Downhole gas-liquid two-phase flow fine control structure and reliability inspection device

Abstract

An underground gas-liquid two-phase flow fine control structure and reliability inspection device comprises a high-pressure gas-liquid two-phase flow device, a heating device, a fine control device, a temperature and pressure acquisition system, a flow testing device, a back pressure valve and a gas blowout device. A gas phase pipeline and a liquid phase pipeline of the high-pressure gas-liquid two-phase flow device are matched with the fine control device through the heating device, a temperature and pressure acquisition system and a flow testing device are correspondingly arranged on a pipeline communicated with the fine control device, and a back pressure valve is arranged on a pipeline communicated with the gas blowout device. According to the fine control structure for the underground gas-liquid two-phase flow, fine control over gas and liquid media under the conditions of different injection amounts, injection pressures and injection temperatures can be achieved, and compared with the prior art, the flow testing range is wider, the testing precision is more accurate, and the testing cost is lower. And a basis is provided for adjustment of the throttling structure in the gas / water injection process, and the method is suitable for application and popularization.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield development and production, and more specifically to a fine control structure for underground gas-liquid two-phase flow and a reliability testing device. Background Art

[0002] In the global enhanced oil recovery projects, gas drive accounts for 64% of the total number of projects, including 35% for thermal recovery, 49% for CO2, 15% for hydrocarbons + nitrogen, and 1% for chemical drive. Gas drive has become the main enhanced oil recovery technology.

[0003] The principle of oil well gas injection is to inject gas into the oil well to change the pressure and temperature conditions inside the oil well, thereby improving the physical properties of the reservoir, increasing the fluidity and recovery rate of crude oil, and also reducing environmental pollution and energy waste. Finely controlled injection of gas-liquid two-phase flow can, on the one hand, effectively reduce the impact of interlayer interference on the injection medium on oil recovery efficiency. Due to the vertical development of the oil layer, there is interlayer interference during general gas injection, and the low permeability layer is basically not well utilized. Most of the injected medium enters the high permeability formation, and the effective injection volume of the low permeability layer is very small. On the other hand, fine control of the injected medium can effectively suppress the fingering effect and increase the sweep rate. The difference between fine control of stratified injection and general injection is that the formation is isolated according to the characteristics of the formation, and the injection is allocated separately to suppress the occurrence of fingering and gas channeling, improve the sweep efficiency, and enhance the displacement effect.

[0004] Therefore, there is an urgent need for a fine control structure and reliability testing device for underground gas-liquid two-phase flow. Summary of the invention

[0005] The present invention overcomes the deficiencies in the prior art and provides a fine control structure for underground gas-liquid two-phase flow and a reliability testing device.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] A fine control structure and reliability inspection device for underground gas-liquid two-phase flow rate, comprising: a high-pressure gas-liquid two-phase flow rate device, a heating device, a fine control device, a temperature and pressure acquisition system, a flow test device, a back pressure valve and a gas blowout device. The gas phase pipeline and the liquid phase pipeline of the high-pressure gas-liquid two-phase flow rate device are arranged in cooperation with the fine control device through the heating device. The temperature and pressure acquisition system and the flow test device are correspondingly arranged on the pipelines connected with the fine control device. The pipelines connected with the fine control device and the gas blowout device are provided with a back pressure valve. A low-flow gas flow channel, a high-flow gas flow channel and a water medium flow channel are arranged in a fixed flow channel control part of the fine control device. The low-flow gas flow channel, the high-flow gas flow channel and the water medium flow channel are connected with the inner cavity of the rotatable control part of the fine control device. The rotatable control part is coaxially connected with the fixed flow channel control part along the long axis. A gas-liquid two-phase fluid inlet end sealing surface is arranged in the rotatable control part. The gas-liquid two-phase fluid inlet end sealing surface matches the outlet position of the low-flow gas flow channel, the high-flow gas flow channel and the water medium flow channel.

[0008] The fixed flow channel control part and the rotatable control part are both annular cylindrical tube bodies, and the inner cavity cross-section of the rotatable control part is an annular structure.

[0009] The sealing surface at the inlet end of the gas-liquid two-phase fluid is a C-shaped structure.

[0010] The low-flow gas flow channel is a continuous S-shaped flow-blocking structure.

[0011] The high-flow gas flow channel is a cylindrical flow-blocking structure.

[0012] The water medium flow channel is a special-shaped flow-blocking structure.

[0013] The high-pressure gas-liquid two-phase flow device includes a nitrogen compressor, a water tank, a liquid carbon dioxide storage tank, a liquid variable frequency booster pump, a carbon dioxide variable frequency booster pump and a liquid recovery device. The nitrogen compressor is connected to the heating device accordingly, the water tank and the liquid carbon dioxide storage tank are connected to the pipelines connected to the nitrogen compressor and the heating device through the liquid variable frequency booster pump and the carbon dioxide variable frequency booster pump respectively, and the pipeline connecting the water tank to the back pressure valve and the gas release device is connected to the liquid recovery device through the carbon dioxide variable frequency booster pump.

[0014] The temperature and pressure acquisition system includes: a temperature acquisition system and a pressure acquisition system. The temperature acquisition system is arranged on the pipeline connecting the heating device and the fine control device, and the pressure acquisition system is arranged at the inlet and outlet of the fine control device respectively.

[0015] The flow testing device includes a first flow meter, a second flow meter and a third flow meter. The first flow meter is arranged on the pipeline connecting the heating device and the fine control device. The inlet pipeline of the fine control device and the inlet pipeline of the back pressure valve are connected through a bypass device. The second flow meter is arranged on the bypass device. The third flow meter is arranged on the pipeline connecting the fine control device and the back pressure valve.

[0016] The beneficial effects of the present invention are as follows: through a fine control structure for underground gas-liquid two-phase flow, fine control of gas and liquid media under different injection volumes, injection pressures, and injection temperatures can be achieved. Compared with previous methods, the flow test range is wider and the test accuracy is more accurate, providing a basis for adjusting the throttling structure during the gas / water injection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 is a cross-sectional view of a fixed flow channel control portion;

[0019] Figure 3 is a cross-sectional view of a rotatable control portion;

[0020] Figure 4 It is a schematic diagram of the structure of a low-flow gas flow channel, a high-flow gas flow channel and a water medium flow channel;

[0021] Figure 5 It is a schematic diagram of the structure of the S-type spoiler;

[0022] Figure 6 This is a graph showing the change in angle of the rotatable control unit and the change in cross-sectional area at the fluid inlet end.

[0023] In the figure, 1. nitrogen compressor; 2. water tank; 3. liquid carbon dioxide storage tank; 4. liquid variable frequency booster pump; 5. carbon dioxide variable frequency booster pump; 6. heating device; 7. temperature acquisition system; 8. first flow meter; 9. fine control device; 91. fixed flow channel control unit; 911. low flow gas flow channel; 912. high flow gas flow channel; 913. water medium flow channel; 914. S-type baffle; 915. locking device; 92. rotatable control unit; 921. sealing surface at the inlet end of gas-liquid two-phase fluid; 10. pressure acquisition system; 11. bypass device; 12. second flow meter; 13. third flow meter; 14. back pressure valve; 15. gas release device; 16. liquid recovery device. DETAILED DESCRIPTION

[0024] Example

[0025] The structure and reliability inspection device for fine control of underground gas-liquid two-phase flow rate include: a high-pressure gas-liquid two-phase flow rate device, a heating device 6, a fine control device 9, a temperature and pressure acquisition system, a flow test device, a back pressure valve 14 and a gas release device 15. The gas phase pipeline and the liquid phase pipeline of the high-pressure gas-liquid two-phase flow rate device are arranged in coordination with the fine control device 9 through the heating device 6. The temperature and pressure acquisition system and the flow test device are correspondingly arranged on the pipeline connected to the fine control device 9. The back pressure valve 14 is arranged on the pipeline connected to the fine control device 9 and the gas release device 15. The fixed flow channel control part of the fine control device 9 A low-flow gas flow channel 911, a high-flow gas flow channel 912 and a water medium flow channel 913 are provided in 91. The low-flow gas flow channel 911, the high-flow gas flow channel 912 and the water medium flow channel 913 are connected to the inner cavity of the rotatable control part 92 of the fine control device 9. The rotatable control part 92 is coaxially rotatably connected with the fixed flow channel control part 91 along the long axis. A gas-liquid two-phase fluid inlet end sealing surface 921 is provided in the rotatable control part 92. The gas-liquid two-phase fluid inlet end sealing surface 921 matches the outlet positions of the low-flow gas flow channel 911, the high-flow gas flow channel 912 and the water medium flow channel 913.

[0026] The fixed flow channel control part and the rotatable control part 92 are both annular cylindrical tubes, and the inner cavity cross-section of the rotatable control part 92 is an annular structure.

[0027] The gas-liquid two-phase fluid inlet sealing surface 921 is a C-shaped structure.

[0028] The high-pressure gas-liquid two-phase flow device includes a nitrogen compressor 1, a water tank 2, a liquid carbon dioxide storage tank 3, a liquid variable frequency booster pump 4, a carbon dioxide variable frequency booster pump 5 and a liquid recovery device 16. The nitrogen compressor 1 is correspondingly connected to the heating device 6. The water tank 2 and the liquid carbon dioxide storage tank 3 are respectively connected to the pipelines connected to the nitrogen compressor 1 and the heating device 6 through the liquid variable frequency booster pump 4 and the carbon dioxide variable frequency booster pump 5. The pipeline connecting the water tank 2 to the back pressure valve 14 and the gas release device 15 is connected to the liquid recovery device 16 through the carbon dioxide variable frequency booster pump 5.

[0029] The temperature and pressure acquisition system includes: a temperature acquisition system 7 and a pressure acquisition system 10. The temperature acquisition system 7 is arranged on a pipeline connecting the heating device 6 and the fine control device 9, and the pressure acquisition system 10 is arranged at the inlet and outlet ends of the fine control device 9 respectively.

[0030] The flow testing device includes a first flow meter 8, a second flow meter 12 and a third flow meter 13. The first flow meter 8 is arranged on the pipeline connecting the heating device 6 and the fine control device 9. The inlet pipeline of the fine control device 9 and the inlet pipeline of the back pressure valve 14 are connected through a bypass device 11. The second flow meter 12 is arranged on the bypass device 11. The third flow meter 13 is arranged on the pipeline connecting the fine control device 9 and the back pressure valve 14.

[0031] like Figure 1-3 As shown, the working principle of the present invention is as follows.

[0032] In this solution, the high-pressure gas-liquid two-phase flow device and the heating device 6 provide the fine control device 9 with the corresponding gas flow and liquid, and the fine control device 9 controls the mixing. The temperature and pressure acquisition system and the flow test device are used to monitor the overall data.

[0033] Further, if Figure 1 As shown, the high-pressure gas-liquid two-phase flow device is directly pressurized by the nitrogen compressor 1 to the displacement and pressure required for the experiment; the water in the water tank 2 is pressurized by the liquid variable frequency booster pump 4 to the displacement and pressure required for the experiment, and the liquid carbon dioxide storage tank 3 is pressurized by the carbon dioxide variable frequency booster pump 5 to the displacement and pressure required for the experiment.

[0034] like Figure 2 and Figure 3 As shown, the fine control device 9 adjusts the gas-liquid two-phase inlet flow area by controlling the angle of the rotatable control part 92 to perform preliminary flow control, and on the other hand, realizes fine control of the flow through the three different flow channels of the fixed flow channel control part 91. The fine control device 9 controls the relative movement of the gas-liquid two-phase fluid inlet sealing surface 921 and the inlet of the low-flow gas flow channel 911, the high-flow gas flow channel 912 and the water medium flow channel 913 through the mutual rotation between the fixed flow channel control part 91 and the rotatable control part 92, so that the gas-liquid two-phase fluid inlet sealing surface 921 can control the flow of the above three flow channels for mixing.

[0035] Furthermore, the low-flow gas flow channel 911 is a continuous S-shaped flow-blocking structure, which increases friction resistance when the airflow passes through to achieve fine control under low gas volume conditions.

[0036] The high-flow gas flow channel 912 is a cylindrical flow-blocking structure, and the cylindrical flow area is adjusted according to the amount of gas injection to achieve fine control under large gas volume conditions.

[0037] The water medium flow channel 913 is a special-shaped flow-blocking structure. The flow area is adjusted according to the amount of water injection to achieve fine control under different water injection conditions. In this embodiment, the water medium flow channel 913 adopts a C-shaped and arc-shaped cross-section.

[0038] Furthermore, low-flow nitrogen, compressed air and carbon dioxide enter the pipeline heating device 6 through the variable frequency booster pump 5 or the nitrogen compressor 1. The power of the heating device is adjusted to allow the nitrogen, compressed air and carbon dioxide to fully absorb heat. After being heated to the experimental temperature, they enter the fine control device 9, and the rotary control unit 2 is adjusted to expose the inlet end of the low-flow gas flow channel 911. When the gas passes through, the flow channel direction changes once, the flow velocity changes from high to low once, and the flow state and flow field distribution also change accordingly, thereby generating local energy loss and forming a throttling pressure difference, which can maximize the friction resistance of the gas flow and achieve fine control of the gas flow at low displacement.

[0039] High-flow nitrogen, compressed air and carbon dioxide enter the pipeline heating device 6 through the variable frequency booster pump 5 or the nitrogen compressor 1. The power of the heating device is adjusted to allow the nitrogen, compressed air and carbon dioxide to fully absorb heat. After the temperature is raised to the experimental temperature, they enter the fine control device 9. The rotary control unit 92 is adjusted to expose the inlet end of the high-flow gas flow channel 912. By adjusting the flow area of ​​the gas through the flow channel, the flow state and flow field distribution are changed accordingly, the flow velocity is changed to generate local energy loss, and a throttling pressure difference is formed to achieve fine control of the gas flow at high flow.

[0040] Different water injection amounts enter the pipeline heating device 6 through the liquid variable frequency booster pump 4. The power of the heating device is adjusted to allow the water to fully absorb heat. After the water is heated to the experimental temperature, it enters the fine control device 9. The rotating control part 92 is adjusted to expose the inlet end of the water medium flow channel 913. By adjusting the flow area of ​​the water through the flow channel, the flow field distribution is changed accordingly, the flow velocity is changed to generate local energy loss, and a throttling pressure difference is formed to achieve fine control of the flow rate under different water injection amounts.

[0041] Furthermore, the pressure acquisition system 10 tests the throttling control capability of the fine control device by acquiring the inlet pressure P1 and the outlet pressure P2. The back pressure valve 14 is used to adjust the pressure P2 at the rear end of the fine control device 9 to simulate different formation pressures.

[0042] The first flowmeter 8 is used to test the total gas-liquid two-phase flow rate of the experimental process; the second flowmeter 12 is used to measure the flow rate of the gas-liquid two-phase medium after throttling; the third flowmeter 13 is used to measure the flow rate of the gas-liquid two-phase medium in the bypass device 11.

[0043] The gas release device 15 and the liquid recovery device 16 are used to release the nitrogen and compressed air generated in the experiment and to recover the liquid water and carbon dioxide for secondary utilization.

[0044] Further, if Figure 4 and Figure 5As shown, in this embodiment, the structure of the low-flow gas flow channel 911 is improved. In the prior art, the inner groove of the continuous S is not processed. In this embodiment, the S-shaped flow blocking member 914 is fastened in the low-flow gas flow channel 911 through a locking device 915, thereby realizing the setting of a continuous S-shaped flow blocking structure in the low-flow gas flow channel 911 and overcoming the existing technical problems.

[0045] Preferably, in this embodiment, the parameters of the nitrogen compressor 1 are in the displacement range of 0 to 1200 m 3 / h, pressure range 0 ~ 35MPa. The pressure acquisition system 10 adopts a pressure sensor, and selects PG208 protective pressure transmitter, with a pressure range of 0 ~ 100MPa. The fine control device 9 uses a precipitation hardened stainless steel as the main material of the device, and the material has the characteristics of high strength and corrosion resistance. The heating device 6 uses electric heating for heating, and the temperature range is 0 ~ 120 ° C. The flowmeters all use mass flowmeters, and the test range is 0.2 ~ 1000t / h. The interface connection method used in this embodiment is an internal thread interface. The sealing method is based on the reference standard of the seals between the parts, and adopts fluororubber materials that meet the requirements of gas explosion protection.

[0046] The reliability test experimental conditions in this embodiment are shown in Table 1.

[0047] Table 1

[0048]

[0049]

[0050] Further, the steps of verifying the reliability of the fine control structure in this embodiment are as follows: Figure 1 As shown, the nitrogen compressor 1 and the carbon dioxide increasing pump 5 increase the pressure of the mixed medium of nitrogen and carbon dioxide in the liquid carbon dioxide storage tank 3 to 15MPa, and transport it to the heating device 6 to increase the temperature to 100°C. The nitrogen is in gaseous state and the carbon dioxide is in supercritical state. The first flowmeter 8 measures the total flow Q1 of the mixed medium in the pipeline. According to the experimental setting flow adjustment fine control device 9 inlet end face size and back pressure valve 14 opening, the outlet pressure is controlled to 8MPa. At the same time, the flow Q2 at the rear end is tested by the third flowmeter 13. The test data is compared with the experimental setting flow. The flow test experimental results are shown in Table 2 and Figure 6 shown.

[0051] Table 2

[0052]

[0053] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A fine control structure and reliability test device for underground gas-liquid two-phase flow, characterized in that: include: A high-pressure gas-liquid two-phase flow device, a heating device, a fine control device, a temperature and pressure acquisition system, a flow testing device, a back pressure valve and a gas release device. The gas phase pipeline and the liquid phase pipeline of the high-pressure gas-liquid two-phase flow device are arranged in cooperation with the fine control device through the heating device. The pipelines connected to the fine control device are correspondingly provided with a temperature and pressure acquisition system and a flow testing device. A back pressure valve is provided on the pipeline connected to the fine control device and the gas release device. A low-flow gas flow channel, a high-flow gas flow channel and a water medium flow channel are provided in the fixed flow channel control part of the fine control device. The low-flow gas flow channel, the high-flow gas flow channel and the water medium flow channel are connected to the inner cavity of the rotatable control part of the fine control device. The rotatable control part is coaxially connected to the fixed flow channel control part along the long axis. A gas-liquid two-phase fluid inlet end sealing surface is provided in the rotatable control part. The gas-liquid two-phase fluid inlet end sealing surface matches the outlet position of the low-flow gas flow channel, the high-flow gas flow channel and the water medium flow channel.

2. The downhole gas-liquid two-phase flow fine control structure and reliability inspection device according to claim 1 is characterized in that: The fixed flow channel control part and the rotatable control part are both annular cylindrical tubes, and the inner cavity cross-section of the rotatable control part is an annular structure.

3. The downhole gas-liquid two-phase flow fine control structure and reliability inspection device according to claim 2 is characterized in that: The sealing surface at the gas-liquid two-phase fluid inlet end is a C-shaped structure.

4. The downhole gas-liquid two-phase flow fine control structure and reliability inspection device according to claim 1 is characterized in that: The low-flow gas flow channel is a continuous S-shaped flow-blocking structure.

5. The downhole gas-liquid two-phase flow fine control structure and reliability inspection device according to claim 1 is characterized in that: The high-flow gas flow channel is a cylindrical flow-blocking structure.

6. The downhole gas-liquid two-phase flow fine control structure and reliability inspection device according to claim 1 is characterized by: The water medium flow channel is a special-shaped flow-blocking structure.

7. The downhole gas-liquid two-phase flow fine control structure and reliability inspection device according to claim 1 is characterized by: The high-pressure gas-liquid two-phase flow device includes a nitrogen compressor, a water tank, a liquid carbon dioxide storage tank, a liquid variable frequency booster pump, a carbon dioxide variable frequency booster pump and a liquid recovery device. The nitrogen compressor is connected to the heating device accordingly. The water tank and the liquid carbon dioxide storage tank are respectively connected to the pipeline connecting the nitrogen compressor and the heating device through the liquid variable frequency booster pump and the carbon dioxide variable frequency booster pump. The pipeline connecting the water tank to the back pressure valve and the gas release device is connected to the liquid recovery device through the carbon dioxide variable frequency booster pump.

8. The downhole gas-liquid two-phase flow fine control structure and reliability inspection device according to claim 1 is characterized in that: The temperature and pressure acquisition system includes: a temperature acquisition system and a pressure acquisition system. The temperature acquisition system is arranged on a pipeline connecting the heating device and the fine control device, and the pressure acquisition system is arranged at the inlet and outlet ends of the fine control device respectively.

9. The downhole gas-liquid two-phase flow fine control structure and reliability inspection device according to claim 1 is characterized by: The flow testing device includes a first flow meter, a second flow meter and a third flow meter. The first flow meter is arranged on the pipeline connecting the heating device and the fine control device. The inlet pipeline of the fine control device and the inlet pipeline of the back pressure valve are connected through a bypass device. The second flow meter is arranged on the bypass device. The third flow meter is arranged on the pipeline connecting the fine control device and the back pressure valve.

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