A front structure for shale gas horizontal well liquid discharge

Abstract

The utility model relates to the field of gas well liquid discharge, disclose a shale gas horizontal well liquid discharge's preposed structure for discharging the liquid accumulation of horizontal well section, including casing inner drainage unit, casing inner drainage unit includes casing, wellhead fixed pulley set, well bottom fixed pulley set and first drainage device, the casing includes vertical section and horizontal section, vertical section extends to ground, wellhead fixed pulley set is fixed in vertical section upper end, well bottom fixed pulley set is fixed in horizontal section, and wellhead fixed pulley set and well bottom fixed pulley set between being provided with first circulation traction, first circulation traction, wellhead fixed pulley set and well bottom fixed pulley set form first liquid discharge route, and first drainage device sets up on first circulation traction and can move on first liquid discharge route. Through the first drainage device and first liquid discharge route of moving on first drainage route, solve the problem that the present liquid discharge mode cannot carry out the liquid discharge to horizontal well section because of the limited downhole depth.

Description

Technical Field

[0001] This utility model relates to the field of gas well drainage technology, specifically to a pre-structure for drainage of shale gas horizontal wells. Background Technology

[0002] Currently, shale gas extraction faces the problem of liquid accumulation. When the liquid accumulation is severe, it can lead to a decrease in gas well production capacity or even flooding and shutdown. Liquid accumulation in shale gas wells is an important factor restricting production capacity.

[0003] Currently, common methods for draining fluid from shale gas wells include plunger drainage, gas lift drainage, foam drainage, jet pump drainage, and electric submersible pump drainage. Alternatively, pressurization can be used to reduce wellhead pressure and utilize the gas lift pressure differential for drainage, or a combination of these methods can be employed. However, due to limitations in well depth, the problem of draining fluid from horizontal well sections cannot be solved. Utility Model Content

[0004] The present invention aims to provide a pre-flush structure for shale gas horizontal wells to solve the problem of limited well depth.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a pre-flush structure for draining liquid from a shale gas horizontal well, used to drain accumulated liquid in the horizontal well section, including a casing drainage unit. The casing drainage unit includes a casing, a wellhead fixed pulley group, a well bottom fixed pulley group, and a first drainage device. The casing includes a vertical section and a horizontal section. The vertical section extends upward to the ground. The wellhead fixed pulley group is fixed inside the upper end of the vertical section, and the well bottom fixed pulley group is fixed inside the horizontal section. A first circulation traction is provided between the wellhead fixed pulley group and the well bottom fixed pulley group. The first circulation traction, the wellhead fixed pulley group, and the well bottom fixed pulley group form a first drainage route. The first drainage device is set on the first circulation traction and can move along the first drainage route.

[0006] The beneficial effects of this solution are as follows: by moving the first drainage device and the first drainage route on the first drainage route, the accumulated liquid in the horizontal section can be discharged. The structure is simple and the design is reasonable. It can effectively avoid the problem that the existing drainage method cannot solve the drainage problem in the horizontal well section due to the limited depth of the well.

[0007] Furthermore, a flange is provided on the vertical section of the casing, and the flange is connected to a first blowout preventer. The wellhead fixing pulley group is fixedly installed inside the first blowout preventer.

[0008] Beneficial effects: By installing a flange on the vertical section of the casing and connecting it to the first blowout preventer, the wellhead fixing pulley assembly can be securely fixed inside the first blowout preventer, effectively enhancing the stability and safety of the structure. Simultaneously, this design better prevents unexpected situations such as wellhead blowouts during fluid drainage, further improving the reliability and safety of this pre-installed structure during fluid drainage operations.

[0009] Furthermore, it also includes an external motor, which includes an output shaft connected to a fixed pulley block at the wellhead, thereby driving the first cyclic traction rotation, which in turn drives the first drainage device to move, allowing the first drainage device to move along the first drainage path.

[0010] Beneficial effects: The external motor enables automatic drive of the first cycle traction, making the movement of the first drainage device more precise and controllable, better adapting to the drainage needs under different well conditions, enhancing the adaptability and flexibility of the device, and improving the working performance and reliability of the entire front structure, providing a stronger guarantee for shale gas horizontal well drainage operations.

[0011] Furthermore, it also includes a control unit, which includes a control platform and a sensor. The sensor is electrically connected to the control platform, and the control platform is electrically connected to an external motor. The sensor is installed on the drainage device, which includes a drainage body and a rope clamp. The rope clamp is installed on the drainage body and electrically connected to the sensor. The rope clamp is engaged with the circulating traction device and electrically connected to the sensor. After receiving a signal transmitted by the control platform, the sensor controls the rope clamp to tighten or loosen.

[0012] Beneficial effects: 1. The control unit enables intelligent control of the entire drainage process, improving the accuracy and efficiency of the drainage operation; 2. The sensor can monitor the status of the drainage device in real time and feed the information back to the control platform, allowing the platform to make timely adjustments and ensuring smooth drainage operations; 3. The electrical connection between the rope clamp and the sensor, as well as the sensor's control of the rope clamp, makes the movement of the drainage device along the drainage path more stable and reliable, avoiding unexpected situations; 4. By controlling the external motor through the control platform, the drainage speed and force can be flexibly adjusted according to actual needs, further improving the drainage effect; 5. This intelligent control method greatly reduces the need for manual intervention and improves the safety and convenience of the operation.

[0013] Furthermore, it also includes an internal drain unit for the oil pipe, which includes an oil pipe, an upper fixed pulley group, a lower fixed pulley group, and a second drain device. The oil pipe includes an oil pipe head and an oil pipe bottom from top to bottom. The oil pipe head is connected to a second blowout preventer. The upper fixed pulley group is fixedly installed inside the second blowout preventer, and the lower fixed pulley group is fixedly installed at the bottom of the oil pipe. A first circulation traction is provided between the upper fixed pulley group and the lower fixed pulley group. The second circulation traction, the upper fixed pulley group, and the lower fixed pulley group form a second drainage route. The second drain device is installed on the second circulation traction and can move on the second drainage route.

[0014] Beneficial effects: After adding the tubing, the operating trajectory of the casing drainage device is restricted. After adding the tubing drainage unit, a second drainage route is formed by the second circulation traction, the upper fixed pulley group and the lower fixed pulley group. The second drainage device can move on this route and discharge the accumulated liquid in the casing and tubing to the ground in a relay manner, so as to avoid the accumulation of liquid from affecting the gas production work, thereby improving drainage efficiency and ensuring the smooth progress of gas production work.

[0015] Furthermore, the drainage device has a built-in receiving cavity containing a foaming agent.

[0016] Beneficial effects: The foaming agent stored in the built-in containment cavity of the drainage device can generate a large number of bubbles during the drainage process, which helps to reduce the surface tension of the liquid and improve the drainage efficiency.

[0017] The foaming method utilizes the bubbles generated by foaming agents to increase the viscosity of the accumulated liquid, thereby further improving the drainage effect.

[0018] This setup allows the drainage system to handle accumulated liquid more effectively, ensuring the normal operation of shale gas horizontal wells.

[0019] The use of foaming agents increases the flexibility and adaptability of drainage, enabling it to meet drainage needs under different circumstances. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of Embodiment 1 of the present utility model;

[0021] Figure 2 This is a schematic diagram of Embodiment 2 of the present invention;

[0022] The reference numerals in the accompanying drawings include: casing 11, first blowout preventer 111, tubing 12, second blowout preventer 121, gas tree 13, wellhead fixed pulley block 211, bottom hole fixed pulley block 212, first drainage device 213, first circulation traction 214, upper fixed pulley block 221, lower fixed pulley block 222, second drainage device 223, second circulation traction 224, first external motor 311, second external motor 312, and control platform 32. Detailed Implementation

[0023] The following detailed description illustrates the specific implementation method:

[0024] Example 1

[0025] For gas wells where only casing has been installed and the liquid has accumulated in the horizontal section, it is now necessary to drain the liquid from the horizontal section.

[0026] Example 1 is basically as shown in the appendix. Figure 1 As shown, Figure 1The diagram illustrates a pre-drainage structure for a shale gas horizontal well, comprising an in-casing drainage unit and a control unit. The in-casing drainage unit includes a casing 11, a wellhead fixed pulley assembly 211, a bottom-hole fixed pulley assembly 212, and a first drainage device 213. The casing 11 includes a vertical section and a horizontal section. A flange is welded to the vertical section of the casing 11, and the flange is connected to a first blowout preventer 111. The wellhead fixed pulley assembly 211 is fixedly installed inside the first blowout preventer 111, and the bottom-hole fixed pulley assembly 212 is fixed inside the horizontal section. A first circulating traction 214 is provided between the wellhead fixed pulley assembly 211 and the bottom-hole fixed pulley assembly 212. The first circulating traction 214 has a certain elasticity, thereby ensuring that the first drainage device 213 can be driven by the first circulating traction 214 through the corners of the horizontal and vertical sections of the casing 11.

[0027] The control unit includes a first external motor 311, a control platform 32, and a sensor. The first external motor 311 includes an output shaft, which is connected to the wellhead fixed pulley group 211. The first circulating traction 214, the wellhead fixed pulley group 211, and the bottom fixed pulley group 212 form a first drainage route. The first drainage device 213 is mounted on the first circulating traction 214 and can move along the first drainage route. Thus, the first external motor 311 acts as a power source to drive the first drainage device 213 to move along the first drainage route, thereby draining the accumulated liquid in the horizontal section of the casing 11.

[0028] The sensor is electrically connected to the control platform 32, and the control platform 32 is electrically connected to the external motor. The sensor is installed on the first drainage device 213, which includes a drainage body and a rope clamp. The rope clamp is fixed to the drainage body by bolts and electrically connected to the sensor. The rope clamp is engaged with the circulating traction and electrically connected to the sensor. After receiving the signal transmitted by the control platform 32, the sensor controls the rope clamp to tighten or loosen.

[0029] The specific implementation process is as follows:

[0030] During installation, the wellhead fixed pulley assembly 211 is welded inside the first blowout preventer 111, and the bottom fixed pulley assembly 212 is welded to the horizontal section of the casing 11. A first circulating traction 214 is installed between the wellhead fixed pulley assembly 211 and the bottom fixed pulley assembly 212. A first external motor 311 is connected to the outside of the wellhead fixed pulley assembly 211, and the intelligent control platform 3232 is electrically connected to the first external motor 311. Thus, using the first external motor 311 as a power source, the wellhead fixed pulley assembly 211 and the bottom fixed pulley assembly 212 circulate and traction the tubing 12 to form a first drainage path, allowing the first drainage device 213 to move along the first drainage path.

[0031] Work Plan: Before drainage, the drainage device inside casing 11 is located near the bottom-hole fixed pulley block 212. During drainage, an external motor is started as the power source. The first intelligent control platform 3232 is used to set parameters such as the drainage method (in this embodiment, the drainage method is pumping out fluid with a pump), the drainage section, and the movement speed of the drainage device. The first intelligent control platform 3232 sends a signal to start the drainage device inside casing 11. The drainage device inside casing 11 performs drainage work according to the control signal requirements. Since tubing 12 is not installed, the accumulated fluid in the horizontal well can be directly discharged to the wellhead. After drainage is completed, the drainage device inside casing 11 is returned to the vicinity of the lower fixed pulley block 222 and the bottom-hole fixed pulley block 212.

[0032] Example 2

[0033] For gas wells that have already had tubing 12 installed, and for gas wells with accumulated fluid in the horizontal section or already inside tubing 12, it is now necessary to drain the accumulated fluid from the gas well.

[0034] like Figure 2 As shown, based on Embodiment 1, an internal draining unit is also included. This unit comprises an oil pipe 12, an upper fixed pulley assembly 221, a lower fixed pulley assembly 222, and a second draining device 223. The oil pipe 12 includes a pipe head and a pipe bottom from top to bottom. The pipe head is connected to a gas-producing tree 13 via a flange. The upper end of the gas-producing tree is connected to a second blowout preventer 121 via a flange. The upper fixed pulley assembly 221 is fixedly installed inside the second blowout preventer 121, and the lower fixed pulley assembly 222 is fixedly installed at the bottom of the oil pipe 12. A first circulating traction 214 is provided between the upper and lower fixed pulley assemblies 221 and 222. The second circulating traction 224, the upper fixed pulley assembly 221, and the lower fixed pulley assembly 222 form a second drainage path. The second draining device 223 is mounted on the second circulating traction 224 and can move along the second drainage path. The second draining device 223 is the same as the first draining device 213 and will not be described again here.

[0035] The control unit also includes a second external motor that drives the second cyclic traction 224. The second external motor is also electrically connected to the intelligent control platform 32, thereby controlling the movement of the second cyclic traction 224 through the intelligent control platform 32, and thus controlling the movement of the second drainage device in the oil pipe.

[0036] Work Plan: Before drainage, the drainage devices inside the tubing 12 and casing 11 are located near the lower fixed pulley block 222 and the bottom-of-well fixed pulley block 212, respectively. Since the tubing 12 has already been installed, the first drainage device 213 can only move in the horizontal section of the casing 11. During drainage, the first external motor 311 and the second external motor 312 are started as power sources. The intelligent control platform 3232 is used to set parameters such as the drainage method of the casing 11 drainage device (in this embodiment, the drainage method is pumping out the fluid using an oil pump), the drainage well section, and the moving speed of the drainage device. The intelligent control platform 3232 transmits a signal to start the casing 11 drainage device, which then performs drainage work according to the control signal requirements, draining the accumulated fluid in the horizontal well to the vicinity of the tubing 12. The intelligent control platform 3232 is used to set parameters such as the drainage method of the tubing 12 drainage device (in this embodiment, the drainage method is pumping out the fluid using an oil pump), the drainage well section, and the moving speed of the drainage device. The second intelligent control platform 3232 sends a signal to activate the drainage device inside the tubing 12. The drainage device inside the tubing 12 then performs drainage work according to the control signal, draining the accumulated fluid from the tubing 12 to the wellhead. After drainage is completed, the drainage devices inside the tubing 12 and casing 11 are returned to the vicinity of the lower fixed pulley block 222 and the bottom-hole fixed pulley block 212. The above description is merely an embodiment of this utility model; common technical solutions and / or characteristics are not described in detail here. It should be noted that the technical means for solving problems in the above embodiments of this utility model can be combined to solve multiple technical problems simultaneously. For those skilled in the art, several modifications and improvements can be made without departing from the technical solution of this utility model, and these should also be considered within the scope of protection of this utility model. These will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A pre-flush structure for draining fluid from a shale gas horizontal well, used to drain accumulated fluid from the horizontal well section, characterized in that: The system includes an in-casing drainage unit, which comprises a casing, a wellhead fixed pulley group, a well bottom fixed pulley group, and a first drainage device. The casing includes a vertical section and a horizontal section. The vertical section extends upward to the ground. The wellhead fixed pulley group is fixed inside the upper end of the vertical section, and the well bottom fixed pulley group is fixed inside the horizontal section. A first circulation traction is provided between the wellhead fixed pulley group and the well bottom fixed pulley group. The first circulation traction, the wellhead fixed pulley group, and the well bottom fixed pulley group form a first drainage path. The first drainage device is set on the first circulation traction and can move along the first drainage path.

2. The pre-flush structure for shale gas horizontal well fluid drainage according to claim 1, characterized in that: A flange is installed at the upper end of the vertical section of the casing, and the flange is connected to the first blowout preventer. The wellhead fixing pulley group is fixedly installed inside the first blowout preventer.

3. The pre-flush structure for shale gas horizontal well fluid drainage according to claim 2, characterized in that: It also includes a control unit, which includes an external motor and an output shaft. The output shaft is connected to a fixed pulley block at the wellhead, thereby driving the first cyclic traction to rotate, which in turn drives the first drainage device to move, so that the first drainage device can move on the first drainage path.

4. The pre-flush structure for shale gas horizontal well fluid drainage according to claim 3, characterized in that: The control unit also includes a control platform and a sensor. The sensor is electrically connected to the control platform, and the control platform is electrically connected to an external motor. The sensor is installed on the drainage device, which includes a drainage body and a rope clamp. The rope clamp is installed on the drainage body and electrically connected to the sensor. The rope clamp is engaged with the cyclic traction and electrically connected to the sensor. After receiving a signal from the control platform, the sensor controls the rope clamp to tighten or loosen.

5. The pre-flush structure for shale gas horizontal well fluid drainage according to claim 1, characterized in that: It also includes an internal drain unit for the oil pipe, which includes an oil pipe, an upper fixed pulley group, a lower fixed pulley group, and a second drain device. The oil pipe includes an oil pipe head and an oil pipe bottom from top to bottom. The oil pipe head is connected to a second blowout preventer. The upper fixed pulley group is fixedly installed inside the second blowout preventer, and the lower fixed pulley group is fixedly installed at the bottom of the oil pipe. A first circulation traction is provided between the upper fixed pulley group and the lower fixed pulley group. The second circulation traction, the upper fixed pulley group, and the lower fixed pulley group form a second drainage route. The second drain device is installed on the second circulation traction and can move on the second drainage route.

6. The pre-flush structure for shale gas horizontal well fluid drainage according to claim 1, characterized in that: The drainage device has a built-in receiving cavity containing a foaming agent.

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