A high pressure oil well bore paraffin removal device and method of use

Abstract

The application discloses a high-pressure oil well shaft wax removal device and a use method thereof, which comprises a cable head, an upper-end heating cutter head, a weight rod and a lower-end heating cutter head which are sequentially spliced. The cable head comprises a pin seat, an insulating sleeve wrapped outside the pin seat, a pressure-bearing shell arranged outside the insulating sleeve, a plug-in hole opened on the insulating sleeve, an insulating tube inserted into the plug-in hole, a conductive rod inserted into the insulating tube and connected with the pin seat, a second insulating pad sleeved on the conductive rod and a cable connector mounted on one end of the conductive rod. The weight rod comprises a shell, a plug-in hole opened in the shell and a single-core pin sleeve arranged on the plug-in hole. The application has the beneficial effects that the problems of wax deposition in the shaft and the oil pipe can be quickly solved, the construction cost is greatly reduced, the labor intensity of personnel is reduced, the production of the oil and gas well is accelerated, the construction period is greatly shortened and the operation cost is reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of R53 new well workover operation and supporting technology in oil and gas extraction, specifically involving a high-pressure oil wellbore dewaxing device and its usage method. Background Technology

[0002] Waxing in oil and gas wells is a common problem in oilfield production, which directly affects the normal production of oil and gas wells. Common methods such as mechanical, thermal, and chemical wax removal are not applicable to some high-pressure and high-yield wells. Using coiled tubing for hot oil unblocking can solve the waxing problem in a short time, but it cannot completely cure the problem in the long run. Coiled tubing unblocking has a long construction period and high cost, and heating the oil during construction poses significant safety hazards. Summary of the Invention

[0003] The purpose of this invention is to provide a high-pressure oil wellbore dewaxing device and its usage method, which can quickly solve the problem of wax buildup in wellbores and tubing.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a high-pressure oil wellbore dewaxing device, comprising a cable head, an upper heating cutter head, a weighting rod, and a lower heating cutter head connected in sequence; The cable head includes a pin socket, an insulating sleeve wrapped around the outside of the pin socket, a pressure-bearing housing disposed outside the insulating sleeve, a plug hole opened on the insulating sleeve, an insulating tube inserted into the plug hole, a conductive rod inserted into the insulating tube and connected to the pin socket, a second insulating pad sleeved on the conductive rod, and a cable connector installed at one end of the conductive rod. The weighting rod includes a housing, a socket inside the housing, and a single-core pin assembly disposed on the socket.

[0005] As a preferred embodiment of the present invention, it further includes a first insulating pad disposed inside the housing to prevent the metal portion of the socket from contacting the housing.

[0006] As a preferred embodiment of the present invention, one end of the pin holder is connected to the conductive rod by a thread, and the other end of the pin holder is connected to the single-core pin by a thread.

[0007] As a preferred embodiment of the present invention, one end of the lower heating blade is a tapered tip, and the length of the lower heating blade is 90-110mm.

[0008] As a preferred embodiment of the present invention, the effective length of the weighting rod is 900-1100 mm and the temperature resistance is 90-110℃.

[0009] As a preferred embodiment of the present invention, the effective length of the upper heating blade is 800-960mm, and the outer shell of the upper heating blade is made of stainless steel and the interior is made of ceramic. The heating power of the upper heating blade is ≤2000W.

[0010] As a preferred embodiment of the present invention, the effective length of the lower heating blade is 1400-1600mm, and the outer shell of the lower heating blade is made of stainless steel and the interior is made of ceramic. The heating power of the lower heating blade is ≤5000W.

[0011] This invention also discloses a method for using a high-pressure oil wellbore dewaxing device, comprising the following steps: Connect a pressure-bearing tee to the wellhead, connect one end to a pressure-bearing manual cable blowout preventer, connect the upper end of the cable blowout preventer to the blowout preventer pipe, and connect the other end of the tee to the vent line leading to the sludge tank; connect the ground instruments and auxiliary devices, place the tool string inside the cable blowout preventer pipe, operate the electric winch, and leave room for a high depth of cable; use a crane to lift the blowout preventer pipe to the wellhead and connect the blowout preventer pipe to the wellhead; Open the blowout preventer, operate the cable winch to put the dewaxing tool string into the oil pipe, lower the tool string, and pay close attention to the tension changes. When the tension decreases instantaneously, it means that the dewaxing tool string has reached the waxing section. The ground temperature monitoring and control system is activated. As the temperature gradually rises, the tension value also gradually increases, and the cable continues to be lowered for wax melting. When the tension value returns to normal, the wax removal work is completed, and the tool string is removed. The melted wax is removed from the wellbore by controlling the pressure release at the wellhead or flushing the well, ensuring the cleanliness of the wellbore.

[0012] Compared with the prior art, the beneficial effects of the present invention are: It can quickly solve the problem of wax buildup in wellbores and tubing, greatly reducing construction costs, alleviating the labor intensity of personnel, accelerating the production of oil and gas wells, and significantly shortening the construction cycle and reducing operating costs. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the cable head structure of the present invention; Figure 3 This is a schematic diagram of the weighted rod structure of the present invention; Figure 4 This is a schematic diagram of the dewaxing system of the present invention; In the diagram: 1. Cable head; 11. Insulating sleeve; 12. Insulating tube; 13. Second insulating pad; 14. Cable joint; 15. Pressure-bearing housing; 16. Conductive rod; 17. Pin socket; 2. Upper heating blade; 3. Weight rod; 31. Socket; 32. First insulating pad; 33. Outer shell; 34. Single-core pin assembly; 4. Lower heating blade; 5. Power control box; 6. Ground temperature control system; 7. Cable winch. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0015] Please see Figures 1-3 This is the first embodiment of the present invention. This embodiment provides a high-pressure oil well barrel dewaxing device, which includes a cable head 1, an upper heating cutter head 2, a weighting rod 3, and a lower heating cutter head 4, which are connected in sequence. The cable head 1 includes a pin seat 17, which is connected to a threaded single-core pin and also connected to a conductive rod 16 via threads, serving as a conductor and connector. An insulating sleeve 11 is wrapped around the outside of the pin seat 17, and a pressure-bearing housing 15 is disposed outside the insulating sleeve 11. The insulating sleeve 11 keeps the pin seat 17 and the pressure-bearing housing 15 insulated. A plug hole is opened on the insulating sleeve 11 to realize the plug hole. An insulating tube 12 is inserted into the plug hole. A conductive rod 16 is inserted into the insulating tube 12. A second insulating pad 13 is sleeved on the conductive rod 16. A cable connector 14 is installed at one end of the conductive rod 16. The weighted rod 3 includes a housing 33 and a socket 31 opened inside the housing 33. The socket 31 is composed of an outer insulating layer and a core metal conductive part. A single-core pin assembly 34 is set on the socket 31, which is equivalent to screwing a single-core pin on the socket. The pin and the socket serve as a circuit connection.

[0016] In this embodiment, preferably, a first insulating pad 32 is disposed inside the housing 33 to prevent the metal part of the socket 31 from contacting the housing 33, thereby avoiding short circuit.

[0017] In this embodiment, preferably, one end of the lower heating blade 4 is a tapered tip, and the length of the lower heating blade 4 is 90-110mm.

[0018] In this embodiment, preferably, the effective length of the weight rod 3 is 900mm, the temperature resistance is 90℃, the weight rod 3 is connected to the 38 single-core cable head at the top and the heating cutter head at the bottom, and the middle is mainly composed of a whole through wire to realize the transmission of electrical signals, while ensuring high pressure sealing and insulation. During the operation, the weight rod 3 is used to maintain tension, counteract the influence of well pressure, and ensure smooth lowering and normal operation of the dewaxing instrument.

[0019] In this embodiment, preferably, the effective length of the upper heating head 2 is 800mm, and the effective length of the lower heating head 4 is 1400mm. Both the upper heating head 2 and the lower heating head 4 have shells made of precipitation-hardened stainless steel to improve their oxidation resistance at high temperatures. Internally, ceramic is used for insulation and isolation, with a temperature resistance exceeding 1000°C to meet the strength and insulation requirements during high-power heating. The heating power of the upper heating head 2 is ≤2000W, and the heating power of the lower heating head 4 is ≤5000W. The heating head is the main working part for thermal dewaxing. It generates heat through electric heating to heat the wax layer in the oil pipe above its melting point, making the wax layer melt for easy removal and discharge. The heating head consists of an upper head and a lower head, both of which can be heated. The upper head effectively solves the problem of recrystallization after the wax melts, facilitating the lifting of the instrument. The heating head's heating power is adjusted by the ground temperature control system 6 to maintain the heating temperature, ensuring the normal and stable operation of the dewaxing process.

[0020] A method for using a high-pressure oil wellbore dewaxing device includes the following steps: Connect a pressure-bearing tee to the wellhead, connect one end to a pressure-bearing manual cable blowout preventer, connect the upper end of the cable blowout preventer to the blowout preventer pipe, and connect the other end of the tee to the vent line leading to the sludge tank; connect the ground instruments and auxiliary devices, place the tool string inside the cable blowout preventer pipe, operate the electric winch, and leave room for a high depth of cable; use a crane to lift the blowout preventer pipe to the wellhead and connect the blowout preventer pipe to the wellhead; Open the blowout preventer, operate the cable winch to put the dewaxing tool string into the oil pipe, lower the tool string, and pay close attention to the tension changes. When the tension decreases instantaneously, it means that the dewaxing tool string has reached the waxing section. The ground temperature monitoring and control system is activated. As the temperature gradually rises, the tension value also gradually increases, and the cable continues to be lowered for wax melting. When the tension value returns to normal, the wax removal work is completed, and the tool string is removed. The melted wax is removed from the wellbore by controlling the pressure release at the wellhead or flushing the well, ensuring the cleanliness of the wellbore.

[0021] The wax removal system consists of the following components: Figure 4 As shown, the surface section consists of a high-power power control box 5, a high-current special cable, a special cable winch 7 (including a depth measurement and control system), pulleys, tension gauges, etc., while the well instrument section consists of a single-core cable head, a weight rod 3, a wax melting cutter head body, etc. Working process: 380V AC power is connected from the well site to the winch control box to power the winch motor. Then, 220V AC power is connected to the high-power DC power control box 5. The high-power DC power converts the AC power to DC power, which is then transmitted to the high-power heater downhole through the single-core cable on the winch. The surface temperature control system 6 adjusts the current to control the heating power of the downhole heating cutter head, so that the cutter head generates a high temperature of 300℃ to melt the wax and achieve the purpose of dewaxing. The winch control system controls the winch motor and can perform operations such as winding, unwinding, speed adjustment, and stopping the winch.

[0022] The surface temperature control system 6 is used for the operation of the well tool string. It can monitor voltage and current and control the temperature of the tool head by adjusting the output current and voltage. Input AC voltage: 220VAC, output DC voltage: 0-1000VDC, output current: 0-10A, maximum output power: 8000W.

[0023] The cable winch 7 is equipped with: a 4KW motor, manual brake, meter counter, cable guide, manual clutch, and manual crank handle; the maximum lifting weight is 1.2T, and the maximum rope winding speed at the maximum load (400Kg) is 40m / min, which is adjustable; it has an electric slip ring for winding, unwinding, and stopping the cable (emergency braking in special circumstances); it can automatically wind the cable; it has a built-in meter counter with high accuracy and small error, and the cable winch control box can display the winding and unwinding length; it has a built-in clutch and a crank handle, allowing manual cable winding in extreme situations; it has a built-in power-off brake function and a manual brake; the cable winch control box can display the tension value in real time; and it is equipped with a winch fixing device for easy anchoring of the cable winch during on-site operations.

[0024] The existing cable uses a single core of 2.5mm², which cannot withstand prolonged increases in power supply voltage; the newly made cable uses a single core of 3mm²; the special cable has a withstand voltage of 1500VDC, an insulation resistance of 15000MΩ, a temperature resistance of ≥150℃, a maximum tensile strength of 45KN, a length of 1200m, and a cable weight of approximately 312Kg, and the length is sufficient to meet the on-site wax melting requirements.

[0025] The single-core cable head 1 connects to a fixed 8mm diameter single-core cable at the top and to a Φ38mm downhole instrument at the bottom, connecting the single-core cable to other parts to achieve electrical signal transmission while ensuring high-voltage sealing and insulation. Example 2

[0026] Please see Figures 1-4 This is the second embodiment of the present invention, which is based on the previous embodiment, but differs in that: The effective length of the weight rod 3 is 1000mm, and the temperature resistance is 100℃. The weight rod 3 is connected to the 38 single-core cable head at the top and the heating cutter head at the bottom. The middle part is mainly composed of a whole through wire to realize the transmission of electrical signals, while ensuring high-pressure sealing and insulation. During the operation, the weight rod 3 is used to maintain tension, counteract the influence of well pressure, and ensure smooth lowering and normal operation of the dewaxing instrument.

[0027] The effective length of the upper heating cutter head 2 is 880mm, and the effective length of the lower heating cutter head 4 is 1500mm. Example 3

[0028] Please see Figures 1-4 This is the third embodiment of the present invention, which is based on the previous embodiment, but differs in that: The effective length of the weight rod 3 is 1100mm, and the temperature resistance is 110℃. The weight rod 3 is connected to the 38 single-core cable head at the top and to the heating cutter head at the bottom. The middle part is mainly composed of a whole through wire to realize the transmission of electrical signals, while ensuring high-pressure sealing and insulation. During the operation, the weight rod 3 is used to maintain tension, counteract the influence of well pressure, and ensure smooth lowering and normal operation of the dewaxing instrument.

[0029] The effective length of the upper heating cutter head 2 is 960mm, and the effective length of the lower heating cutter head 4 is 1600mm.

[0030] Successful application cases of this technology in 2023: On July 7, 2023, an electro-wax melting operation was carried out at the G127H well in the Laojunmiao Oil Production Plant of Yumen Oilfield. The G127H well is an old self-flowing well in the field, which is facing shutdown due to severe wax buildup. The on-site application showed that the wax melting effect was significant.

[0031] Although embodiments of the invention have been shown and described in detail above, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-pressure oil wellbore dewaxing device, characterized in that: It includes a cable head (1), an upper heating blade (2), a weight rod (3), and a lower heating blade (4) that are spliced ​​together in sequence. The cable head (1) includes a pin socket (17), an insulating sleeve (11) wrapped around the outside of the pin socket (17), a pressure-bearing housing (15) disposed on the outside of the insulating sleeve (11), a plug hole opened on the insulating sleeve (11), an insulating tube (12) inserted into the plug hole, a conductive rod (16) inserted into the insulating tube (12) and connected to the pin socket (17), a second insulating pad (13) sleeved on the conductive rod (16), and a cable connector (14) installed at one end of the conductive rod (16). The weighted rod (3) includes a housing (33), a socket (31) opened inside the housing (33), the socket (31) is composed of an outer insulating layer and a core metal conductive part, and a single core pin assembly (34) is provided on the socket (31).

2. The high-pressure oil wellbore dewaxing device according to claim 1, characterized in that: It also includes a first insulating pad (32) disposed inside the housing (33) to prevent the metal part of the socket (31) from contacting the housing (33).

3. The high-pressure oil wellbore dewaxing device according to claim 1, characterized in that: One end of the pin holder (17) is connected to the conductive rod (16) by a thread, and the other end of the pin holder (17) is connected to the single-core pin by a thread.

4. The high-pressure oil wellbore dewaxing device according to claim 1, characterized in that: One end of the lower heating blade (4) is a tapered tip, and the length of the lower heating blade (4) is 90-110mm.

5. The high-pressure oil wellbore dewaxing device according to claim 1, characterized in that: The effective length of the weighted rod (3) is 900-1100mm, and the temperature resistance is 90-110℃.

6. The high-pressure oil wellbore dewaxing device according to claim 1, characterized in that: The effective length of the upper heating blade (2) is 800-960mm, and the outer shell of the upper heating blade (2) is made of stainless steel and the interior is made of ceramic. The heating power of the upper heating blade (2) is ≤2000W.

7. The high-pressure oil wellbore dewaxing device according to claim 1, characterized in that: The effective length of the lower heating blade (4) is 1400-1600mm, and the outer shell of the lower heating blade (4) is made of stainless steel and the interior is made of ceramic. The heating power of the lower heating blade (4) is ≤5000W.

8. The method of using a high-pressure oil wellbore dewaxing device according to any one of claims 1-7, characterized in that: Includes the following steps: Connect a pressure-bearing tee to the wellhead, connect one end to a pressure-bearing manual cable blowout preventer, connect the upper end of the cable blowout preventer to the blowout preventer pipe, and connect the other end of the tee to the vent line leading to the sludge tank; connect the ground instruments and auxiliary devices, place the tool string inside the cable blowout preventer pipe, operate the electric winch, and leave room for a high depth of cable; use a crane to lift the blowout preventer pipe to the wellhead and connect the blowout preventer pipe to the wellhead; Open the blowout preventer, operate the cable winch to put the dewaxing tool string into the oil pipe, lower the tool string, and pay close attention to the tension changes. When the tension decreases instantaneously, it means that the dewaxing tool string has reached the waxing section. The ground temperature monitoring and control system is activated. As the temperature gradually rises, the tension value also gradually increases, and the cable continues to be lowered for wax melting. When the tension value returns to normal, the dewaxing work is complete, and the tool string is removed. The melted wax is removed from the wellbore by controlling the pressure release at the wellhead or flushing the well, ensuring the cleanliness of the wellbore.

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