Wax removal and control oil pipe for oil well and wax removal and control method

Abstract

The invention discloses a paraffin removal and control oil pipe for an oil well and a paraffin removal and control method, and belongs to the technical field of oil-gas field development. The intelligent heating system is arranged between the inner pipe and the outer pipe, heat release can be intelligently controlled according to the oil well condition, the release temperature can reach 90 DEG C, multiple times of heating and circulating heat release can be achieved, high-melting-point wax which is not easy to solve on the inner wall of the oil pipe can be removed, intelligent heating control is achieved, and the service life of the oil pipe is prolonged. The defect that a conventional electric heating oil pipe is high in heating energy consumption all the time is overcome. When the wax-proof oil pipe is used for wax prevention, a heating system can be intelligently controlled to work according to the operation period of an oil well (determined according to the specific wax precipitation period of the oil well), a pipe column does not need to be pulled out when wax removal work is carried out, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a wax removal and prevention oil pipe for oil wells and a wax removal and prevention method. Background Art

[0002] Severe wax deposition during the production process of oil wells will affect the normal fluid production of the oil wells, and may even cause wax to get stuck in the tubing string or block the surface pipeline. This not only requires a lot of manpower, material and financial resources to carry out frequent well washing and pump inspection operations, but also directly affects the production of the oil wells.

[0003] Oil fields usually use chemical wax removal, regular hot washing and physical wax removal to maintain normal production of oil wells. Chemical wax removal is to add wax removal agents to dissolve or disperse the precipitated wax, so that it is dissolved or suspended in small particles in the crude oil of the oil well and flows out with the oil well fluid. Commonly used wax removal agents include toluene, xylene, etc., which dissolve wax quickly, but have problems such as low ignition point and easy ignition, poor environmental performance, and high labor intensity of workers. Physical wax removal includes hot washing, mechanical wax removal, electromagnetic wax removal, electric heating and other technologies. Hot washing has the disadvantages of high frequency of hot washing and pollution of oil layers. Mechanical wax removal increases labor intensity and production costs. Electromagnetic wax removal has limited effect. Conventional electric heating consumes a lot of energy, which increases production costs.

[0004] Thermal insulation and anti-wax coating is a common method used to maintain fluid temperature. CN218669245U "Anti-wax insulation oil pipe for petroleum mining" uses epoxy phenolic resin for thermal insulation and nano-aerogel insulation felt for thermal insulation and anti-wax; CN 218206611 U "An oil pipe short circuit with anti-wax function" is a composite piezoelectric material filled between the inner and outer pipes, and is used to form a positive piezoelectric effect deep in the formation to form a local electric field and micro-current and magnetic field, thereby enhancing the activity of water molecules and wax molecules in the crude oil in the inner pipe. CN 207348801 U "An efficient thermal insulation and heat preservation oil pipe" forms a closed annular space between the inner pipe and the oil pipe body, and sets an insulation layer in the annular space.

[0005] At present, wax deposition is a common problem in most shale oil horizontal wells in oil fields. The wax component content of shale oil is 23.6%, which is a high-wax crude oil (national standard: ≥10%). The C31-C60 component accounts for 31.70%, and the wax melting point is 66.8℃, which is higher than other strata in the same area. Wax is accompanied by impurities such as rock cuttings and is deposited in the wellbore within 800 meters from the wellhead, which is the main factor causing wax sticking and wax plugging. If the temperature of the wax deposition section is increased, the amount of paraffin deposition on the oil pipe wall will decrease significantly. Conventional thermal insulation and anti-wax coatings are more effective for waxes below C30, but not so effective for waxes with high melting points. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a wax removal and anti-wax oil pipe and a wax removal and anti-wax method for oil wells, which are used to solve the technical problems of low wax removal efficiency and poor anti-wax effect of existing thermal insulation and anti-wax coatings for C30 and above.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention discloses a wax-cleaning and wax-proofing oil pipe for oil wells, comprising an inner pipe, an outer pipe, an intelligent heating system and a welding ring; the inner pipe is nested in the outer pipe, an annular space is formed between the inner pipe and the outer pipe, and a welding ring is used at the bottom end of the annular space to fix the inner pipe and the outer pipe together;

[0009] The intelligent heating system is in contact with the inner tube and the outer tube, so as to remove wax deposits from the inner tube and the outer tube.

[0010] Furthermore, the intelligent heating system includes a vibration device, an electric heating tube, a sodium acetate supersaturated solution, a temperature sensor and a control device;

[0011] The supersaturated sodium acetate solution is placed in the annular space, and the vibration device and the temperature sensor are both placed in the supersaturated sodium acetate solution; the electric heating tube is wound on the outer surface of the inner tube; the control device is respectively connected to the vibration device, the electric heating tube and the temperature sensor to provide instructions for starting the vibration device and the electric heating tube.

[0012] Furthermore, the electric heating tube is spirally wound on the outer surface of the inner tube.

[0013] Furthermore, the control device is also connected to a power supply device.

[0014] Furthermore, the vibration device includes a vibration motor and a vibration rod; the vibration rod is placed in a supersaturated sodium acetate solution and connected to the vibration motor to achieve vibration; the vibration motor is connected to a control device.

[0015] The invention also discloses a wax removal and prevention method, comprising the following steps:

[0016] When the oil well runs for a cycle, the intelligent heating system is controlled to turn on, and the heating system heats up, causing the wax deposits on the surface of the inner and outer pipes to fall off.

[0017] Furthermore, the intelligent heating system includes a vibration device, an electric heating tube, a sodium acetate supersaturated solution, a temperature sensor and a control device;

[0018] The sodium acetate supersaturated solution is placed in the annular space, and the vibration device and the temperature sensor are both placed in the sodium acetate supersaturated solution; the electric heating tube is wound around the outer surface of the inner tube; the control device is respectively connected to the vibration device, the electric heating tube and the temperature sensor to provide instructions for starting the vibration device and the electric heating tube;

[0019] When cleaning the wax, the following steps are included:

[0020] S1: When the oil well runs for a cycle, the control device sends out a command to make the vibration device vibrate, and then the supersaturated sodium acetate solution turns into crystals and releases heat. The heat released is transferred to the wax deposits on the surface of the inner and outer pipes, causing them to fall off;

[0021] S2: When the temperature sensor detects that the temperature of the sodium acetate supersaturated solution is lower than the preset value, the electric heating tube is automatically started to heat the sodium acetate supersaturated solution until it can satisfy the sodium acetate supersaturated solution to return to liquid, and the vibration device is controlled to work again, and the step of S1 is repeated until the wax deposits on the surface of the inner tube and the outer tube 7 are completely removed.

[0022] Furthermore, the vibration device includes a vibration motor and a vibration rod; the control device issues an instruction so that the vibration motor drives the vibration rod to vibrate in the supersaturated sodium acetate solution.

[0023] Furthermore, the sodium acetate supersaturated solution, the vibration rod and the temperature sensor are all located in the annular space; and the control device, the vibration motor and the power supply device are all located at the wellhead.

[0024] Furthermore, when the wax-cleaning and wax-proofing oil pipe for oil wells is in use, the lowering depth is 500 to 800 meters from the wellhead.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention discloses a wax-cleaning and wax-preventing oil pipe for oil wells. An intelligent heating system is arranged between an inner pipe and an outer pipe, so that heat release can be intelligently controlled according to the situation of the oil well. The release temperature can reach 90°C, and multiple heating and cyclic heat release can be achieved. High-melting-point wax that is difficult to remove from the inner wall of the oil pipe can be removed. The intelligent heating control achieved solves the shortcoming of conventional electrically heated oil pipes that consumes a lot of energy due to continuous heating.

[0027] The present invention also discloses a method for removing wax using the above-mentioned wax removal and wax prevention oil pipe for oil wells. According to the operation cycle of the oil well, the heating system is intelligently controlled to operate. When the wax removal work is performed, there is no need to pull out the pipe column, thereby improving production efficiency.

[0028] Furthermore, the intelligent control heating system consists of a vibration device, an electric heating tube, a supersaturated solution of sodium acetate, a temperature sensor and a control device. The supersaturated solution of sodium acetate in the heat-insulating and wax-proof oil pipe can release heat energy at the moment of crystallization, and the temperature can reach 90°C. Multiple heating and cyclic heat release can remove high-melting-point wax that is difficult to remove from the inner wall of the oil pipe. It can work in a cycle according to the wax deposition situation of the oil well, solving the problem that high-melting-point wax above C30 is difficult to dissolve. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic structural diagram of a wax-removing and wax-proofing oil pipe for oil wells according to the present invention;

[0030] Among them: 1-temperature sensor; 2-electric heating tube; 3-inner tube; 4-control device; 5-power supply device; 6-vibration motor; 7-outer tube; 8-vibration rod; 9-welding ring; 10-sodium acetate supersaturated solution. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0034] like Figure 1As shown, the present invention discloses a wax cleaning and prevention oil pipe for oil wells, comprising an inner pipe 3, an outer pipe 7, an intelligent heating system and a welding ring 9; the inner pipe 3 is nested in the outer pipe 7, an annular space is formed between the inner pipe 3 and the outer pipe 7, and the inner pipe 3 and the outer pipe 7 are fixedly connected at the bottom end of the annular space by a welding ring 9; the intelligent heating system can realize multiple heating and cyclic heat release, and can remove high-melting-point wax that is difficult to remove from the inner wall of the oil pipe, thereby realizing intelligent heating control.

[0035] Preferably, the intelligent heating system comprises a vibration device, an electric heating tube 2, a supersaturated sodium acetate solution 10, a temperature sensor 1 and a control device 4; the control device 4 is also connected to a power supply device 5.

[0036] Preferably, the electric heating tube 2 is spirally wound on the outer surface of the inner tube 3 .

[0037] Preferably, the sodium acetate supersaturated solution 10 is placed in the annular space, and the vibration device and the temperature sensor 1 are both placed in the sodium acetate supersaturated solution 10; the electric heating tube 2 is wound on the outer surface of the inner tube 3; the control device 4 is respectively connected to the vibration device, the electric heating tube 2 and the temperature sensor 1 to provide instructions for starting the vibration device and the electric heating tube 2;

[0038] Preferably, the vibration device includes a vibration motor 6 and a vibration rod 8; the vibration rod 8 is placed in a supersaturated sodium acetate solution 10 and connected to the vibration motor 6 to achieve vibration; the vibration motor 6 is connected to the control device 4.

[0039] Preferably, the control device 4, the vibration motor 6 and the power supply device 5 are all located at the wellhead; the sodium acetate supersaturated solution 10, the vibration rod 8 and the temperature sensor 1 are all located in the annular space.

[0040] Example 1

[0041] The wax removal and wax prevention method for the oil well wax removal and wax prevention oil pipe of the present invention comprises the following steps:

[0042] When the oil well runs for a cycle (the cycle is determined according to the wax formation cycle or wax formation situation of the oil well), the control device 4 issues a command, the vibration motor 6 drives the vibration rod 8 to vibrate, the supersaturated solution 10 of sodium acetate turns into crystals and releases heat, the oil pipe heats up, and the heat is transferred to the wax deposits on the inner surface of the oil pipe. At this time, the temperature sensor 1 senses that the temperature of the supersaturated solution 10 of sodium acetate is lower than the preset value, and automatically starts the power supply device 5 to heat the electric heating tube 2, so that the supersaturated solution 10 of sodium acetate is restored to liquid, and vibrates and releases heat again, and circulates until the wax deposits on the inner wall of the oil pipe are removed.

[0043] In the above process, the oil well cycle can be selected to be 30 days to 90 days according to the wax formation cycle or wax formation situation of the oil well.

[0044] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A wax-proof oil pipe for oil wells, characterized in that: The invention comprises an inner tube (3), an outer tube (7), an intelligent heating system and a welding ring (9); the inner tube (3) is nested in the outer tube (7), an annular space is formed between the inner tube (3) and the outer tube (7), and a welding ring (9) is used at the bottom end of the annular space to fix the inner tube (3) and the outer tube (7); The intelligent heating system is in contact with the inner tube (3) and the outer tube (7) to remove wax deposits on the surfaces of the inner tube (3) and the outer tube (7).

2. The wax-removing and anti-wax oil pipe for oil wells according to claim 1, characterized in that: The intelligent heating system comprises a vibration device, an electric heating tube (2), a sodium acetate supersaturated solution (10), a temperature sensor (1) and a control device (4); The sodium acetate supersaturated solution (10) is placed in the annular space, and the vibration device and the temperature sensor (1) are both placed in the sodium acetate supersaturated solution (10); the electric heating tube (2) is wound around the outer surface of the inner tube (3); and the control device (4) is respectively connected to the vibration device, the electric heating tube (2) and the temperature sensor (1) to provide instructions for starting the vibration device and the electric heating tube (2).

3. The wax-removing and anti-wax oil pipe for oil wells according to claim 2, characterized in that: The electric heating tube (2) is spirally wound and arranged on the outer surface of the inner tube (3).

4. The wax-removing and anti-wax oil pipe for oil wells according to claim 2, characterized in that: The control device (4) is also connected to a power supply device (5).

5. The wax-removing and anti-wax oil pipe for oil wells according to claim 4, characterized in that: The vibration device comprises a vibration motor (6) and a vibration rod (8); the vibration rod (8) is placed in a sodium acetate supersaturated solution (10) and connected to the vibration motor (6) to achieve vibration; the vibration motor (6) is connected to a control device (4).

6. A method for removing wax and preventing wax from oil wells using the wax and preventing wax pipe according to claim 1, characterized in that: The following steps are involved: When the oil well runs for a cycle, the intelligent heating system is controlled to be turned on, and the heating system heats up, so that the wax deposits on the surface of the inner tube (3) and the outer tube (7) fall off.

7. The method for removing wax and preventing paraffin according to claim 6 using the oil well wax and preventing paraffin oil pipe according to claim 1, characterized in that: The intelligent heating system comprises a vibration device, an electric heating tube (2), a sodium acetate supersaturated solution (10), a temperature sensor (1) and a control device (4); The sodium acetate supersaturated solution (10) is placed in the annular space, and the vibration device and the temperature sensor (1) are both placed in the sodium acetate supersaturated solution (10); the electric heating tube (2) is wound around the outer surface of the inner tube (3); the control device (4) is respectively connected to the vibration device, the electric heating tube (2) and the temperature sensor (1) to provide instructions for starting the vibration device and the electric heating tube (2); When cleaning the wax, the following steps are included: S1: When the oil well runs for a cycle, the control device (4) issues a command to make the vibration device vibrate, so that the sodium acetate supersaturated solution (10) turns into crystals and releases heat, and the heat released is transferred to the wax deposits on the surface of the inner tube (3) and the outer tube (7), causing them to fall off; S2: When the temperature sensor (1) detects that the temperature of the sodium acetate supersaturated solution (10) is lower than a preset value, the electric heating tube (2) is automatically started to heat the sodium acetate supersaturated solution (10) until the sodium acetate supersaturated solution (10) is restored to liquid form, and the vibration device is controlled to work again, and the step S1 is repeated until the wax deposits on the surfaces of the inner tube (3) and the outer tube (7) are completely removed.

8. The method for removing wax and preventing paraffin according to claim 7 using the oil well wax and preventing paraffin oil pipe according to claim 1, characterized in that: The vibration device comprises a vibration motor (6) and a vibration rod (8); the control device (4) issues an instruction so that the vibration motor (6) drives the vibration rod (8) to vibrate in the sodium acetate supersaturated solution (10).

9. The method for removing wax and preventing paraffin according to claim 8 using the oil well wax and preventing paraffin oil pipe according to claim 1, characterized in that: The sodium acetate supersaturated solution (10), the vibration rod (8) and the temperature sensor (1) are all located in the annular space; the control device (4), the vibration motor (6) and the power supply device (5) are all located at the wellhead.

10. The wax removal and prevention method according to claim 8 using the wax removal and prevention oil pipe for oil wells according to claim 1, wherein the wax removal and prevention oil pipe for oil wells is lowered to a depth of 500 to 800 meters from the wellhead when in use.

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