Gas anchor structure for coal-bed gas well

Abstract

The utility model relates to the technical field of coal-bed gas exploitation equipment, in particular to a gas anchor structure for a coal-bed gas well. The gas anchor structure for the coal-bed gas well comprises an outer sleeve, an oil pipe which is coaxially arranged is fixedly installed in the outer sleeve, an annular cavity between the outer sleeve and the oil pipe forms an annular cavity structure, and a plurality of annularly-distributed slits are formed in the outer sleeve; an air guide component is arranged in the annular cavity, and a sand setting component is installed at the bottom of the outer sleeve. According to the gas anchor structure for the coal-bed gas well, the floating ring and the abutting rod are driven by gas pressure to control opening and closing of the steel ball, automatic adjustment of a gas channel is achieved, the gas anchor structure can adapt to different gas flows and pressures, the gas-liquid separation efficiency and stability are greatly improved, and gas locking is effectively prevented.

Description

Technical Field

[0001] This utility model relates to the technical field of coalbed methane extraction equipment, and in particular to a gas anchor structure for coalbed methane wells. Background Technology

[0002] In coalbed methane extraction, gas anchors are crucial downhole tools installed below the pumping unit. Their core function is to achieve gas-liquid separation and sand filtration. The principle is to utilize gravity differences to separate free gas in the well fluid before it enters the pump and discharges it through an exhaust channel. Simultaneously, it prevents or reduces the entry of solid impurities such as sand into the pump, thereby improving pump efficiency, extending pump maintenance intervals, and protecting the pump body. Traditional gas anchors often rely on simple settling chambers or fixed separation elements (such as hydrocyclones or baffles). When gas flow rates fluctuate significantly, especially when gas content is high (large gas-liquid ratio) or flow velocity is high, the separation effect becomes unstable, and gas can easily enter the pump along with the liquid, causing gas lock and severely reducing pump efficiency.

[0003] Therefore, it is necessary to provide a new gas anchor structure for coalbed methane wells to solve the above-mentioned technical problems. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a gas anchor structure for coalbed methane wells.

[0005] The gas anchor structure for coalbed methane wells provided by this utility model includes an outer sleeve, in which an oil pipe is fixedly installed on the inner sleeve, and the annular cavity between the outer sleeve and the oil pipe forms an annular cavity structure. Multiple annularly distributed slits are opened on the outer sleeve.

[0006] The annular cavity is provided with an air guiding component, and the air guiding component includes a fixed ring. The fixed ring is fixedly installed in the annular cavity and located above the slit. A floating ring is installed in the annular cavity below the fixed ring. The floating ring has multiple annularly distributed through cavities. Each through cavity is provided with a steel ball for sealing the through cavity. An abutment rod coaxially arranged with the through cavity is installed on the fixed ring.

[0007] The bottom of the outer sleeve is equipped with a sand settling component, which includes a sand settling tail pipe through which sand is collected.

[0008] Preferably, the cavity at the bottom of the passage is provided with an expanding cavity, the steel ball is located inside the expanding cavity, and a tension spring is fixedly installed on the upper spherical surface of the steel ball. A fixing ring is fixedly installed on the top of the tension spring, and the fixing ring is fixedly installed on the upper surface of the floating ring and coaxially arranged with the passage.

[0009] Preferably, the fixed ring has multiple annularly distributed exhaust chambers, and multiple guide rods are fixedly installed at the bottom of the fixed ring, the guide rods passing through the floating ring and slidably connected to the floating ring.

[0010] Preferably, a coaxially arranged oil guide pipe is fixedly installed inside the sand settling tailpipe by a docking frame, and an annular cavity is formed on the docking frame.

[0011] Preferably, the top openings of the sand-collecting tailpipe and the oil guide pipe are provided with mating threaded joints, and the bottom opening of the annular cavity is provided with a threaded joint.

[0012] Preferably, a bearing ring is installed inside the oil guide pipe, and a filter screen is placed on the bearing ring.

[0013] Preferably, a threaded joint communicating with the oil pipe is fixedly installed at the top of the outer sleeve.

[0014] Preferably, the oil pipe has an exhaust port installed on its side wall near the top.

[0015] Compared with related technologies, the gas anchor structure for coalbed methane wells provided by this utility model has the following beneficial effects:

[0016] 1. This utility model utilizes air pressure to drive the floating ring and the abutment rod to control the opening and closing of the steel ball, thereby realizing the automatic adjustment of the gas channel. It can adapt to different gas flow rates and pressures, greatly improve the gas-liquid separation efficiency and stability, and effectively prevent airlock.

[0017] 2. The sand settling component designed in this utility model allows most of the sand and gravel impurities in the droplets to automatically settle to the bottom of the sand settling tail pipe, while some particles are also filtered by the filter screen. Because the particulate impurities are mainly filtered by sedimentation, there is less sand and gravel attached to the bottom of the filter screen, which greatly extends the cleaning and replacement cycle of the filter screen, while the sand settling tail pipe is cleaned by staff. Attached Figure Description

[0018] Figure 1 A schematic diagram of a preferred embodiment of the gas anchor structure for coalbed methane wells provided by this utility model;

[0019] Figure 2 for Figure 1 The diagram shows a cross-sectional view of the structure.

[0020] Figure 3 for Figure 2 A schematic cross-sectional view of the outer casing and tubing shown.

[0021] Figure 4 for Figure 1 The diagram shows the structure of the air guiding component.

[0022] Figure 5 for Figure 2 The diagram shows the structure of the sedimentation component.

[0023] Figure 6 for Figure 2 The diagram shows the structure of the filter screen.

[0024] The diagram labels are as follows: 1. Outer tube; 1a. Slit; 11. Exhaust port; 2. Oil pipe; 21. Threaded joint; 1-2a. Annular cavity; 1-2. Threaded opening; 3. Air guide component; 31. Fixing ring; 31a. Exhaust cavity; 32. Floating ring; 32a. Through cavity; 32b. Expanding cavity; 33. Steel ball; 331. Mounting ring; 332. Tension spring; 34. Abutting rod; 35. Guide rod; 4. Sand settling component; 41. Sand settling tailpipe; 42. Connecting frame; 42a. Annular cavity; 43. Oil guide pipe; 44. Bearing ring; 45. Connecting threaded opening; 5. Filter screen. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model 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 merely illustrative of the present utility model and are not intended to limit the present utility model.

[0026] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0027] Please see Figures 1 to 6 This utility model provides a gas anchor structure for coalbed methane wells, which includes an outer casing 1, an oil pipe 2, a gas guiding component 3, and a sand settling component 4.

[0028] In the embodiments of this utility model, please refer to Figures 1 to 6 An oil pipe 2 is fixedly installed inside the outer sleeve 1, and the annular cavity between the outer sleeve 1 and the oil pipe 2 forms an annular cavity 1-2a structure. Multiple annularly distributed slits 1a are opened on the outer sleeve 1. A threaded joint 21 communicating with the oil pipe 2 is fixedly installed at the top of the outer sleeve 1, and an exhaust port 11 is installed on the side wall of the oil pipe 2 near the top.

[0029] It should be noted that: the fluid in the wellbore structure of the coalbed methane well enters the annular cavity 1-2a through the slit 1a on the outer casing 1. In the annular cavity 1-2a, the flow velocity decreases due to the increased flow cross-sectional area. Under low-speed conditions, the bubbles naturally rise due to buoyancy and accumulate at the top of the annular space, while the liquid sinks under the action of gravity and accumulates at the bottom of the annular space.

[0030] In the embodiments of this utility model, please refer to Figures 1 to 6An air guiding component 3 is provided in the annular cavity 1-2a, and the air guiding component 3 includes a fixing ring 31. The fixing ring 31 is fixedly installed in the annular cavity 1-2a and located above the slit 1a. A floating ring 32 is installed in the annular cavity 1-2a below the fixing ring 31. Multiple annularly distributed through cavities 32a are opened in the floating ring 32. Each through cavity 32a is provided with a steel ball 33 for sealing the through cavity 32a. Specifically, the cavity opening at the bottom of the through cavity 32a is provided with an expanding cavity 32b. The steel ball 33 is located in the expanding cavity 32b. A tension spring 332 is fixedly installed on the upper spherical surface of the steel ball 33. An installation ring 331 is fixedly installed on the top of the tension spring 332. The installation ring 331 is fixedly installed on the upper surface of the floating ring 32 and is coaxially arranged with the through cavity 32a. An abutment rod 34 coaxially arranged with the through cavity 32a is installed on the fixing ring 31.

[0031] It should be noted that: when the bubble rises and contacts the float ring 32, the bubble can be broken. At the same time, the gas gathers and pushes the float ring 32 upward until the abutting rod 34 abuts against the steel ball 33. As the air pressure increases, the float ring 32 continues to slide upward along the guide rod 35. At this time, the abutting rod 34 slides down against the steel ball 33 and out of the expansion cavity 32b. Therefore, the gas rises through the passage cavity 32a past the float ring 32 and is then discharged into the connected air pipe through the exhaust port 11.

[0032] Therefore, by using air pressure to drive the floating ring 32 and the abutment rod 34 to control the opening and closing of the steel ball 33, the automatic adjustment of the gas channel is realized, which can adapt to different gas flow rates and pressures, greatly improve the gas-liquid separation efficiency and stability, effectively prevent air lock, and the design of the gas component 3 allows the gas to float and be discharged in an orderly manner through the passage cavity 32a, avoiding the accumulation of gas and pressure fluctuations in the annular cavity 1-2a, and optimizing the gas discharge process.

[0033] Furthermore, the fixed ring 31 has multiple annularly distributed exhaust chambers 31a, and multiple guide rods 35 are fixedly installed at the bottom of the fixed ring 31. The guide rods 35 pass through the floating ring 32 and are slidably connected to the floating ring 32, thereby improving the stability of the floating ring 32's upward movement and preventing the abutment rod 34 from being misaligned with the through cavity 32a due to the floating ring 32 rotating.

[0034] In the embodiments of this utility model, please refer to Figures 1 to 6 The bottom of the outer casing 1 is equipped with a sand settling component 4, which includes a sand settling tail pipe 41. Sand is collected through the sand settling tail pipe 41. A coaxially arranged oil guide pipe 43 is fixedly installed inside the sand settling tail pipe 41 through a docking frame 42. An annular cavity 42a is opened on the docking frame 42. A bearing ring 44 is installed inside the oil guide pipe 43, and a filter screen 5 is placed on the bearing ring 44. The top openings of the sand settling tail pipe 41 and the oil guide pipe 43 are provided with docking threaded ports 45, and the bottom opening of the annular cavity 1-2a is provided with threaded ports 1-2.

[0035] It should be noted that: the filter screen 5 is placed on the bearing ring 44, and then the sand settling tail pipe 41 is fixedly connected to the bottom thread of the sleeve 1 using the connecting screw 45, so that the bottom of the oil pipe 2 abuts against the filter screen 5. At the same time, the oil guide pipe 43 is connected to the oil pipe 2. After the denser droplets sink, they enter the gap between the sand settling tail pipe 41 and the oil guide pipe 43, and then enter the oil guide pipe 43, and rise from the oil guide pipe 43 into the oil pipe 2. Most of the sand and gravel impurities in the droplets can automatically settle to the bottom of the sand settling tail pipe 41, and some particles are also filtered by the filter screen 5. Because the particulate impurities are mainly filtered by sedimentation, there is less sand and gravel attached to the bottom of the filter screen 5, which greatly extends the cleaning and replacement cycle of the filter screen 5. The sand settling tail pipe 41 is cleaned by the staff.

[0036] In a further optimized solution: one or more detachable sand discharge valves or sand cleaning ports (not shown in the figure) can be added to the side wall of the sand settling pipe 41 near the bottom. When needed (such as during well workover operations or when the well is full of sand according to downhole monitoring data), the sand discharge valve or sand cleaning port can be opened to flush or discharge the deposited sand particles without disassembling the entire sand settling component 4, thereby further enhancing the anti-clogging capability and long-term operational stability of the equipment.

[0037] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A gas anchor structure for coalbed methane wells, comprising an outer casing (1), wherein a coaxially arranged oil pipe (2) is fixedly installed inside the outer casing (1), and the annular cavity between the outer casing (1) and the oil pipe (2) constitutes an annular cavity (1-2a) structure, wherein the outer casing (1) is provided with a plurality of annularly distributed slits (1a), characterized in that: The annular cavity (1-2a) is provided with an air guiding component (3), and the air guiding component (3) includes a fixing ring (31). The fixing ring (31) is fixedly installed in the annular cavity (1-2a) and located above the slit (1a). A floating ring (32) with sliding connection is installed in the annular cavity (1-2a) below the fixing ring (31). Multiple annularly distributed through cavities (32a) are opened in the floating ring (32). Each through cavity (32a) is provided with a steel ball (33) for sealing the through cavity (32a). An abutment rod (34) coaxially arranged with the through cavity (32a) is installed on the fixing ring (31). The outer casing (1) is equipped with a sedimentation component (4) at the bottom. The sedimentation component (4) includes a sedimentation tail pipe (41) through which sediment is collected.

2. The gas anchor structure for a coal bed methane well according to claim 1, characterized by, The cavity at the bottom of the through cavity (32a) is provided with an enlarged cavity (32b), the steel ball (33) is located in the enlarged cavity (32b), and a tension spring (332) is fixedly installed on the upper spherical surface of the steel ball (33). An installation ring (331) is fixedly installed on the top of the tension spring (332), and the installation ring (331) is fixedly installed on the upper surface of the floating ring (32) and coaxially arranged with the through cavity (32a).

3. The gas anchor structure for a coal bed methane well according to claim 2, characterized by, The fixed ring (31) has multiple annularly distributed exhaust chambers (31a), and multiple guide rods (35) are fixedly installed at the bottom of the fixed ring (31). The guide rods (35) pass through the floating ring (32) and are slidably connected to the floating ring (32).

4. The gas anchor structure for coalbed methane wells according to claim 1, characterized in that, The sand-collecting tailpipe (41) is fixedly installed with an oil guide pipe (43) arranged coaxially through a docking frame (42), and the docking frame (42) is provided with an annular cavity (42a).

5. The gas anchor structure for coalbed methane wells according to claim 4, characterized in that, The top openings of the sand-collecting tail pipe (41) and the oil guide pipe (43) are provided with connecting screw holes (45), and the bottom opening of the annular cavity (1-2a) is provided with threaded openings (1-2).

6. The gas anchor structure for coalbed methane wells according to claim 5, characterized in that, The oil guide pipe (43) is equipped with a bearing ring (44), and a filter screen (5) is placed on the bearing ring (44).

7. The gas anchor structure for coalbed methane wells according to claim 1, characterized in that, The top of the outer sleeve (1) is fixedly installed with a threaded joint (21) that communicates with the oil pipe (2).

8. The gas anchor structure for coalbed methane wells according to claim 1, characterized in that, The oil pipe (2) has an exhaust port (11) installed on the side wall near the top.

Images