Shale oil horizontal well high-pressure drainage system and method

Abstract

The invention belongs to the technical field of petroleum yield increasing transformation, and particularly relates to a shale oil horizontal well high-pressure drainage system and method. The drainage and mining system comprises a wellhead casing gate valve, a drainage and mining device, a control system and a pressure transmitter, the drainage and mining device comprises a four-way joint, an oil nozzle valve and a parallel gate valve which are communicated in sequence, the four-way joint is communicated with the wellhead casing gate valve, and a production oil nozzle is installed in the oil nozzle valve. The pressure transmitter is installed to monitor the discharge and production pressure in real time, so that the production oil nozzle with the proper specification is adjusted and installed according to the wellhead pressure and the liquid amount. The production oil nozzle is mounted in the oil nozzle valve, so that sufficient mounting positions can be provided for the production oil nozzle, the production oil nozzle is mounted along the flow direction of production oil, and the oil nozzle can be firmer when subjected to impact and rotating force of the oil flow during normal production; the problems of loosening and tripping of oil nozzle threads caused by rotating force generated by high-pressure fluid are solved.

Description

Technical Field

[0001] This invention belongs to the field of petroleum production enhancement and transformation technology, specifically relating to a high-pressure drainage system and method for shale oil horizontal wells. Background Technology

[0002] Shale oil, as an unconventional oil and gas resource, has become a new favorite in the global energy market due to its large reserves, concentrated distribution, and increasingly mature development technologies. Jimsar shale oil is one of the billion-ton-level large oilfields discovered by China National Petroleum Corporation's Xinjiang Oilfield Company in recent years. It has now entered the stage of batch drilling and production development. These wells are characterized by high drainage pressure, sand content in the initial drainage volume, and sand production. In the early stages of development, conventional nozzle-casing technology was used for drainage when these wells were put into production. While this met development needs to some extent, several problems have emerged as wells were put into production. These include the erosion of nozzles due to sand production during drainage, requiring frequent replacements; loosening and disengagement of nozzle threads due to the rotational force generated by high-pressure fluids; difficulty in cleaning clogged nozzles; and well control and environmental issues caused by the lack of pressure control measures at the rear end of the nozzle casing.

[0003] CN201520030619.7 discloses a skid-mounted device for high-pressure shale gas extraction, including a desanding skid, a heating furnace skid, and a separation and metering skid. The separation and metering skid houses a gas-liquid separator, with flow meters installed on both the liquid and gas outlet pipes. The desanding skid's inlet is a gas source inlet, and its outlet is connected to both the heating furnace skid's inlet pipe and the gas-liquid separator's inlet pipe. Valves are installed on both the heating furnace skid's and the gas-liquid separator's inlet pipes. The heating furnace skid's outlet is also connected to the gas-liquid separator's inlet pipe. This solution integrates desanding, heating, throttling, separation, and metering functions, but it does not solve the aforementioned problems associated with oil and gas nozzles. Summary of the Invention

[0004] The purpose of this invention is to provide a high-pressure drainage system for shale oil horizontal wells, overcoming the aforementioned technical problems in the prior art.

[0005] Another objective of this invention is to provide a high-pressure drainage method for shale oil horizontal wells, which improves on-site work efficiency and safety.

[0006] Therefore, the technical solution provided by the present invention is as follows: A high-pressure drainage system for shale oil horizontal wells includes a wellhead casing gate valve, a drainage device, a control system, and a pressure transmitter. The pressure transmitter is installed on the wellhead casing gate valve, the drainage device is connected to the wellhead casing gate valve, and the pressure transmitter is electrically connected to the control system. The drainage device includes a four-way valve, an oil nozzle valve, and a parallel gate valve connected in sequence. The four-way valve is connected to the wellhead casing gate valve. A production oil nozzle is installed inside the oil nozzle valve. The four-way valve, the oil nozzle valve, and the parallel gate valve are all integrally forged.

[0007] The borehole diameter of the drainage device and the wellhead casing gate valve.

[0008] The four-way valve is connected to an oil nozzle mounting valve, and the four-way valve and the oil nozzle mounting valve are connected by a flange.

[0009] The production nozzle is threaded and installed inside the nozzle valve.

[0010] The flow channel and nozzle surface of the production nozzle are both coated with an erosion-resistant alloy coating and are machined into one piece.

[0011] The production nozzle is installed in the direction of the production oil flow.

[0012] A high-pressure drainage method for shale oil horizontal wells is proposed, which employs a high-pressure drainage system for shale oil horizontal wells. The control system monitors the drainage pressure of the horizontal well in real time through a pressure transmitter. Based on the drainage pressure and fluid volume, the appropriate specifications of the production nozzles are replaced and adjusted, and corresponding production system parameters are established.

[0013] When replacing the production nozzle, first close the wellhead casing gate valve, remove the nozzle installation valve, remove the production nozzle, install the new production nozzle in the direction of production oil flow, and finally install the nozzle installation valve.

[0014] If sand blockage occurs during production, production can be quickly restored by replacing the entire oil nozzle valve.

[0015] The beneficial effects of this invention are: The high-pressure drainage system for shale oil horizontal wells provided by this invention allows for real-time monitoring of drainage pressure via a pressure transmitter. This enables the adjustment of the installed production nozzle to an appropriate specification based on wellhead pressure and fluid volume. By installing the production nozzle within the nozzle valve, ample installation space is provided, allowing for an enlarged nozzle design. This integrates the alloy and erosion-resistant components of the nozzle's flow passage with the nozzle itself, resulting in higher working strength and impact resistance after the nozzle is subjected to high-pressure fluid or high-pressure sand-containing fluid.

[0016] The nozzle of this invention is installed in the direction of the production oil flow. During normal production, when subjected to the impact and rotational force of the oil flow, this ensures a tighter seal on the nozzle, resolving the problem of loosening and disengagement of the nozzle threads caused by the rotational force generated by the high-pressure fluid. A control valve is designed at the rear end of the nozzle valve, further ensuring safety and well control risks. Simultaneously, the nominal diameter design, consistent with the wellhead equipment, facilitates sand removal operations. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of one embodiment of the present invention; Figure 2 This is a cross-sectional view of the oil nozzle valve.

[0018] In the diagram: 1. Wellhead casing gate valve; 2. Pressure transmitter; 3. Parallel gate valve; 4. Oil nozzle valve; 5. Four-way valve; 6. Threaded flange; 7. Oil nozzle installation valve; 8. Production oil nozzle. Detailed Implementation

[0019] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0020] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0021] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0022] Example 1 This embodiment provides a high-pressure drainage system for shale oil horizontal wells, including a wellhead casing gate valve 1, a drainage device, a control system, and a pressure transmitter 2. The pressure transmitter 2 is installed on the wellhead casing gate valve 1, the drainage device is connected to the wellhead casing gate valve 1, and the pressure transmitter 2 is electrically connected to the control system. The high-pressure drainage system for shale oil horizontal wells provided by this invention can monitor the drainage pressure in real time by installing a pressure transmitter 2, thereby adjusting the installation of production nozzles 8 of appropriate specifications according to the wellhead pressure and fluid volume. This system can meet the production requirements of high-pressure drainage in shale oil horizontal wells, providing equipment and safety guarantees for the smooth commissioning of new wells and safe production during the drainage phase, further improving the production efficiency and safety performance of new wells.

[0023] Example 2 Based on Example 1, this example provides a high-pressure drainage system for shale oil horizontal wells, such as... Figure 1As shown, the drainage device includes a four-way valve 5, an oil nozzle valve 4, and a parallel gate valve 3 connected in sequence. The four-way valve 5 is connected to the wellhead casing gate valve 1. The oil nozzle valve 4 is equipped with a production oil nozzle 8. The four-way valve 5, the oil nozzle valve 4, and the parallel gate valve 3 are all integrally forged.

[0024] The production nozzle 8 is installed inside the nozzle valve 4. The pressure-bearing body of the entire drainage device is a forged structure, possessing superior mechanical properties and strength to ensure safe use during the high-pressure drainage stage. The four-way valve 5 connects to the wellhead casing gate valve 1, the drainage device, the nozzle installation valve 7, and the threaded flange 6.

[0025] Example 3 Based on Example 1, this example provides a high-pressure drainage system for shale oil horizontal wells, wherein the drainage device and the wellhead casing gate valve 1 have different diameters.

[0026] The drainage unit adopts the same nominal diameter design as the wellhead, making it easier to clean or replace the entire nozzle valve 4 after sand blockage occurs, allowing for rapid resumption of production. (The original drainage process was particularly difficult to clean after sand discharge, and failure to clean in time could easily lead to more serious sand blockage or sand burial).

[0027] Example 4 Based on Example 2, this example provides a high-pressure drainage system for shale oil horizontal wells. The four-way valve 5 is connected to an oil nozzle installation valve 7, and the four-way valve 5 and the oil nozzle installation valve 7 are connected by a flange.

[0028] When installing the nozzle, operate from the nozzle installation valve 7. First, close the casing production valve, then remove the nozzle installation valve 7. Use a special tool to remove the original nozzle, and then install the new nozzle into the nozzle valve 4. The nozzle installation valve 7 also provides further effective protection for safety and environmental requirements in the event of nozzle failure.

[0029] Example 5 Based on Example 2, this example provides a high-pressure drainage system for shale oil horizontal wells, wherein the production nozzle 8 is threadedly installed inside the nozzle valve 4.

[0030] The production nozzle 8 is installed in the direction of the production oil flow.

[0031] The production nozzle 8 is installed in the direction of the production oil flow. When subjected to the impact and rotational force of the oil flow during normal production, the threads can be tightened, making the nozzle more secure and preventing the production nozzle 8 from loosening or disengaging.

[0032] Example 6 Based on Example 2, this example provides a high-pressure drainage system for shale oil horizontal wells. The flow passage and nozzle surface of the production nozzle 8 are both coated with an erosion-resistant alloy coating and are integrated into one piece.

[0033] like Figure 2 As shown, since the oil nozzle valve 4 has more installation positions for the oil nozzle, the oil nozzle has been enlarged. This allows the alloy and erosion-resistant parts of the oil nozzle flow channel to be integrated with the oil nozzle as one unit (conventional oil nozzles cannot be designed to be processed separately due to their small size, and only the alloy coating is applied to the surface of the flow channel). This gives the oil nozzle higher working strength and impact resistance after being impacted by high-pressure fluid or high-pressure sand-containing fluid.

[0034] Example 7 This embodiment provides a high-pressure drainage method for shale oil horizontal wells. It adopts a high-pressure drainage system for shale oil horizontal wells. The control system monitors the drainage pressure of the horizontal well in real time through a pressure transmitter. Based on the drainage pressure and fluid volume, it replaces and adjusts the production nozzle 8 of appropriate specifications and formulates corresponding production system parameters.

[0035] This method monitors the drainage pressure of shale oil horizontal wells and adjusts the specifications of the nozzles accordingly based on the drainage fluid volume of a single well, thereby formulating reasonable production system parameters.

[0036] When replacing the production nozzle 8, first close the wellhead casing gate valve 1, remove the nozzle installation valve 7, remove the production nozzle 8, then install the new production nozzle 8 in the direction of production oil flow, and finally install the nozzle installation valve 7.

[0037] If sand blockage occurs during production, production can be quickly restored by replacing the entire oil nozzle valve 4.

[0038] This invention is applicable to all oil wells developed using unconventional methods or volumetric fracturing techniques, and is particularly suitable for wells with high sand content and sand-producing characteristics. It can solve problems encountered during the opening and drainage of shale oil horizontal wells, such as the erosion of nozzles caused by sand production requiring frequent replacement, loosening and disengagement of nozzle threads due to the rotational force generated by high-pressure fluids, difficulty in cleaning clogged nozzles, and well control and environmental risks caused by the lack of pressure control measures at the rear end of the nozzle sleeve.

[0039] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A high-pressure drainage system for shale oil horizontal wells, characterized in that: It includes a wellhead casing gate valve, a drainage device, a control system, and a pressure transmitter. The pressure transmitter is installed on the wellhead casing gate valve. The drainage device is connected to the wellhead casing gate valve, and the pressure transmitter is electrically connected to the control system.

2. The shale oil horizontal well high-pressure drainage system according to claim 1, characterized in that: The drainage device includes a four-way valve, an oil nozzle valve, and a parallel gate valve connected in sequence. The four-way valve is connected to the wellhead casing gate valve. A production oil nozzle is installed inside the oil nozzle valve. The four-way valve, the oil nozzle valve, and the parallel gate valve are all integrally forged.

3. The shale oil horizontal well high-pressure drainage system according to claim 1, characterized in that: The borehole diameter of the drainage device and the wellhead casing gate valve.

4. A shale oil horizontal well high-pressure drainage system according to claim 2, characterized in that: The four-way valve is connected to an oil nozzle mounting valve, and the four-way valve and the oil nozzle mounting valve are connected by a flange.

5. A shale oil horizontal well high-pressure drainage system according to claim 2, characterized in that: The production nozzle thread is installed inside the nozzle valve.

6. A high-pressure drainage system for shale oil horizontal wells according to claim 2, characterized in that: The flow channel and nozzle surface of the production nozzle are both coated with an erosion-resistant alloy coating and are machined into one piece.

7. A shale oil horizontal well high-pressure drainage system according to claim 5, characterized in that: The production nozzle is installed in the direction of the production oil flow.

8. A high-pressure drainage method for shale oil horizontal wells, employing the high-pressure drainage system for shale oil horizontal wells as described in claim 4, characterized in that: The control system monitors the horizontal well drainage pressure in real time through a pressure transmitter. Based on the drainage pressure and fluid volume, it replaces and adjusts the appropriate production nozzles and sets corresponding production system parameters.

9. A high-pressure drainage method for shale oil horizontal wells according to claim 8, characterized in that: When replacing the production nozzle, first close the wellhead casing gate valve, remove the nozzle installation valve, remove the production nozzle, install the new production nozzle in the direction of production oil flow, and finally install the nozzle installation valve.

10. A high-pressure drainage method for shale oil horizontal wells according to claim 8, characterized in that: If sand blockage occurs during production, production can be quickly restored by replacing the entire oil nozzle valve.

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