Wax-proof oil pipe with thermal insulation layer

Abstract

The present invention discloses a wax-proof oil pipe with a thermal insulation layer, which includes a plurality of oil pipe units connected in sequence, a socket joint fixedly connected to the outer surface of each oil pipe unit, and a first cable connected between adjacent socket joints; an N-type thermoelectric element is embedded in the oil pipe unit at the top, and a P-type thermoelectric element is embedded in the oil pipe unit at the bottom, both the N-type thermoelectric element and the P-type thermoelectric element are connected to a second cable, and the second cable is connected to the first cable through the socket joint; except for the oil pipe units at the two ends, the remaining oil pipe units are wrapped with heating wires, and the heating wires are connected to the socket joints; the present invention utilizes the temperature difference between the wellhead and the bottom of the well to prevent wax from forming on the oil pipe, thereby reducing the time and manpower costs of crude oil extraction.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas production equipment in oil fields, and relates to a wax-proof oil pipe with a heat-insulating insulating layer. Background Art

[0002] During oil well production, paraffin wax often crystallizes and condenses on the production tubing, clinging to the metal surface of the tubing and causing wax buildup. Wax buildup can narrow the oil flow path, increasing the upward and downward resistance of the sucker rod and increasing the load. If wax is not removed promptly, severe buildup can cause the sucker rod to become stuck in the tubing, even leading to rod breakage.

[0003] Existing oil fields often use chemical or physical wax removal methods to maintain normal production of oil wells. Physical wax removal includes technologies such as hot washing, electrically heated pump rods, mechanical wax removal, and electromagnetic wax removal, but this increases labor intensity and production costs. Chemical wax removal involves adding commonly used wax removal agents, such as carbon tetrachloride, toluene, and oil-soluble alkyl ammonium salts. These wax removal agents dissolve or disperse the precipitated wax, causing it to be dissolved or suspended in small particles in the crude oil of the oil well and flow out with the oil well fluid. Although these agents have a quick effect after addition, they also face problems such as increased cost, low flash point, susceptibility to fire, and poor environmental performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a wax-proof oil pipe with a heat-insulating insulation layer, which solves the problem in the prior art that manual wax removal is required when wax is deposited on the pipe column.

[0005] The technical solution adopted by the present invention is that the wax-proof oil pipe with a thermal insulation layer includes a plurality of oil pipe units connected in sequence, the outer surface of each oil pipe unit is fixedly connected to a socket joint, and a first cable is connected between adjacent socket joints; the oil pipe unit at the top is embedded with an N-type thermoelectric element, and the oil pipe unit at the bottom is embedded with a P-type thermoelectric element, both the N-type thermoelectric element and the P-type thermoelectric element are connected to a second cable, and the second cable is connected to the first cable through a socket joint; except for the oil pipe units at both ends, the remaining oil pipe units are wrapped with heating wires, and the heating wires are connected to the socket joints.

[0006] The present invention is also characterized in that: the oil pipe unit includes an inner pipe, the inner wall of the inner pipe is coated with a hydrophobic coating, the outer wall of the inner pipe is sequentially coated with a thermal insulation layer and an outer protective layer, the socket joint is fixed to the surface of the outer protective layer, the N-type thermoelectric element and the P-type thermoelectric element are both embedded in the thermal insulation layer, and the heating wire is wound around the outer wall of the inner pipe;

[0007] The number of N-type thermoelectric elements is m, and conductive sheets are connected between the multiple N-type thermoelectric elements; the number of P-type thermoelectric elements is m, and conductive sheets are connected between the multiple P-type thermoelectric elements, where m is a positive integer ≥ 2;

[0008] The first cable and the second cable each include m thin metal wires, and the outer surfaces of the first cable and the second cable are covered with insulating rubber;

[0009] Two adjacent tubing units are connected by tubing couplings;

[0010] The socket joint is fixed to the outer surface of the outer protective layer through the positioning groove;

[0011] The number of turns of the heating wire wrapped around the inner tube gradually decreases to one turn every z sections of the oil pipe unit, where z is a positive integer ≥ 1;

[0012] When tubing units are connected by tubing couplings, a sealing rubber ring made of nitrile material is installed in the gap between the two tubing units;

[0013] The thermal insulation layer is made of nanofiber material.

[0014] The beneficial effects of the present invention are:

[0015] 1. This invention embeds an N-type thermoelectric element and a P-type thermoelectric element inside the oil pipe to form a thermocouple. This utilizes the temperature difference between the wellhead and the bottom of the well to prevent wax deposition in the oil pipe, thereby reducing the time and labor costs of crude oil extraction.

[0016] 2. The inner wall of the inner tube of the present invention is coated with a hydrophobic coating, and the outer wall of the inner tube is covered with a thermal insulation layer and an outer protective layer. The design is reasonable and can achieve the effect of heat preservation;

[0017] 3. In the present invention, a sealing rubber ring and an oil pipe coupling made of nitrile material are installed in the gap between the two oil pipes, which have good heat resistance and sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the middle oil pipe of the present invention;

[0019] Figure 2 It is a schematic structural diagram of the oil pipe at the top of the present invention;

[0020] Figure 3 It is a structural schematic diagram of the oil pipe at the bottom end of the present invention;

[0021] Figure 4 It is a schematic diagram of the temperature difference heating circuit connection of the present invention.

[0022] In the figure, 1. oil pipe unit, 101. inner pipe, 102. hydrophobic coating, 103. thermal insulation layer, 104. outer protective layer, 2. N-type thermoelectric element, 3. P-type thermoelectric element, 4. socket joint, 5. first cable, 6. heating wire, 7. oil pipe coupling, 8. sealing rubber ring, 9. second cable. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0024] Example 1

[0025] like Figure 1 As shown, the tubing unit 1 comprises multiple sections connected in sequence. The tubing unit 1 mainly comprises an inner tube 101, the inner wall of the inner tube 101 being coated with a hydrophobic coating 102, and the outer wall of the inner tube 101 being sequentially coated with a thermal insulation layer 103 and an outer protective layer 104. The thermal insulation layer 103 is made of a nanofiber material to achieve thermal insulation and wax resistance. The outer surface of the outer protective layer 104 is provided with a groove fixedly connected to a socket joint 4, which is fixed to the outer surface of the outer protective layer 104 via a positioning groove. A first cable 5 is connected between two adjacent socket joints 4 on the tubing unit 1.

[0026] like Figure 2 、 Figure 4 As shown, the top oil pipe unit 1 has m grooves between the thermal insulation layer 103 and the inner pipe 101, in which N-type thermoelectric elements 2 are placed. The N-type thermoelectric elements 2 are connected by low-resistance conductive sheets, as shown in FIG. Figure 3 As shown, the oil pipe unit 1 at the bottom is provided with m grooves between the thermal insulation layer 103 and the inner tube 101, in which P-type thermoelectric elements 3 are placed. The P-type thermoelectric elements 3 are connected by low-resistance conductive sheets. The N-type thermoelectric element and the P-type thermoelectric element are both connected with a second cable 9. The second cable 9 is connected to the first cable 5 through a socket joint 4. The first cable 5 and the second cable 9 are internally provided with m thin metal wires wrapped with insulating rubber, where m is a positive integer ≥ 2. At this time, the N-type thermoelectric element 2 and the P-type thermoelectric element 3 are connected by a low-resistance conductive sheet to form a thermocouple. The thermocouples are connected in series with m thin metal wires to form a combined thermoelectric power supply composed of multiple thermocouples, and the N-type thermoelectric element 2 and the P-type thermoelectric element 3 respectively form the two poles of the thermoelectric power supply;

[0027] Except for the oil pipe units 1 at both ends, the outer wall of the inner tube 101 inside the other oil pipe units 1 is wrapped with a heating wire 6, which is connected to the socket joints 4 at both ends. The number of turns of the heating wire 6 wrapped around the inner tube 101 gradually decreases to one turn for every z oil pipe units, where z is a positive integer ≥ 1. Two adjacent oil pipe units 1 are connected by an oil pipe coupling 7, and a sealing rubber ring 8 made of nitrile material is installed in the gap between the two oil pipes.

[0028] After cleaning the wellbore, first lower the oil pipe with the P-type thermoelectric element 3, tighten the threaded buckle of the oil pipe coupling 7 to fasten it to the next oil pipe, insert the wear-resistant and waterproof quick socket joint 4, and connect m thin metal wires in series with m P-type thermoelectric elements in sequence. According to the heating power of the heating wire and the wax deposition condition of the oil pipe, for the section with severe wax deposition (800m from the wellhead), lower the oil pipe with 6 turns of heating wire into 800m, and then lower the oil pipe with 6 turns of heating wire every two oil pipes, and successively lower other oil pipe units 1 until the last oil pipe with the N-type thermoelectric element 2.

[0029] Example 2

[0030] like Figure 1 As shown, the tubing unit 1 comprises multiple sections connected in sequence. The tubing unit 1 mainly comprises an inner tube 101, the inner wall of the inner tube 101 being coated with a hydrophobic coating 102, and the outer wall of the inner tube 101 being sequentially coated with a thermal insulation layer 103 and an outer protective layer 104. The thermal insulation layer 103 is made of a nanofiber material to achieve thermal insulation and wax resistance. The outer surface of the outer protective layer 104 is provided with a groove fixedly connected to a socket joint 4, which is fixed to the outer surface of the outer protective layer 104 via a positioning groove. A first cable 5 is connected between two adjacent socket joints 4 on the tubing unit 1.

[0031] like Figure 2 、 Figure 4 As shown, the top oil pipe unit 1 has m grooves between the thermal insulation layer 103 and the inner pipe 101, in which N-type thermoelectric elements 2 are placed. The N-type thermoelectric elements 2 are connected by low-resistance conductive sheets, as shown in FIG. Figure 3 As shown, the oil pipe unit 1 at the bottom is provided with m grooves between the thermal insulation layer 103 and the inner tube 101, in which P-type thermoelectric elements 3 are placed. The P-type thermoelectric elements 3 are connected by low-resistance conductive sheets. The N-type thermoelectric element and the P-type thermoelectric element are both connected with a second cable 9. The second cable 9 is connected to the first cable 5 through a socket joint 4. The first cable 5 and the second cable 9 are internally provided with m thin metal wires wrapped with insulating rubber, where m is a positive integer ≥ 2. At this time, the N-type thermoelectric element 2 and the P-type thermoelectric element 3 are connected by a low-resistance conductive sheet to form a thermocouple. The thermocouples are connected in series with m thin metal wires to form a combined thermoelectric power supply composed of multiple thermocouples, and the N-type thermoelectric element 2 and the P-type thermoelectric element 3 respectively form the two poles of the thermoelectric power supply;

[0032] Except for the oil pipe units 1 at both ends, the outer wall of the inner tube 101 inside the other oil pipe units 1 is wrapped with a heating wire 6, which is connected to the socket joints 4 at both ends. The number of turns of the heating wire 6 wrapped around the inner tube 101 gradually decreases to one turn for every z oil pipe units, where z is a positive integer ≥ 1. Two adjacent oil pipe units 1 are connected by an oil pipe coupling 7, and a sealing rubber ring 8 made of nitrile material is installed in the gap between the two oil pipes.

[0033] After cleaning the wellbore, first lower the oil pipe with the P-type thermoelectric element 3, tighten the threaded buckle of the oil pipe coupling 7 to fasten it to the next oil pipe, insert the wear-resistant and waterproof quick socket joint 4, and connect m thin metal wires in series with m P-type thermoelectric elements in sequence. According to the heating power of the heating wire and the wax deposition condition of the oil pipe, for the section with severe wax deposition (500m from the wellhead), lower the oil pipe with 6 turns of heating wire into 500m, and then lower the oil pipe with heating wire 6 every two oil pipes, and successively lower other oil pipe units 1 until the last oil pipe with the N-type thermoelectric element 2.

[0034] Example 3

[0035] like Figure 1 As shown, the tubing unit 1 comprises multiple sections connected in sequence. The tubing unit 1 mainly comprises an inner tube 101, the inner wall of the inner tube 101 being coated with a hydrophobic coating 102, and the outer wall of the inner tube 101 being sequentially coated with a thermal insulation layer 103 and an outer protective layer 104. The thermal insulation layer 103 is made of a nanofiber material to achieve thermal insulation and wax resistance. The outer surface of the outer protective layer 104 is provided with a groove fixedly connected to a socket joint 4, which is fixed to the outer surface of the outer protective layer 104 via a positioning groove. A first cable 5 is connected between two adjacent socket joints 4 on the tubing unit 1.

[0036] like Figure 2 、 Figure 4 As shown, the top oil pipe unit 1 has m grooves between the thermal insulation layer 103 and the inner pipe 101, in which N-type thermoelectric elements 2 are placed. The N-type thermoelectric elements 2 are connected by low-resistance conductive sheets, as shown in FIG. Figure 3 As shown, the oil pipe unit 1 at the bottom is provided with m grooves between the thermal insulation layer 103 and the inner tube 101, in which P-type thermoelectric elements 3 are placed. The P-type thermoelectric elements 3 are connected by low-resistance conductive sheets. The N-type thermoelectric element and the P-type thermoelectric element are both connected with a second cable 9. The second cable 9 is connected to the first cable 5 through a socket joint 4. The first cable 5 and the second cable 9 are internally provided with m thin metal wires wrapped with insulating rubber, where m is a positive integer ≥ 2. At this time, the N-type thermoelectric element 2 and the P-type thermoelectric element 3 are connected by a low-resistance conductive sheet to form a thermocouple. The thermocouples are connected in series with m thin metal wires to form a combined thermoelectric power supply composed of multiple thermocouples, and the N-type thermoelectric element 2 and the P-type thermoelectric element 3 respectively form the two poles of the thermoelectric power supply;

[0037] Except for the oil pipe units 1 at both ends, the outer wall of the inner tube 101 inside the other oil pipe units 1 is wrapped with a heating wire 6, which is connected to the socket joints 4 at both ends. The number of turns of the heating wire 6 wrapped around the inner tube 101 gradually decreases to one turn for every z oil pipe units, where z is a positive integer ≥ 1. Two adjacent oil pipe units 1 are connected by an oil pipe coupling 7, and a sealing rubber ring 8 made of nitrile material is installed in the gap between the two oil pipes.

[0038] After cleaning the wellbore, first lower the oil pipe with the P-type thermoelectric element 3, tighten the threaded buckle of the oil pipe coupling 7 to fasten it to the next oil pipe, insert the wear-resistant and waterproof quick socket joint 4, and connect m thin metal wires in series with m P-type thermoelectric elements in sequence. According to the heating power of the heating wire and the wax deposition condition of the oil pipe, for the section with severe wax deposition (300m from the wellhead), lower the oil pipe with 6 turns of heating wire into 300m, and then lower the oil pipe with heating wire 6 every two oil pipes, and successively lower other oil pipe units 1 until the last oil pipe with the N-type thermoelectric element 2.

[0039] Example 4

[0040] like Figure 1 As shown, the tubing unit 1 comprises multiple sections connected in sequence. The tubing unit 1 mainly comprises an inner tube 101, the inner wall of the inner tube 101 being coated with a hydrophobic coating 102, and the outer wall of the inner tube 101 being sequentially coated with a thermal insulation layer 103 and an outer protective layer 104. The thermal insulation layer 103 is made of a nanofiber material to achieve thermal insulation and wax resistance. The outer surface of the outer protective layer 104 is provided with a groove fixedly connected to a socket joint 4, which is fixed to the outer surface of the outer protective layer 104 via a positioning groove. A first cable 5 is connected between two adjacent socket joints 4 on the tubing unit 1.

[0041] like Figure 2 、 Figure 4 As shown, the top oil pipe unit 1 has m grooves between the thermal insulation layer 103 and the inner pipe 101, in which N-type thermoelectric elements 2 are placed. The N-type thermoelectric elements 2 are connected by low-resistance conductive sheets, as shown in FIG. Figure 3As shown, the oil pipe unit 1 at the bottom is provided with m grooves between the thermal insulation layer 103 and the inner tube 101, in which P-type thermoelectric elements 3 are placed. The P-type thermoelectric elements 3 are connected by low-resistance conductive sheets. The N-type thermoelectric element and the P-type thermoelectric element are both connected with a second cable 9. The second cable 9 is connected to the first cable 5 through a socket joint 4. The first cable 5 and the second cable 9 are internally provided with m thin metal wires wrapped with insulating rubber, where m is a positive integer ≥ 2. At this time, the N-type thermoelectric element 2 and the P-type thermoelectric element 3 are connected by a low-resistance conductive sheet to form a thermocouple. The thermocouples are connected in series with m thin metal wires to form a combined thermoelectric power supply composed of multiple thermocouples, and the N-type thermoelectric element 2 and the P-type thermoelectric element 3 respectively form the two poles of the thermoelectric power supply;

[0042] Except for the oil pipe units 1 at both ends, the outer wall of the inner tube 101 inside the other oil pipe units 1 is wrapped with a heating wire 6, which is connected to the socket joints 4 at both ends. The number of turns of the heating wire 6 wrapped around the inner tube 101 gradually decreases to one turn for every z oil pipe units, where z is a positive integer ≥ 1. Two adjacent oil pipe units 1 are connected by an oil pipe coupling 7, and a sealing rubber ring 8 made of nitrile material is installed in the gap between the two oil pipes.

[0043] After cleaning the wellbore, first lower the oil pipe with the P-type thermoelectric element 3, tighten the threaded buckle of the oil pipe coupling 7 to fasten it to the next oil pipe, insert the wear-resistant and waterproof quick socket joint 4, and connect m thin metal wires in series with m P-type thermoelectric elements in sequence. According to the heating power of the heating wire and the wax deposition condition of the oil pipe, for the section with severe wax deposition (200m from the wellhead), lower the oil pipe with 6 turns of heating wire into 200m, and then lower the oil pipe with heating wire 6 every two oil pipes, and successively lower other oil pipe units 1 until the last oil pipe with the N-type thermoelectric element 2.

Claims

1. Wax-proof oil pipe with thermal insulation layer, characterized in that: It comprises a plurality of oil pipe units (1) connected in sequence, wherein a socket joint (4) is fixedly connected to the outer surface of each oil pipe unit (1), and a first cable (5) is connected between adjacent socket joints (4); The top oil pipe unit (1) is embedded with an N-type thermoelectric element (2), and the bottom oil pipe unit (1) is embedded with a P-type thermoelectric element (3). The N-type thermoelectric element (2) and the P-type thermoelectric element are both connected to a second cable (9), and the second cable (9) is connected to the first cable (5) through a socket joint (4). Except for the oil pipe units (1) at both ends, the remaining oil pipe units (1) are wrapped with a heating wire (6), and the heating wire (6) is connected to the socket joint (4). The oil pipe unit (1) comprises an inner pipe (101), the inner wall of the inner pipe (101) is coated with a hydrophobic coating (102), the outer wall of the inner pipe (101) is sequentially coated with a thermal insulation layer (103) and an outer protective layer (104), the socket joint (4) is fixed to the surface of the outer protective layer (104), the N-type thermoelectric element (2) and the P-type thermoelectric element (3) are both embedded in the thermal insulation layer (103), and the heating wire (6) is wound around the outer wall of the inner pipe (101); The number of the N-type thermoelectric elements (2) is m, and conductive sheets are connected between the plurality of the N-type thermoelectric elements (2); the number of the P-type thermoelectric elements (3) is m, and conductive sheets are connected between the plurality of the P-type thermoelectric elements (3), wherein m is a positive integer ≥ 2; The first cable (5) and the second cable (9) each comprise m thin metal wires, and the outer surfaces of the first cable (5) and the second cable (9) are covered with insulating rubber; Two adjacent sections of the oil pipe units (1) are connected by using an oil pipe coupling (7); The socket joint (4) is fixed to the outer surface of the outer protective layer (104) via a positioning groove; The number of turns of the heating wire (6) wrapped around the inner tube (101) gradually decreases to one turn for every z sections of the oil pipe unit (1), where z is a positive integer ≥ 1.

2. The wax-proof oil pipe with thermal insulation layer according to claim 1, characterized in that: When the oil pipe units (1) are connected by using an oil pipe coupling (7), a sealing rubber ring (8) made of nitrile material is installed in the gap between the two sections of the oil pipe units (1).

3. The wax-proof oil pipe with thermal insulation layer according to claim 2, characterized in that: The thermal insulation layer (103) is made of nanofiber material.

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