Gas well liquid drainage device

Abstract

The invention belongs to the technical field of gas production equipment, and particularly provides a liquid drainage device for a gas well. The gas well liquid drainage device comprises a gas pipeline and a closed foam scrubbing agent storage container with set pressure bearing capacity, one end of the gas pipeline is provided with a connector used for being connected with a wellhead, and the foam scrubbing agent storage container is communicated with the gas pipeline through a liquid outlet pipeline; an atomization generator used for atomizing the foam scrubbing agent is arranged on a conveying path between the communication position of the liquid outlet pipeline and the gas pipeline and the connector, or the connector is an atomization nozzle provided with an atomization cavity to atomize the foam scrubbing agent. According to the invention, the combination of pressurized gas lift and foam drainage is realized, the atomized foam scrubbing agent is conveyed into the well bottom, the reaction of the foam scrubbing agent and well liquid is accelerated, the consumption of the foam scrubbing agent is reduced, the drainage efficiency is improved, the operation safety is improved, and the drainage operation of a deep well within 6000 meters can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas production equipment, and particularly relates to a liquid drainage device for gas wells. Background Art

[0002] When a gas well enters the late stage of exploitation, due to the attenuation of formation energy, the energy at the bottom of the well is insufficient to carry the produced water in the gas reservoir to the bottom surface. Liquid accumulates inside the wellbore, forming a liquid column, resulting in problems such as excessive production pressure difference and water flooding in the gas well, seriously affecting the normal exploitation of natural gas. Therefore, it is necessary to timely drain the accumulated liquid in the wellbore to ensure the normal production of the gas well.

[0003] In the prior art, the commonly used processes for draining liquid from the wellbore are pressurized gas lift and foam drainage. Pressurized gas lift uses external high-pressure gas (natural gas or nitrogen) to be injected into the wellbore that needs to drain the accumulated liquid at the bottom of the well through a gas pipeline, and utilizes the expansion energy of the high-pressure gas to drain the accumulated liquid at the bottom of the well out of the wellbore. Foam drainage is to add a foam drainage agent into the wellbore from the wellhead. After the accumulated liquid in the wellbore comes into contact with the foam drainage agent, a large amount of low-density water-containing foam is generated under the agitation of the natural gas flow rising at the bottom of the well. The foam is carried to the bottom surface along with the natural gas flow, thereby bringing the accumulated liquid at the bottom of the well out of the wellbore.

[0004] However, when there is a large amount of accumulated liquid in the wellbore or there is kill fluid or fracturing fluid left after operations, and the liquid column is relatively high, if the pressurized gas lift method is adopted, it is necessary to pressurize the external high-pressure gas for a long time until the pressure of the external high-pressure gas is greater than the liquid column pressure in the well to drain the well fluid. This method has high energy consumption, and there are also relatively large safety risks and low efficiency. If the foam drainage method is adopted, due to insufficient lifting energy of the liquid column at the bottom of the well, it is difficult to generate foam even when adding a foam drainage agent. Even if a large amount of foam drainage agent is added to the well and a large amount of foam is generated, it is difficult to drain the foam out of the well. Summary of the Invention

[0005] The purpose of the present invention is to provide a liquid drainage device for gas wells to solve the technical problems in the prior art that for the well conditions with a relatively high liquid column in the well, the pressurized gas lift method has low liquid drainage efficiency, high energy consumption, insufficient safety, and poor effect even when a large amount of foam drainage agent needs to be added.

[0006] To achieve the above purpose, the technical solution of the liquid drainage device for gas wells provided by the present invention is as follows:

[0007] A liquid drainage device for a gas well, including a gas pipeline, one end of the gas pipeline is provided with a connection joint for connecting to the wellhead. This liquid drainage device for a gas well further includes a foam drainage agent storage container with a set pressure-bearing capacity and being airtight. The foam drainage agent storage container is communicated with the gas pipeline through a liquid outlet pipeline; on the conveying path between the position where the liquid outlet pipeline is communicated with the gas pipeline and the connection joint, there is an atomization generator for atomizing the foam drainage agent or the connection joint is an atomizing nozzle with an atomization chamber for atomizing the foam drainage agent.

[0008] As a further improvement, an intake pipeline is also communicated between the gas pipeline and the foam drainage agent storage container, and the position where the liquid outlet pipeline is communicated with the foam drainage agent storage container is higher than the position where the liquid outlet pipeline is communicated with the gas pipeline.

[0009] As a further improvement, the foam drainage agent storage container is also provided with a filling port for filling the foam drainage agent and a vent valve for pressure relief.

[0010] As a further improvement, a liquid outlet valve is provided on the liquid outlet pipeline, and an intake valve is provided on the intake pipeline.

[0011] As a further improvement, the liquid outlet valve is a throttle valve with a controllable opening degree.

[0012] As a further improvement, the foam drainage agent storage container is installed on the gas pipeline through a mounting bracket.

[0013] As a further improvement, the atomizing nozzle includes a connection head and an atomizing head hermetically connected to the connection head. The connection head internally has an inlet channel, and the inlet channel includes a large-diameter hole and a small-diameter hole. The large-diameter hole forms an atomization chamber. The atomizing head internally has an outlet channel hole. The atomizing head includes an insertion part inserted into the large-diameter hole, and the insertion part has an impact part facing the small-diameter hole. The outlet channel hole and the atomization chamber are communicated through a plurality of flow holes provided on the atomizing head. The flow cross-sectional area of the small-diameter hole is not greater than the total flow cross-sectional area of the flow holes.

[0014] As a further improvement, one end of the outlet channel hole is closed, and the closed end forms the impact part, and the flow holes are provided on the hole side wall of the outlet channel hole.

[0015] As a further improvement, the outer peripheral surface of the closed end of the outlet channel hole is spherical.

[0016] As a further improvement, the atomizing head includes an external thread section with an external thread, and the large-diameter hole includes an internal thread section with an internal thread. The atomizing head is hermetically connected through the external thread section and the internal thread section of the large-diameter hole.

[0017] The beneficial effects of the present invention are as follows: The present invention belongs to an exploratory invention. During use, high-pressure gas can be introduced into the gas pipeline, and the gas pipeline is connected to the wellhead through a connecting joint or an atomizing nozzle. At this time, the high-pressure gas can enter the wellhead. Since there is also a foam drainage agent storage container, and the foam drainage agent storage container is connected to the gas pipeline through a liquid outlet pipeline, the foam drainage agent in the foam drainage agent storage container can flow into the gas pipeline from the liquid outlet pipeline. After entering the gas pipeline, the gas-liquid mixture formed by the foam drainage agent and the high-pressure gas moves forward (towards the wellhead) synchronously. Due to the configuration of an atomizing generator or an atomizing nozzle, when the gas-liquid mixture passes through the atomizing generator or the atomizing nozzle, the foam drainage agent will be atomized into small droplets, so that the specific surface area of the foam drainage agent is enlarged several times. After the mixture formed by the high-pressure gas and the small droplets reaches the bottom of the well, when the small droplets come into contact with the accumulated liquid at the bottom of the well, there is a large contact area. At the same time, under the agitation of the high-pressure gas, the atomized foam drainage agent will quickly react fully with the accumulated liquid at the bottom of the well, generating a large amount of water-containing foam, reducing the density of the accumulated liquid, and under the action of the high-pressure gas, the water-containing foam is quickly discharged from the wellhead, thereby discharging the accumulated liquid at the bottom of the well. Compared with the prior art, the present invention realizes the combination of pressurized gas lift and foam drainage, uses the pressure of high-pressure gas to atomize the foam drainage agent and send the foam drainage agent to the bottom of the well, accelerates the reaction between the foam drainage agent and the well fluid, reduces the dosage of the foam drainage agent, improves the drainage efficiency, and the density of the accumulated liquid at the bottom of the well after reacting with the foam drainage agent is also relatively small. Therefore, it does not require particularly high pressure of the high-pressure gas, and the operation process is relatively safe. Deep well drainage operations within 6000 meters can be realized. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the gas well drainage device in the present invention;

[0019] Figure 2 is Figure 1 a sectional view of the structure of the atomizing nozzle in

[0020] Figure 3 is Figure 2 a sectional view of the structure of the atomizing head in

[0021] Description of the Reference Numerals:

[0022] 1. Atomizing nozzle; 2. First vent valve; 3. Wellhead check valve; 4. Reducing joint; 5. Pipe nipple; 6. Bracket; 7. Intake valve; 8. Intake pipe; 9. Filling check valve; 10. Foam drainage agent storage container; 11. Second vent valve; 12. Liquid outlet pipeline; 13. Liquid outlet valve; 14. Connector; 15. Atomizing chamber; 16. End; 17. Flow hole; 18. Hole wall; 19. Outlet channel hole; 20. Internal thread section; 21. External thread section. Detailed Description of the Invention

[0023] To solve the problems in the background art, the basic technical concept of the present invention is to connect a foam drainage agent storage container to the gas pipeline of the pressurized gas lift drainage device to add the foam drainage agent into the gas pipeline, and at the same time, an atomization generating device capable of atomizing the foam drainage agent is added to the gas pipeline. In this way, when in use, the gas-liquid mixture formed by the foam drainage agent and the high-pressure gas passes through the atomization generating device under the pressure of the high-pressure gas, forming a mixture of the foam drainage agent and gas in the form of small droplets, and is introduced into the bottom of the well. After the foam drainage agent is atomized, its specific surface area is increased, and at the same time, with the stirring action of the high-pressure gas, it can quickly react with the bottom-hole liquid to form a foam containing liquid. Under the action of the high-pressure gas, the foam is carried out of the wellhead to realize liquid drainage.

[0024] The following further describes the present invention in detail with reference to the embodiments.

[0025] Specific embodiments of the gas well drainage device provided by the present invention:

[0026] The gas well drainage device provided in this embodiment is as Figure 1 shown, including a gas pipeline, which can be used to connect to an external high-pressure gas source. The high-pressure gas can pass through the gas pipeline to the wellhead and reach the bottom of the well through the pipe string in the gas well. One end of the gas pipeline is provided with a connection joint for connecting to the wellhead. In actual use, the gas pipeline can directly use the gas pipeline in the existing enhanced gas lift drainage device.

[0027] Specifically, the gas pipeline successively includes an atomizing nozzle 1, a first vent valve 2, a wellhead check valve 3, a reducing joint 4, and a pipeline short section 5 from front to back (the end for connecting to the wellhead is the front). The pipeline short section 5 is connected to a section of pipeline with a diameter smaller than that of the pipeline short section 5 through the reducing joint 4, and the atomizing nozzle 1, the first vent valve 2, and the wellhead check valve 3 are connected to the pipeline with a diameter smaller than that of the pipeline short section 5. The overall structure of the atomizing nozzle 1 is as Figure 1 and Figure 2 shown. It includes an inlet end and an outlet end. The inlet end is connected to the pipeline, and the outlet end is used to connect to the wellhead. Specifically, as a feasible technical solution, external threads can be provided at the inlet end and the outlet end of the atomizing nozzle 1. When connecting, it is screwed onto the pipeline and the wellhead through the external threads. Of course, in other embodiments, the atomizing nozzle 1 can also be inserted into the pipeline with an interference fit, and the sealing can still be ensured.

[0028] When it is not necessary to ventilate the well, the first vent valve 2 can be opened to release the pressure inside the gas pipeline. In other embodiments, the first vent valve 2 may not be provided in the gas pipeline. To release the pressure in the gas pipeline, the vent valve can be provided at the wellhead. The wellhead check valve 3 is provided to prevent the liquid accumulation in the well from flowing back into the gas pipeline. In other embodiments, the wellhead check valve 3 may not be provided in the gas pipeline, but the wellhead check valve 3 can be directly provided at the wellhead. Regarding the specific form of the gas pipeline, those of ordinary skill in the art can flexibly set it with reference to the gas pipeline of the pressurized gas lift device, and no specific introduction will be made here.

[0029] The liquid drainage device for gas wells further includes a foam drainage agent storage container 10. The inside of the foam drainage agent storage container 10 can be used to store liquid foam drainage agent, and it is connected to the gas pipeline through the liquid outlet pipeline 12. The foam drainage agent in the foam drainage agent storage container 10 can be injected into the gas pipeline through the liquid outlet pipeline 12. Since it is necessary to connect to the pressurized gas pipeline, the foam drainage agent storage container 10 should be a container with a set pressure-bearing capacity and airtight. Specifically, the foam drainage agent storage container 10 in this embodiment is also connected to the gas pipeline through the air inlet pipeline 8. The pressure inside the foam drainage agent storage container 10 is balanced with that of the gas pipeline. At this time, only by installing the foam drainage agent storage container 10 at a higher position and ensuring that the position where the liquid outlet pipeline 12 is connected to the foam drainage agent storage container 10 is higher than the position where the liquid outlet pipeline 12 is connected to the gas pipeline. In this way, there is no need to connect a pressurizing device to the foam drainage agent storage container 10, and there will be no phenomenon that the high-pressure gas inside the gas pipeline enters the foam drainage agent storage container 10 and causes pressure buildup. The foam drainage agent storage container 10 in this embodiment is directly installed on the pipeline nipple 5 through the bracket 6.

[0030] To meet the requirement of adding foam drainage agent online during use, in this embodiment, a liquid outlet valve 13 is provided on the liquid outlet pipeline 12, an air inlet valve 7 is provided on the air inlet pipeline 8, and a filling port and a second vent valve 11 are provided on the foam drainage agent storage container 10. The foam drainage agent can be injected into the foam drainage agent storage container 10 through the filling port. Specifically, during operation, the air inlet valve 7 and the liquid outlet valve 13 can be closed, and then the second vent valve 11 can be opened to release the pressure inside the foam drainage agent storage container 10, and then the foam drainage agent can be injected into the foam drainage agent storage container 10 through the filling port. After the injection is completed, the filling port can be sealed, the second vent valve 11 can be closed, and the liquid outlet valve 13 and the air inlet valve 7 can be opened. A filling check valve 9 is provided at the position of the filling port in this embodiment. The flow direction of the filling check valve 9 is such that the foam drainage agent can enter the foam drainage agent storage container 10. In this way, after the foam drainage agent is injected, it can be automatically sealed, with high efficiency. Of course, in other embodiments, a detachable sealing cover plate can also be provided at the filling port.

[0031] Further, the liquid outlet valve 13 in this embodiment is selected as a throttle valve with adjustable opening degree. In this way, the injection speed of the foam drainage agent into the gas pipeline can be actively controlled to achieve precise injection. Of course, in other embodiments, a globe valve with a constant flow cross-section can also be selected, which can also control the on-off of the liquid outlet pipeline 12.

[0032] In other embodiments, the liquid outlet valve 13 and the intake valve 7 may not be provided on the liquid outlet pipeline 12 and the intake pipeline 8, and the filling port and the second vent valve 11 can be retained. At this time, the liquid outlet pipeline 12, the intake pipeline 8, and the gas pipeline or the foam drainage agent storage container 10 are set as detachable structures. When the foam drainage agent needs to be filled, the foam drainage agent storage container 10 can be removed. In this case, online filling of the foam drainage agent cannot be achieved, and a short shutdown is actually required. However, two foam drainage agent storage containers 10 can be provided, and one of the foam drainage agent storage containers 10 is in a fully loaded standby state, so that the foam drainage agent storage container 10 can be quickly replaced. Of course, in other embodiments, the foam drainage agent storage container may not even be provided with a filling port and a second vent valve 11, and a new foam drainage agent storage container can be replaced separately after emptying the foam drainage agent in the foam drainage agent storage container each time.

[0033] The atomizing nozzle 1 in this embodiment is as Figure 1 - Figure 3 shown, including a connector 14 and an atomizing head. The atomizing head is connected to the connector 14. The connector 14 is used to connect to the gas pipeline and is equivalent to the inlet end of the atomizing nozzle 1. The gas in the gas pipeline and the foam drainage agent storage container 10 can enter through the connector 14 and be ejected from the atomizing head. The atomizing head is equivalent to the outlet end of the atomizing nozzle 1. To avoid the problem of pressure buildup in the atomizing nozzle 1, the cross-sectional area of the flow passage at the inlet end should not be greater than the cross-sectional area of the flow passage at the outlet end.

[0034] As Figure 2 shown, the inside of the connector 14 has an inlet passage, and the inlet passage includes a large-diameter hole and a small-diameter hole. The small-diameter hole is located at the inlet end of the atomizing nozzle 1. The inside of the atomizing head has an outlet passage hole 19. The atomizing head includes an insertion part inserted into the large-diameter hole of the inlet passage, and the insertion part has an impact part facing the small-diameter hole. In this way, the mixture of high-pressure gas and foam drainage agent entering from the small-diameter hole can impact on the impact part. The large-diameter hole forms an atomizing chamber 15. The mixture of foam drainage agent and high-pressure gas acting on the impact part can diverge into small droplets in the atomizing chamber 15 and be atomized once. The atomizing head is also provided with a number of flow holes 17. The atomizing chamber 15 and the outlet passage hole 19 are connected through the flow holes 17. In this way, the atomized small droplets in the atomizing chamber 15 can enter the outlet passage hole 19 through the flow holes 17. The cross-sectional area of a single flow hole 17 is smaller than the cross-sectional area of the small-diameter hole, but the total cross-sectional area of all the flow holes 17 should not be less than the cross-sectional area of the small-diameter hole. By setting the dispersed flow holes 17 in this way, the small droplets of the foam drainage agent can be atomized twice, with a better atomizing effect.

[0035] Further, in this embodiment, the end portion 16 of the outlet passage hole 19 is closed, and the closed end portion 16 forms an impact portion, so that a better impact dispersion effect, that is, an atomization effect, can be achieved. Specifically, the outer peripheral surface of the end portion 16 is a spherical surface. Setting it as a spherical surface can disperse the foam drainage agent around and collide with the hole wall 18 of the large-diameter hole, and the effect is better. Of course, in other embodiments, the outer peripheral surface of the end portion 16 can also be a flat surface or an arc surface, which can also play a certain role in impact dispersion.

[0036] Since the end portion 16 of the outlet passage hole 19 is closed, the flow-through hole 17 in this embodiment is provided on the hole wall 18 of the outlet passage hole 19. At this time, high-pressure gas and small-droplet-shaped foam drainage agent can enter the outlet passage hole 19 through the hole wall 18 of the outlet passage hole 19. In other embodiments, the end portion 16 of the outlet passage hole 19 can also be not closed, that is, the flow-through hole 17 can also be provided at the end portion 16 of the outlet passage hole 19. In this case, the atomization effect will be weakened, but the flow-through cross-sectional area of a single flow-through hole 17 can be appropriately reduced, and the number of flow-through holes 17 can be increased.

[0037] The atomizing head and the connecting head 14 in this embodiment are hermetically connected through a threaded structure. Specifically, as Figure 2 and Figure 3 shown, the atomizing head includes an external thread section 21 provided with an external thread, and the large-diameter hole of the connecting head 14 includes an internal thread section 20 provided with an internal thread. During installation, the atomizing head can be screwed into the large-diameter hole. In other embodiments, other forms other than the threaded structure can be used. For example, the outer diameter of the atomizing head can be appropriately increased and press-fitted into the large-diameter hole; or a screw hole can be provided at one end of the atomizing head ( Figure 2 the left end in

[0038] ), a threaded hole is provided at one end of the large-diameter hole, and the atomizing head is press-fitted onto the connecting head 14 through a screw.

[0039] In other embodiments, the atomizing nozzle 1 can also directly purchase an atomizing nozzle of another form in the prior art from the market, which has an atomizing chamber 15 and can be connected to the gas pipeline and the wellhead. Figure 2, for example, an external thread is provided on the connector 14, and an internal thread is provided inside the gas pipeline. The atomization generator can be directly screwed and installed on the inner wall of the gas pipeline through the connector 14.

[0040] Through the above analysis, it can be seen that when the present invention is actually used, it combines the advantages of pressurized gas lift and foam drainage for liquid removal, and by means of atomization, the specific surface area of the foam drainage agent is increased, and the atomized foam drainage agent is sent into the bottom of the well by high-pressure gas, so that a quick reaction between the foam drainage agent and the bottom-hole accumulated liquid can be realized to form a liquid-containing foam, with high efficiency and saving of the foam drainage agent. The applicant has conducted actual liquid removal tests in the internal test gas wells (at the 6000-meter level). When the upward gas flow velocity reaches 0.1 m / s - 0.3 m / s, the foam can be discharged, so there is no need to configure an ultra-high-pressure pressurized gas lift device, and the safety is better.

[0041] Finally, it should be noted that the above-mentioned are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still make modifications to the technical solutions recorded in the foregoing embodiments without creative efforts, or make equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A liquid drainage device for a gas well, characterized in that, It includes a gas pipeline. One end of the gas pipeline is provided with a connection joint for connecting to the wellhead. The liquid drainage device for gas wells further includes a foam drainage agent storage container with a set pressure-bearing capacity and being airtight. The foam drainage agent storage container is communicated with the gas pipeline through a liquid outlet pipeline. On the conveying path between the position where the liquid outlet pipeline is communicated with the gas pipeline and the connection joint, there is an atomization generator for atomizing the foam drainage agent or the connection joint is an atomizing nozzle with an atomization chamber for atomizing the foam drainage agent.

2. The gas well liquid drainage device according to claim 1, characterized in that An air inlet pipeline is also communicated between the gas pipeline and the foam drainage agent storage container. The position where the liquid outlet pipeline is communicated with the foam drainage agent storage container is higher than the position where the liquid outlet pipeline is communicated with the gas pipeline.

3. The gas well liquid drainage device according to claim 2, characterized in that, The foam drainage agent storage container is also provided with a filling port for filling the foam drainage agent and a vent valve for pressure relief.

4. The gas well liquid drainage device according to claim 3, characterized in that, A liquid outlet valve is provided on the liquid outlet pipeline, and an air inlet valve is provided on the air inlet pipeline.

5. The gas well liquid drainage device according to claim 4, characterized in that, The liquid outlet valve is a throttle valve with a controllable opening degree.

6. The gas well liquid drainage device according to any one of claims 2-5, characterized in that, The foam drainage agent storage container is installed on the gas pipeline through a mounting bracket.

7. The gas well liquid drainage device according to any one of claims 1-5, characterized in that, The atomizing nozzle includes a connector and an atomizing head hermetically connected to the connector. The connector internally has an inlet passage, and the inlet passage includes a large-diameter hole and a small-diameter hole. The large-diameter hole forms an atomization chamber. The atomizing head internally has an outlet passage hole. The atomizing head includes an insertion part inserted into the large-diameter hole, and the insertion part has an impact part facing the small-diameter hole. The outlet passage hole and the atomization chamber are communicated through a plurality of flow holes provided on the atomizing head. The flow cross-sectional area of the small-diameter hole is not greater than the total flow cross-sectional area of the flow holes.

8. The liquid drainage device for a gas well according to claim 7, characterized in that, One end of the outlet passage hole is closed, and the closed end forms the impact part. The flow holes are provided on the hole side wall of the outlet passage hole.

9. The gas well liquid drainage device according to claim 8, characterized in that, The outer peripheral surface of the closed end of the outlet passage hole is spherical.

10. The liquid drainage device for a gas well according to claim 7, characterized in that, The atomizing head includes an external thread section provided with an external thread. The large-diameter hole includes an internal thread section provided with an internal thread. The atomizing head is hermetically connected through the external thread section and the internal thread section of the large-diameter hole.

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