under actuation pressure in accordance with one or more embodiments of the present invention. When sufficient actuation pressure is applied, hydraulic fluid may be injected from the surface (not shown) into a hydraulic fluid intake port (not shown) and communicated via a first hydraulic fluid passage (not shown) disposed within the lower packing housing (not shown) to second hydraulic fluid passage  611  disposed within seat housing  644 . Second hydraulic fluid passage  611  may communicate hydraulic fluid to third hydraulic fluid passage  613  of hydraulic chamber housing  672 . Third hydraulic fluid passage  613  may communicate hydraulic fluid to piston shoulder chamber  681 . 
       FIG. 10A  shows a cross-sectional view of a closure device, such as, for example, ball  652  of a deep-set wireline-retrievable subsurface safety valve  500  in a closed state in accordance with one or more embodiments of the present invention. When deep-set wireline-retrievable subsurface safety valve  500  is in the closed state, ball  652  is on seat  636 , thereby preventing production flow through flow ports  648 . When the operator wishes to open valve  500 , hydraulic actuation pressure is communicated via the control line (not shown). As it begins to pressure up, production fluids  1005  may flow through flow ports  648  and into equalization ports  1010  to dart ports  1020  and then to the other side of closure device  652  via insert  1040  and insert equalization ports  1030 . Over time, this has the effect of equalizing the pressure from below the closure device  652  with the pressure above closure device  652 , thereby equalizing the pressure across it. Continuing,  FIG. 10B  shows a cross-sectional view of a closure device, such as, for example, ball  652  of a deep-set wireline-retrievable subsurface safety valve  500  in an open state in accordance with one or more embodiments of the present invention. As the hydraulic actuation pressure increases, and the pressure across the closure device  652  is equalized, closure device  652  moves off seat hard  636  and soft seat  640 , thereby enabling production flow through flow ports  648 . 
       FIG. 11  shows a light intervention vessel  305  performing a method of intervention in a failed deep-set tubing-retrievable subsurface safety valve  105  in a deepwater or ultra-deepwater subsea well  110  in accordance with one or more embodiments of the present invention. When a deep-set tubing-retrievable subsurface safety valve  105  disposed in a deepwater or ultra-deepwater well fails, for whatever reason, a light intervention vessel  305  may be brought onto the well site. The light intervention vessel  305  may establish access to the interior of the production tubing  140  disposed within subsea well  110  via a coiled-tubing, slickline, or wireline system. A wireline-deployable lockout tool or tools may be run in to an interior of the failed tubing-retrievable subsurface safety valve  105  to facilitate locking out the failed valve  105  in the open position. A wireline-deployable communication tool (not shown) may be run into the interior of the failed deep-set tubing-retrievable subsurface safety valve  105 . The communication tool may be precisely located to facilitate communicating the failed valve  105 . In certain embodiments, the communication tool may cut or grind a radial port into an interior facing portion of the failed deep-set tubing retrievable subsurface safety valve  105  to communicate a hydraulic chamber housing of the failed deep-set tubing-retrievable subsurface safety valve and potentially prepare the failed valve  105  to receive the deep-set wireline retrievable subsurface safety valve  500  (not shown). 
     Once locked out and communicated, a deep-set wireline retrievable subsurface safety valve  500  (not shown) may be run into a central lumen of the failed tubing-retrievable subsurface safety valve  105 . The deep-set wireline-retrievable subsurface safety valve  500  (not shown) may be landed within a no-go shoulder or other profile of the failed tubing-retrievable subsurface safety valve  105 . Once landed, the deep-set wireline-retrievable subsurface safety valve  500  (not shown) may be locked into place at a location within the failed tubing-retrievable subsurface safety valve  105  that facilitates communication with the hydraulic chamber of the failed tubing-retrievable subsurface safety valve  105 . Once installed, an FPSO  1100  may provide hydraulic actuation fluid from a surface-controlled pump system to the deep-set wireline-retrievable subsurface safety valve via a conduit that fluidly connects the wet tree  130  to the control line (not shown) of the failed deep-set tubing-retrievable subsurface safety valve  105 . Because deep-set wireline-retrievable subsurface safety valve  500  (not shown) includes a closure actuation mechanism that is disposed below the closure device, where the actuation mechanism includes a pressure-balanced piston that is exposed to wellbore fluids on both distal ends of the piston, and the closure device includes an equalization system that equalizes pressure across the closure device to facilitate opening, the deep-set wireline-retrievable subsurface safety valve is capable of operation at deepwater and ultra-deepwater depths. 
     Advantages of one or more embodiments of the present invention may include one or more of the following: 
     In one or more embodiments of the present invention, method of intervention in a failed deep-set tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well does not require re-completion of the well and substantially reduces non-productive downtime, lost profits, and costs associated with resuming production. Advantageously, the production tubing, including the failed deep-set tubing-retrievable subsurface safety valve, does not have to be pulled, dramatically simplifying operations and reducing costs. 
     In one or more embodiments of the present invention, method of intervention in a failed deep-set tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well may use a light intervention vessel rather than a conventional drilling rig, substantially expediting operations and reducing costs. 
     In one or more embodiments of the present invention, method of intervention in a failed deep-set tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well uses a deep-set wireline-retrievable subsurface safety valve having a closure actuation mechanism disposed below a closure device. 
     In one or more embodiments of the present invention, method of intervention in a failed deep-set tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well uses a deep-set wireline-retrievable subsurface safety valve having an actuation mechanism including a pressure-balanced piston that is exposed to wellbore fluids on both distal ends of the piston, thereby allowing the piston to actuate the closure device in deepwater and ultra-deepwater subsea wells with significant hydrostatic head. 
     In one or more embodiments of the present invention, method of intervention in a failed deep-set tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well uses a deep-set wireline-retrievable subsurface safety valve having a closure device that includes equalization means configured to equalize pressure across the closure device to facilitate opening the closure device. 
     In one or more embodiments of the present invention method of intervention in a failed deep-set tubing-retrievable subsurface safety valve disposed in a deepwater or ultra-deepwater subsea well establishes surface-control by communicating the hydraulic chamber housing of the failed deep-set tubing retrievable subsurface safety valve with the hydraulic chamber of the wireline-retrievable subsurface safety valve. 
     While the present invention has been described with respect to the above-noted embodiments, those skilled in the art, having the benefit of this disclosure, will recognize that other embodiments may be devised that are within the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the appended claims.