Electric self-adaptive downhole throttler

Abstract

The invention discloses an electric self-adaptive downhole throttler which is connected to the tail end of an oil pipe and descends to a designed well depth position along with the oil pipe, and a matching program of in-well pressure and a corresponding throttling nozzle is arranged in the downhole throttler. When a well is opened for production, the motor automatically adjusts the position of the valve rod in the throttling pipe according to the pressure of the position and a preset program, so that the opening degree of the throttling nozzle is controlled, and high-pressure airflow is subjected to throttling and pressure reduction at the throttling pipe and then passes through an oil pipe for production. The underground throttler is simple in structure and reliable in principle, the adjusting process of the throttling nozzle is simple and rapid, the flow throttler does not need to be salvaged and the throttling nozzle does not need to be replaced in production adjusting operation, a large amount of time cost and economic cost can be saved for a production unit, and gas well development efficiency and benefits are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas development, and particularly relates to an electric self-adaptive downhole throttle. Background Art

[0002] China is rich in natural gas resources and has good development prospects and potential. In the initial stage of natural gas exploitation, the wellhead pressure is usually high, and the high-pressure natural gas in the well needs to be depressurized to the pressure of the gathering pipeline network before it can be normally output. The conventional method is to install a throttle valve on the ground for throttling and pressure reduction. Natural gas throttling is a process of temperature and pressure reduction. If the produced natural gas contains a certain amount of water, ground throttling is likely to generate natural gas hydrates, blocking the gas transmission pipeline, affecting the normal production of gas wells, and even causing safety accidents in severe cases. To solve the above problems, many domestic oil and gas fields recommend using downhole throttling process technology.

[0003] The downhole throttling process technology is to install a downhole throttle at an appropriate position of the tubing, use a throttle nozzle to achieve throttling and pressure reduction of the gas flow in the wellbore, and at the same time use the geothermal temperature to heat the low-temperature natural gas after throttling, so that the gas flow temperature is higher than the natural gas hydrate formation temperature under this pressure condition, thereby preventing the formation of natural gas hydrates. However, the existing downhole throttles have many deficiencies. Especially when adjusting production, it is necessary to use wireline operations to fish out the downhole throttle, replace the throttle nozzle on the ground and then re-lower it. The operation cycle is long and the construction cost is high, especially for gas wells that require multiple production adjustment operations. Summary of the Invention

[0004] The purpose of the present invention is to provide an electric self-adaptive downhole throttle, which can automatically control the motor to adjust the opening degree of the throttle nozzle according to the wellbore pressure, greatly saving the time cost and economic cost of production adjustment, and improving the development efficiency and benefits of gas wells.

[0005] To achieve the above purpose, the present invention provides an electric self-adaptive downhole throttle, including: an upper joint, a double-male nipple, a reducing nipple, a slotted tube, a conversion joint, an electrical cylinder and a lower joint connected in sequence;

[0006] Wherein, a throttle tube with air inlet holes on the tube wall is arranged in the slotted tube, and a valve stem is arranged in the throttle tube; a sensor for transmitting signals to the control circuit board is arranged in the lower joint; the electrical cylinder includes a connected motor and a control circuit board; the front end of the valve stem is arranged in the throttle tube, and the bottom end is connected to the motor for adjusting the number of opened air inlet holes of the throttle tube;

[0007] Wherein, a matching program of wellbore pressure and corresponding throttle nozzle is set in the control circuit board.

[0008] Technical Effects and Advantages of the Present Invention

[0009] 1. After the downhole throttle is connected to the tubing, it is lowered into the well without using a wireline operation to lower the throttle, saving operation time and cost.

[0010] 2. A matching program for the wellbore pressure and the corresponding throttle nozzle is set inside the downhole throttle. The throttle nozzle opening is automatically adjusted by an electric motor according to the pressure at the current position according to a preset program. Throttle production adjustment does not require wireline operation, further saving operation time and cost.

[0011] Other features and advantages of the present invention will be described in the following specification, and, in part, will be apparent from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structure pointed out in the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a cross-sectional view of an electric self-adaptive downhole throttle;

[0013] Figure 2 It is a cross-sectional view of a throttle pipe;

[0014] Figure 3 It is a cross-sectional view of a slotted cylinder;

[0015] Reference numerals: 1 - upper sub; 2 - double-male nipple; 3 - shear sleeve; 4 - pin; 5 - reduced-diameter nipple; 6 - slotted cylinder; 7 - throttle pipe; 8 - valve stem; 9 - adapter; 10 - electrical cylinder; 11 - motor; 12 - control circuit board; 13 - support frame; 14 - battery; 15 - sensor; 16 - lower sub; A1 to A6 - O-ring seals. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the implementation conditions of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0018] The downhole throttling process technology installs a downhole throttle at an appropriate position of the tubing, uses a throttle nozzle to achieve throttling and pressure reduction of the gas flow in the wellbore, and at the same time uses the geothermal temperature to heat the low-temperature natural gas after throttling, so that the gas flow temperature is higher than the natural gas hydrate formation temperature under this pressure condition, thereby preventing the formation of natural gas hydrates. However, there are many deficiencies in the existing downhole throttles. Especially when adjusting production, it is necessary to use wireline operations to fish out the downhole throttle, replace the throttle nozzle on the ground and then re-lower it. The operation cycle is long and the construction cost is high, especially for gas wells that require multiple production adjustment operations.

[0019] To solve the deficiencies of the existing technology, the present invention discloses an electric self-adaptive downhole throttle. This downhole throttle is connected to the end of the tubing and is lowered to the designed well depth position along with the tubing. And this downhole throttle is built-in with a matching program for well pressure and the corresponding throttle nozzle. When starting production, the motor automatically adjusts the position of the valve stem in the throttle tube according to the pressure at the position it is in according to a preset program, thereby controlling the opening of the throttle nozzle. The high-pressure gas flow is throttled and pressure-reduced at the throttle tube and then produced through the tubing. When the motor fails or the throttling fails for other reasons, the pin on the shear sleeve can be cut by ball stuffing and pressure holding, and the natural gas in the well enters the tubing for production through the annular gas flow channel exposed on the double-mother nipple after moving down through the shear sleeve. This downhole throttle has a simple structure and reliable principle. The adjustment process of the throttle nozzle is simple and fast. The production adjustment operation does not require fishing out the throttle and replacing the throttle nozzle, which can save a large amount of time cost and economic cost for the production unit and improve the development efficiency and benefits of gas wells.

[0020] To better understand this solution, the following is a detailed introduction to the electric self-adaptive downhole throttle in combination with Figure 1 for the electric self-adaptive downhole throttle.

[0021] An electric self-adaptive downhole throttle includes: an upper joint 1, a double-mother nipple 2, a reducing nipple 5, a slotted cylinder 6, a conversion joint 9, an electrical cylinder 10, and a lower joint 16 that are connected in sequence.

[0022] Among them, the upper joint 1, double-mother nipple 2, reducing nipple 5, slotted barrel 6, adapter 9, electrical barrel 10 and lower joint 16 are sequentially thread-connected, and the outer diameter and material of the tool are the same as those of the tubing coupling. Except for the threaded connections at both ends of the slotted barrel 6 that do not require sealing, all other threaded connections are sealed with O-ring seals (A1 - A6).

[0023] Among them, the throttle tube 7 is placed inside the slotted barrel 6. There are multiple groups of circumferentially evenly distributed air inlet holes on the wall of the throttle tube 7. The two ends of the throttle tube are respectively inserted into the reducing nipple 5 and the adapter 9, and are kept coaxial with the slotted barrel 6, the reducing nipple 5 and the adapter 9, as Figure 2 shown.

[0024] Among them, multiple short slots are staggeredly and circumferentially evenly distributed on the wall of the slotted barrel 6, which is convenient for high-pressure natural gas in the well to flow in and block impurities, as Figure 3 shown.

[0025] Among them, the motor 11, control circuit board 12, support frame 13 and battery 14 are placed inside the electrical barrel 10. The support frame 13 is used to separate the internal motor 11, control circuit board 12 and battery 13, and at the same time plays a role in fixing and shock absorption.

[0026] The control circuit board 12 is pre-programmed with the matching program between the well pressure and the corresponding choke nozzle. After receiving the pressure sensor signal, it automatically controls the motor to move the valve stem 8.

[0027] Among them, the valve stem 8 is connected to the motor 11. The front end of the valve stem 8 extends into the throttle tube 7, and is sealed with the throttle tube 7 by an O-ring seal, and is controlled by the motor 11 to move inside the throttle tube 7. By changing the position of the valve stem 8 inside the throttle tube 7, the number of opened air inlet holes of the throttle tube 7 is controlled, so as to adjust the opening degree of the choke nozzle and realize the throttling and pressure reduction of the high-pressure gas in the well.

[0028] Among them, the sensor 15 is a pressure sensor, which is installed inside the lower joint 16 and transmits the collected pressure signal to the control circuit board 12.

[0029] Among them, multiple key grooves are circumferentially evenly distributed on the wall of the double-mother nipple 2, and multiple pin holes are circumferentially evenly distributed at the lower end of the key grooves.

[0030] Among them, the shear sleeve 3 is placed inside the double-mother nipple 2, and is fixed and sealed with the double-mother nipple through pins and O-ring seals to prevent the well fluid from entering the tool interior.

[0031] To better understand this solution, the following also explains the usage method of the electric adaptive downhole choke, specifically: set the matching program of the preset well pressure and the corresponding choke nozzle in the control circuit board. The downhole choke is connected to the end of the tubing and lowered to the designed well depth position along with the tubing. During well production, the electric device automatically adjusts the position of the valve stem in the choke tube according to the pressure at the location according to the preset program, thereby controlling the opening of the choke nozzle. The high-pressure gas is throttled and depressurized at the choke tube and then produced through the tubing. This invention eliminates the need for wireline operations to lower the choke and adjust production, saving operation time and costs.

[0032] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform 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. An electric self - adaptive downhole throttle, characterized in that, Comprising: An upper joint (1), a double female nipple (2), a reducing nipple (5), a slotted barrel (6), a swivel joint (9), an electrical barrel (10) and a lower joint (16) connected in sequence; Wherein, a throttle tube (7) with air inlet holes on the tube wall is arranged in the slotted barrel (6), and a valve rod (8) is arranged in the throttle tube (7); a sensor (15) for transmitting signals to a control circuit board (12) is arranged in the lower joint (16); the electrical barrel (10) includes a connected motor (11) and a control circuit board (12); the front end of the valve rod (8) is arranged in the throttle tube (7), and the bottom end is connected to the motor (11) for adjusting the number of opened air inlet holes of the throttle tube (7); Wherein, a matching program of the well pressure and the corresponding choke nozzle is set in the control circuit board (12).

2. The electro - dynamic adaptive downhole choke according to claim 1, characterized in that, The upper joint (1), the double female nipple (2), the reducing nipple (5), the slotted barrel (6), the swivel joint (9), the electrical barrel (10) and the lower joint (16) are sequentially threadedly connected.

3. The electro - type adaptive downhole throttle according to claim 1, wherein Both ends of the throttle tube (7) are respectively inserted on the reducing nipple (5) and the swivel joint (9).

4. The electro - dynamic self - adaptive downhole choke according to claim 1, characterized in that, A plurality of short slots are circumferentially staggered and evenly distributed on the tube wall of the slotted barrel (6) for the high-pressure natural gas in the well to flow in and block impurities.

5. The electro - dynamic adaptive downhole throttle according to claim 1, characterized in that, The electrical barrel (10) further includes: a support frame (13) and a battery (14); Wherein, the support frame (13) is used to separate the motor (11), the control circuit board (12) and the battery (13).

6. The electro - dynamic adaptive downhole choke according to claim 1, wherein The valve rod (8) and the throttle tube (7) are sealed by an O-ring.

7. The electro-mechanical adaptive downhole choker according to claim 1, wherein A plurality of keyways are circumferentially evenly distributed on the tube wall of the double female nipple (2).

8. The electro - dynamic self - adaptive downhole throttle according to claim 7, characterized in that, A plurality of pin holes are circumferentially evenly distributed at the lower end of the keyway.

9. The electro - dynamic adaptive downhole throttle according to claim 8, characterized in that, A shear sleeve (3) is arranged in the double female nipple (2).

10. The electro - dynamic adaptive downhole throttle according to claim 9, characterized in that, The shear sleeve (3) is fixed and sealed to the double female nipple (2) through pins and an O-ring.

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