The present invention relates to devices used in artificial lift systems for producing oil and gas from wells drilled into the earth's crust. More specifically, the present invention relates to an apparatus for securing and releasing a plunger that enables a plunger-assisted artificial lift system.
Artificial lift systems are used to enable production of oil and gas from wells that, due to the removal of oil and gas from a subsurface hydrocarbon-bearing formation, lack the reservoir pressure to sustain continuous flow to surface production facilities and equipment. In one type of artificial lift system called the plunger lift system, gas is injected at the surface into an annulus intermediate the casing and a production tubing, and forced down the annulus to a set of perforations in the bottom of the production tubing to enter the production tubing and thereby lighten the column of fluid in the production tubing to promote the flow of the column of fluid to the surface. A plunger is disposed within the production tubing. A control valve is closed to prevent fluid from escaping the section of the production tubing. The fluid entering the production tubing from the formation and the gas injected into the annulus causes the pressure within the production tubing to increase, especially as gas bubbles migrate towards the lower pressure at the top of the production tubing. At a predetermined upper pressure threshold, or after a predetermined time period, the surface valve is opened to allow the pressurized fluid within the production tubing to escape the production tubing and to flow from the well, through the surface valve and to a flow line or a production storage tank. The plunger in the production tubing is carried to the surface as the fluid in the production tubing surges to the surface. The plunger acts like a piston as it travels to the surface to assist in displacing fluid from the production tubing. The plunger is captured and secured within the lubricator to remove it from the flowpath through which fluids move as they are released from the wellhead.
After the production tubing is depressurized, the surface valve is closed in preparation for another cycle. The plunger is released to sink within the production tubing. Formation fluids begin flowing into the production tubing and the cycle is then repeated.
Details relating to the plunger-assisted gas lift system can be found on a website operated by Kimray, Inc. at https://www.youtube.com/watch?v=ETixMStzlW0 and also in the published patent application, U.S. Patent Application Publication No. 2023/0019787. Various types of plungers can be used with embodiments of the apparatus of the present invention. The plunger-assisted gas lift system operates on a repeating cycle basis, the cycle length being determined by factors including the gas/oil ratio of the fluids entering the well at the geologic formation, the rate at which gas is injected into the annulus of the well, the level at which the gas in the annulus enters the production tubing to mix with the fluids from the geologic formation, the bottom hole pressure of the well and other factors.
One embodiment of the plunger catcher actuator of the present invention provides an apparatus to cooperate with a plunger-assisted gas lift system being used to produce fluids from a well drilled into the earth's crust and in communication within the earth's crust with a hydrocarbon-bearing subsurface geologic formation. The plunger catcher actuator is electrically-powered and includes an electric motor to extend a plunger rod outwardly and away from case of the actuator and, upon deactivation, to withdraw the plunger rod inwardly and into the case. A proximal end of the plunger rod is received through a wall of the case and into the interior of the case to couple with a rotatable output shaft of the electric motor through an intermediate linkage. A distal end of the plunger rod is connectable to a plunger catcher that is movable with the plunger rod outwardly away from the case with the plunger rod to engage and secure the plunger within or proximal to the lubricator, and then movable with the plunger rod inwardly towards the case with the plunger rod to disengage and release the plunger.
One embodiment of the plunger catcher actuator of the present invention that can be used with a plunger-assisted gas lift system comprises a case having a mounting member for coupling the case in a fixed position relative to a lubricator on a wellhead, the case having an aperture to receive a plunger rod, an electric motor connectable to a source of electrical current and an output shaft controllably rotatable by the electric motor. At least a portion of the output shaft is disposed within an interior space of the case, and that portion is coupled to a proximal end of a plunger rod. The actuator includes a current sensor to detect the current being provided to the electric motor and to generate a signal to a processor/controller corresponding to the sensed current. The processor/controller is activatable by a signal from a plunger sensor disposed within or proximal to the lubricator of the wellhead, and compares the signal from the current sensor to a set point. The processor/controller generates a control signal to the electric motor to generate a predetermined amount of torque to the output shaft. A lever arm is coupled to the output shaft of the electric motor at a first end of the lever arm, and coupled to the plunger rod at the second end of the lever arm. Upon activation of the motor by the processor/controller, rotation of the output shaft by the electric motor rotates the lever arm to extend the plunger rod outwardly from the case. The torque applied by the motor to the rotary shaft produces a predetermined amount of torque to the output shaft, and the electric motor continues to produce that amount of torque until the control signal is changed or interrupted.
In one embodiment of the plunger catcher actuator of the present invention, a motor enclosure that is connected to the case, and the electric motor may resides within the motor enclosure. The rotary shaft extends from the electric motor and penetrates a wall of the motor enclosure and an adjacent wall of the case. A shaft seal may be provided intermediate a wall of the case and the rotary shaft. Similarly, the case may include a seal disposed intermediate the plunger rod and a wall of the case. The seals prevent unwanted contaminants from entering the case and/or the motor enclosure. The case and/or the motor enclosure may be of an explosion proof construction. In one embodiment of the plunger catcher actuator of the present invention, the source of electrical current may be a battery, and the battery may be connected to at least one electrical current-generating solar panel exposed to sunlight to provide for recharging the battery.
An embodiment of a method of the present invention may enable reliable and efficient capturing and securing a plunger within a lubricator of a wellhead to enable the use of a plunger-assisted gas lift system, and may comprise the steps of providing a case connectable to the lubricator on a wellhead, the case having an aperture to receive a proximal end of a plunger rod, providing a motor coupled to a source of electrical current, the motor having a rotary shaft that is rotatable by the motor. The method may further include the step of providing a linkage intermediate the rotary shaft and the proximal end of the plunger rod received into the case to impart an actuating force to displace the plunger rod in an outwardly direction from the case. The method may further include the step of coupling a plunger catcher to a distal end of the plunger rod that is outside the case and in a position to be extended, upon activation of the motor, into the lubricator of the wellhead. The method may further include the step of providing a plunger sensor proximal to or within the lubricator and adjacent to the plunger catcher on the distal end of the plunger rod to generate a signal upon detection of the plunger within the lubricator, and the step of providing a processor/controller to control the amount of current provided by the source of electrical current to the motor upon receiving the signal from the plunger sensor indicating the arrival of the plunger within the lubricator. The plunger sensor, upon arrival of the plunger within the lubricator, generates a signal to the processor/controller which activates the motor by delivering a predetermined electrical current from the source of electrical current to the motor to drive the plunger rod outwardly from the case to engage the plunger catcher against the plunger, thereby securing the plunger within the lubricator.
One embodiment of the method of the present invention further includes the step of providing a pressure sensor to generate a signal to the processor/controller upon detection of a predetermined drop in pressure within the lubricator. Upon detection of the predetermined pressure threshold, the processor/controller activates the motor to turn the rotary shaft in an opposite direction to thereby retract the plunger rod inwardly into the case to move the plunger catcher away from the plunger to release the plunger.
One embodiment of the method of the present invention further includes the step of providing a timer to generate a signal to the processor/controller upon elapse of a predetermined time interval after an event such as, for example, opening of a control valve to unload the pressurized well or capture of the plunger within the lubricator. Upon detection of the elapse of the predetermined time period, the processor/controller activates the motor to turn the rotary shaft in an opposite direction to thereby retract the plunger rod inwardly into the case to move the plunger catcher away from the plunger to release the plunger.
One embodiment of the method of the present invention incudes the steps of providing a solar panel to generate electrical current, connecting the solar panel to a battery and connecting the battery to the motor to provide electrical current to operate the motor to move the plunger rod. The solar panel provides for efficient and reliable charging of a battery to energize the motor upon receiving a command signal from the processor/controller.
One embodiment of the method of the present invention includes the step of providing a motor enclosure adjacent to the case to enclose the motor and/or the processor/controller.
One embodiment of the method of the present invention includes the step of providing sealing elements round the plunger rod to isolate the case from pressurized fluids within the lubricator.
One embodiment of the method of the present invention includes the steps of determining the desired amount of force to be applied to the plunger rod to secure the plunger within the lubricator and determining the desired amount of torque to be imparted by the motor to the shaft to impart the desired amount of force to the plunger rod. A further step of the method may include determining the desired amount of electrical current to be provided to the motor to generate the desired amount of torque. The method may further include the steps of entering into the processor/controller a set point corresponding to the desired amount of electrical current to be provided to the motor and programming the processor/controller to deliver the desired amount of electrical current from the source of electrical current upon receiving the signal from the plunger sensor.
Eventually, after most of the injected gas, gas liberated from depressured formation fluid and the gas liberated from the formation fluids escape the well 110 through the control valve 132, the control valve 132 and the bypass valve 122 are restored to the closed position.
A wide variety of plungers that can be utilized with a plunger-assisted gas lift system can be made, and the present invention is directed to the assembly that can be used to capture the plunger upon detected entry into the lubricator of a wellhead and then to later release the plunger to sink downwardly within the bore of the production tubing to finally land on a seat at the bottom of the wellbore, and in that manner control the movement of plunger.
The present invention is directed to automated plunger catcher actuator that applies a predetermined amount of force to a plunger rod that is coupled to a plunger catcher disposed on a distal end of the plunger rod. The plunger rod penetrates the wall of the lubricator intermediate the interior space within the lubricator and the automated plunger actuator of the present invention.
The motor 34 is controlled by a processor/controller 38. The plunger sensor 117 (not shown in
The shaft 14 of
A wide variety of linkages can be used to coupled the rotatable shaft 14 to the plunger rod 50 to enable torque applied by the motor 34 to the shaft 14 to impart a predetermined amount of displacing force to the plunger rod 50. The linkage shown in
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components and/or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.
The corresponding structures, materials, acts, and equivalents of all means or steps plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
This application depends from and claims priority to U.S. Provisional Patent Application Ser. No. 63/347,109 filed on May 31, 2022, which application is incorporated by reference herein.
Number | Date | Country | |
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63347109 | May 2022 | US |