Multifunctional multi-stage gas lift oil recovery simulation system and experimental method

Abstract

The application discloses a multifunctional multistage gas lift oil production simulation system and an experimental method, belongs to the technical field of oil production simulation experiment devices, and comprises a simulation device, wherein the simulation device comprises a wellhead device, a simulation oil pipe, a simulation casing and a well bottom device; the upper and lower ends of the simulation oil pipe and the simulation casing are connected with the wellhead device and the well bottom device respectively; the simulation casing is arranged on the outer side of the simulation oil pipe; a gas lift valve is connected to the lateral wall of the simulation oil pipe; and an oil casing communication valve is connected to the outer side of the simulation casing. On the basis of simulating the structure of a gas lift pipe column, an electromagnetic control type gas lift valve, a differential pressure sensor and a PLC control system are introduced to replace a conventional pressure / differential pressure control type gas lift valve. In addition, the optimization design and reasonable layout of various subsystems of the experimental system, such as the wellhead, the well bottom, the pipe column, gas-liquid supply, measurement and control, are achieved, one machine has multiple functions, the application range of the existing gas lift oil production simulation device is widened, and the problems in the prior art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to a multifunctional multi-stage gas lift oil production simulation system and experimental method, belonging to the technical field of oil production simulation experiment device. BACKGROUND

[0002] Gas lift oil production is a mechanical oil production method with strong adaptability to oil well production conditions. It is not only widely used in high gas-oil ratio reservoirs, especially in deep wells, offshore oil wells, horizontal wells, directional wells and cluster wells with high gas-oil ratio and high production, but also can be applied to oil wells with low liquid production rate and difficult to start production. The gas lift valve is a key downhole tool of the gas lift oil production device, which functions to reduce the starting pressure and discharge the liquid in the annular space of the oil casing. When the gas lift gas enters the tubing from the upper stage gas lift valve, the annular liquid level drops to the lower stage gas lift valve, the upper stage gas lift valve does not close, and the discharge rate of the liquid in the annular space of the oil casing will decrease, which may cause the gas lift to be in the starting process all the time, and unable to reach a stable working process, thereby affecting the gas lift oil production. The existing gas lift simulation device cannot simulate the above process because the closing pressure of the gas lift valve cannot be adjusted, and thus the optimization of the closing pressure and the influence of the closing pressure on the gas lift cannot be studied. At the same time, the gas-liquid mixed flow in the tubing during the gas lift process has similarities with the multiphase pipe flow in the tubing during the production process of the flowing well, and the annular gas pressure water flow during the gas lift process has similarities with the gas invasion pressure well at the bottom of the well. However, the existing gas lift oil production simulation device does not consider the above similarities and does not make corresponding design and integration, resulting in single function and limiting its application range.

[0003] The existing gas lift oil production experimental device with a pressure / differential pressure control type gas lift valve as the core component has a high gas lift valve switching response pressure, the gas lift gas can only flow along the path of wellhead-gas lift valve-wellhead, the liquid can only flow along the path of well bottom-wellhead, the device size is consistent with the field size, which leads to the fact that the device can only simulate the gas lift oil production lifting process, has single function, fixed gas-liquid flow path, and difficult to adjust the test condition parameters, and cannot effectively carry out the optimization of the closing pressure of the gas lift valve and the influence of the closing pressure on the gas lift production, cannot carry out the simulation of the wellbore multiphase flow law in the tubing channel alone, and cannot simulate the gas invasion using the pressure well gas-liquid flow law simulation.

[0004] At present, the gas lift oil production process simulation device is mainly developed on the basis of field gas lift oil production test, such as Chinese patents with publication numbers CN 108230866A, CN 104343421A, CN 114562241A and CN 114991723A. These field-sized gas lift oil production devices can effectively solve the problem of gas lift oil production process parameter optimization of specific oil wells or blocks in an oilfield, but have problems such as single function, fixed gas-liquid flow path, and difficulty in adjusting test condition parameters, which leads to the fact that they can only simulate the gas lift oil production lifting process, cannot effectively carry out the research on the gas lift valve closing pressure optimization and the influence of the closing pressure on the gas lift production, and cannot separately use the tubing channel to carry out the simulation of the wellbore multiphase flow law or simulate the gas invasion pressure well gas-liquid flow law. In addition, the field-sized gas lift device also has problems such as high test cost, high risk, long cycle, and the like, which limit its large-scale application.

[0005] At present, there are few laboratory-sized gas lift oil production physical simulation devices, and even fewer devices with superior functions and performance. The patents with publication numbers CN 110424931A and CN 205016137U both use gas-controlled gas lift valves (pressure / differential pressure controlled gas lift valves), the closing pressure of which cannot be adjusted, and the gas-liquid flow path is also fixed, which cannot carry out the research on the gas lift valve closing pressure optimization and the influence of the closing pressure on the gas lift production, nor can it carry out the simulation of multiphase pipe flow and gas invasion pressure well. Based on the above problems, how to design a multifunctional multi-stage gas lift oil production simulation system and experimental method has become an urgent need at present. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a multifunctional multi-stage gas lift oil production simulation system and experimental method, which solves the problems in the prior art.

[0007] The multifunctional multi-stage gas lift oil production simulation system provided by the present application comprises a simulation device, wherein the simulation device comprises a wellhead device, a simulation tubing, a simulation casing and a bottom hole device, the upper and lower ends of the simulation tubing and the simulation casing are connected with the wellhead device and the bottom hole device respectively, the simulation casing is sleeved outside the simulation tubing, the side wall of the simulation tubing is connected with a gas lift valve, the outside of the simulation casing is connected with an oil-casing communication valve, an oil-casing annular structure is formed between the simulation casing and the simulation tubing, the oil-casing annular structure serves as a flow channel for gas lift gas flowing from the wellhead device to the gas lift valve and annulus liquid flowing from the bottom hole device to the simulation tubing, and the gas-liquid mixture flows out along the simulation tubing through the wellhead device in the gas lift process, and the outside of the simulation device is further connected with a gas-liquid flow metering mechanism.

[0008] Further, the gas-liquid flow metering mechanism comprises a first flow meter module and a second flow meter module, the first flow meter module is connected with the gas injection pipeline of the simulation device, the first flow meter module is connected with an air compressor, the second flow meter module is connected with the liquid injection pipeline of the simulation device, and the second flow meter module is connected with a centrifugal pump and a water tank.

[0009] Further, the gas injection pipeline is connected with the wellhead device through the first flow meter module, the liquid injection pipeline is connected with the well bottom device through the second flow meter module, or the gas injection pipeline is connected with the well bottom device through the first flow meter module, the liquid injection pipeline is connected with the wellhead device through the second flow meter module, or the liquid injection pipeline is connected with the wellhead device through the second flow meter module, and the gas injection pipeline is connected with the well bottom device through the first flow meter module.

[0010] Further, the first flow meter module and the second flow meter module each comprise two paths, one path is provided with a large-range flow meter, and the other path is provided with a small-range flow meter.

[0011] Further, the data acquisition control system further comprises a gas-liquid flow meter, a pressure transmitter, a differential pressure transmitter and a controller, and is used for monitoring the real-time change curve of the well bottom pressure in the gas lifting process.

[0012] Further, the differential pressure sensor is connected between the wellhead device and the well bottom device, the differential pressure sensor is connected with the data acquisition control system, and the well bottom device is provided with a well bottom device one-way valve.

[0013] Further, the wellhead device is externally connected with a gas-liquid separation tank and a vent valve.

[0014] The multifunctional multi-stage gas lifting oil recovery simulation experiment method comprises a gas lifting oil recovery experiment method, a multiphase pipe flow simulation experiment method and a gas invasion well killing simulation experiment method.

[0015] S1: selecting a gas lifting pipe column structure;

[0016] S2: using the data acquisition control system to make the gas lifting valve in an open state, selecting a small-range liquid injection pipeline, and injecting liquid into the oil pipe and the oil jacket annulus at a small flow rate, the gas lifting valve comprises a first-stage gas lifting valve and a second-stage gas lifting valve which are distributed upward and downward, the liquid level is made to exceed the first-stage gas lifting valve through the vent valve, the liquid level height is kept stable, and then the vent valve is closed.

[0017] S3: Gas lift valve manual closing valve gas lift simulation: open the valve of the large range gas injection pipeline, adjust the gas flow, supply gas to the oil jacket annular structure, the oil jacket annular structure liquid surface drops, when the oil jacket annular structure liquid surface drops to the second stage gas lift valve, the first stage gas lift valve is selected to be closed in manual control mode, and the second stage gas lift valve is closed in turn when the oil jacket annular structure liquid surface drops to the bottom of the well, and the gas lift simulation is completed after the gas lift lifting pressure is stable;

[0018] S4: Gas lift valve automatic closing valve gas lift simulation: first manually close the second stage gas lift valve, then set the first stage gas lift valve to an automatic closing gas lift valve control mode, manually set the gas lift valve closing height, open the valve of the large range gas injection pipeline, adjust the gas flow, supply gas to the oil jacket annular structure, the oil jacket annular structure liquid surface drops, and when the oil jacket annular structure liquid surface drops to the set liquid level height, the gas lift valve is closed, and the gas lift simulation is completed when the gas lift gas enters the tubing from the bottom of the well and works stably, which can realize gas lift simulation under different gas lift valve closing pressures.

[0019] Further, the multiphase pipe flow simulation experiment method comprises the following steps:

[0020] S11: Close the oil jacket communication valve, open the one-way valve connected to the bottom hole device, and establish a single oil pipe flow channel;

[0021] S12: According to the gas and liquid flow, select the corresponding range of gas and liquid flow meters, start the air compressor, slowly open the liquid injection pipeline valve, slowly increase the valve opening within the liquid flow meter range, and adjust the flow to the experimental flow. At this time, the simulation oil pipe starts to fill with liquid;

[0022] S13: After the simulation oil pipe is filled with liquid, slowly open the gas injection pipeline valve, adjust the gas amount, and observe the gas-liquid two-phase flow structure in the simulation oil pipe;

[0023] S14: After the flow pattern is stable, the multiphase flow pressure distribution calculation module in the data acquisition control system is used to input different oil pipe heights, calculate the pressure and flow pattern at the height, and record the bottom hole flow pressure, wellhead pressure and different height pressures;

[0024] S15: Change different gas and liquid flows to test experimental data under different flow patterns and obtain pressure distribution characteristics under different flow patterns.

[0025] Further, the gas invasion well killing simulation experiment method comprises the following steps:

[0026] S21: Open the oil jacket communication valve, the one-way valve connected to the bottom hole device, and close the vent valve to establish an oil jacket annular space-tubing-wellhead reverse circulation flow channel;

[0027] S22: open the centrifugal pump, adjust the liquid flow, inject liquid into the reverse circulation flow channel, then select different range of gas injection channel, adjust the gas invasion gas flow, simulate the gas invasion process, and record the gas invasion gas flow;

[0028] S23: increase the liquid injection speed, and record the liquid flow and bottom hole pressure when no gas invasion gas is observed in the wellbore;

[0029] S24: change different gas invasion gas flow, and obtain the gas invasion well control law under different gas invasion gas conditions.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] The multifunctional multi-stage gas lift oil production simulation system and experimental method introduce an electromagnetic control type gas lift valve, a differential pressure sensor and a PLC control system to replace the traditional pressure / differential pressure control type gas lift valve on the basis of simulating the structure of the gas lift string, and the wellhead, the bottom hole, the string, the gas-liquid supply, the measurement and control and other subsystems of the experimental system are optimized and reasonably arranged, the wellhead and bottom hole gas injection and liquid injection branches and large and small range measurement systems and other modules are added, so that the gas lift oil production process simulation, the gas lift valve closing pressure optimization and the simulation of the influence of the gas lift valve closing pressure on the gas lift process, the gas invasion well control simulation and the multiphase pipe flow simulation from the bottom up can be carried out, one machine has multiple functions, the application range of the existing gas lift oil production simulation device is widened, the equipment cost is effectively saved, and the economic benefit is improved.

[0032] The problems of the prior art, such as single function, fixed gas-liquid flow path, difficult adjustment of test condition parameters, high test cost, high risk, long test period, large-scale application is limited, etc. of the gas lift oil production experimental device with a pressure / differential pressure control type gas lift valve as the core component on site, the problem of the laboratory size gas lift oil production physical simulation device that the valve closing pressure is not adjustable, the gas-liquid flow path is fixed, and the function is single, which makes the existing gas lift oil production device only simulate the gas lift oil production lifting process, cannot effectively carry out the gas lift valve closing pressure optimization and the research on the influence of the closing pressure on the gas lift production, cannot separately use the tubing channel to carry out the simulation of the wellbore multiphase flow law, and cannot simulate the gas invasion well control gas-liquid flow law. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a structure schematic diagram of embodiment 1 in the multifunctional multi-stage gas lift oil production simulation system of the present application;

[0034] Figure 2 It is a structure schematic diagram of embodiment 2 in the multifunctional multi-stage gas lift oil production simulation system of the present application;

[0035] Figure 3Structure diagram of embodiment 3 in the multifunctional multistage gas lift oil production simulation system of the application;

[0036] In the figure: 1, wellhead device; 2, gas lift valve; 3, simulation casing; 4, simulation tubing; 5, oil casing communication valve; 6, data acquisition control system; 7, bottom hole device; 8, differential pressure sensor; 9, first valve; 10, vent valve; 11, second valve; 12, second large range flowmeter; 13, air compressor; 14, second small range flowmeter; 15, first large range flowmeter; 16, first small range flowmeter; 17, centrifugal pump; 18, water tank; 19, gas-liquid separation tank; 20, bottom hole device check valve. DETAILED DESCRIPTION

[0037] The application will be further described below in combination with the drawings and embodiments:

[0038] As Figure 1 shown, the multifunctional multistage gas lift oil production simulation system of the application comprises a simulation device, the simulation device comprising a wellhead device 1, a simulation tubing 4, a simulation casing 3 and a bottom hole device 7, the upper and lower ends of the simulation tubing 4 and the simulation casing 3 being connected to the wellhead device 1 and the bottom hole device 7 respectively, the simulation casing 3 being sleeved on the outside of the simulation tubing 4, the side wall of the simulation tubing 4 being connected with a gas lift valve 2, the outside of the simulation casing 3 being connected with an oil casing communication valve 5, an oil casing annulus structure being formed between the simulation casing 3 and the simulation tubing 4, the oil casing annulus structure serving as a flow channel for gas lift gas flowing from the wellhead device 1 to the gas lift valve 2 and for annulus liquid flowing from the bottom hole device 7 to the simulation tubing 4, a gas-liquid mixture flowing out along the simulation tubing 4 and through the wellhead device 1 in the gas lift process, the outside of the simulation device being further connected with a gas-liquid flowmetering mechanism.

[0039] The gas-liquid flowmetering mechanism comprises a first flowmeter module and a second flowmeter module, the first flowmeter module being connected to a gas injection pipeline of the simulation device, the first flowmeter module being connected with an air compressor 13, the second flowmeter module being connected to a liquid injection pipeline of the simulation device, the second flowmeter module being connected with a centrifugal pump 17 and a water tank 18.

[0040] The multifunctional multistage gas lift oil production simulation system of the application comprises a gas lift oil production simulation system, a tubing multiphase pipe flow simulation system and a gas invasion well killing system, the multiphase pipe flow simulation, the gas lift oil production simulation and the gas invasion well killing simulation being organically integrated to realize one machine with multiple functions, and different embodiments will be specifically exemplified below.

[0041] Embodiment 1:

[0042] As Figure 1As shown, the multifunctional multistage gas lift oil production simulation system is a gas lift oil production simulation experiment system, the wellhead device 1 is connected and fixed with the simulation oil pipe 4 and the casing pipe, and provides annular gas lift gas, a gas flow passage controlled by a gas lift valve, and a passage for oil pipe fluid flowing out of the wellhead.

[0043] The gas-liquid separation tank 19 is used for separating gas in the gas-liquid mixture produced by the wellhead, and the separated liquid flows back to the water tank 18 through a pipeline.

[0044] The simulation oil pipe 4 is connected with the wellhead device 1 and the well bottom device 7, and the side wall is processed with an interface for installing an electromagnetic control type gas lift valve, and the gas-liquid mixture flows out along the oil pipe through the wellhead device 1 in the gas lift process.

[0045] The simulation casing pipe 3 is connected with the wellhead device 1 and the well bottom device 7, and forms an oil-casing annulus with the simulation oil pipe 4, which is used as a flow passage for gas lift gas flowing from the wellhead to the gas lift valve 2 and for annular liquid flowing from the well bottom to the oil pipe.

[0046] The well bottom device 7 is composed of a base, an oil-casing communication valve 5, and a well bottom device one-way valve, which is used for controlling oil-casing communication and the case that the fluid in the oil pipe flows reversely to the water tank 18. The well bottom device one-way valve is arranged at a position where the well bottom device is connected with the outside.

[0047] The rated pressure of the air compressor 13 and the centrifugal pump 17 is basically matched to prevent the occurrence of gas lock water and water lock gas. The gas injection pipeline is connected with the wellhead device 1 through the second large-range flow meter 12 and the second small-range flow meter 14. The second large-range flow meter 12 and the second small-range flow meter 14 are gas flow meters. The water injection pipeline is connected with the well bottom device 7 through the first large-range flow meter 15 and the first small-range flow meter 16. The first large-range flow meter 15 and the first small-range flow meter 16 are liquid flow meters.

[0048] The first flow meter module and the second flow meter module each include two paths, one of which is provided with a large-range flow meter, and the other of which is provided with a small-range flow meter. The first flow meter module includes the first large-range flow meter 15 and the first small-range flow meter 16, and the second flow meter module includes the second large-range flow meter 12 and the second small-range flow meter 14. The first flow meter module is connected with the first valve 9 on the outside, and the second flow meter module is connected with the second valve 11 on the outside.

[0049] The large-range and small-range gas and liquid flow meters are used for accurately measuring the gas-liquid flow under different experimental conditions. In the simulation gas lift, the large-range gas flow meter and the small-range liquid flow meter should be selected.

[0050] In this embodiment, a data acquisition control system 6 is further included, which comprises a gas-liquid flow meter, a pressure transmitter, a differential pressure transmitter and a controller, and is used for monitoring the real-time change curve of the well bottom pressure in the gas lifting process.

[0051] In this embodiment, a differential pressure sensor 8 is further connected between the wellhead device 1 and the well bottom device 7, and the differential pressure sensor 8 is connected to the data acquisition control system 6.

[0052] In this embodiment, the wellhead device 1 is externally connected to a gas-liquid separation tank 19 and a vent valve 10.

[0053] The gas lift valve 2 is an electromagnetic control type gas lift valve, the differential pressure sensor 8 and the data acquisition control system 6 are used for controlling the opening and closing of the gas lift valve 2 and collecting pressure and flow data. The gas lift valve switch control includes two modes of manual control and automatic control. In the manual mode, the opening and closing states of the two gas lift valves can be controlled through the buttons of the first-stage gas lift valve and the second-stage gas lift valve, and the green button indicates that the gas lift valve is opened, and the red button indicates that the gas lift valve is closed. In the automatic mode, the opening and closing states of the first-stage gas lift valve can be automatically controlled. First, the pipe string height at which the first-stage gas lift valve is closed is set, and after the automatic mode button is clicked, the indicator light changes from red to green, indicating that the automatic mode setting is successful, at this time, the opening and closing of the first-stage gas lift valve is switched to the automatic control mode and cannot be manually switched. When the differential pressure value is equal to the pressure value corresponding to the set valve closing height, the first-stage gas lift valve is closed and remains closed as the annular liquid column descends. The opening and closing states of the second-stage gas lift valve can be manually controlled. After the experiment is completed, the manual mode button can be clicked, at this time, the indicator light turns red, and the opening and closing of the two gas lift valves returns to the manual control mode. By setting the valve closing pressure of the first-stage gas lift valve, the valve closing pressure optimization of the gas lift valve and the influence of the valve closing pressure of the gas lift valve on the gas lifting can be realized.

[0054] The data acquisition control system 6 includes gas-liquid flow meters, pressure transmitters, differential pressure transmitters, PLC modules and other electrical components, and can monitor the real-time change curve of the well bottom pressure in the gas lifting process in real time, and is used for analyzing the pressure change law of the gas lifted from the annulus along the gas lift valve 2 into the tubing.

[0055] The specific application of this embodiment is:

[0056] (1) Selecting the gas lift pipe string structure:

[0057] ① Open the tubing-casing communication valve 5 and the well bottom device check valve 20 to establish a gas lift pipe string system considering that the gas lifted gas passes through the tubing and the casing annulus to back pressure the formation;

[0058] ② Or open the tubing-casing communication valve 5 and close the well bottom device check valve 20 to establish a gas lift pipe string system considering that the gas lifted gas passes through the casing annulus to back pressure the formation;

[0059] ③ or close the tubing-casing communication valve 5, open the bottom hole device check valve 20, and establish a gas lift string system considering the gas lift gas passing through the tubing to back pressure the formation;

[0060] ④ or close the tubing-casing communication valve 5, close the bottom hole device check valve 20, and establish a gas lift string system without the gas lift gas back pressure the formation;

[0061] (2) using the data acquisition and control system 6 to make the two gas lift valves 2 in the open state, selecting a small range of liquid path pipeline, turning on the water pump power supply, and injecting liquid into the tubing and the tubing-casing annulus with a small flow rate, through the vent valve 10, making the liquid level exceed the first stage gas lift valve and keeping the liquid level height stable, and then closing the vent valve 10;

[0062] (3) gas lift valve manual closing simulation: opening the large range gas path valve, adjusting the gas flow rate, supplying gas into the annulus, and lowering the annulus liquid level, when the annulus liquid level is lowered to the second stage gas lift valve, selecting the manual control mode to close the first stage gas lift valve. In turn, when the annulus liquid level is lowered to the bottom hole, the second stage gas lift valve is closed, and after the gas lift lifting pressure is stable, the gas lift simulation is completed;

[0063] (4) gas lift valve automatic closing simulation: first manually closing the second stage gas lift valve, then setting the first stage gas lift valve as the automatic closing gas lift valve control mode, manually setting the gas lift valve closing height, opening the large range gas path valve, adjusting the gas flow rate, supplying gas into the annulus, and lowering the annulus liquid level, when the annulus liquid level is lowered to the set liquid level height, the gas lift valve is closed, and when the gas lift gas enters the tubing from the bottom hole and works stably, the gas lift simulation is completed, and the gas lift simulation under different gas lift valve closing pressures can be realized;

[0064] (5) during the gas lift simulation, when gas is supplied into the annulus, starting the stopwatch, recording the bottom hole flow pressure, annulus gas injection pressure, gas flow rate, and liquid flow rate at different times (initial, tubing liquid outlet, first stage, second stage gas lift valve, and bottom hole gas inlet), and through the comparison and analysis of the pressure and flow rate data, the gas lift valve closing pressure optimization and the influence of the closing pressure on the gas lift can be studied.

[0065] Example 2:

[0066] As shown in Figure 2 , the multifunctional multi-stage gas lift oil recovery simulation system described in this embodiment is a multiphase pipe flow simulation experiment system, and the system composition is consistent with the structure of the gas lift oil recovery simulation system, the difference lies in that the gas injection pipeline is connected with the bottom hole device 7 through the first flow meter module, and the liquid injection pipeline is connected with the wellhead device 1 through the second flow meter module; the data acquisition and control system 6 is adjusted to the pressure distribution calculation software interface.

[0067] The specific application of this embodiment is:

[0068] (1) Close the oil sleeve communication valve, open the one-way valve, and establish a single oil pipe flow channel;

[0069] (2) Select the corresponding range of gas and liquid flow meters according to the gas and liquid flow, turn on the water pump power supply, start the air compressor 13, slowly open the liquid valve, slowly increase the valve opening within the liquid flow range, adjust the flow to the experimental flow, at this time, the oil pipe starts to fill with liquid, slowly open the gas valve, adjust the gas amount, and observe the gas-liquid two-phase flow structure in the oil pipe;

[0070] (3) After the flow pattern is stable, use the multiphase flow pressure distribution calculation module in the data acquisition control system 6 to input different oil pipe heights, calculate the pressure and flow pattern at the height, and record the bottom hole flowing pressure, wellhead pressure, and different height pressures;

[0071] (4) Change different gas and liquid flow rates to test experimental data under different flow patterns, and obtain pressure distribution characteristics under different flow patterns.

[0072] Example 3:

[0073] As shown in Figure 3 , the multifunctional multi-stage gas lift oil recovery simulation system described in this embodiment is a gas invasion well simulation experiment system, and the system composition is consistent with that of example 1, the difference lies in that the liquid injection pipeline is connected with the wellhead device 1 through the second flow meter module, and the gas injection pipeline is connected with the bottom hole device 7 through the first flow meter module. The data acquisition control system is adjusted to the real-time data monitoring interface.

[0074] The specific application of this embodiment is:

[0075] (1) Open the oil sleeve communication valve 5 and the bottom hole device one-way valve 20, close the vent valve 10, and establish an oil sleeve annulus-oil pipe-wellhead reverse circulation flow channel;

[0076] (2) Open the centrifugal pump 17, adjust the liquid flow, inject liquid into the reverse circulation flow channel, then select different ranges of gas channels, adjust the gas invasion gas flow, simulate the gas invasion process, and record the gas invasion gas flow;

[0077] (3) Increase the liquid injection speed, and when no gas invasion gas is observed in the wellbore, record the liquid flow and bottom hole pressure at this time;

[0078] (4) Change different gas invasion gas flow rates to obtain gas invasion well rules under different gas invasion gas conditions.

[0079] Example 4:

[0080] The multifunctional multi-stage gas lift oil recovery simulation experiment method described in the present application includes a gas lift oil recovery experiment method, a multiphase pipe flow simulation experiment method, and a gas invasion well simulation experiment method, wherein the gas lift oil recovery experiment method comprises the following steps:

[0081] (1) Adjust the multifunctional multi-stage gas lift oil recovery simulation system to realize the gas lift oil recovery simulation process as shown in Figure 1

[0082] (2) Use the data acquisition control system 6 to manually close the gas lift valve 2, then open the oil sleeve communication valve 5 and the downhole device check valve 20, simulate the gas lift simulation under the condition of no gas lift valve and only downhole shoe gas injection, and the gas lift gas passes through the tubing and annulus to react on the formation; the data are shown in Table 1:

[0083] Table 1 Pressure corresponding to different time Table 1

[0084]

[0085]

[0086] (3) Use the data acquisition control system 6 to manually open the gas lift valve 2, then open the oil sleeve communication valve 5 and the downhole device check valve 20, simulate the gas lift simulation under the condition of two gas lift valves and pipeline three-point gas injection, and the gas lift gas passes through the tubing and annulus to react on the formation; the data are shown in Table 2:

[0087] Table 2 Pressure corresponding to different time Table 2

[0088]

[0089] (4) Use the data acquisition control system 6 to manually open the gas lift valve 2, then open the oil sleeve communication valve 5 and close the downhole device check valve 20, simulate the gas lift simulation under the condition of two gas lift valves, and the gas lift gas passes through the annulus to react on the formation; the data are shown in Table 3:

[0090] Table 3 Pressure corresponding to different time Table 3

[0091]

[0092] (5) Use the data acquisition control system 6 to manually open the gas lift valve 2, then close the oil sleeve communication valve 5 and close the downhole device check valve 20, simulate the gas lift simulation under the condition of two gas lift valves, and the gas lift gas does not react on the formation; the data are shown in Table 4:

[0093] Table 4 Pressure corresponding to different time Table 4

[0094]

[0095]

[0096] ​(6) Using the data acquisition and control system 6, the first-stage gas lift valve is set to automatic control. Then, the oil casing connecting valve 5 and the bottom hole device check valve 20 are closed to simulate gas lift under different valve closing pressure conditions. The data are as follows: t2 is the time when the annular fluid level reaches the valve closing height, and t3 is the time when the annular fluid level reaches the second-stage gas lift valve. The data are shown in Table 5 below.

[0097] Table 5 shows the pressure at different times.

[0098]

[0099] Example 5:

[0100] The multiphase pipe flow simulation experimental method of the present invention includes the following steps:

[0101] (1) Close the oil casing connecting valve 9, open the bottom hole device check valve 20, and establish a single oil pipe flow channel;

[0102] (2) Select the appropriate gas and liquid flow meters according to the gas and liquid flow rates, turn on the water pump power, start the air compressor 13, slowly open the liquid valve, and slowly increase the valve opening within the liquid flow meter range to adjust the flow rate to the experimental flow rate. At this time, liquid begins to enter the oil pipe. After the oil pipe is full of liquid, slowly open the gas valve, adjust the gas volume, and observe the gas-liquid two-phase flow structure in the oil pipe;

[0103] (3) After the flow pattern stabilizes, use the multiphase flow pressure distribution calculation module in the data acquisition and control system to input different tubing heights, calculate the pressure and flow pattern at that height, and record the bottom hole pressure, wellhead pressure, and pressure at different heights.

[0104] (4) By varying the gas and liquid flow rates and testing experimental data under different flow patterns, the pressure distribution characteristics under different flow patterns can be obtained. The test data are shown in Table 6 below:

[0105] Table 6 Pressure gauges at different altitudes

[0106]

[0107] Example 6:

[0108] The gas intrusion well simulation experimental method of the present invention specifically includes the following steps:

[0109] (1) Open the oil casing connecting valve 5 and the bottom hole device check valve 20, close the vent valve 10, and establish a reverse circulation flow channel between the oil casing annulus, tubing and wellhead.

[0110] (2) open the centrifugal pump 17, adjust the liquid flow, inject liquid to the reverse circulation flow channel, then select different range of gas channel, adjust the gas invasion gas flow, simulate the gas invasion process, and record the gas invasion gas flow;

[0111] (3) increase the injection speed, and record the liquid flow and bottom hole pressure when no gas invasion gas is observed in the wellbore;

[0112] (4) change different gas invasion gas flows, and obtain the gas invasion well killing law under different gas invasion gas conditions.

[0113] Table 7 gas invasion well killing law under different gas invasion gas conditions

[0114]

[0115] The experimental method of the embodiment of the present application integrates multiphase pipe flow simulation, gas lifting oil production simulation and gas invasion well killing simulation, and can be realized through one experimental system, so that one machine has multiple functions, the application range of the existing gas lifting oil production simulation device is widened, and the equipment cost is effectively saved.

[0116] In the description of the present application, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0117] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "set", "mount", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or indirectly connected through an intermediate medium, or it can be connected inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0118] The basic principles and main features of the present application and the advantages of the present application have been shown and described. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A multifunctional, multi-stage gas lift oil recovery simulation experimental method, characterized in that: The simulation device comprises a wellhead device (1), a simulation tubing (4), a simulation casing (3) and a well bottom device (7), the upper and lower ends of the simulation tubing (4) and the simulation casing (3) are connected with the wellhead device (1) and the well bottom device (7) respectively, the simulation casing (3) is sleeved outside the simulation tubing (4), the side wall of the simulation tubing (4) is connected with a gas lift valve (2), the outside of the simulation casing (3) is connected with an oil casing communication valve (5), an oil casing annular structure is formed between the simulation casing (3) and the simulation tubing (4), the oil casing annular structure serves as a flow channel for gas lift gas flowing from the wellhead device (1) to the gas lift valve (2) and annular space liquid flowing from the well bottom device (7) to the simulation tubing (4), and the gas-liquid mixture flows out along the simulation tubing (4) through the wellhead device (1) during the gas lift process, and the outside of the simulation device is further connected with a gas-liquid flow metering mechanism. The experimental method comprises a gas lift oil production experimental method, a multiphase pipe flow simulation experimental method and a gas channeling well killing simulation experimental method, wherein the gas lift oil production experimental method comprises the following steps: S1: selecting a gas lift pipe column structure; S2: using a data acquisition control system to make the gas lift valve be in an open state, selecting a small range liquid injection pipeline, and injecting liquid into the simulation tubing (4) and the oil casing annular structure at a small flow rate, the gas lift valve (2) comprising a first stage gas lift valve and a second stage gas lift valve distributed upward and downward, the liquid level being higher than the first stage gas lift valve by means of a vent valve (10) and keeping the liquid level height stable, and then closing the vent valve (10); S3: gas lift simulation with manual valve closing: opening the valve of the large range gas injection pipeline, adjusting the gas flow rate, supplying gas into the oil casing annular structure, lowering the liquid level of the oil casing annular structure, selecting the manual control mode to close the first stage gas lift valve when the liquid level of the oil casing annular structure is lowered to the second stage gas lift valve, and sequentially closing the second stage gas lift valve when the liquid level of the oil casing annular structure is lowered to the well bottom, and completing the gas lift simulation after the gas lift lifting pressure is stable; S4: gas lift simulation with automatic valve closing: manually closing the second stage gas lift valve, setting the first stage gas lift valve to the automatic closing gas lift valve control mode, manually setting the gas lift valve closing height, opening the valve of the large range gas injection pipeline, adjusting the gas flow rate, supplying gas into the oil casing annular structure, lowering the liquid level of the oil casing annular structure, closing the first stage gas lift valve when the liquid level of the oil casing annular structure is lowered to the set liquid level height, and ending the gas lift simulation when the gas lift gas enters the tubing from the well bottom and works stably, which can realize the gas lift simulation under different gas lift valve closing pressures; The multiphase pipe flow simulation experimental method comprises the following steps: S11: closing the oil casing communication valve (5) and opening the well bottom device one-way valve (20) to establish a single tubing flow channel; S12: selecting the corresponding range gas and liquid flow meters according to the gas and liquid flow rates, starting the air compressor (13), slowly opening the valve of the liquid injection pipeline, slowly increasing the valve opening degree within the liquid flow meter range, adjusting the flow rate to the experimental flow rate, at this time, the simulation tubing (4) starts to fill with liquid; S13: When the simulation tubing (4) is filled with liquid, slowly open the valve of the gas injection pipeline, adjust the amount of gas, and observe the gas-liquid two-phase flow structure in the simulation tubing; S14: After the flow pattern stabilizes, use the multiphase flow pressure distribution calculation module in the data acquisition control system (6) to input different tubing heights, calculate the pressure and flow pattern at that height, and record the bottom hole flowing pressure, wellhead pressure, and pressure at different heights; S15: Change the different gas and liquid flow rates to test experimental data under different flow patterns and obtain pressure distribution characteristics under different flow patterns.

2. The multifunctional multi-stage gas lift oil recovery simulation experiment method according to claim 1, characterized in that: The gas-liquid flow metering mechanism includes a first flow meter module and a second flow meter module, the first flow meter module is connected to the gas injection pipeline of the simulation device, and the first flow meter module is connected to an air compressor (13); the second flow meter module is connected to the liquid injection pipeline of the simulation device, and the second flow meter module is connected to a centrifugal pump (17) and a water tank (18).

3. The multifunctional multi-stage gas lift oil recovery simulation experiment method according to claim 2, characterized in that: The gas injection pipeline is connected to the wellhead device (1) through the first flow meter module, the liquid injection pipeline is connected to the bottom hole device (7) through the second flow meter module; or the gas injection pipeline is connected to the bottom hole device (7) through the first flow meter module, the liquid injection pipeline is connected to the wellhead device (1) through the second flow meter module; or the liquid injection pipeline is connected to the wellhead device (1) through the second flow meter module, and the gas injection pipeline is connected to the bottom hole device (7) through the first flow meter module.

4. The multifunctional multi-stage gas lift oil recovery simulation experiment method according to claim 3, characterized in that: The first flow meter module and the second flow meter module each include two paths, one path is provided with a large-range flow meter, and the other path is provided with a small-range flow meter.

5. The multifunctional multi-stage gas lift oil recovery simulation experiment method according to claim 1 or 3, characterized in that: It also includes a data acquisition control system (6), which includes a gas-liquid flow meter, a pressure transmitter, a differential pressure transmitter, and a controller for real-time monitoring of the real-time change curve of the bottom hole pressure during gas lifting.

6. The multifunctional multi-stage gas lift oil recovery simulation experimental method according to claim 5, characterized in that: The wellhead device (1) and the bottom hole device (7) are also connected to a differential pressure sensor (8), which is connected to the data acquisition control system (6).

7. The multifunctional multi-stage gas lift oil recovery simulation experiment method according to claim 1 or 3, characterized in that: The wellhead device (1) is externally connected to a gas-liquid separation tank (19) and a vent valve (10), and the bottom hole device (7) is provided with a bottom hole device check valve (20).

8. The multifunctional multi-stage gas lift oil recovery simulation experiment method according to claim 7, characterized in that: The gas invasion well killing simulation experiment method includes the following steps: S21: Open the oil sleeve communication valve (5) and the bottom hole device check valve (20), close the vent valve (10), and establish a reverse circulation flow channel of the oil sleeve annulus-tubing-wellhead; S22: Open the centrifugal pump (17), adjust the liquid flow rate, inject liquid into the reverse circulation flow channel, then select different range gas injection channels, adjust the gas invasion gas flow rate, simulate the gas invasion process, and record the gas invasion gas flow rate; S23: Increase the liquid injection speed, and when no gas invasion gas is observed in the wellbore, record the liquid flow rate and the bottom hole pressure at that time; S24: Change the different gas invasion gas flow rates to obtain the gas invasion well killing law under different gas invasion gas conditions.

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