Automatic control system and method for annulus pressure of oil and gas well

Abstract

The invention discloses an oil and gas well annulus pressure automatic control system and method.The oil and gas well annulus pressure automatic control system comprises a plurality of annulus pipelines connected to a Christmas tree, each annulus pipeline comprises a pressure sensor and an electric control valve which are sequentially connected, and a storage tank is connected to each electric control valve; a first one-way valve and a first fluid flowmeter are sequentially connected between the electric control valve and an inlet in the top of the storage tank, a second one-way valve, a hydraulic pump and a second fluid flowmeter are sequentially connected between the electric control valve and a first outlet in the bottom of the storage tank, and a second outlet is formed in the top of the storage tank. The pressure sensor, the first fluid flowmeter and the second fluid flowmeter are jointly connected with a data processing center, the data processing center is connected with a man-machine interaction interface and a controller, the controller is connected with the electric control valve and the hydraulic pump at the same time, timely injection of the annulus protection fluid is conducted based on annulus pressure monitoring, and the control precision is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of petroleum engineering, and specifically relates to an automatic control system and method for annulus pressure in oil and gas wells. Background Technique

[0002] At present, with the continuous improvement of oil and gas extraction technologies, more and more gas wells with deep burial, high temperature, high pressure, and containing hydrogen sulfide and the like have been developed. Most of these gas wells show annulus pressure after the well testing is completed. Annulus pressure is a very important indicator in well integrity detection. It will affect the production and reduce the recovery rate in the light case, and in the heavy case, it will cause well kick, blowout, and even damage the well integrity, not only causing huge financial losses, but also possibly causing casualties.

[0003] In order to achieve the safety management of oil and gas wells, especially the control of annulus pressure, and ensure the production of production wells and the safety of dead wells, the annulus pressure control system is particularly important. The traditional annulus pressure control system requires manual monitoring and judgment, wasting human resources. Summary of the Invention

[0004] The present invention provides an automatic control system and method for annulus pressure in oil and gas wells, which solves the problem that the existing annulus pressure control system requires manual monitoring and judgment.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An automatic control system for annulus pressure in oil and gas wells includes an annulus pipeline connected to the Christmas tree. The annulus pipeline includes a pressure sensor and an electric control valve connected in sequence. A storage tank is connected to the electric control valve. A first liquid flowmeter is connected in sequence between the electric control valve and the inlet at the top of the storage tank. A hydraulic pump and a second liquid flowmeter are connected between the electric control valve and the first outlet at the bottom of the storage tank. The pressure sensor, the first liquid flowmeter, and the second liquid flowmeter are commonly connected to a data processing center. A human-machine interaction interface and a controller are connected to the data processing center. The controller is simultaneously connected to the electric control valve and the hydraulic pump.

[0007] Preferably, the first check valve and the second check valve are provided with a return spring.

[0008] An automatic control method for annulus pressure in oil and gas wells includes:

[0009] The pressure sensor continuously monitors the pressure in the annulus pipeline wellhead and transmits the real-time monitoring data to the data processing center for comparison with the preset safe range of annulus pipeline pressure;

[0010] When the annulus pressure is within the normal range, the pressure sensor continuously detects the pressure. When the annulus pressure data is not within the safe range, the data processing center analyzes this pressure and transmits an instruction to the controller according to the analysis result;

[0011] The controller controls the electric control valve and the hydraulic pump according to the instruction;

[0012] The pressure sensor continuously monitors the pressure in the annulus pipe wellhead and transmits the real-time monitoring data to the data processing center. When the data reaches the preset safe range of the annulus pipe pressure, the controller controls the electric control valve and the hydraulic pump again.

[0013] Preferably, when the annulus pressure exceeds the safe range, at this time the pressure sensor transmits the data to the data processing center. The data processing center analyzes this high pressure. If this high pressure meets the condition of exceeding the warning range, the data processing center issues an instruction to the controller, and the controller opens the electric control valve.

[0014] Preferably, the warning range is that the high pressure continues to rise or remains stable outside a safe range value for 24 hours.

[0015] Preferably, when the annulus pressure is lower than the safe range, at this time the pressure sensor transmits the data to the data processing center. The data processing center analyzes this low pressure. If this low pressure exceeds the warning range, the data processing center issues an instruction to the controller. At this time, the controller controls to open the hydraulic pump and the electric control valve.

[0016] Preferably, the warning range is that the low pressure continues to drop or remains stable outside a safe range value for 24 hours.

[0017] Preferably, the controller first opens the hydraulic pump and then opens the electric control valve after an interval of time.

[0018] Preferably, when there is low pressure in the annulus and the annulus pressure cannot reach the safe range through the automatic control system for a long time, at this time the data processing center analyzes the data of the pressure sensor and transmits the data to the human-machine interface. At this time, the controller switches the electric control valve and the hydraulic pump to manual adjustment.

[0019] Preferably, when there is high pressure in the annulus and the annulus pressure cannot reach the safe range through the automatic control system for a long time, at this time the data processing center analyzes the data of the pressure sensor and transmits the data to the human-machine interface. At this time, the controller switches the electric control valve to manual adjustment.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides an automatic control system for annulus pressure in oil and gas wells, including a plurality of annulus pipelines connected to the Christmas tree. Each annulus pipeline includes a pressure sensor and an electrically controlled valve connected in sequence. A storage tank is connected to the electrically controlled valve. A first check valve and a first liquid flowmeter are connected in sequence between the electrically controlled valve and the inlet at the top of the storage tank. A second check valve, a hydraulic pump, and a second liquid flowmeter are connected in sequence between the electrically controlled valve and the first outlet at the bottom of the storage tank. A second outlet is provided at the top of the storage tank. The pressure sensor, the first liquid flowmeter, and the second liquid flowmeter are commonly connected to a data processing center. A human-machine interaction interface and a controller are connected to the data processing center. The controller is simultaneously connected to the electrically controlled valve and the hydraulic pump, enabling timely injection of annulus protection fluid based on annulus pressure monitoring with high control accuracy. By using the system of the present invention, the change of annulus pressure can be grasped in real time, and the wellbore integrity of risk wells can be improved based on pressure warning, with high automation and intelligence levels. Description of the Drawings

[0021] Figure 1 is a schematic diagram of the Christmas tree and annulus of an automatic control system and method for annulus pressure in oil and gas wells according to the present invention;

[0022] Figure 2 is an overall schematic diagram of an automatic control system and method for annulus pressure in oil and gas wells according to the present invention;

[0023] Figure 3 is a general layout of the automatic control system of an automatic control system and method for annulus pressure in oil and gas wells according to the present invention;

[0024] Figure 4 is an operation logic diagram under the condition of high pressure in the annulus of an automatic control system and method for annulus pressure in oil and gas wells according to the present invention;

[0025] Figure 5 is an operation logic diagram under the condition of low pressure in the annulus of an automatic control system and method for annulus pressure in oil and gas wells according to the present invention; In the figure, 1, rock formation; 2, oil layer; 3, D annulus; 4, C annulus; 5, B annulus; 6, ground; a, left joint of annulus pipeline; 7, pressure sensor; 8, electrically controlled valve; b, right joint of annulus pipeline; c, Y-shaped pipeline; 9, first check valve; 10, first liquid flowmeter; 11, first inlet; 12, hydraulic pump; 13, first outlet; 14, second outlet; 15, storage tank; 16, second liquid flowmeter; 17, third check valve; 18, controller; 19, data processing center; 20, human-machine interaction interface; A, annulus pressure system; B, Christmas tree. Detailed Embodiments

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Components of the embodiments of the present invention generally described and illustrated in the figures herein can be arranged and designed in a variety of different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0028] It should be noted that like reference numerals and letters denote like items in the following figures. Therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

[0029] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships in which the inventive product is customarily placed during use, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0030] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0031] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, if terms such as "set", "installed", "connected", "coupled" are understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] As shown Figure 1 in the figure, the christmas tree is fixed on the surface of formation 6, and the oil reservoir 2 is located below the rock formation 1; the outermost casing is cemented and fixed to the rock formation 1 through a cement sheath, and the casings are cemented and fixed to each other through a cement sheath; an annulus A is formed between the tubing and the production casing, an annulus B 5 is formed between the production casing and the inner technical casing, an annulus C 4 is formed between the inner technical casing and the outer technical casing, and an annulus D 3 is formed between the outer technical casing and the outermost casing.

[0034] As shown Figure 3 in the figure, the present invention provides an automatic control system for annulus pressure in oil and gas wells, which is characterized in that it includes a plurality of annulus pipes connected to the christmas tree B. Each of the annulus pipes includes a pressure sensor 7 and an electrically controlled valve 8 connected in sequence. A storage tank 15 is connected to the electrically controlled valve 8. A first one-way valve 9 and a first liquid flowmeter 10 are connected in sequence between the electrically controlled valve 8 and the inlet at the top of the storage tank 15. A second one-way valve 17, a hydraulic pump 12 and a second liquid flowmeter 16 are connected in sequence between the electrically controlled valve 8 and the first outlet 13 at the bottom of the storage tank 15. A second outlet 14 is provided at the top of the storage tank 15. The pressure sensor 7, the first liquid flowmeter 10 and the second liquid flowmeter 16 are commonly connected to a data processing center 19. A human-machine interface 20 and a controller 18 are connected to the data processing center 19. The controller 18 is simultaneously connected to the electrically controlled valve 8 and the hydraulic pump 12.

[0035] The first one-way valve 9 and the second one-way valve 17 are provided with return springs.

[0036] As shown Figure 4 and Figure 5 in the figure, the present invention also provides an automatic control method for annulus pressure in oil and gas wells, including:

[0037] The pressure sensor 7 continuously monitors the pressure in the wellhead of the annulus pipe and transmits the real-time monitoring data to the data processing center 19 for comparison with the preset safe range of annulus pipe pressure.

[0038] When the annulus pressure is within the normal range, the pressure sensor 7 will continuously detect the pressure. When the annulus pressure data is not within the safe range, the data processing center 19 analyzes this pressure and transmits an instruction to the controller 18 according to the analysis result;

[0039] The controller 18 controls the electrically controlled valve 8 and the hydraulic pump 12 according to the instruction;

[0040] The pressure sensor 7 continuously monitors the pressure in the wellhead of the annulus pipe and transmits the real-time monitoring data to the data processing center 19. When the data reaches the preset safe range of annulus pipe pressure, the controller 18 controls the electrically controlled valve 8 and the hydraulic pump 12 again.

[0041] When the annulus pressure exceeds the safe range, the pressure sensor 7 transmits data to the data processing center 19. The data processing center 19 analyzes this high pressure. If this high pressure meets the condition of exceeding the warning range, the data processing center 19 issues an instruction to the controller 18, and the controller 18 opens the electric control valve 8.

[0042] The warning range is that the high pressure continues to rise or remains stable outside a safe range value for 24 hours.

[0043] When the annulus pressure is lower than the safe range, the pressure sensor 7 transmits data to the data processing center 19. The data processing center 19 analyzes this low pressure. If this low pressure exceeds the warning range, the data processing center 19 issues an instruction to the controller 18. At this time, the controller 18 controls to open the hydraulic pump 12 and the electric control valve 8.

[0044] The warning range is that the low pressure continues to drop or remains stable outside a safe range value for 24 hours.

[0045] The controller 18 first opens the hydraulic pump 12 and then opens the electric control valve 8 after an interval of time.

[0046] When there is a low pressure in the annulus and the annulus pressure cannot reach the safe range through the automatic control system for a long time, the data processing center 19 analyzes the data of the pressure sensor 7 and transmits the data to the human-machine interface 20. At this time, the controller 18 switches the electric control valve 8 and the hydraulic pump 12 to manual adjustment.

[0047] When there is a high pressure in the annulus and the annulus pressure cannot reach the safe range through the automatic control system for a long time, the data processing center 19 analyzes the data of the pressure sensor 7 and transmits the data to the human-machine interface 20. At this time, the controller 18 switches the electric control valve 8 to manual adjustment.

[0048] Embodiment 1:

[0049] As Figures 1-5 shown, an automatic control system and method for annulus pressure of an oil and gas well include an annulus pipeline. The left joint a of the annulus pipeline is connected to the annulus of the Christmas tree, and the right joint b of the annulus pipeline is connected to the Y-shaped pipeline c. Inside the joint of the annulus pipeline, a pressure sensor 7 and an electric control valve 8 are installed in sequence. The upper end of the Y-shaped pipe is the annulus liquid outlet, and a check valve 9 with a return spring and a liquid flowmeter 10 are installed in sequence and connected to the first inlet 13 of the storage tank 15. The lower end of the Y-shaped pipe is the annulus liquid inlet, and a check valve 17 with a return spring, a hydraulic pump 12 and a liquid flowmeter 16 are installed in sequence and connected to the first outlet 13 of the storage tank 15.

[0050] The annulus pressure system A is connected to the Christmas tree B. The pressure sensor 7 can monitor the pressure in the wellhead of the Christmas tree B in real time and transmit the real-time monitoring data to the data processing center 19 for comparison with the preset safe range of the annulus pipeline pressure. The data processing center is a functional module in the automatic control of the annulus pressure. It can store, judge, analyze the data and make the most reasonable choice. If the annulus pressure is within the normal range, the pressure sensor 7 will continuously detect the pressure. When the annulus pressure exceeds the safe range, at this time, the pressure sensor 7 transmits the data to the data processing center 19. The data processing center 19 will analyze this high pressure. If this high pressure continues to rise or remains stable outside a safe range value for more than 24 hours, the data processing center 19 further issues an instruction to the controller 18. The controller 18 automatically controls to open the electric control valve 8. At this time, the liquid in the Christmas tree B flows through the upper end of the Y-shaped pipeline along the valve, passes through the first check valve 9 and the first liquid flowmeter and enters the storage tank 15. When passing through the lower end of the Y-shaped pipeline, due to the existence of the check valve with a return spring, the annulus liquid cannot pass through the lower end of the Y-shaped pipeline. During this process, the pressure sensor 7 detects the annulus pressure and transmits the real-time data to the data processing center 19. At this time, the data processing center 19 will analyze the real-time data. When the data is within the safe range of the annulus with pressure and reaches stability, at this time, it will make another judgment and transmit the instruction to the controller 18. The controller 18 automatically controls the electric control valve 8 to remain closed to achieve the annulus pressure balance. When the annulus pressure is lower than the safe range, at this time, the pressure sensor 7 transmits the data to the data processing center 19. The data processing center 19 will analyze this low pressure. If this low pressure continues to drop or remains stable outside a safe range value for more than 24 hours, the data processing center 19 further issues an instruction to the controller 18. At this time, the controller 18 will give priority to opening the hydraulic pump 12 and open the electric control valve 8 after an interval of time. The liquid in the storage tank 15 is pumped into the annulus pipeline through the hydraulic pump 12. During the process of pumping the liquid, a part of the liquid will flow through the upper end of the Y-shaped pipeline and pass through the storage tank. However, due to the existence of the pressure difference, it has no impact on the annulus pressure compensation. Only by reasonably calculating the value of the liquid flowmeter installed at the lower end of the Y-shaped pipeline can this impact be ignored. Or a bypass valve can be installed at the upper end of the Y-shaped pipeline and the preset pressure is set to the maximum pressure of the annulus with pressure, then this impact can also be avoided. During this period, the pressure sensor 7 detects the annulus pressure and transmits the real-time data to the data processing center 19. At this time, the data processing center 19 will analyze the real-time data. When the data is within the safe range of the annulus with pressure and reaches stability, at this time, it will make another judgment and transmit the instruction to the controller 18. At this time, the controller 18 will automatically control to close the valve 24 and close the hydraulic pump 12 after an interval of time to achieve the annulus pressure balance.

[0051] In the described automatic control system and method for the annulus pressure of an oil and gas well, when the annulus has low pressure and the automatic control system fails to bring the annulus pressure to the safe range for a long time, at this time, the data processing center 19 analyzes the data of the pressure sensor 7 and transmits the data to the human-machine interface 20. At this time, the controller 18 switches the electric control valve 8 and the hydraulic pump 12 to manual adjustment for manual operation and detection.

[0052] In the described automatic control system and method for the annulus pressure of an oil and gas well, when the annulus has high pressure and the automatic control system fails to bring the annulus pressure to the safe range for a long time, at this time, the data processing center 19 analyzes the data of the pressure sensor 7 and transmits the data to the human-machine interface 20 for manual operation and detection.

[0053] Embodiment 2:

[0054] Taking the casing annulus as an example. First, calculate and determine the maximum allowable pressure value of the annulus and set the warning pressure value. The annulus pressure system A monitors the annulus pressure. The annulus pressure system A transmits the measured data to the data processing center through the pressure sensor 7. The data processing center makes a real-time judgment on the measured data. If the measured annulus pressure is below the warning value, continuous monitoring is sufficient. When the casing annulus is continuously pressurized due to thermal expansion caused by high temperature or casing connection and other reasons, and the pressure exceeds the warning value but is less than the maximum allowable pressure value, if it lasts for 24 hours, the data processing center 19 issues an instruction to relieve the pressure of the casing annulus. If the pressure of the casing annulus exceeds the maximum allowable pressure, the pressure of the casing annulus is directly relieved. The fluid produced by relieving the pressure of the casing annulus flows into the storage tank.

[0055] There is a minimum allowable pressure in the annulus of a high-pressure gas well. First, calculate and determine the minimum allowable pressure value of the annulus and set the warning pressure value. Of course, if the casing annulus pressure is greater than the warning value, continuous monitoring is sufficient. When the casing annulus pressure is less than the warning value but greater than the minimum allowable pressure value, if it lasts for 24 hours, the data processing center 19 issues an instruction to inject annulus protection fluid into the casing annulus from the storage tank. If the casing annulus pressure is less than the minimum allowable value, the annulus protection fluid is directly injected into the casing annulus from the storage tank.

[0056] Although the embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments and application fields. The above specific embodiments are merely illustrative and guiding, rather than restrictive. Under the inspiration of the specification, those of ordinary skill in the art can also make many forms without departing from the scope protected by the claims of the present invention, and these all belong to the scope of protection of the present invention.

Claims

1. An automatic control system for annulus pressure in oil and gas wells, characterized in that, It includes an annulus pipeline connected to a Christmas tree (B). The annulus pipeline includes a pressure sensor (7) and an electrically controlled valve (8) connected in sequence. A storage tank (15) is connected to the electrically controlled valve (8). A first liquid flowmeter (10) is connected in sequence between the electrically controlled valve (8) and the inlet at the top of the storage tank (15). A hydraulic pump (12) and a second liquid flowmeter (16) are connected between the electrically controlled valve (8) and the first outlet (13) at the bottom of the storage tank (15). The pressure sensor (7), the first liquid flowmeter (10), and the second liquid flowmeter (16) are commonly connected to a data processing center (19). A human-machine interaction interface (20) and a controller (18) are connected to the data processing center (19). The controller (18) is simultaneously connected to the electrically controlled valve (8) and the hydraulic pump (12).

2. The automatic control system for annulus pressure of oil and gas wells according to claim 1, wherein The first one-way valve (9) and the second one-way valve (17) are provided with return springs.

3. An automatic control method for the annulus pressure of an oil and gas well, based on the automatic control system for the annulus pressure of an oil and gas well according to any one of claims 1-2, characterized in that, It includes: The pressure sensor (7) monitors the pressure in the annulus pipeline wellhead in real time and transmits the real-time monitoring data to the data processing center (19) for comparison with the preset safe pressure range of the annulus pipeline. When the annulus pressure is within the normal range, the pressure sensor (7) continuously detects the pressure. When the annulus pressure data is not within the safe range, the data processing center (19) analyzes this pressure and transmits an instruction to the controller (18) according to the analysis result. The controller (18) controls the electrically controlled valve (8) and the hydraulic pump (12) according to the instruction. The pressure sensor (7) continuously monitors the pressure in the annulus pipeline wellhead and transmits the real-time monitoring data to the data processing center (19). When the data reaches the preset safe pressure range of the annulus pipeline, the controller (18) controls the electrically controlled valve (8) and the hydraulic pump (12) again.

4. The automatic control method for the annulus pressure of an oil and gas well according to claim 3, wherein When the annulus pressure exceeds the safe range, at this time the pressure sensor (7) transmits the data to the data processing center (19). The data processing center (19) analyzes this high pressure. If this high pressure meets the condition of exceeding the warning range, the data processing center (19) issues an instruction to the controller (18), and the controller (18) opens the electrically controlled valve (8).

5. The automatic control method for annulus pressure of oil and gas wells according to claim 4, characterized in that, The warning range is that the high pressure continuously rises or remains stable outside a safe range value for 24 hours.

6. The automatic control method for the annulus pressure of an oil and gas well according to claim 3, wherein, When the annulus pressure is lower than the safe range, at this time the pressure sensor (7) transmits the data to the data processing center (19). The data processing center (19) analyzes this low pressure. If this low pressure exceeds the warning range, the data processing center (19) issues an instruction to the controller (18). At this time, the controller (18) controls to open the hydraulic pump (12) and the electrically controlled valve (8).

7. The automatic control method for the annulus pressure of an oil and gas well according to claim 6, wherein The warning range is that the low pressure continuously drops or remains stable outside a safe range value for 24 hours.

8. The automatic control method for the annulus pressure of an oil and gas well according to claim 6, characterized in that, The controller (18) first opens the hydraulic pump (12) and then opens the electrically controlled valve (8) after an interval of time.

9. The automatic control method for the annulus pressure of an oil and gas well according to claim 3, characterized in that, When the annulus is under low pressure and the annulus pressure cannot reach the safe range through the automatic control system for a long time, at this time, the data processing center (19) analyzes the data of the pressure sensor (7) and transmits the data to the human-machine interaction interface (20). At this time, the controller (18) switches the electrically controlled valve (8) and the hydraulic pump (12) to manual adjustment.

10. A method for automatically controlling the annulus pressure of an oil and gas well according to claim 3, characterized in that, When the annulus is under high pressure and the annulus pressure cannot reach the safe range through the automatic control system for a long time, at this time, the data processing center (19) analyzes the data of the pressure sensor (7) and transmits the data to the human-machine interaction interface (20). At this time, the controller (18) switches the electrically controlled valve (8) to manual adjustment.

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