Gas-liquid simultaneous production and injection process system

Abstract

The present application relates to a kind of gas-liquid simultaneous injection and production process system, the system includes packer and electric pump unit, and liquid pump unit includes gas-liquid separator and liquid pump;The upper portion of packer is connected with gas flow pipe and liquid flow pipe, and gas-liquid simultaneous injection and production process system further includes wellhead device, and wellhead device includes tubing head, and liquid flow pipe and gas flow pipe are hung in tubing head, and tubing head has gas flow interface communicated with gas flow pipe, liquid flow interface communicated with liquid flow pipe and injection water interface communicated with the upper oil sleeve annulus of the upper portion of packer, and wellhead injection and production device further includes for the injection water interface and injection water interface to be connected to measure the injection water volume and / or injection water pressure and other process parameters in liquid flow pipe and measure the injection water volume and / or injection water pressure and other process parameters in liquid flow pipe and measure the injection water volume and / or injection water pressure and other process parameters in liquid flow pipe and measure the injection water volume and / or injection water pressure and other process parameters in liquid flow pipe and measure the injection water volume and / or injection water pressure and other process parameters in liquid flow pipe and measure the injection water volume and / or injection water pressure and other process parameters in liquid flow pipe and measure the injection water volume and / or injection water pressure of backflow line, and the measuring device for measuring the injection water pressure and other process parameters is installed on backflow line, which effectively solves the problem that no special downhole detection instrument exists in the prior art, so that injection process parameters cannot be directly measured, and the motor of liquid pump has the risk of dry burning.

Description

Technical Field

[0001] This invention relates to a gas-liquid co-production and injection process system, belonging to the field of gas-liquid co-production and injection technology. Background Technology

[0002] High water-cut gas reservoirs often experience gas-liquid co-production, reduced production due to wellbore fluid accumulation, and even water flooding shutdowns during the later stages of development. Current technologies typically employ gas lift, mechanical pumping, or electric pumps to transport the accumulated fluid from the well to a surface wastewater treatment system. After treatment, the fluid is then injected back into the well into the injection zone via a water injection network. However, for many remote wells and newly developed blocks, inadequate surface infrastructure and the lack of wastewater treatment systems mean that produced water cannot be treated. Discharging it externally would pollute the environment, while reinjecting water or laying reinjection pipelines would be prohibitively expensive. In such cases, gas wells can only rely on their own pressure for gas-liquid co-production. However, when the well pressure drops to the point where it is insufficient to carry the produced water to the surface, the liquid accumulates in the wellbore, severely impacting gas production. Many wells shut down due to water flooding, significantly affecting the block's development outcome.

[0003] To address the aforementioned problems, Chinese invention patent application CN113530491A discloses a cable packer, a same-well production and injection process string, and a same-well production and injection system. The same-well production and injection system includes a same-well production and injection process string and a surface electric pump unit control device. The same-well production and injection process string includes a submersible electric pump unit located below the water injection layer and a cable packer located above the submersible electric pump unit. The submersible electric pump unit includes a motor, a gas-liquid separator, and a liquid pump arranged sequentially from bottom to top. The motor provides power to the liquid pump. The gas-liquid separator has a gas-liquid separation liquid outlet and a gas-liquid separation gas outlet, which are connected to the annulus at the gas-liquid separator. The cable packer includes an outer central tube and an inner central tube located inside the outer central tube, forming an annular channel between the inner and outer central tubes. The inner central tube is connected to the liquid outlet of the gas-liquid separator to form a liquid flow channel. A liquid outlet is located at the top of the cable packer, connecting the liquid flow channel to the annulus above the cable packer, for injecting water from the liquid flow channel into the injection layer. A gas inlet is located at the bottom of the cable packer, connecting the annular channel between the inner and outer central tubes to the annulus at the gas-liquid separator to form a gas flow channel. An upper tubing connected to the upper end of the cable packer, communicating with the gas flow channel, allows gas from the gas flow channel to be extracted to the wellhead.

[0004] In the same-well production and injection process string of the aforementioned patent document, since the liquid outlet is used to connect the liquid flow channel with the annulus above the cable packer, water in the liquid flow channel can be directly reinjected into the injection layer in the well through the liquid outlet. However, since there are currently no mature and reliable downhole monitoring and metering instruments for water injection process parameters such as produced fluid volume, reinjected water volume, and injection pressure, it is not possible to directly measure water injection process parameters such as produced fluid volume, reinjected water volume, and injection pressure downhole. Consequently, it is also impossible to accurately measure and control water injection process parameters such as produced fluid volume, reinjected water volume, and injection pressure. Furthermore, when the produced fluid volume cannot be accurately measured, it is easy to cause the pump to run dry, the pump to stop due to low pump efficiency, or even the pump motor to burn out due to insufficient produced fluid volume. When the motor burns out, the motor or the pump must be replaced, which increases costs. Summary of the Invention

[0005] The purpose of this invention is to provide a gas-liquid co-production and injection process system to solve the problems in the existing technology, which are that the water injection process parameters cannot be directly measured due to the lack of mature and reliable downhole monitoring and metering instruments, and the risk of dry burning of the liquid pump motor.

[0006] To achieve the above objectives, the gas-liquid co-production and injection process system of the present invention adopts the following technical solution:

[0007] A gas-liquid co-production and injection system includes a packer and a liquid pump unit connected below the packer. The liquid pump unit includes a gas-liquid separator and a liquid pump. The packer includes an inner central pipe and an outer central pipe. The inner central pipe receives liquid separated by the gas-liquid separator, and a lower annular channel between the inner and outer central pipes receives gas separated by the gas-liquid separator. A gas flow pipe communicating with the lower annular channel is connected above the packer, and a liquid flow pipe communicating with the inner central pipe is also connected above the packer. The well production and injection process system also includes a wellhead device, which includes a tubing head, a fluid flow pipe, and a gas flow pipe suspended inside the tubing head. The tubing head has a gas flow interface that communicates with the gas flow pipe and is used to connect to the gas production pipeline, a fluid flow interface that communicates with the fluid flow pipe, and a water injection interface that communicates with the upper annulus above the packer. The wellhead device also includes a reinjection pipeline for connecting the fluid flow interface and the water injection interface to reinject the liquid in the fluid flow pipe back into the water injection layer. A measuring device for measuring water injection process parameters is installed on the reinjection pipeline.

[0008] The beneficial effects of the above technical solution are as follows: In the gas-liquid co-production and injection process system of the present invention, since a liquid flow pipe connected to the inner central pipe is also connected above the packer, and since the wellhead device at the wellhead includes a tubing head, and both the liquid flow pipe and the gas flow pipe are suspended inside the tubing head, and the tubing head has a gas flow interface connected to the gas flow pipe and used to connect to the gas production pipeline, and a liquid flow interface connected to the liquid flow pipe, the gas separated by the gas-liquid separator can be transported to the gas production pipeline through the lower annular channel between the inner central pipe and the outer central pipe, the gas flow pipe, and the gas flow interface to achieve gas production. The lower annular channel, the gas flow pipe, and part of the channel inside the tubing head constitute the gas flow channel, and the liquid separated by the gas-liquid separator can be transported through the inner central pipe... The tubing head, consisting of the tubing, fluid flow pipe, and fluid flow interface, is discharged after the tubing. The inner central pipe, fluid flow pipe, and a portion of the channel within the tubing head constitute the fluid flow channel. Since the tubing head also has a water injection interface connecting to the upper annulus above the packer, the wellhead assembly includes a reinjection line connecting the fluid flow interface and the water injection interface. A measuring device for measuring water injection process parameters is installed on the reinjection line. This allows the fluid in the fluid flow channel to be reinjected into the water injection layer. Compared to existing technologies, because the reinjection line is located at the wellhead, the measuring device on the reinjection line can directly measure the water injection process parameters, thus enabling accurate measurement of these parameters. Furthermore, accurate measurement of the water injection process parameters can indirectly monitor the operation of the fluid pump, preventing pump idling, low efficiency leading to pump shutdown, or even dry-burning of the pump motor due to insufficient fluid production. This avoids the need to replace the motor or pump, reducing costs.

[0009] Furthermore, the wellhead injection and production device also includes a connector fixedly connected to the fluid flow interface. The connector has a reinjection interface that communicates with the fluid flow interface, and the reinjection pipeline is connected between the reinjection interface and the water injection interface.

[0010] The beneficial effects of the above technical solution are as follows: by setting up a connecting component, the reinjection pipeline and the fluid interface can be connected through the connecting component, that is, the direct connection between the reinjection pipeline and the oil pipe head is avoided through the connecting component, which can simplify the structure of the reinjection pipeline to a certain extent.

[0011] Furthermore, the connecting element includes a connecting element body and a first upper valve. The reinjection interface is disposed on the connecting element body and is connected to the reinjection pipeline through the first upper valve. The first upper valve is used to control the reinjection flow rate in the reinjection pipeline. The measuring device includes a first upper pressure gauge installed downstream of the first upper valve.

[0012] The beneficial effects of the above technical solution are as follows: setting up a first upper pressure gauge facilitates the measurement of water injection pressure on the reinjection pipeline and ensures the accuracy of the water injection pressure measurement; setting up a first upper valve not only controls the connection between the reinjection pipeline and the liquid flow pipe, but also adjusts the flow rate of reinjected water in the reinjection pipeline to ensure accurate measurement of the reinjected water volume. In addition, the first upper valve also facilitates the daily maintenance and replacement of the measuring device.

[0013] Furthermore, the connecting component body is also provided with a closed interface that communicates with the liquid flow interface and the reinjection interface. The connecting component also includes a second upper valve. The closed interface is connected to a closed pipeline through the second upper valve, and a second upper pressure gauge is installed on the closed pipeline.

[0014] The beneficial effects of the above technical solution are as follows: Since the closed interface is connected to the liquid flow interface and the reinjection interface, the closed pipeline connected to the closed interface is also connected to the liquid flow interface and the reinjection interface. Thus, the second upper pressure gauge installed on the closed pipeline can not only measure the pressure in the liquid flow pipe, but also accurately obtain the change in reinjection water pressure after adjustment by the first upper valve by comparing the measurement data of the second upper pressure gauge with that of the first upper pressure gauge, so as to ensure the adjustment effect of the first upper valve. The second upper valve is set so that when the second upper pressure gauge is not in use, the closed pipeline and the liquid flow pipe can be isolated by the second upper valve, reducing the unnecessary working time of the second upper pressure gauge, and also facilitating the installation of the closed pipeline and the second upper pressure gauge.

[0015] Furthermore, a shut-off valve is installed on the closed pipeline between the second upper pressure gauge and the second upper valve.

[0016] The beneficial effects of the above technical solution are as follows: by setting a shut-off valve, the second pressure gauge can be replaced without operating the second upper valve, and at the same time, the second upper pressure gauge is protected to prevent excessive pressure in the liquid flow pipe from damaging the second upper pressure gauge.

[0017] Furthermore, the connecting element includes a connecting element body and a third upper valve, which is connected between the connecting element body and the liquid flow interface and is used to control the connection and disconnection between the connecting element and the liquid flow pipe.

[0018] The beneficial effects of the above technical solution are as follows: by setting a third upper valve, the connection between the liquid flow pipe and the connecting component body can be directly controlled through the third upper valve, which facilitates the overall control of the on / off of the liquid flow pipe and the connecting component body. At the same time, when water reinjection is not performed, the use of the connecting component can be avoided, reducing the usage time of the connecting component. In addition, the third upper valve also facilitates the installation and disassembly of the various components on the connecting component.

[0019] Furthermore, the liquid flow pipe is installed inside the air flow pipe, and the oil pipe head includes an upper oil pipe head and a lower oil pipe head arranged vertically. The air flow pipe is suspended inside the lower oil pipe head and connected to the upper oil pipe head. The water injection interface is located on the lower oil pipe head, and the air flow interface is located on the upper oil pipe head.

[0020] The beneficial effects of the above technical solution are as follows: the liquid flow pipe is installed inside the gas flow pipe, which not only allows gas to be transported through the upper annular channel formed between the liquid flow pipe and the gas flow pipe, but also reduces the arrangement space for both, making it easier to install the liquid flow pipe and the gas flow pipe in the well; the upper and lower oil pipe heads are arranged vertically to suspend the gas flow pipe and the liquid flow pipe respectively, which facilitates the suspension of the gas flow pipe and the liquid flow pipe at the wellhead.

[0021] Furthermore, the measuring device includes a flow meter.

[0022] The beneficial effects of the above technical solution are: it can directly measure the flow rate of reinjected water through a flow meter, thereby achieving accurate measurement of the reinjected water volume and facilitating the control of the reinjected water volume.

[0023] Furthermore, the airflow interface is located on the side opposite to the reinjection pipeline or perpendicular to the reinjection pipeline.

[0024] The beneficial effects of the above technical solution are: it can avoid interference between the gas extraction pipeline and the reinjection pipeline, and facilitates the installation of the gas extraction pipeline.

[0025] Furthermore, the packer is a cable packer, the pump is an electric pump, and the tubing head also has a cable interface for the cable used to power the motor of the electric pump to pass through.

[0026] The beneficial effects of the above technical solution are that, by using a cable packer, not only can the sealing between the water injection layer and the production layer be achieved, but it also facilitates the passage of cables. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the gas-liquid co-production and injection process system in this invention;

[0028] Figure 2 This is a schematic diagram of the cable packer in the gas-liquid co-production and injection process tubing of the present invention;

[0029] Figure 3 This is a cross-sectional view of the wellhead device in the gas-liquid co-production and injection process system of the present invention.

[0030] In the diagram: 10. Production layer; 20. Water injection layer; 30. Lower oil sleeve annulus; 40. Upper oil sleeve annulus; 50. Cable packer; 51. Seal; 52. Inner central tube; 53. Outer central tube; 60. Outer oil pipe; 70. Submersible electric pump unit; 71. Motor; 72. Gas-liquid separator; 73. Centrifugal pump; 80. Cable; 90. Liquid flow pipe; 100. Gas flow pipe; 110. Sleeve head; 120. Lower oil pipe head; 121. Lower oil pipe four-way connector; 122. Lower oil pipe hanger; 123. First lower valve; 124. Second lower valve; 130. First branch; 140. Lower pressure gauge 150. Upper oil pipe head; 151. Upper oil pipe four-way connector; 152. Upper oil pipe hanger; 153. First intermediate valve; 154. Second intermediate valve; 160. Second branch line; 170. Gas extraction pipeline; 180. Intermediate pressure gauge; 190. First flow meter; 200. Adapter flange; 210. Four-way connector; 220. First upper valve; 230. Second upper valve; 240. Third upper valve; 250. Fourth upper valve; 260. Reinjection pipeline; 270. First upper pressure gauge; 280. Second flow meter; 290. Closed pipeline; 300. Second upper pressure gauge; 310. Shut-off valve. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0033] It should be noted that, in specific embodiments of the present invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the use of phrases such as "comprising a…" to define an element does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0034] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] In the description of this invention, unless otherwise explicitly specified and limited, the term "provided with" should be interpreted broadly. For example, the object "provided with" can be a part of the body, or it can be separately arranged from the body and connected to the body. This connection can be a detachable connection or a non-detachable connection. Those skilled in the art can understand the specific meaning of the above terms in this invention through specific circumstances.

[0036] Example 1 of the gas-liquid co-production and injection process system of the present invention:

[0037] like Figure 1 As shown, the gas-liquid co-production and injection process system includes a gas-liquid co-production and injection process string, which includes a packer and a liquid pump unit connected below the packer. In this embodiment, as... Figure 2As shown, the packer is a cable packer 50, which includes a sealing element 51 and an inner central tube 52 and an outer central tube 53 arranged at intervals. The sealing element 51 is used to set between the water injection layer 20 and the production layer 10, and the setting of the sealing element 51 can divide the oil sleeve annulus into an upper oil sleeve annulus 40 located above the sealing element 51 and a lower oil sleeve annulus 30 located below the sealing element 51. The upper oil sleeve annulus 40 communicates with the water injection layer 20, and the lower oil sleeve annulus 30 communicates with the production layer 10. In addition, since the cable packer is prior art, such as the cable packer disclosed in Chinese invention patent application with publication number CN113530491A, the specific structure of the cable packer will not be described in detail.

[0038] like Figure 1 As shown, the pump unit is a submersible electric pump unit 70. The submersible electric pump unit 70 is connected to the cable packer 50 through an external oil pipe 60. The cable 80 outside the wellhead can pass downward through the lower annular channel and connect to the submersible electric pump unit 70 to supply power to the submersible electric pump unit 70. The cable 80 and the cable packer 80 are sealed together.

[0039] like Figure 1 As shown, the submersible electric pump unit 70 includes a motor 71, a gas-liquid separator 72, and a liquid pump, wherein the liquid pump is a centrifugal pump 73, i.e., the liquid pump is an electric pump, and the motor 71 provides power to the centrifugal pump 73. The gas-liquid separator 72 is used to separate natural gas and liquid in the production layer 10, and the gas-liquid separator 72 has a liquid outlet for the separated liquid to flow out and a gas outlet for the separated gas to flow out. The gas outlet is connected to the lower oil casing annulus 30, the liquid outlet is connected to the inlet of the centrifugal pump 73, and the outlet of the centrifugal pump 73 is connected to the outer oil pipe 60. The liquid separated by the gas-liquid separator 72 is pressurized by the centrifugal pump 73 and transported to the outer oil pipe 60. The outer oil pipe 60 is connected to the cable packer 50 and is connected to the inner central pipe 52, so that the inner central pipe 52 can be connected to the liquid outlet through the outer oil pipe 60. A lower annular channel is formed between the inner central tube 52 and the outer central tube 53. The cable packer 50 is provided with an air inlet that connects the lower annular channel and the lower oil jacket annulus 30. Gas discharged from the gas outlet of the gas-liquid separator 72 into the lower oil jacket annulus 30 can enter the lower annular channel through the air inlet.

[0040] like Figure 1 and Figure 2As shown, the gas-liquid co-production and injection process string also includes a liquid flow pipe 90 and a gas flow pipe 100 connected above the cable packer 50. The liquid flow pipe 90 is installed inside the gas flow pipe 100, and the liquid flow pipe 90 is the inner oil pipe, while the gas flow pipe 100 is the outer oil pipe. An upper annular channel is formed between the liquid flow pipe 90 and the gas flow pipe 100, and the liquid flow pipe 90 is connected to the inner central pipe 52. The liquid in the inner central pipe 52 can flow upward into the liquid flow pipe 90. The upper annular channel is connected to the lower annular channel, and the natural gas in the lower annular channel can flow upward into the upper annular channel.

[0041] like Figure 1 and Figure 3 As shown, the gas-liquid co-production and injection system also includes a wellhead device located at the wellhead. The wellhead device includes a lower tubing head 120 and an upper tubing head 150 arranged vertically and connected by flanges. The lower tubing head 120 includes a lower tubing cross 121 and a lower tubing hanger 122. The lower tubing hanger 122 is sealed and assembled within the lower tubing cross 121 and located at the upper part of the lower tubing cross 121. The lower tubing cross 121 has a first upper interface, a first lower interface, a first left interface, and a first right interface. The first lower interface is bolted to the casing head 110, and the lower tubing cross 121 communicates with the upper casing annulus 40. Thus, the lower tubing cross 121 communicates with the water injection layer 20 through the upper casing annulus 40. The gas flow pipe 100 passes upward through the first lower interface and is suspended within the lower tubing cross 121 by the lower tubing hanger 122. The first right interface is also connected to the upper oil sleeve annulus 40. The first left interface is connected to the first branch 130 through the first lower valve 123. The cable 80 passes through the first branch 130 in a sealed manner and enters the upper oil sleeve annulus 40 through the lower oil pipe four-way 121. The first left interface constitutes a cable interface for the cable 80 used to supply power to the motor 71 of the electric pump. A lower pressure gauge 140 is installed on the first branch 130, which is used to measure the pressure in the upper oil sleeve annulus 40.

[0042] like Figure 1 and Figure 3As shown, the upper oil pipe head 150 includes an upper oil pipe cross 151 and an upper oil pipe hanger 152. The upper oil pipe hanger 152 is sealed and assembled inside the upper oil pipe cross 151 and is located at the upper part of the upper oil pipe cross 151. The fluid flow pipe 90 passes upward through the air flow pipe 100 and the lower oil pipe hanger 122 and is suspended inside the upper oil pipe cross 151 by the upper oil pipe hanger 152. The upper oil pipe cross 151 has a second upper interface, a second lower interface, a second left interface, and a second right interface. The second upper interface is connected to the fluid flow pipe 90, forming a fluid flow interface connected to the fluid flow pipe 90. The second lower interface is bolted to the first upper interface, and the air flow pipe 100 is connected to the upper oil pipe cross 151. That is, the upper annular channel between the air flow pipe 100 and the fluid flow pipe 90 is connected to the upper oil pipe cross 151. The upper oil pipe cross 151, the upper annular channel, and the lower annular channel together form an air flow channel. The second right interface is connected to the second branch 160 via the first intermediate valve 153, and the second left interface is connected to the gas sampling pipeline 170 via the second intermediate valve 154. That is, the gas sampling pipeline 170 is connected to the gas flow channel, and the second left interface constitutes a gas flow interface connected to the gas flow pipe 100 and used to connect the gas sampling pipeline 170. A medium pressure gauge 180 and a first flow meter 190 located downstream of the medium pressure gauge 180 are installed on the gas sampling pipeline 170 to measure the gas sampling pressure through the medium pressure gauge 180 and to measure the gas sampling volume through the first flow meter 190.

[0043] like Figure 1 and Figure 3 As shown, the wellhead assembly also includes a connecting member connected above the upper tubing head 150 via a flange. The connecting member includes a transition flange 200 and a connecting member body located above the transition flange 200. In this embodiment, the connecting member body is a four-way connector 210, which has a third upper interface, a third lower interface, a third left interface, and a third right interface. The connecting member also includes a first upper valve 220 connected to the third right interface, a second upper valve 230 connected to the third left interface, a third upper valve 240 connected to the third lower interface, and a fourth upper valve 250 connected to the third upper interface. The adapter flange 200 is bolted to the second upper interface, and the third lower interface is connected to the adapter flange 200 through the third upper valve 240. The fluid pipe 90 is connected to the connecting member through the second upper interface, that is, the third left interface and the third right interface are also connected to the fluid pipe 90. The third upper valve 240 is used to control the connection between the connecting member and the fluid pipe 90. The connecting member, the fluid pipe 90, the inner central pipe 52 and the outer oil pipe 60 together constitute a fluid flow channel for conveying liquid.

[0044] like Figure 1 and Figure 3As shown, the wellhead device also includes a reinjection pipeline 260. The upper end of the reinjection pipeline 260 is connected to the third right interface via a first upper valve 220, and the lower end is connected to the first right interface via a second lower valve 124. This allows the liquid in the fluid flow pipe 90 to be reinjected into the water injection layer 20 via the reinjection pipeline 260. The first right interface constitutes the water injection interface, and the third right interface constitutes the reinjection interface. The airflow interface is located on the side opposite to the reinjection pipeline 260. A measuring device is installed on the reinjection pipeline 260. In this embodiment, the measuring device includes a second flow meter 280 installed downstream of the first upper valve 220 and a first upper pressure gauge 270 located between the second flow meter 280 and the first upper valve 220. The second flow meter 280 measures the reinjection water flow rate on the reinjection pipeline 260, and the first upper pressure gauge 270 measures the water injection pressure on the reinjection pipeline 260.

[0045] The third left interface is connected to a closed pipeline 290 via a second upper valve 230. A second upper pressure gauge 300 is installed downstream of the second upper valve 230, and a shut-off valve 310 is located between the second upper pressure gauge 300 and the second upper valve 230. The second upper valve 230 controls the connection between the closed pipeline and the four-way connector 210. The shut-off valve 310 protects the second upper pressure gauge 300 from excessive pressure in the liquid flow pipe 90, preventing damage. By comparing the measurement data from the second upper pressure gauge 300 with that of the first upper pressure gauge 270, the change in reinjection water pressure after adjustment by the first upper valve 220 can be accurately obtained, ensuring the effectiveness of the adjustment by the first upper valve 220.

[0046] In addition, the gas-liquid co-production and injection process system also includes an electric pump unit control device. The composition of the electric pump unit control device and its relationship with the submersible electric pump unit 70 are the same as those of the surface electric pump unit control device in the Chinese invention patent application with publication number CN113530491A, and will not be repeated here.

[0047] Compared with the prior art, the gas-liquid co-production and injection process system of the present invention, since the reinjection pipeline is set at the wellhead, can directly measure process parameters such as reinjection volume and injection pressure outside the well through the measuring device installed on the reinjection pipeline, thereby facilitating the accurate measurement and control of process parameters such as reinjection volume and injection pressure.

[0048] Example 2 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that the packer in this example is the first packer in the gas-liquid co-production and injection water-gas separation technology disclosed in Chinese invention patent application with publication number CN109296351A. In this case, the liquid pump can also be a water pump with a battery.

[0049] Example 3 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that the gas flow interface is set on the side that is perpendicular to the reinjection pipeline in this example.

[0050] Example 4 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that the measuring device in this example only includes the first upper pressure gauge. In other examples, the measuring device may only include the flow meter. In this case, the second upper pressure gauge may not be provided.

[0051] Example 5 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that in this example, there is no third upper valve connected between the connecting body and the liquid flow interface, and the connection and disconnection between the connecting body and the liquid flow pipe are not controlled.

[0052] Example 6 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that in this example, the shut-off valve located between the second upper pressure gauge and the second upper valve is not installed on the closed pipeline. At this time, only the second upper pressure gauge is installed on the closed pipeline.

[0053] Example 7 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that in this example, no second pressure gauge is installed on the closed pipeline. In this case, the pressure in the liquid flow pipe is not measured.

[0054] Example 8 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that the wellhead device in this example does not include a connecting piece. In this case, the reinjection pipeline is directly connected to the liquid flow interface.

[0055] Example 9 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that in this example, the liquid flow pipe is set outside the gas flow pipe. In this case, the tubing head can be composed of only one tubing head. For example, the tubing head five-way connector in the parallel double tubing wellhead device and its usage method disclosed in Chinese invention patent application with publication number CN103775043A. The liquid flow pipe and the gas flow pipe are both suspended inside the tubing head five-way connector. The liquid flow interface, the gas flow interface and the water injection interface are all set on the tubing head five-way connector.

[0056] Example 10 of the gas-liquid co-production and injection process system of the present invention: The difference between this example and Example 1 is that the measuring device in this example can also measure process parameters such as the flow rate and temperature of the reinjected water.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A gas-liquid co-production and injection process system, comprising a packer and a liquid pump unit connected below the packer, the liquid pump unit comprising a gas-liquid separator (72) and a liquid pump, the packer comprising an inner central pipe (52) and an outer central pipe (53), the inner central pipe (52) being supplied with liquid separated by the gas-liquid separator (72), and a lower annular channel between the inner central pipe (52) and the outer central pipe (53) being supplied with gas separated by the gas-liquid separator (72); a gas flow pipe (100) communicating with the lower annular channel is connected above the packer, characterized in that, Above the packer is a liquid flow pipe that communicates with the inner central pipe and passes through the gas flow pipe. The gas-liquid co-production and injection process system also includes a wellhead device, which includes an upper tubing head, a lower tubing head, and a reinjection pipeline. The gas flow pipe is suspended inside the lower tubing head, and the upper end of the liquid flow pipe passes through the gas flow pipe and is suspended inside the upper tubing head. The upper tubing head has a gas flow interface that communicates with the gas flow pipe and is used to connect to the gas production pipeline, and a liquid flow interface that communicates with the liquid flow pipe. The lower tubing head has a water injection interface that communicates with the upper annulus above the packer. The reinjection pipeline connects the liquid flow interface and the water injection interface to reinject the liquid in the liquid flow pipe back to the water injection layer. A measuring device for measuring water injection process parameters is installed on the reinjection pipeline.

2. The gas-liquid co-production and injection process system according to claim 1, characterized in that, The wellhead device also includes a connector fixedly connected to the fluid interface, the connector having a reinjection interface connected to the fluid interface, and a reinjection pipeline (260) connected between the reinjection interface and the water injection interface.

3. The gas-liquid co-production and injection process system according to claim 2, characterized in that, The connecting element includes a connecting element body and a first upper valve (220). The reinjection interface is set on the connecting element body and is connected to the reinjection pipeline (260) through the first upper valve (220). The first upper valve (220) is used to control the reinjection flow rate in the reinjection pipeline (260). The measuring device includes a first upper pressure gauge (270) installed downstream of the first upper valve (220).

4. The gas-liquid co-production and injection process system according to claim 3, characterized in that, The connecting component body is also provided with a closed interface that communicates with the liquid flow interface and the reinjection interface. The connecting component also includes a second upper valve (230). The closed interface is connected to a closed pipeline (290) through the second upper valve (230). A second upper pressure gauge (300) is installed on the closed pipeline (290).

5. The gas-liquid co-production and injection process system according to claim 4, characterized in that, A shut-off valve (310) is also installed on the closed pipeline (290) between the second upper pressure gauge (300) and the second upper valve (230).

6. The gas-liquid co-production and injection process system according to any one of claims 2 to 5, characterized in that, The connecting element includes the connecting element body and the third upper valve (240). The third upper valve (240) is connected between the connecting element body and the liquid flow interface. The third upper valve (240) is used to control the connection and disconnection between the connecting element and the liquid flow pipe (90).

7. The gas-liquid co-production and injection process system according to any one of claims 1 to 5, characterized in that, The lower interface of the lower oil pipe head is fixedly connected to the sleeve head by bolts.

8. The gas-liquid co-production and injection process system according to any one of claims 1 to 5, characterized in that, The measuring device includes a flow meter.

9. The gas-liquid co-production and injection process system according to any one of claims 1 to 5, characterized in that, The airflow interface is located on the side opposite to the reinjection line (260) or perpendicular to the reinjection line (260).

10. The gas-liquid co-production and injection process system according to any one of claims 1 to 5, characterized in that, The packer is a cable packer (50), the pump is an electric pump, and the oil pipe head also has a cable interface through which a cable (80) for powering the motor (71) of the electric pump passes.

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