Patent Publication Number: US-2022220834-A1

Title: Electric Remote Operated Gas Lift Mandrel

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/137,723 filed Jan. 14, 2021 entitled, “Electric Remote Operated Gas Lift Mandrel,” the disclosure of which is incorporated by reference as if set forth in its entirety herein. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to the field of oil and gas production, and more particularly to a gas lift system that incorporates an improved gas lift module. 
     BACKGROUND 
     Gas lift is a technique in which pressurized gaseous fluids are used to reduce the density of the produced fluids to allow the formation pressure to push the less dense mixture to the surface. In annulus-to-tubing systems, pressurized gases are injected from the surface into the annulus, where the pressurized gases enter the tubing string through a series of gas lift valves. Alternatively, in tubing-to-annulus systems, pressurized gases are injected into the tubing string and discharged into the annulus, where the gases help to produce fluids out of the annulus. 
     The gas lift valves can be configured to automatically open when the pressure gradient between the annulus and the production tubing exceeds the closing force holding each gas lift valve in a closed position. In most installations, each of the gas lift mandrels within the gas lift system is deployed above a packer or other zone isolation device to ensure that liquids and wellbore fluids do not interfere with the operation of the gas lift valve. Increasing the pressure in the annular space above the packer will force the gas lift valves to open at a threshold pressure, thereby injecting pressured gases into the production tubing or the annulus. 
     To permit the unimpeded production of wellbore fluids through the production tubing, the gas lift valves are housed within “side pocket mandrels” that include a valve pocket that is laterally offset from the production tubing. Because the gas lift valves are contained in these laterally offset valve pockets, tools can be deployed and retrieved through the open primary passage of the side pocket mandrel. The predetermined position of the gas lift valves within the production tubing string controls the entry points for gas into the production string. 
     A common problem in gas lift completions is the management of interventions required to accommodate unforeseen well operations. For example, while setting packers and testing tubing by increasing the pressure within the annulus, “dummy” valves are typically installed within the side pocket mandrels to prevent flow of completion fluids from the annulus into the production tubing, or from the production tubing into the annulus. Once the packers have been set, the dummy valves are replaced with types of gas lift valves that permit flow into the production string from the annulus. 
     As another example, when it becomes necessary to unload the well, the gas lift valves must be closed as the fluid level in the well drops to prevent the gas within the annulus from escaping through an open gas lift valve. This requires operators to plan the unloading sequence and valve parameters for a specific well given a set of assumed production parameters within the well. Because the operation of gas lift valves cannot be easily adjusted once the gas lift valves have been installed, typical gas lift systems cannot be easily adapted to changing production parameters within the well. There is, therefore, a need for an improved gas lift system that overcomes these and other deficiencies in the prior art. 
     SUMMARY OF THE INVENTION 
     In one aspect, embodiments of the present disclosure are directed to a side pocket mandrel for use within a gas lift system deployed in a well that has an annular space surrounding the gas lift system. The side pocket mandrel includes a central body that includes a central bore, a gas lift valve pocket, a gas lift valve installed within the gas lift valve pocket, and a motorized choke valve assembly. The gas lift valve pocket is laterally offset from the central body and the gas lift valve pocket includes a gas lift valve port that communicates fluid from the annular space to the gas lift valve pocket. The motorized choke valve assembly includes an internal tubing port that extends from the central bore to the gas lift valve pocket, a valve member configured to selectively cover some or all of the internal tubing port, and an actuator configured to drive the valve member. 
     In another aspect, embodiments of the present disclosure are directed to a side pocket mandrel for use within a gas lift system deployed in a well that has an annular space surrounding the gas lift system. In these embodiments, the side pocket mandrel includes a central body that includes a central bore, a gas lift valve pocket that is laterally offset from the central body, an internal tubing port that extends from the central bore to the gas lift valve pocket, an automatic closing valve assembly, and a gas lift valve. The gas lift valve pocket includes a gas lift valve port that communicates fluid from the annular space to the gas lift valve pocket. The automatic closing valve assembly includes a floating piston configured to move between a retracted position that permits flow through the gas lift valve port and a deployed position that prevents flow through the gas lift valve port, and a spring configured to apply a force to urge the floating piston into the deployed position. The gas lift valve forces the floating piston into the retracted position when the gas lift valve is installed within the gas lift valve pocket. 
     In yet another aspect, embodiments of the present disclosure are directed to a method of operating a gas lift system deployed in a well that has an annular space surrounding the gas lift system, where the gas lift system includes a gas lift module with a central body and a side pocket mandrel that includes a gas lift valve that controls the movement of fluids either: (i) from the annular space into the gas lift valve pocket through a gas lift valve port; or (ii) from the production tubing into the annular space through the gas lift valve port. The method includes the steps of blocking an internal tubing port that extends between a central bore in the central body and the gas lift valve pocket, increasing the pressure in the annulus or production tubing, unblocking the internal tubing port to create a pressure differential across the gas lift valve that forces the gas lift valve into an open position, and permitting pressurized gas to pass through the gas lift valve port and the internal tubing port. 
     In yet another aspect, embodiments of the present disclosure are directed to a method of operating a gas lift system deployed in a well that has an annular space surrounding the gas lift system, where the gas lift system includes a gas lift module with a central body and a side pocket mandrel that includes a gas lift valve that controls the movement of fluids from the annular space into the gas lift valve pocket through a gas lift valve port. In these embodiments, the method includes the steps of providing an automatic closing valve assembly within the side pocket mandrel, removing the gas lift valve from the gas live valve pocket, and deploying the automatic closing valve assembly to close the gas lift valve port. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a gas lift system deployed in a conventional well. 
         FIG. 2  is a side view of a side pocket mandrel constructed in accordance with an embodiment of the invention. 
         FIG. 3  is a side cross-sectional view of the side pocket mandrel, gas lift valve and electric choke in a closed position. 
         FIG. 4  is a side cross-sectional view of a first embodiment of the side pocket mandrel, gas lift valve and electric choke in an open position. 
         FIG. 5  is a side cross-sectional view of the side pocket mandrel, gas lift valve and electric choke of  FIG. 4  in a partially open position. 
         FIG. 6  is a side cross-sectional view of a second embodiment of the side pocket mandrel, gas lift valve and electric choke in an open position. 
         FIG. 7  is a side cross-sectional view of the side pocket mandrel, gas lift valve and electric choke of  FIG. 6  in a partially open position. 
         FIG. 8  provides a cross-sectional view of an embodiment of the gas lift module that includes an automatic closing assembly in a retracted position. 
         FIG. 9  provides a cross-sectional view of an embodiment of the gas lift module that includes an automatic closing assembly in a deployed position. 
     
    
    
     WRITTEN DESCRIPTION 
     As used herein, the term “petroleum” refers broadly to all mineral hydrocarbons, such as crude oil, gas and combinations of oil and gas. The term “fluid” refers generally to both gases and liquids, and “two-phase” or “multiphase” refers to a fluid that includes a mixture of gases and liquids. “Upstream” and “downstream” can be used as positional references based on the movement of a stream of fluids from an upstream position in the wellbore to a downstream position on the surface. Although embodiments of the present invention may be disclosed in connection with a conventional well that is substantially vertically oriented, it will be appreciated that embodiments may also find utility in horizontal, deviated or unconventional wells. 
     Turning to  FIG. 1 , shown therein is a gas lift system  100  disposed in a well  102 . The well  102  includes a casing  104  and a series of perforations  106  that admit wellbore fluids from a producing geologic formation  108  through the casing  104  into the well  102 . An annular space  110  is formed between the gas lift system  100  and the casing  104 . The gas lift system  100  is connected to production tubing  112  that conveys produced wellbore fluids from the formation  108 , through the gas lift system  100 , to a wellhead  114  on the surface. 
     The gas lift system  100  includes one or more gas lift modules  116 . The gas lift modules  116  each include a side pocket mandrel  118 , which may be connected to a pup joint  120 . An inlet pipe  122  extends through one or more packers  124  into a lower zone of the well  102  closer to the perforations  106 . In this way, produced fluids are carried through the inlet pipe  122  into the lowermost (upstream) gas lift module  116 . The produced fluids are carried through the gas lift system  100  and the production tubing  112 , which conveys the produced fluids through the wellhead  114  to surface-based storage or processing facilities. 
     In accordance with well-established gas lift principles, pressurized fluids or gases are injected from a gas supply  200  on the surface into the annular space  110  surrounding the gas lift system  100 . When the pressure gradient between the annular space  110  and the interior of the production tubing  112  exceeds a threshold value, the gas lift modules  116  admit the pressurized gases into the production tubing  112  through the side pocket mandrel  118 . The pressurized gases combine with the produced fluids in the gas lift modules  116  to reduce the overall density of the fluid, which facilitates the recovery of the produced fluids from the well  102 . The gas lift system  100  may find utility in recovering liquid and multiphase hydrocarbons, as well as in unloading water-based fluids from the well  102 . 
     Turning to  FIGS. 2-5 , shown therein are various depictions of the gas lift module  116 . As best illustrated in the cross-sectional views in  FIGS. 3-5 , the side pocket mandrel  118  includes a central body  126  and a gas lift valve pocket  128  within the side pocket mandrel  118 . The central body  126  includes a central bore  130 . The gas lift valve pocket  128  laterally offset and separated from the central bore  130 . The side pocket mandrel  118  includes a gas lift valve  132  within the gas lift valve pocket  128 . The gas lift valve  132  controls the passage of fluids from the annulus through a gas lift valve port  134  in response to pressure in the annulus  110  that exceeds the threshold opening pressure for the gas lift valve  132 . For tubing-to-annulus systems, the gas lift valve  132  controls the passage of fluids from the production tubing  112  to the annular space  110 . 
     When the gas lift valve  132  opens, fluid from the annulus  110  is admitted through the gas lift valve port  134  into the side pocket mandrel  118 . In typical side pocket mandrels, the pressurized fluid is directed from the gas lift valve pocket  128  into the central bore  130 , where it joins fluids produced from the perforations  106 . Unlike prior art gas lift modules, the gas lift module  116  includes a motorized choke valve assembly  136  that is connected to the gas lift valve pocket  128 . The motorized choke valve assembly  136  includes an internal tubing port  138  extending between the gas lift valve pocket  128  and the central bore  130 , a valve member  140 , an actuator  142 , a communications module  144 , and a power source  146 . 
     In exemplary embodiments, the actuator  142  is an electric motor that controllably deploys or retracts the valve member  140  relative the internal tubing port  138  to place the motorized choke valve assembly  136  in a closed position ( FIG. 3 ), an open position ( FIG. 4 ), or a partially opened position ( FIG. 5 ). The actuator  142  can drive the valve member  140  through a solenoid mechanism, a rotating mechanism in which the valve member  140  includes a threaded shaft, or any other linear actuating mechanism that permits the valve member  140  to be precisely positioned with respect to the internal tubing port  138 . It will be appreciated that the valve member  140  can be constructed as a simple piston that is sized and configured to block the internal tubing port  138 , or as an element that includes internal passages that only permit flow through the internal tubing port  138  when the passages are aligned with the internal tubing port  138  through, for example, axial or rotational alignment. 
     The actuator  142  operates in response to a command signal issued by the communications module  144 . The communications module  144  can be configured to receive control signals from the surface or other downhole equipment using standard downhole communication protocols and modalities, including wireless RF, acoustic (pressure pulse) and wired. The communications module  144  is configured to receive a control signal, process the control signal, and output a command signal to the actuator  142  in response to the control signal. In exemplary embodiments, the gas lift system  100  includes a plurality of gas lift modules  116 , which each include a motorized choke valve assembly  136  that can be independently controlled apart from the other motorized choke valve assemblies  136  within the gas lift system  100 . This permits the operator to selectively place one or more of the plurality of gas lift modules  116  in an open state while keeping the remaining gas lift modules  116  in a closed state. 
     The communications module  144  and actuator  142  are provided with power from the power source  146 . In exemplary embodiments, the power source  146  is a battery that is sufficiently charged before the gas lift module  116  is installed to carry out the planned operations. In other embodiments, the power source  146  includes a battery that can be remotely charged from the surface or through other wellbore equipment. Although exemplary embodiments of the motorized choke valve assembly  136  include an electric motor and electric battery, it will be appreciated that in other embodiments the actuator  142  and power source  146  are based on hydraulic, pneumatic, or a combination of hydraulic, pneumatic and electric systems. 
     In an exemplary method of operation, the motorized choke valve assembly  136  is moved into a closed position by sending a signal to the communications module  144  to close the internal tubing port  138  with the valve member  140 . Once the internal tubing port  138  has been closed by the valve member  140 , gases from the annular space  110  cannot pass through the internal tubing port  138  to the central bore  130 . Once the trapped pressure within gas lift valve pocket  128  has equalized with the pressure in the annular space  110 , the gas lift valve  132  may close. For example, while setting the packer  124 , it may be desirable to close the motorized choke valve assemblies  136  in all of the gas lift modules  116  so that maximum fluid pressure can be applied to the packer  124  through the annular space  110 . 
     When it becomes desirable to allow fluids from the annular space  110  to enter the production tubing  112  through the gas lift module  116 , the motorized choke valve assembly  136  can be placed into an open state by sending a signal to the communications module  144  to fully or partially retract the valve member  140  from the internal tubing port  138 . Once the gas lift valve  132  has been opened by pressure within the annular space  110 , the fluids are then permitted to pass through the gas lift valve pocket  128  into the central bore  130  through the internal tubing port  138 . It will be appreciated that the motorized choke valve assembly  136  can be opened before or after gases are injected into the annular space  110  to open the gas lift valve  132 . Although the embodiment depicted in  FIGS. 4-5  has been illustrated and described in connection with an annulus-to-tubing system, the same embodiment can also be used in connection with a tubing-to-annulus system in which pressurized gas is injected into the production tubing  112  and discharged through the gas lift module  116  into the annular space  110 . 
     The ability to selectively enable and disable the gas lift valve  132  with the motorized choke valve assembly  136  significantly improves the versatility of the gas lift system  100  by allowing the operator to respond to a condition in which preventing the flow of fluids between the gas lift valve pocket and the central bore is desirable. For example, while the well  102  is being unloaded of excess fluid in the annular space  110 , the motorized choke valve assembly  136  can be activated to selectively disable the gas lift valve  132  in a gas lift module  116  that is no longer under the liquid level in the annular space  110 . Without the ability to selectively disable the gas lift valve  132  within the gas lift module  116 , pressure within the annular space  110  would tend to escape through the “dry” gas lift module  116 , thereby decreasing the efficiency of the unloading operation. In this way, the motorized choke valve assembly  136  enables the operator to only open those gas lift modules  116  that are useful in unloading the well  102 . 
     Thus, the remotely actuated motorized choke valve assembly  136  provides the operator with more precise control of individual gas lift modules  116  within the gas lift system  100  without the need for complicated pre-installation configurations of multiple gas lift valves  132  within the gas lift system  100 . Additionally, this provides the operator with the ability to respond to unforeseen conditions that develop in the well  102  after the gas lift system  100  has been installed, without the need to remove the gas lift system  100  or carry out disruptive and expensive interventions while the gas lift system  100  is in the well  102 . Instead of removing the gas lift valve  132  to change the size or type of the gas lift valve  132  to be installed in the gas lift valve pocket  128 , the motorized choke valve assembly  136  can be activated to increase or reduce flow through the side pocket mandrel  118 . 
     In a second embodiment depicted in  FIGS. 5-6 , the motorized choke valve assembly  136  includes an onboard computer  156  and one or more sensors  158 . The onboard computer can be powered by the power source  146  and configured to automatically control the operation of the motorized choke valve assembly  136  in response to measurements made by the sensors  158 . The sensors  158  can be configured to measure conditions at or near the gas lift module  116 . In some embodiments, the sensors  158  are configured to determine the pressure differential between the production tubing  112  and the annular space  110  and output representative signals to the onboard computer  156 . The onboard computer  156  is programmed to process the signals generated by the sensors  158  and apply a responsive control scheme for the motorized choke valve assembly  136 . It will be noted that  FIGS. 6 and 7  depict a tubing-to-annulus system in which pressurized gas is injected into the production tubing  112  and discharged through the gas lift module  116  into the annular space  110 . The embodiment depicted in  FIGS. 6-7  can also be used with annulus-to-tubing systems (as depicted in  FIGS. 4-5 ). 
     Turning to  FIGS. 8 and 9 , shown therein are cross-sectional views of the side pocket mandrel  118  constructed in accordance with an additional embodiment of the present invention. As depicted in  FIGS. 6 and 7 , the side pocket mandrel  118  includes an automatic closing valve assembly  148  that prevents flow through the side pocket mandrel  118  when then the gas lift valve  132  is removed from the side pocket mandrel  118 . The automatic closing valve assembly  148  includes a floating piston  150  that includes a through-passage  152 . The automatic closing valve assembly  148  includes a spring  154  that presses the floating piston  150  against the gas lift valve  132 . 
     The automatic closing valve assembly  148  is installed within the gas lift valve pocket  128  prior to deploying the gas lift module  116  into the well  102 . When the gas lift valve  132  is installed within the gas lift valve pocket  128  (as depicted in  FIG. 6 ), the gas lift valve  132  pushes the floating piston  150  into a retracted position against the force applied by the spring  154 . When the gas lift valve  132  opens in response to a sufficient pressure differential, fluid from the annular space  110  is allowed to travel through the gas lift valve port  134 , through the gas lift valve  132 , through the through-passage  152  of the floating piston  150 , and into the central bore  130  of the gas lift module  116  through the internal tubing port  138 . The latch mechanism that holds the gas lift valve  132  within the gas lift valve pocket  128  prevents the gas lift valve  132  from being pushed out of the gas lift valve pocket  128  by the spring  154 . 
     When the gas lift valve  132  is removed, the spring  154  forces the floating piston  150  into a deployed position depicted in  FIG. 7 . In the deployed position, the floating piston  150  blocks the gas lift valve port  134  to prevent flow of gases or fluids from the annular space  110  into the gas lift module  116 . At the same time, the automatic closing valve assembly  148  prevents the unintended escape of production fluids passing through the gas lift module  116  by closing the external gas lift valve ports  134  that would otherwise place the interior of the side pocket mandrel  118  to the annular space  110 . Although the embodiment depicted in  FIGS. 8-9  has been illustrated and described in connection with an annulus-to-tubing system, the same embodiment can also be used in connection with a tubing-to-annulus system in which pressurized gas is injected into the production tubing  112  and discharged through the gas lift module  116  into the annular space  110 . 
     It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and functions of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. It will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other systems without departing from the scope and spirit of the present invention.