Coal bed gas vertical well small-aperture directional water conservancy jet unblocking device

Abstract

The utility model discloses a coal bed gas vertical well small-aperture directional water conservancy jet unblocking device, and relates to the technical field of coal bed gas yield increase. Comprising a ground construction mechanism, an underground peeping and positioning mechanism, an underground guiding mechanism and a self-spraying blockage removing mechanism. The ground construction mechanism comprises a high-pressure pump and a drainage assisting pump which are located on the ground. The underground peeping positioning mechanism comprises a visual camera shooting mechanism and a first gyroscope which are used for detecting a blocked part in the early stage; the underground guide mechanism comprises a second gyroscope and a guider; the self-injection plug removal mechanism comprises an oil pipe, a continuous oil pipe, a high-pressure hose and a self-traction nozzle; according to the utility model, the stress of a production layer supporting material can be redistributed, a large number of gaps are formed, the original gap net is communicated, and the effect of large-area reconstruction of a blocked reservoir is realized; the problems that gas well production reduction is serious due to the fact that a coal bed gas vertical well production layer seepage channel is blocked, and a conventional blocking removal measure is poor in effect are solved.

Description

Technical Field

[0001] This utility model relates to the field of coalbed methane production enhancement technology, specifically a small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells. Background Technology

[0002] Vertical wells are an important well type in coalbed methane (CBM) development, and "hydraulic fracturing + quartz sand proppant" is the most common method for CBM reservoir stimulation. During CBM vertical well production, the problem of quartz sand and coal powder clogging the production zone's seepage channels, and even burying the wellbore, is frequently encountered. Currently, this problem is mainly solved by conventional well washing for unclogging, nitrogen foam well washing for unclogging, secondary hydraulic fracturing for unclogging, pulse unclogging, microbial unclogging, and acid unclogging. These methods can only address production zone blockage near the wellbore and cannot change the proppant stress and fracture distribution further away from the wellbore, thus their effectiveness in completely resolving production zone blockage is not significant. Specifically, they have the following drawbacks:

[0003] 1. For unblocking the producing formation, conventional unblocking methods generally apply unblocking measures indiscriminately around the wellbore. The untargeted unblocking direction may block the existing unobstructed seepage channels of the producing formation, resulting in poor effectiveness.

[0004] 2. Conventional unblocking mainly acts directly on the periphery of the well, which has a limited unblocking range and limited effect on unblocking at the far end of the well. Utility Model Content

[0005] This invention overcomes the shortcomings of existing technologies by proposing a small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells. This device solves the problem of severe production reduction caused by blockage of the seepage channels in the producing layer of coalbed methane vertical wells, and the ineffectiveness of conventional unblocking measures.

[0006] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0007] A small-diameter directional hydraulic jetting unblocking device for coalbed methane vertical wells includes a ground construction mechanism, a downhole inspection and positioning mechanism, a downhole guiding mechanism, and a self-jetting unblocking mechanism;

[0008] The ground construction equipment includes a high-pressure pump and a drainage pump located on the ground;

[0009] The downhole observation and positioning mechanism includes a visual camera mechanism and a first gyroscope for preliminary detection of blockages;

[0010] The downhole guiding mechanism includes a second gyroscope and a guide;

[0011] The self-jetting unblocking mechanism includes an oil pipe, a continuous oil pipe, a high-pressure hose, and a self-traction nozzle;

[0012] The coalbed methane vertical well is equipped with tubing. One end of the coiled tubing runs through the well, and the high-pressure pump is connected to the other end of the coiled tubing. A guide is connected to the bottom of the tubing, and the guide has an L-shaped channel running vertically through it. The horizontal section of the L-shaped channel communicates with the producing formation, and the vertical section communicates with the annulus between the tubing and the coiled tubing. One end of the high-pressure hose is connected to the bottom of the coiled tubing and is located within the L-shaped channel. The other end of the high-pressure hose passes through the L-shaped channel and exits from the bottom of the L-shaped channel, extending into the producing formation. The other end of the high-pressure hose is connected to a self-traction nozzle. The guide has a bell-shaped channel. The larger end of the bell-shaped channel communicates with the horizontal section of the L-shaped channel of the guide, and the smaller end of the bell-shaped channel communicates with the vertical section of the L-shaped channel of the guide, connecting the annulus between the tubing and the coiled tubing. The end of the tubing outside the coalbed methane vertical well is connected to the drainage pump. A second gyroscope is connected to the tubing above the guide.

[0013] Furthermore, the ground construction mechanism also includes a sedimentation tank and a clear water tank set on the ground; the drainage pump is connected to the sedimentation tank, and the high-pressure pump is connected to the clear water tank.

[0014] Furthermore, the sedimentation tank and the clear water tank are connected by a flexible hose at a depth of / above the tank depth, and a filter device is installed at the joint in the sedimentation tank.

[0015] Furthermore, two sluice windows are symmetrically arranged on the bottom horizontal section of the guide. The sluice windows are located below the funnel-shaped channel and the top of the sluice windows are connected to the funnel-shaped channel. The bottom of the sluice windows are connected to the coalbed methane vertical well.

[0016] Furthermore, a seal is installed at the upper end of the tubing, and one end of the continuous tubing passes through the seal and runs inside the tubing.

[0017] Furthermore, the inner wall of the coalbed methane vertical well is equipped with a casing, and the end of the casing at the wellhead of the coalbed methane vertical well is equipped with a wellhead sealing flange, which seals the annulus between the casing and the tubing.

[0018] Furthermore, a stabilizer is fitted onto the upper outer wall of the guide.

[0019] Furthermore, the self-traction nozzle has three sand-flushing holes at its front end and a conical structure on its rear side wall, with six boosting sand-discharging holes evenly distributed on the side wall of the conical structure; the diameter of the boosting sand-discharging holes is larger than that of the sand-flushing holes.

[0020] The beneficial effects of this utility model compared to the prior art are as follows:

[0021] This invention addresses coalbed methane vertical wells with blocked production layers. It utilizes a downhole gyroscope to precisely locate the blocked orifice, employs coiled tubing as the carrier of the unblocking tool, and uses a combination of a self-traction nozzle and a flexible high-pressure hose as the unblocking actuator. This flushes out the compacted quartz sand and coal powder from the blocked channel, creating new small cavities. This redistributes the stress in the production layer's supporting material, forming numerous fissures that connect the existing fracture network, achieving a large-scale transformation of the blocked reservoir. Specifically, it has the following effects:

[0022] (1) High precision in unblocking direction: This utility model can accurately locate the specific location of the blockage in the production layer and achieve unblocking of the blockage channel through directional unblocking.

[0023] (2) Long unblocking channel and wide coverage area: This utility model uses a combination of "self-traction nozzle + flexible high-pressure hose" to recreate the production channel with a radial diameter of about 100m in the wellbore, change the stress distribution of the compacted production layer, form more gaps, and effectively connect the existing seepage network to achieve a large-scale expansion of the effective network volume.

[0024] (3) Good construction effect and strong targeted unblocking: This utility model is designed for coalbed methane producing layers that have been modified, with dense network of interlayer pressure fractures. The fractures contain fine particles such as quartz sand and coal powder, which are highly resistant to flushing. In particular, the fine particles such as coal powder with small particle size and low density in the fractures are easily flushed back into the wellbore and guide device with the backflushing fluid, and finally pumped to the surface with the tubing, which is not likely to cause downhole accumulation; while the coal blocks (particles) and quartz sand with large particle size and high density in the fractures can mostly be retained in the gaps to continue to play the role of supporting the fracture network.

[0025] (4) Strong continuity of operation and high construction efficiency: After completing the operation in one direction, the continuous oil pipe can be lifted up and the "flexible high pressure hose + self-traction nozzle" tool combination can be suspended in the oil pipe above the guide. After adjusting the guide, the "flexible high pressure hose + self-traction nozzle" tool combination can be lowered to the target hole. There is no need to completely remove the self-jetting unblocking device, and the continuous operation is strong.

[0026] (5) The materials used for unblocking are environmentally friendly and the amount used is small: This utility model only uses a portion of clean water as flushing fluid during the operation. No other chemical agents are used. The discharged water is conventional drainage water containing quartz sand and coal powder, and it can be recycled. The whole unblocking operation is relatively environmentally friendly. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the layout of the ground operation facility of this utility model;

[0028] Figure 2 This is a cross-sectional view of the guide.

[0029] Figure 3 This is a side view of the self-traction nozzle;

[0030] Figure 4 This is a top-view sectional view of a self-traction nozzle.

[0031] Figure label:

[0032] 1-Sedimentation tank, 2-Clear water tank, 3-High pressure pump, 4-Drainage pump, 5-Center, 6-Second gyroscope, 7-Guide, 8-Tubing, 9-Continuous tubing, 10-High pressure hose, 11-Self-traction nozzle, 12-Coalbed methane vertical well, 13-Sealer, 14-Wellhead sealing flange, 15-Production zone, 16-Flare channel, 17-Leaky window, 111-Sand flushing hole, 112-Drainage hole. Detailed Implementation

[0033] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, this utility model will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it. The technical solution of this utility model will be described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0034] See Figures 1 to 4 This embodiment proposes a small-diameter directional hydraulic jetting unblocking device for coalbed methane vertical wells; it includes a ground construction mechanism, a downhole inspection and positioning mechanism, a downhole guiding mechanism, and a self-jetting unblocking mechanism.

[0035] The ground construction mechanism includes a sedimentation tank 1, a clear water tank 2, a high-pressure pump 3, and a drainage pump 4, all installed on the ground.

[0036] The downhole observation and positioning mechanism includes a visual camera mechanism and a first gyroscope; the visual camera mechanism and the first gyroscope are used for preliminary detection of blockages.

[0037] The downhole guiding mechanism includes a centralizer 5, a second gyroscope 6, and a guide 7;

[0038] The self-jetting unblocking mechanism includes an oil pipe 8, a continuous oil pipe 9, a high-pressure hose 10, and a self-traction nozzle 11.

[0039] Specifically, the inner wall of the coalbed methane vertical well 12 is equipped with a casing, and a tubing 8 is installed inside the coalbed methane vertical well 12. A sealer 13 is installed at the upper end of the tubing 8. One end of the coiled tubing 9 passes through the sealer 13 and is installed inside the tubing 8. The sealer 13 seals the annulus between the tubing 8 and the coiled tubing 9. A wellhead sealing flange 14 is installed at the end of the casing at the wellhead of the coalbed methane vertical well 12. The wellhead sealing flange 14 is used to strictly seal the annulus between the casing and the tubing 8. The clear water tank 2 is connected to the high-pressure pump 3, and the high-pressure pump 3 is connected to the other end of the coiled tubing 9. The end of the tubing 8 located outside the coalbed methane vertical well 12 is connected to the settling tank 1 through the auxiliary pump 4. The settling tank 1 is connected to the clear water tank 12 through a filter screen or filter.

[0040] The sedimentation tank 1 is used to settle and filter the return fluid containing quartz sand and coal powder; the clear water tank 2 is used to store clear water and provide high-pressure fluid to the high-pressure pump 3, which is introduced into the formation through the coiled tubing 9 as flushing fluid; the high-pressure pump 3 is used to provide high-pressure flushing fluid to the coiled tubing 9 and drive the high-pressure hose 10 and the self-traction nozzle 11 to work; the auxiliary pump 4 connects the annulus between the tubing 8 and the coiled tubing 9 to assist in the discharge of the return fluid.

[0041] The bottom of the tubing 8 is connected to a guide 7, which is an L-shaped structure used to change the direction of the vertically downward high-pressure hose 10. The guide 7 has an L-shaped channel running vertically through it. The horizontal section of the L-shaped channel is connected to the production layer 15, and the vertical section of the L-shaped channel is connected to the annulus between the tubing 8 and the continuous tubing 9. One end of the high-pressure hose 10 is connected to the bottom of the continuous tubing 9 and is located in the L-shaped channel. The other end of the high-pressure hose 10 passes through the L-shaped channel and exits from the outlet at the bottom of the L-shaped channel into the production layer 15. The other end of the high-pressure hose 10 is connected to the self-traction nozzle 11.

[0042] The guide 7 is provided with a funnel-shaped channel 16. The larger end of the funnel-shaped channel 16 is connected to the horizontal section of the L-shaped channel of the guide 7, and the smaller end of the funnel-shaped channel 16 is connected to the annulus between the tubing 8 and the continuous tubing 9 through the vertical section of the L-shaped channel of the guide 7. The flushing fluid from the clear water tank 12 is sprayed into the blockage of the production layer 15 through the continuous tubing 9, the high-pressure hose 10 and the self-traction nozzle 11, flushing out the sand / coal powder blocking the production layer channel to form a liquid-solid mixture of sand / coal powder. Under the action of the auxiliary pump 4, the liquid-solid mixture enters the annulus between the tubing 8 and the continuous tubing 9 through the funnel-shaped channel 16 and is then pumped into the settling tank 1.

[0043] Furthermore, two symmetrically arranged perforated windows 17 are provided on the bottom horizontal section of the guide 7. The perforated windows 17 are located below the funnel-shaped channel 16, with their tops connected to the funnel-shaped channel 16 and their bottoms connected to the coalbed methane vertical well 12. Large particles in the liquid-solid mixture entering the funnel-shaped channel 16 fall through the perforated windows 17 under gravity and into the bottom of the coalbed methane vertical well 12, while the remaining portion is pumped away. The perforated windows 17 guide larger volumes of quartz sand and coal powder to fall to the bottom of the well.

[0044] In order to ensure that the upper part of the guide 7 can remain vertical, a straightener 18 is fitted and connected to the upper outer wall of the guide 7. The straightener 18 is a known existing device.

[0045] The second gyroscope 6 is connected to the oil pipe 8 above the guide 7 and serves a directional function.

[0046] It should be noted that in this embodiment, the main body of the guide 7 is made of high-strength steel, and the L-shaped channel of the guide 7 facilitates the passage of the high-pressure hose 10. A centralizer 18 and a second gyroscope 6 are attached to its upper exterior to fix the guide 7 and the precise docking hole; the flared channel 16 of the guide 7 connects to the vertical section of the guide 7, guiding the flushed fine sand and coal dust into the tubing, and then, under the action of the auxiliary pump 4, extracting them from the wellbore through the tubing 8.

[0047] The self-traction nozzle 11 is connected to the end of the high-pressure hose 10. The self-traction nozzle 11 is made of high-strength alloy material, with an outer diameter of 8mm, a spray speed of 300-400m / s, and an orifice diameter of 0.15mm. The front end of the self-traction nozzle 11 has three sand-flushing holes 111, and the rear sidewall of the self-traction nozzle 11 has a conical structure with six evenly distributed propulsion sand-discharging holes 112. The orifice diameter of the propulsion sand-discharging holes 112 is larger than that of the sand-flushing holes 111. During the spraying process, the self-traction nozzle 11 maintains stable discharge volume and pressure, advancing and retreating slowly to achieve sand discharge and enlarge the orifice.

[0048] The working principle of the small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells proposed in this embodiment is as follows:

[0049] The first step is to flush the gas well to the bottom of the well using conventional tubing forward flushing operations to ensure the wellbore is clean and ready for operation.

[0050] The second step involves connecting a visual camera setup and a first gyroscope, extending a steel wire to the perforation location of the 12-stage coalbed methane well. The real-time gas production and sand / coal powder discharge are checked one by one in each perforation. The gas production is compared with that of perforations in different phases during the stable production period. Based on the equipment depth and gyroscope orientation, the location of any blocked perforation is determined. The camera in the visual camera setup is oriented using the first gyroscope to determine the azimuth angle of the perforation, and the depth of the perforation is determined by the camera's downward movement, ultimately achieving precise perforation location.

[0051] The third step is to formulate a specific blockage removal implementation plan based on this; extend the downhole guide mechanism to the location of the blocked orifice, and use the second gyroscope 6 to adjust the orientation of the guide 7, aligning the outlet of the guide 7 with the orifice to provide conditions for the entry of the unblocking equipment; use coiled tubing operation to extend the connected tubing 8, coiled tubing 9, high-pressure hose 10 and self-traction nozzle 11 into the coalbed methane vertical well 12, so that the high-pressure hose 10 and self-traction nozzle 11 pass through the L-shaped channel of the guide 7 and go down to the opening of the blocked orifice.

[0052] The fourth step is to start the ground construction mechanism, turn on the ground high-pressure pump 3, circulate the sand flushing fluid, and drive the high-pressure hose 10 and the self-traction nozzle 11 to enter the production layer channel by themselves. As the sand flushing fluid will be discharged from the booster sand discharge hole 112 under pressure, it can drive the automatic movement and flush out the sand / coal powder blocking the production layer channel through the sand flushing hole 111.

[0053] Simultaneously, the auxiliary pump 4 is activated to assist in extracting the flushing fluid, sand, and coal powder returning from the formation from the annulus of the tubing, which then enters the sedimentation tank 1 for sedimentation and circulation. After completing the planned length of the reconstructed channel and unblocking, conventional tubing flushing operations are then carried out. After the flushing is completed, the production tubing string is run in to resume production.

[0054] It should be noted that in this embodiment, the volume of the grit chamber 1 is 50 m³, the volume of the clear water chamber 2 is 50 m³, the maximum flow rate of the high-pressure pump 3 is 240 L / min, the maximum working pressure is 65 MPa, and the maximum flow rate of the auxiliary pump 4 is 300 L / min. During the preparation phase, 40 m³ of clear water is prepared for the clear water chamber 2, and 30 m³ of clear water is prepared for the grit chamber 1. The two chambers are connected by flexible hoses at a depth of 4 / 5 or more in the chamber walls, and a filter device is installed at the joint in the grit chamber 1.

[0055] It should be noted that in this embodiment, the outer diameter of the continuous tubing 9 is 1 inch (25.4 mm), and the outer diameter of the flexible high-pressure hose 10 is 1 inch (25.4 mm), connected using a dedicated connector. The length of the high-pressure hose 10 is determined according to the planned unblocking operation length.

[0056] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all such deductions or substitutions should be considered to fall within the scope of patent protection determined by the submitted claims.

Claims

1. A small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells, characterized in that, This includes ground construction mechanisms, downhole inspection and positioning mechanisms, downhole guiding mechanisms, and self-jetting unblocking mechanisms; The ground construction mechanism includes a high-pressure pump (3) and a drainage pump (4) located on the ground. The downhole observation and positioning mechanism includes a visual camera mechanism and a first gyroscope for preliminary detection of blockages; The downhole guiding mechanism includes a second gyroscope (6) and a guide (7); The self-jetting unblocking mechanism includes an oil pipe (8), a continuous oil pipe (9), a high-pressure hose (10), and a self-traction nozzle (11). A tubing (8) is installed inside a coalbed methane vertical well (12). One end of a coiled tubing (9) is inserted inside the tubing (8), and a high-pressure pump (3) is connected to the other end of the coiled tubing (9). A guide (7) is connected to the bottom of the tubing (8). An L-shaped channel is installed inside the guide (7). The horizontal section of the L-shaped channel is connected to the producing formation (15), and the vertical section of the L-shaped channel is connected to the annulus between the tubing (8) and the coiled tubing (9). One end of a high-pressure hose (10) is connected to the bottom of the coiled tubing (9), and the high-pressure hose (10) is located in the L-shape. Inside the channel, the other end of the high-pressure hose (10) passes through the L-shaped channel and exits from the bottom of the L-shaped channel into the production layer (15); and the other end of the high-pressure hose (10) is connected to the self-traction nozzle (11); the guide (7) is provided with a bell mouth channel (16), the large end of the bell mouth channel (16) is connected to the horizontal section of the L-shaped channel of the guide (7), and the small end of the bell mouth channel (16) is connected to the vertical section of the L-shaped channel of the guide (7) and communicates the annulus between the tubing (8) and the continuous tubing (9); The tubing (8) is located outside the coalbed methane vertical well (12) and is connected to the drainage pump (4); the second gyroscope (6) is connected to the tubing (8) above the guide (7).

2. The small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells according to claim 1, characterized in that, The ground construction mechanism also includes a sedimentation tank (1) and a clear water tank (2) set on the ground; the drainage pump (4) is connected to the sedimentation tank (1), and the high-pressure pump (3) is connected to the clear water tank (2).

3. The small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells according to claim 2, characterized in that, The sedimentation tank (1) and the clear water tank (2) are connected by a hose at a depth of 4 / 5 or more. A filter device is provided at the joint in the sedimentation tank (1).

4. The small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells according to claim 1, characterized in that, Two sluice windows (17) are symmetrically arranged on the bottom horizontal section of the guide (7). The sluice windows (17) are located below the funnel-mouth channel (16) and the top of the sluice windows (17) is connected to the funnel-mouth channel (16). The bottom of the sluice windows (17) is connected to the coalbed methane vertical well (12).

5. The small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells according to claim 1, characterized in that, A seal (13) is provided at the upper end of the oil pipe (8), and one end of the continuous oil pipe (9) passes through the seal (13) and is installed inside the oil pipe (8).

6. The small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells according to claim 5, characterized in that, The inner wall of the coalbed methane vertical well (12) is equipped with a casing. The wellhead casing end of the coalbed methane vertical well (12) is equipped with a wellhead sealing flange (14), which seals the annulus between the casing and the tubing (8).

7. The small-diameter directional hydraulic jetting unblocking device for coalbed methane vertical wells according to claim 1, characterized in that, A stabilizer (18) is fitted onto the upper outer wall of the guide (7).

8. The small-diameter directional hydraulic jet unblocking device for coalbed methane vertical wells according to claim 1, characterized in that, The self-traction nozzle (11) has three sand flushing holes (111) at the front end. The rear side wall of the self-traction nozzle (11) is a conical structure. Six boosting sand discharge holes (112) are evenly distributed on the side wall of the conical structure. The diameter of the boosting sand discharge holes (112) is larger than that of the sand flushing holes (111).

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