The field of the invention relates generally to controlling gas lift wells, and more specifically, to methods and a system for controlling a gas lift well to enhance the flow of fluid and gas induced by gas lift.
Gas lift uses the injection of gas into a production well to increase the flow of liquids, such as crude oil or water, from the production well. Gas is injected down the casing and ultimately into the tubing of the well at one or more downhole locations to reduce the weight of the hydrostatic column. This effectively reduces the density of the fluid in the well and further reduces the back pressure, allowing the reservoir pressure to lift the fluid out of the well. As the gas rises, the bubbles help to push the fluid ahead. The produced fluid can be oil, water, or a mix of oil and water, typically mixed with some amount of gas.
The gas lift operations are exposed to a wide range of conditions. These vary by well location, reservoir types, etc. Furthermore, well conditions, such as downhole pressure, may change over time. Therefore ideal operating condition of the well may change over time. These conditions may cause variability in the flow of the fluid. These changes in conditions may reduce the efficiency and production of the gas lift well. Further, some gas lift wells may be in remote areas requiring significant effort for personnel to travel to.
In one aspect, a system for enhancing a flow of a fluid induced by a gas lift system is provided. The system includes one or more sensors configured to monitor one or more conditions of the gas lift system and generate signals representing measured data based on the one or more conditions. The system also includes a gas lift control unit comprising a processor and a memory coupled to the processor. The gas lift control unit in communication with that one or more sensors and is configured to control a flow of gas injected in a well by the gas lift system, thereby controlling the flow of the fluid induced by the gas lift system. The gas lift control unit is configured to (a) receiving signals representing measured data from the one or more sensors. The gas lift control unit is also configured to (b) calculating a desired gas injection rate and its associated flow of fluid based, at least in part, on the measured data. The gas lift control unit is further configured to (c) regulating at least one operating characteristic of a compressor associated with the gas lift system based, at least in part, on the desired gas injection rate. Moreover, the gas lift control unit is configured to (d) receiving measured data representing production data. In addition the gas lift control unit is configured to (e) determining a subsequent adjustment based on a comparison of the desired flow of fluid and the production data.
In a further aspect, a computer-based method for enhancing a flow of a fluid induced by a gas lift system is provided. The method is implemented using a gas lift control unit including at least one processor in communication with a memory. The method includes (a) receiving signals representing measured data from one or more sensors. The one or more sensors are configured to monitor one or more conditions of the gas lift system and generate signals representing measured data based on the one or more conditions. The method also includes (b) calculating a desired gas injection rate and its associated flow of fluid based, at least in part, on the measured data. The method further includes (c) regulating at least one operating characteristic of a compressor associated with the gas lift system based, at least in part, on the desired gas injection rate. Moreover, the method includes (d) receiving measured data representing production data. In addition, the method includes (e) determining a subsequent adjustment based on a comparison of the desired flow of fluid and the production data.
In another aspect, a computer-readable storage device having processor-executable instructions embodied thereon for enhancing a flow of a fluid induced by a gas lift system is provided. When executed by a gas lift control unit communicatively coupled to a memory, the processor-executable instructions cause the gas lift control unit to (a) receive signals representing measured data from one or more sensors. The one or more sensors are configured to monitor one or more conditions of the gas lift system and generate signals representing measured data based on the one or more conditions. The processor-executable instructions also cause the gas lift control unit to (b) calculate a desired gas injection rate and its associated flow of fluid based, at least in part, on the measured data. The processor-executable instructions further cause the gas lift control unit to (c) regulate at least one operating characteristic of a compressor associated with the gas lift system based, at least in part, on the desired gas injection rate. Moreover, the processor-executable instructions cause the gas lift control unit to (d) receive measured data representing production data. In addition, the processor-executable instructions cause the gas lift control unit to (e) determine a subsequent adjustment based on a comparison of the desired flow of fluid and the production data.
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.
In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.
The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that may permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
As used herein, the terms “processor” and “computer” and related terms, e.g., “processing device”, “computing device”, and “controller” are not limited to just those integrated circuits referred to in the art as a computer, but broadly refers to a microcontroller, a microcomputer, a programmable logic controller (PLC), a programmable logic unit (PLU), an application specific integrated circuit, and other programmable circuits, and these terms are used interchangeably herein. In the embodiments described herein, memory may include, but is not limited to, a computer-readable medium, such as a random access memory (RAM), and a computer-readable non-volatile medium, such as flash memory. Alternatively, a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), and/or a digital versatile disc (DVD) may also be used. Also, in the embodiments described herein, additional input channels may be, but are not limited to, computer peripherals associated with an operator interface such as a mouse and a keyboard. Alternatively, other computer peripherals may also be used that may include, for example, but not be limited to, a scanner. Furthermore, in the exemplary embodiment, additional output channels may include, but not be limited to, an operator interface monitor.
Further, as used herein, the terms “software” and “firmware” are interchangeable, and include any computer program stored in memory for execution by personal computers, workstations, clients and servers.
As used herein, the term “non-transitory computer-readable media” is intended to be representative of any tangible computer-based device implemented in any method or technology for short-term and long-term storage of information, such as, computer-readable instructions, data structures, program modules and sub-modules, or other data in any device. Therefore, the methods described herein may be encoded as executable instructions embodied in a tangible, non-transitory, computer readable medium, including, without limitation, a storage device and a memory device. Such instructions, when executed by a processor, cause the processor to perform at least a portion of the methods described herein. Moreover, as used herein, the term “non-transitory computer-readable media” includes all tangible, computer-readable media, including, without limitation, non-transitory computer storage devices, including, without limitation, volatile and nonvolatile media, and removable and non-removable media such as a firmware, physical and virtual storage, CD-ROMs, DVDs, and any other digital source such as a network or the Internet, as well as yet to be developed digital means, with the sole exception being a transitory, propagating signal.
Furthermore, as used herein, the term “real-time” refers to at least one of the time of occurrence of the associated events, the time of measurement and collection of predetermined data, the time to process the data, and the time of a system response to the events and the environment. In the embodiments described herein, these activities and events occur substantially instantaneously.
The method and systems described herein provide for managing and enhancing the operation of a gas lift system at a well. Furthermore, the method and systems described herein facilitate more efficient operation of a gas lift system to rapidly respond to changes in conditions of the well. These methods and systems facilitate regulating multiple characteristics of a gas lift system to enhance the amount of time that the gas lift system is operating at peak efficiency based on current and potentially changing well conditions. Also, the system and methods described herein are not limited to any single type of gas lift system or type of well, but may be implemented with any gas lift system that is configured as described herein. For example, the method and systems described herein may be used with any other device capable of producing fluids using a gas lift system. By constantly monitoring conditions in real-time and regulating the operation of the gas lift system based on the conditions, the system and method described herein facilitates more efficient operation of gas lift systems while facilitating consistent and enhanced production.
At the top of well 104, flow tube pressure sensor 118 measures the wellhead tubing pressure. A flow line 120 channels fluids 110 to a separator 122. Separator 122 separates fluid 110 into gas 124, oil, 126, and water 128. Oil 126 is removed by separator 122 and the amount of oil retrieved is metered by oil meter 130. Water 128 is also removed by separator 122 and the amount of water retrieved is metered by water meter 132. Gas 124 is siphoned out of separator 122 through gas line 134. In some embodiments, multi-phase flow meter 136 replaces oil meter 130 and water meter 132. In these embodiments, multi-phase flow meter 136 is used to measure production. Some gas 124 is transferred to a gas pipeline 140 through a gas production meter 138. In the exemplary embodiment, some gas 124 is transferred to a compressor 148 though a flow line 146.
In some embodiments, such as when there is not enough gas pressure to inject into well 104, gas 124 may be obtained and purchased from gas pipeline 140 through a buy back valve 144 and measured by a buy back meter 142. This may occur also when initially placing well 104 into service or restarting well 104 after down time.
Gas 124 enters compressor 148 through compressor suction valve 154. In the example embodiment, compressor 148 includes compressor motor 150. Compressor 148 compresses gas 124. Compressor controller 152 regulates the speed of compressor motor 150. In some embodiments, the speed of compressor motor 150 is measured in regulating the revolutions per minute (RPM) of compressor motor 150. Compressor back pressure valve 156 ensures sufficient discharge pressure for the well and recycles excessive gas back to the compressor suction valve 154. Compressor recycle valve 158 is an overflow valve that reintroduces gas 124 above a certain pressure back into compressor 148 through compressor suction valve 154. Gas 124 flows from compressor 148 to well 104. The amount of gas that is injected into well 104 is measured by gas injection meter 109.
During normal operation of gas lift system 100, gas 124 is compressed by compressor 148. The amount of gas 124 injected into well 104 is controlled by gas injection control valve 102 and measured by gas injection meter 109. In well 104, gas 124 mixes with fluids 110. The mixture of fluids 110 and gas 124 is pushed up through tubing 114 to the top of well 104 by reservoir pressure 112. The mixture of gas 124 and fluids 110 travels through flow line 120 into separator 122, where fluids 110 and gas 124 are separated. A quantity of gas 124 is routed back to compressor 148 to be reinjected into well 104. Excess gas 124 is routed to gas pipeline 140 to be sold or otherwise used elsewhere. In some embodiments, some gas 124 is used to power compressor motor 150.
Sensors 205 are in communication with a gas lift control unit 210. Sensors 205 couple to gas lift control unit 210 through interfaces including, without limitation, a network, such as a local area network (LAN) or a wide area network (WAN), dial-in-connections, cable modems, Internet connection, wireless, and special high-speed Integrated Services Digital Network (ISDN) lines. Sensors 205 receive data about gas lift system 100 operating conditions and report those conditions to gas lift control unit 210. Sensors 205 may include, but are not limited to, injection temperature sensor 106, injection pressure sensor 108, gas injection meter 109, downhole sensors 117, flow tube pressure sensor 118, oil meter 130, water meter 132, multi-phase flow meter 136, gas production meter 138, and buy back meter 142 (all shown in
Gas lift control unit 210 is in communication with compressor controller 152 (shown in
Gas lift control unit 210 is in communication with a plurality of control valves 225. Control valves 225 regulate the various valves in gas lift system 100. In the exemplary embodiment, a control valve 225 regulates the gas injection rate through gas injection rate control valve 102 (shown in
A database server 215 is coupled to database 220, which contains information on a variety of matters, as described below in greater detail. In one embodiment, centralized database 220 is stored on gas lift control unit 210. In an alternative embodiment, database 220 is stored remotely from gas lift control unit 210 and may be non-centralized. In some embodiments, database 220 includes a single database having separated sections or partitions or in other embodiments, database 220 includes multiple databases, each being separate from each other. Database 220 stores condition data received from multiple sensors 205. In addition, and without limitation, database 220 stores constraints, component data, component specifications, equations, and historical data generated as part of collecting condition data from multiple sensors 205.
In some embodiments, gas lift control unit 210 is in communication with a client device 230, also known as a client system 230. Gas lift control unit 210 couples to client device 230 through many interfaces including, without limitation, a network, such as a local area network (LAN) or a wide area network (WAN), dial-in-connections, cable modems, Internet connection, wireless, and special high-speed Integrated Services Digital Network (ISDN) lines. In these embodiments, gas lift control unit 210 transmits data about the operation of gas lift system 100 to client device 230. This data includes, without limitation, data from sensors 205, current RPM, the status of various valves, and other operational data that client device 230 is configured to monitor. Furthermore, gas lift control unit 210 is configured to receive additional instructions from client device 230. Additionally, client device 230 is configured to access database 220 through gas lift control unit 210. Client device 230 is configured to present the data from gas lift control unit 210 to a user. In other embodiments, gas lift control unit 210 includes a display unit (not shown) to display data directly to a user.
User computer device 302 also includes at least one media output component 315 for presenting information to user 301. Media output component 315 is any component capable of conveying information to user 301. In some embodiments, media output component 315 includes an output adapter (not shown) such as a video adapter and/or an audio adapter. An output adapter is operatively coupled to processor 305 and operatively coupleable to an output device such as a display device (e.g., a cathode ray tube (CRT), liquid crystal display (LCD), light emitting diode (LED) display, or “electronic ink” display) or an audio output device (e.g., a speaker or headphones). In some embodiments, media output component 315 is configured to present a graphical user interface (e.g., a web browser and/or a client application) to user 301. A graphical user interface may include, for example, a dashboard for monitoring sensor measurements, a control screen for controlling operation of user computer device 302, and/or an update screen for updating software in user computer device 302. In some embodiments, user computer device 302 includes an input device 320 for receiving input from user 301. User 301 may use input device 320 to, without limitation, select and/or enter one or more sensor measurements to view. Input device 320 may include, for example, a keyboard, a pointing device, a mouse, a stylus, a touch sensitive panel (e.g., a touch pad or a touch screen), a gyroscope, an accelerometer, a position detector, a biometric input device, and/or an audio input device. A single component such as a touch screen may function as both an output device of media output component 315 and input device 320.
User computer device 302 may also include a communication interface 325, communicatively coupled to a remote device such as gas lift control unit 210 (shown in
Stored in memory area 310 are, for example, computer-readable instructions for providing a user interface to user 301 via media output component 315 and, optionally, receiving and processing input from input device 320. The user interface may include, among other possibilities, a web browser and/or a client application. Web browsers enable users, such as user 301, to display and interact with media and other information typically embedded on a web page or a website from gas lift control unit 210. A client application allows user 301 to interact with, for example, gas lift control unit 210. For example, instructions may be stored by a cloud service and the output of the execution of the instructions sent to the media output component 315.
Processor 405 is operatively coupled to a communication interface 415 such that server computer device 401 is capable of communicating with a remote device such as another server computer device 401, client systems 230, sensors 205, control valves 225, compressor controller 152, or gas lift control unit 210 (all shown in
Processor 405 may also be operatively coupled to a storage device 434. Storage device 434 is any computer-operated hardware suitable for storing and/or retrieving data, such as, but not limited to, data associated with database 220 (shown in
In some embodiments, processor 405 is operatively coupled to storage device 434 via a storage interface 420. Storage interface 420 is any component capable of providing processor 405 with access to storage device 434. Storage interface 420 may include, for example, an Advanced Technology Attachment (ATA) adapter, a Serial ATA (SATA) adapter, a Small Computer System Interface (SCSI) adapter, a RAID controller, a SAN adapter, a network adapter, and/or any component providing processor 405 with access to storage device 434.
Processor 405 executes computer-executable instructions for implementing aspects of the disclosure. In some embodiments, processor 405 is transformed into a special purpose microprocessor by executing computer-executable instructions or by otherwise being programmed. For example, processor 405 is programmed with the instructions such as are illustrated in
In the exemplary embodiment, gas lift control unit 210 receives 502 signals representing measured data from one or more sensors 205 (shown in
Gas lift control unit 210 calculates 504 a desired gas injection rate and its associated flow of fluid 110 based, at least in part, on the measured data. In the exemplary embodiment, measured data is based on current conditions in well 104. These conditions may change over time, and accordingly the desired flow of fluid 110 may also change overtime. Step 504 facilitates gas lift control unit 210 constantly updating the enhanced flow rate based on current well conditions. In some embodiments, gas lift control unit 210 analyzes measured data over a period of time to calculate 504 the desired gas injection rate and desired flow of fluid 110.
Gas lift control unit 210 regulates 506 (also known as adjusting or changing) at least one operating characteristic of compressor 148 (shown in
Gas lift control unit 210 receives 508 additional measured data including production data. For example, gas lift control unit 210 receives 508 the production data from flow tube pressure sensor 118, oil meter 130, water meter 132, multi-phase flow meter 136, and/or gas production meter 138. In some embodiments, gas lift control unit 210 analyzes measured data over a period of time to compare 506 to the desired flow of fluid 110. In some embodiments, gas lift control unit 210 instructs that an amount of gas 124 to be injected into well 104 while receiving production data. The amount of gas 124 may vary depending on the current implementation and settings. In some embodiments, gas lift control unit 210 generates a comparison between the production data and the desired flow of fluid 110. Gas lift control unit 210 determines 510 a subsequent adjustment to gas lift system 100 based on the comparison between the desired flow of fluid 110 and the received production data 510. For example, gas lift control unit 210 may determine 510 to increase the RPM of compressor 148. In another example, gas lift control unit 210 may determine 510 that the production indicates that gas lift system 100 is producing at the desired flow of fluid 110 and determine to not take further actions.
In the exemplary embodiment, the above described process 500 is an iterative process and will repeat as conditions in well 104 and the comparison of desired flow of fluid 110 to measured data changes. In some embodiments, desired operating characteristics, methodologies, or other business rules will modify the regulation 506 of compressor 148 and valves. These regulations 506 may be either increases or decreases and may change in magnitude. While system 200 may reach a steady state, process 500 is potentially continuously regulating the settings of gas lift system 100.
The above-described method and system provide for managing and enhancing the operation of a gas lift system at a well. Furthermore, the method and systems described herein facilitate more efficient operation of a gas lift system to rapidly respond to changes in conditions of the well. These methods and systems facilitate regulating multiple characteristics of a gas lift system to enhance the amount of time that the gas lift system is operating at peak efficiency based on current and potentially changing well conditions. Also, the system and methods described herein are not limited to any single type of gas lift system or type of well, but may be implemented with any gas lift system that is configured as described herein. For example, the method and systems described herein may be used with any other device capable of extracting fluids using a gas lift system. By constantly monitoring conditions in real-time and regulating the operation of the gas lift system based on the conditions, the system and method described herein facilitates more efficient operation of gas lift systems while facilitating consistent and enhanced production.
An exemplary technical effect of the methods, systems, and apparatus described herein includes at least one of: (a) rapidly responding to changes in conditions in a well; (b) facilitating consistent flow of oil from a well; (c) automatically enhancing output of a well; and (d) independently operating each well.
Exemplary embodiments of method and systems for controlling a gas lift system are described above in detail. The method and systems described herein are not limited to the specific embodiments described herein, but rather, components of systems or steps of the methods may be utilized independently and separately from other components or steps described herein. For example, the methods may also be used in combination with multiple different gas lift system, and are not limited to practice with only the gas lift systems as described herein. Additionally, the methods may also be used with other fluid sources, and are not limited to practice with only the fluid sources as described herein. Rather, the exemplary embodiments may be implemented and utilized in connection with many other gas lift devices to be operated as described herein.
Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the systems and methods described herein, any feature of a drawing may be referenced or claimed in combination with any feature of any other drawing.
Some embodiments involve the use of one or more electronic or computing devices. Such devices typically include a processor, processing device, or controller, such as a general purpose central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, a reduced instruction set computer (RISC) processor, an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), a programmable logic unit (PLU), a field programmable gate array (FPGA), a digital signal processing (DSP) device, and/or any other circuit or processing device capable of executing the functions described herein. The methods described herein may be encoded as executable instructions embodied in a computer readable medium, including, without limitation, a storage device and/or a memory device. Such instructions, when executed by a processing device, cause the processing device to perform at least a portion of the methods described herein. The above examples are exemplary only, and thus are not intended to limit in any way the definition and/or meaning of the term processor and processing device.
This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.