Thickened oil testing electric heating test pipe column

Abstract

The utility model discloses a kind of thick oil testing electric heating test pipe columns, including the oil pipe column extending to well, the upper portion of oil pipe column is equipped with the casing liquid level control valve capable of controlling casing liquid level height, the upper oil pipe of casing liquid level control valve is sequentially connected with cable protection nipple, heat tracing cable pipe column and cable hanger upwards;The lower portion of oil pipe column is equipped with circulation valve, and the lower end of oil pipe column is connected with formation tester.The lower portion of formation tester is sequentially connected with locking nipple, expansion joint, lifting nipple, packer, wire-wound screen pipe and pressure gauge holder.This thick oil testing electric heating test pipe column can effectively reduce heat loss in heating process, realize thick oil well formation testing and swabbing production integration, speed up testing progress, reduce construction difficulty, improve data acquisition quality, meet thick oil well testing test requirement.

Description

Technical Field

[0001] This utility model relates to an electrically heated tubing, and more particularly to an electrically heated test tubing for heavy oil testing, belonging to the field of heavy oil testing technology in oilfields. Background Technology

[0002] As oilfield exploration and development deepens, heavy oil reservoirs, as a special type of reservoir replacing conventional reserves, are playing an increasingly important role in oilfield exploration and development. Heavy oil reservoirs are high-density, high-viscosity reservoirs. The viscosity of degassed crude oil at the surface is mostly 300-1000 mPa•s, with a freezing point around 40℃. It solidifies very easily below its freezing point, and the solidified strength is considerable. For example, if an oil pipe is blocked by solidified crude oil, it requires a cement truck with a pressure of 15 MPa to clear it. During oil testing and pumping operations, due to pump replacement or discontinuous pumping, crude oil can solidify and adhere to the pipe walls below its freezing point, causing the pumping pump to encounter resistance during lowering and failing to reach the liquid surface; or during pumping and lifting, the solidified crude oil can jam the pump, making it impossible to pump or even breaking the pumping cable. Because pumping operations cannot be carried out normally, it is impossible to obtain the fluidity and production capacity of high-pour-point oil wells for non-flowing wells, and it is also impossible to obtain high-pressure physical property samples of the crude oil.

[0003] Due to the poor physical properties and high pour point of oil reservoirs, data acquisition is relatively difficult, especially for liquid data. Oilfields both domestically and internationally have attempted to develop high-pour-point oil using methods such as steam injection, electric heating rods, and tubing heating. However, these methods are not only complex in process, have long construction cycles, and high investment costs, but the results of liquid data acquisition are still unsatisfactory.

[0004] Jiangsu Oilfield has adopted several methods, including testing first, then installing pumping tubing, combined with hot washing and diesel injection, and using boiler trucks to insulate surface pipelines. Sometimes, by shortening the pumping outlet pipeline, large tanks are directly fed into the wellhead for metering. These measures have enabled data collection in some wells, but the data quality is poor, and high-quality samples are almost impossible to obtain. This approach is not only labor-intensive but also poses safety hazards. In some wells, production facilities have been installed directly, including surface tanks, processes, pumping units, generators, and heating rods, according to the requirements for single-well production. Fluid properties are then determined through production. This method is labor-intensive and time-consuming. Fluid properties can be obtained, but high-quality samples are still impossible to obtain. Once the tested layer has no production value, these facilities must be dismantled, resulting in wasted investment.

[0005] In 2008, research and application of electric heating technology for high-pour-point oil testing were carried out. Through studies on the characteristics of high-pour-point oil, wellbore geothermal gradient, heating power of the heating source, and heating rate, an electric heating cable with automatic temperature control was selected for wellbore heating. Through the optimization and improvement of the test packer, research on the heating process of the surface pumping outlet pipeline, and studies on the wellhead hanger, the method of fixing the electric heating cable in the well, the heating terminal protector, the matching of the heating temperature acquisition system, and safety, the downhole testing, heating, and pumping systems were ensured to operate safely and efficiently. This initially achieved the integration of formation testing and production assessment in high-pour-point oil wells, improving the quality of data acquisition.

[0006] As exploration and development deepen, the specific gravity, viscosity, and pour point of heavy oil in reservoirs are greater. The original downhole cable heating process involves fixing an automatic temperature-controlled electric heating cable to the outer wall of the tubing to heat the wellbore. However, this process results in a large heat dissipation space in the annulus and around the wellbore, a long heating time, and the inability to reach excessively high temperatures (normally 35–40°C). This heating method cannot completely solve the problem of fluid drainage in heavy oil wells.

[0007] In addition, after the packer is set, the unsealing mechanism is prone to scaling, which often makes it difficult for the packer to be unsealed when the tubing needs to be removed. Utility Model Content

[0008] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, and such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0009] In view of the problems existing in the above and / or prior art, this utility model is proposed.

[0010] The purpose of this invention is to overcome the problems existing in the prior art and provide an electrically heated test string for heavy oil well testing. This string can effectively reduce heat loss during the heating process, realize the integration of formation testing and production extraction in heavy oil wells, accelerate the testing progress, reduce construction difficulty, improve data acquisition quality, and meet the requirements for heavy oil well testing.

[0011] To solve the above technical problems, this utility model provides a heavy oil testing electric heating test string, which includes an oil tubing string extending downhole. The upper part of the oil tubing string is equipped with a casing level control valve that can control the liquid level in the casing. Above the casing level control valve, the oil tubing is connected in sequence to a cable protection short section, a heating cable string, and a cable hanger. The lower part of the oil tubing string is equipped with a circulation valve, and the lower end of the oil tubing string is connected to a formation tester.

[0012] As an improvement of this utility model, the casing level control valve includes a control valve upper connector and a control valve lower connector that are threadedly connected and sealed to each other. The control valve upper connector is provided with an upper connector main eccentric hole offset from one side of the axis, and the upper end of the upper connector main eccentric hole is provided with a tapered female thread that connects to the upper oil pipe. The control valve lower connector is provided with a lower connector main eccentric hole offset from one side of the axis. The lower connector main eccentric hole is coaxial with the upper connector main eccentric hole, and the lower end of the lower connector main eccentric hole is provided with a tapered male thread that connects to the lower oil pipe.

[0013] As a further improvement of this utility model, the lower connector of the control valve is also provided with a small eccentric hole offset from the other side of the axis. The lower end of the small eccentric hole is open, and a valve ball is provided at the upper flared end of the small eccentric hole. A spring seat is pressed on the upper end of the valve ball. The spring seat is located in the small eccentric hole of the upper connector. The small eccentric hole of the upper connector and the small eccentric hole of the lower connector are coaxial, and the upper end of the spring abuts against the lower part of the top wall of the small eccentric hole of the upper connector.

[0014] As a further improvement of this utility model, the threaded connection of the upper and lower control valve connectors is radially screwed with anti-loosening screws.

[0015] As a further improvement of this utility model, the bottom of the spring seat is provided with a concave arc surface for the top of the valve ball to be embedded, and the top center of the spring seat is provided with an upwardly extending spring seat center column, and the lower end of the spring is sleeved on the outer periphery of the spring seat center column.

[0016] As a further improvement of this utility model, the lower part of the formation tester is sequentially connected with a locking short section, a telescopic joint, a lifting short section, a packer, a wire-wound screen tube, and a pressure gauge support.

[0017] As a further improvement of this utility model, the packer includes an upper packer connector, the lower end of which is screwed with a rotary release connector and they are sealed to each other. The lower part of the rotary release connector is connected to the central tube through a reverse thread, and the upper cap is screwed to the outer circumference of the upper end of the central tube and connected to the inner wall of the upper end of the rotary release connector through a rotary release shear pin. A backwashing mechanism is connected below the rotary release connector, and a setting mechanism is connected below the backwashing mechanism. A hydraulic drive mechanism is provided below the setting mechanism, and a lower packer connector is connected below the hydraulic drive mechanism.

[0018] As a further improvement of this utility model, the backwashing mechanism includes an upper backwashing sleeve, a backwashing piston, and a backwashing piston seat. The upper backwashing sleeve is screwed to the lower part of the rotary unsealing joint. The backwashing piston is located in the inner cavity of the upper backwashing sleeve and is sleeved on the outer periphery of the central tube. The upper end of the backwashing piston is sealed to the central tube and the upper backwashing sleeve respectively. The lower part of the upper backwashing sleeve is provided with a backwashing liquid inlet hole. The backwashing piston seat is connected to the lower end of the upper backwashing sleeve.

[0019] As a further improvement of this utility model, the setting mechanism includes a rubber tube, a spacer ring, and a rubber tube bushing. The rubber tube bushing is fitted around the outer periphery of the central tube and a gap is left between the rubber tube and the central tube. The rubber tube is fitted around the outer periphery of the rubber tube bushing. Adjacent rubber tubes are separated by spacer rings. The top rubber tube abuts against the bottom of the backwash piston seat.

[0020] As a further improvement of this utility model, the hydraulic drive mechanism includes an upper liquid cylinder, a lower central tube, and a lower liquid cylinder. The upper liquid cylinder is connected below the lower backwash sleeve and its upper part is sealed to the outer wall of the central tube. The lower central tube is connected to the lower end of the central tube, and the lower liquid cylinder is connected below the upper liquid cylinder and its upper part is sealed to the outer wall of the lower central tube. The central tube is provided with a through hole communicating with the hydraulic chamber of the upper liquid cylinder, and the lower central tube is provided with a through hole communicating with the hydraulic chamber of the lower liquid cylinder.

[0021] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. It improves the thermal efficiency of electric heating, reduces heat dissipation in the annulus and wellbore periphery, realizes the integration of formation testing and production extraction in heavy oil wells, accelerates the oil testing progress, reduces construction difficulty, improves the quality of data acquisition, and meets the requirements of oil testing in heavy oil wells.

[0022] 2. Applicable to the requirements of high-pour-point heavy oil testing and production, improve electric heating facilities and enhance thermal efficiency; optimize the process parameters of external electric heating of tubing, select the type of fluid in the annulus, and reduce heat dissipation in the annulus and around the wellbore; the casing level control valve enables the annulus of the casing to be filled with air, and meets well control requirements;

[0023] 3. A rotary unsealing mechanism has been installed inside the packer. When the packer cannot be unsealed normally when it is lifted, the packer can be unsealed by rotating the tubing. This effectively solves the problem of unsealing difficulties caused by scaling, casing dirt and other issues, reduces the risk of major overhauls, and improves the reliability and service life of the packer. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are provided for reference and illustration only and are not intended to limit this utility model. Wherein:

[0025] Figure 1 This is a schematic diagram of the structure of the electrically heated test column for heavy oil testing according to this utility model;

[0026] Figure 2 This is a cross-sectional view of the sleeve level control valve in this utility model;

[0027] Figure 3This is a top view of the lower connector of the control valve in the casing level control valve.

[0028] Figure 4 This is a cross-sectional view of the packer in this utility model;

[0029] In the diagram: A. Cable hanger; B. Heating cable tubing; C. Cable protection sub; D. Casing level control valve; E. Tubing string; F. Circulation valve; G. Formation tester; H. Locking sub; J. Expansion joint; K. Lifting sub; L. Packer; M. Wire-wound screen; N. Pressure gauge support.

[0030] Pipeline level control valve: 1. Upper control valve connector; 2. Main eccentric hole of upper connector; 3. Small eccentric hole of upper connector; 4. Lower control valve connector; 5. Main eccentric hole of lower connector; 6. Small eccentric hole of lower connector; 7. Valve ball; 8. Spring seat; 9. Spring; 10. Anti-loosening screw;

[0031] Packer: 11. Packer upper connector; 12. Upper parallel cap; 13. Rotary release shear pin; 14. Rotary release connector; 15. O-ring; 16. Central tube; 17. Upper backwash sleeve; 17a. Backwash inlet; 18. Backwash piston; 19. Sealing ring; 20. Pressure ring; 21. Backwash piston seat; 22. Rubber sleeve; 23. Spacer ring; 24. Rubber sleeve bushing; 25. Lower backwash sleeve; 25a. Backwash outlet; 26. Upper liquid cylinder; 27. Lower central tube; 28. Lower liquid cylinder; 29. ​​Locking ring; 30. Upper release shear pin; 31. Locking ring seat; 32. Locking sleeve; 33. Sealing ring; 34. Sealing shear pin; 35. Parallel ring; 36. Lower parallel cap; 37. Packer lower connector. Detailed Implementation

[0032] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0033] To make the technical means, creative features, achieved objectives and effects of this utility model easier to understand, the present utility model will be further described below with reference to specific illustrations. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0035] like Figure 1 As shown, the heavy oil test electric heating test string of this utility model includes, from bottom to top, a pressure gauge support cylinder N, a wire-wound screen tube M, a packer L, a lifting sub-section K, a telescopic joint J, a locking sub-section H, and a formation tester G. An oil tubing string E is connected above the formation tester G. A circulation valve F is provided at the lower part of the oil tubing string E, and a casing level control valve D is provided at the upper part of the oil tubing string E. The oil tubing string E continues to be connected above the casing level control valve D, and then the cable protection sub-section C, the heat tracing cable string B, and the cable suspension device A are connected upwards in sequence.

[0036] Wellbore temperature increases with well depth, typically reaching 15–20°C at the wellhead, increasing by 2–3°C per 100 meters. This creates a non-uniform thermal field. To provide heating along the wellbore above the crude oil's freezing point, only strip-type electric heating is feasible. The heating energy source is lowered into the well along with the tubing string and features automatic power adjustment. After power is applied, the output power automatically adjusts in the reverse direction of the temperature gradient along the well depth, maintaining a relatively constant temperature along the line. This prevents localized overheating and cable burnout, and the heating element is pressure and temperature resistant.

[0037] The currently used electric heating cables are automatically temperature-controlled, with an electric power of 30-60KW, a constant temperature of 50-60℃, a temperature resistance of 105℃, and a maximum heating length of 1200m. Appropriate power and length can be selected based on the characteristics of high-pour-point oil. The electric heating cable consists of a metal armor, insulation layer, conductor, terminal, and heating element. The armor protects the insulation layer from damage, and the insulation layer prevents contact between the annular liquid and the electrical components. The conductor supplies power to the heating element, and the terminal provides a bottom seal. This cable has explosion-proof properties in oil and gas environments. The cross-sectional area of ​​the conductor core has been increased from 2mm² to 4mm², improving the product's heating power and safe current carrying capacity.

[0038] The electrical control cabinet preferably uses a transformer control cabinet, which can provide 380V, 450V, 550V, and 650V voltages. Increasing the voltage accelerates the heating speed of the wellbore and shortens the heating time, while decreasing the voltage maintains a constant temperature and reduces energy consumption. The control cabinet is equipped with automatic load identification display and well temperature display, which facilitates timely adjustment of output voltage and output power, ensuring safety while keeping the oil well heating device in optimal working condition.

[0039] The process parameters for external electric heating of the tubing were optimized, and the type of fluid in the annulus was selected to reduce heat loss from the annulus and the wellbore perimeter. A calculation program was developed to calculate the heat loss from the wellbore at different times, temperatures, and depths. The power loss trend per 100m and the total power loss trend with the number of heating days were analyzed when the annulus consisted of water and air. Water has a thermal conductivity of 0.64 W / (m•℃), while air has a thermal conductivity of 0.022 W / (m•℃). Compared to water, air has better insulation properties and can effectively reduce heat loss during the heating process. Therefore, air is the preferred fluid for electric heating of heavy oil wells. To achieve this, the fluid level in the casing must be controlled below the level of the heating cable using the casing level control valve D.

[0040] like Figure 2 , Figure 3 As shown, the casing level control valve D includes a threaded upper control valve connector 1 and a lower control valve connector 4 that are mutually sealed. Anti-loosening screws 10 are radially screwed into the threaded connection of the upper control valve connector 1 and the lower control valve connector 4. The upper control valve connector 1 has an upper connector main eccentric hole 2 offset from the axis, and the upper end of the upper connector main eccentric hole 2 has a tapered female thread connected to the upper oil pipe. The lower control valve connector 4 has a lower connector main eccentric hole 5 offset from the axis, and the lower connector main eccentric hole 5 is coaxial with the upper connector main eccentric hole 2. The lower end of the lower connector main eccentric hole 5 has a tapered male thread connected to the lower oil pipe.

[0041] The maximum outer diameter of the upper control valve connector 1 and the lower control valve connector 4 is φ114mm. The inner diameter of the main eccentric hole 2 of the upper connector and the main eccentric hole 5 of the lower connector is φ62mm, which serves as a test channel. The minimum sealing pressure is 70MPa and the working temperature is 150℃. The upper end of the main eccentric hole 2 of the upper connector is provided with a tapered female thread of 27 / 8UPTBG, and the lower end of the main eccentric hole 5 of the lower connector is provided with a tapered male thread of 27 / 8UPTBG.

[0042] The lower connector 4 of the control valve is also provided with a small eccentric hole 6 offset from the other side of the axis. The inner diameter of the small eccentric hole 6 is φ20mm. The lower end of the small eccentric hole 6 is open, and a valve ball 7 with a diameter of 23-24mm is provided at the upper flared end of the small eccentric hole 6. A spring seat 8 is pressed against the upper end of the valve ball 7. The bottom of the spring seat 8 is provided with a concave arc surface for the top of the valve ball 7 to be inserted. The center of the top of the spring seat 8 is provided with an upwardly extending spring seat center column. The lower end of the spring 9 is sleeved on the outer circumference of the spring seat center column. The spring seat 8 is located in the small eccentric hole 3 of the upper connector. The small eccentric hole 3 of the upper connector is coaxial with the small eccentric hole 6 of the lower connector, and the upper end of the spring 9 abuts against the lower part of the top wall of the small eccentric hole 3 of the upper connector.

[0043] When the tubing string is first inserted into the well, the tension of spring 9 sets the valve ball 7 at the upper flared end of the small eccentric hole 6 in the lower connector. When the tubing string reaches the predetermined depth, under the pressure of the annular fluid column, the valve ball 7 overcomes the tension of spring 9 and floats upward, causing the casing level control valve D to open. The annular fluid enters the tubing and eventually reaches equilibrium. The inflow volume ensures that the annulus of the heating cable at the top of the casing is filled with air. Then, under the action of spring 9, the casing level control valve D closes.

[0044] like Figure 4 As shown, the packer L includes an upper packer connector 11, an upper cap 12, a rotary release shear pin 13, a rotary release connector 14, an O-ring 15, a central tube 16, an upper backwash sleeve 17, a backwash piston 18, a sealing ring 19, a pressure ring 20, a backwash piston seat 21, a rubber sleeve 22, a spacer ring 23, a rubber sleeve bushing 24, a lower backwash sleeve 25, an upper liquid cylinder 26, a lower central tube 27, a lower liquid cylinder 28, a locking ring 29, an upper release shear pin 30, a locking ring seat 31, a locking sleeve 32, a setting ring 33, a setting shear pin 34, a parallel ring 35, a lower cap 36, and a lower packer connector 37.

[0045] The upper external thread of the rotary release connector 14 is screwed onto the lower internal thread of the packer upper connector 11. Two O-rings 15 are embedded below the upper external thread of the rotary release connector 14, sealing the lower inner wall of the packer upper connector 11. The lower end of the packer upper connector 11 abuts against the outer step of the rotary release connector 14. The lower reverse internal thread of the rotary release connector 14 connects to the reverse external thread on the outer circumference of the center tube 16. The upper cap 12 is screwed onto the upper end of the center tube 16, with its outer wall abutting against the upper inner wall of the rotary release connector 14. The rotary release shear pin 13 secures the rotary release connector 14 to the upper cap 12. The bottom of the upper cap 12 is supported on the upper step of the center tube 16.

[0046] The upper internal thread of the upper backwash sleeve 17 is screwed onto the outer periphery of the lower external thread of the rotary unsealing connector 14. Two O-rings are embedded below the lower external thread of the rotary unsealing connector 14 to seal with the upper inner wall of the upper backwash sleeve 17. The upper port of the upper backwash sleeve 17 abuts against the lower outer step of the rotary unsealing connector 14.

[0047] The backwash piston 18 is located between the outer wall of the central tube 16 and the inner wall of the upper backwash sleeve 17. The inner wall of the upper sealing section of the backwash piston 18 is fitted with two piston inner sealing rings to achieve a seal with the outer wall of the central tube 16, and the outer wall of the upper sealing section of the backwash piston 18 is fitted with two piston outer sealing rings to achieve a seal with the inner wall of the upper backwash sleeve 17.

[0048] The external thread of the pressure ring 20 is connected to the lower internal thread of the backwash piston 18, and the outer circumference of the pressure ring 20 is sealed with the lower port of the backwash piston 18 by a sealing ring 19. The lower inner circumference of the backwash piston 18 is provided with an annular cavity for the insertion of the rubber sleeve 24. Two sealing rings are embedded in the inner wall of the annular cavity so that the backwash piston 18 can be sealed with the upper outer wall of the rubber sleeve 24 after it moves down.

[0049] The upper external thread of the backwash piston seat 21 is connected to the lower internal thread of the upper backwash sleeve 17. The rubber sleeve 24 is fitted around the outer circumference of the central tube 16, with a gap between it and the central tube 16 to serve as a backwash fluid flow channel. A sealing ring is embedded in the lower inner wall of the backwash piston seat 21 to achieve a seal with the upper outer wall of the rubber sleeve 24. The upper end of the backwash piston seat 21 is provided with a flared opening. When the backwash piston 18 descends to engage with the backwash piston seat 21, the outer conical surface of the sealing ring 19 seals with the flared opening of the backwash piston seat 21.

[0050] The rubber sleeve 22 and spacer ring 23 are fitted around the outer periphery of the rubber sleeve bushing 24. The rubber sleeve 22 has three sections, which are separated from each other by the spacer ring 23. The top rubber sleeve abuts against the bottom of the backwash piston seat 21, and the bottom rubber sleeve abuts against the top of the lower backwash sleeve 25. The internal thread of the lower backwash sleeve 25 is screwed into the lower external thread of the rubber sleeve bushing 24 and sealed by a sealing ring.

[0051] The upper external thread of the upper liquid cylinder 26 is screwed into the lower internal thread of the lower backwash sleeve 25, and the lower end of the lower backwash sleeve 25 abuts against the outer step of the upper liquid cylinder 26.

[0052] The upper sealing section of the upper cylinder 26 is fitted with a sealing ring that seals the outer wall of the central tube 16. Below the sealing section is the hydraulic chamber of the upper cylinder 26. The lower part of the central tube 16 is provided with a radial hole that communicates with the hydraulic chamber of the upper cylinder 26.

[0053] The upper end of the lower central tube 27 is threaded to the lower end of the central tube 16, and the expanded section of the upper end of the lower central tube 27 is sealed to the inner wall below the hydraulic chamber of the upper cylinder 26 through a sealing ring.

[0054] The upper external thread of the lower liquid cylinder 28 is connected to the lower internal thread of the upper liquid cylinder 26. The inner wall of the upper sealing end of the lower liquid cylinder 28 is fitted with a sealing ring that seals the outer wall of the lower central tube 27. A hydraulic chamber is provided below the upper sealing end of the lower liquid cylinder 28. A radial hole is provided at the lower part of the lower central tube 27 that communicates with the hydraulic chamber of the lower liquid cylinder 28.

[0055] The upper end of the packer lower connector 37 is connected to the lower end of the lower center tube 27 via an internal thread. The outer wall of the upper large diameter section of the packer lower connector 37 is fitted with a sealing ring to seal the inner wall below the sealing section of the lower liquid cylinder 28.

[0056] Locking ring 29 and locking ring seat 31 are fitted onto the outer periphery of the middle section of the packer lower connector 37. The lifting release shear pin 30 fixes the locking ring seat 31 to the packer lower connector 37. The upper external thread of the locking sleeve 32 connects to the lower internal thread of the lower liquid cylinder 28. The locking sleeve 32 has internal ratchet teeth that engage unidirectionally with the external ratchet teeth of the locking ring 29. The lower external thread of the locking sleeve 32 connects to the upper internal thread of the setting ring 33. A coupling ring 35 is fitted onto the outer periphery of the middle section of the packer lower connector 37. The setting shear pin 34 fixes the setting ring 33 and the coupling ring 35. The top outer edge of the coupling ring 35 abuts against the lower part of the locking sleeve 32. The lower internal thread of the lower coupling cap 36 connects to the middle external thread of the packer lower connector 37.

[0057] Working principle of packer L:

[0058] 1. Setting the Packer: After lowering the packer to the designed depth in the well, pressure is applied to the tubing. Fluid enters the annulus between the central tube 16 and the rotary unsealing joint 14 through the upper fluid hole of the central tube 16, pushing the backwash piston 18 downward. The backwash piston 18 pushes the backwash piston seat 21 downward to compress the rubber sleeve 22. Simultaneously, fluid enters the hydraulic chamber between the central tube 16 and the upper cylinder 26 through the lower fluid hole of the central tube 16, and enters the hydraulic chamber between the lower central tube 27 and the lower cylinder 28 through the fluid hole of the lower central tube 27, pushing the upper cylinder 26 and the lower cylinder 28 upward synchronously. The upper cylinder 26 pushes the lower backwash sleeve 25 upward to compress the rubber sleeve 22. The rubber sleeve 22 expands under the upper and lower compression forces, sealing the inner wall of the casing; at this time, the backwash piston 18 reaches the outer periphery of the rubber sleeve bushing 24 and seals against it.

[0059] When the hydraulic cylinder 28 moves the locking sleeve 32 upward, locking the locking sleeve 32 with the locking ring 29, and the locking sleeve 32 pulls the setting ring 33, causing the setting shear pin 34 to be broken by the setting ring 33, the setting is successful.

[0060] II. Unsealing: When the packer needs to be unsealed and removed from the tubing after construction is completed, the following two unsealing methods can be used:

[0061] 1. Lifting and Unsealing Method: Lift the tubing string, which sequentially pulls the packer upper connector 11, the rotary unsealing connector 14, the upper backwash sleeve 17, and the backwash piston seat 21 upwards, releasing the upper support force on the rubber sleeve. Simultaneously, the tubing string sequentially pulls the packer upper connector 11, the rotary unsealing connector 14, the central tube 16, the lower central tube 27, and the packer lower connector 37 upwards. Since the locking ring 29 and the locking ring seat 31 are locked by the locking sleeve 32 after the packer is set, when the packer lower connector 37 moves upwards, the lifting and unsealing shear pin 30 is sheared, the locking fails, and the lower support force on the rubber sleeve is released. At this time, the rubber sleeve rebounds under its own elasticity and separates from the sleeve wall, allowing the tubing string to be lifted out.

[0062] 2. Rotary unsealing method: If lifting the tubing fails to unseal the packer, rotate the tubing forward, causing the packer upper connector 11 and the rotary unsealing connector 14 to rotate forward. Since the rotary unsealing connector 14 and the central tube 16 are connected by a reverse thread, which is equivalent to a screw mechanism, the central tube 16 moves downward, shears the rotary unsealing shear pin 13, and continues to move downward. At the same time, it pushes the lower central tube 27 and the lower packer connector 37 to move downward together. The lower packer connector 37 sequentially drives the locking ring 29, locking sleeve 32, lower liquid cylinder 28, upper liquid cylinder 26, lower backwash sleeve 25, and rubber sleeve bushing 24 to move downward. The upper and lower support forces of the rubber sleeve are released, and the rubber sleeve rebounds under its own elasticity, allowing the tubing to be lifted out.

[0063] The above description is merely a preferred embodiment of the present utility model, showing and describing the basic principles, main features, and advantages of the present utility model. It is not intended to limit the scope of patent protection of the present utility model. Those skilled in the art should understand that the present utility model is not limited to the above embodiments. In addition to the above embodiments, the present utility model may have other implementations without departing from the spirit and scope of the present utility model. Various changes and improvements to the present utility model are also possible. All technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present utility model. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents. Technical features not described in the present utility model can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A heavy oil testing electrically heated tubing string, comprising a tubing string (E) extending downhole, characterized in that, The upper part of the tubing string (E) is equipped with a casing level control valve (D) that can control the liquid level in the casing. Above the casing level control valve (D), the tubing is connected in sequence to a cable protection short section (C), a heating cable string (B), and a cable hanger (A). The lower part of the tubing string (E) is equipped with a circulation valve (F), and the lower end of the tubing string (E) is connected to a formation tester (G).

2. The electrically heated test column for heavy oil testing according to claim 1, characterized in that: The casing level control valve (D) includes a threaded and mutually sealed upper control valve connector (1) and a lower control valve connector (4). The upper control valve connector (1) is provided with an upper connector main eccentric hole (2) offset from the axis. The upper end of the upper connector main eccentric hole (2) is provided with a tapered female thread connected to the upper oil pipe. The lower control valve connector (4) is provided with a lower connector main eccentric hole (5) offset from the axis. The lower connector main eccentric hole (5) is coaxial with the upper connector main eccentric hole (2), and the lower end of the lower connector main eccentric hole (5) is provided with a tapered male thread connected to the lower oil pipe.

3. The electrically heated test column for heavy oil testing according to claim 2, characterized in that: The lower connector (4) of the control valve is also provided with a small eccentric hole (6) offset from the other side of the axis. The lower end of the small eccentric hole (6) is open, and a valve ball (7) is provided at the upper end of the small eccentric hole (6). A spring seat (8) is pressed on the upper end of the valve ball (7). The spring seat (8) is located in the small eccentric hole (3) of the upper connector. The small eccentric hole (3) of the upper connector and the small eccentric hole (6) of the lower connector are coaxial, and the upper end of the spring (9) abuts against the lower top wall of the small eccentric hole (3).

4. The electrically heated test column for heavy oil testing according to claim 2, characterized in that: The upper connector (1) and lower connector (4) of the control valve are radially screwed with anti-loosening screws (10).

5. The electrically heated test column for heavy oil testing according to claim 3, characterized in that: The bottom of the spring seat (8) is provided with a concave arc surface for the top of the valve ball (7) to be embedded. The top center of the spring seat (8) is provided with an upwardly extending spring seat center column. The lower end of the spring (9) is sleeved on the outer periphery of the spring seat center column.

6. The electrically heated test column for heavy oil testing according to claim 1, characterized in that: The formation tester (G) is connected in sequence to a locking section (H), a telescopic joint (J), a lifting section (K), a packer (L), a wire-wound screen tube (M), and a pressure gauge support (N).

7. The electrically heated test column for heavy oil testing according to claim 6, characterized in that: The packer includes a packer upper connector (11), the lower end of which is screwed with a rotary release connector (14) and they are sealed to each other. The lower part of the rotary release connector (14) is connected to the central tube (16) through a reverse internal thread. The upper cap (12) is screwed to the outer periphery of the upper end of the central tube (16) and is connected to the inner wall of the upper end of the rotary release connector (14) through a rotary release shear pin (13). A backwashing mechanism is connected below the rotary release connector (14), and a setting mechanism is connected below the backwashing mechanism. A hydraulic drive mechanism is provided below the setting mechanism, and a packer lower connector (37) is connected below the hydraulic drive mechanism.

8. The electrically heated test column for heavy oil testing according to claim 7, characterized in that: The backwashing mechanism includes an upper backwash sleeve (17), a backwash piston (18), and a backwash piston seat (21). The upper backwash sleeve (17) is screwed to the lower part of the rotary unsealing joint (14). The backwash piston (18) is located in the inner cavity of the upper backwash sleeve (17) and is sleeved on the outer periphery of the central tube (16). The upper end of the backwash piston (18) is sealed to the central tube (16) and the upper backwash sleeve (17) respectively. The lower part of the upper backwash sleeve (17) is provided with a backwash inlet hole (17a). The backwash piston seat (21) is connected to the lower end of the upper backwash sleeve (17).

9. The electrically heated test column for heavy oil testing according to claim 8, characterized in that: The setting mechanism includes a rubber tube (22), a spacer ring (23), and a rubber tube bushing (24). The rubber tube bushing (24) is fitted around the outer periphery of the central tube (16) and has a gap between it and the central tube (16). The rubber tube (22) is fitted around the outer periphery of the rubber tube bushing (24). Adjacent rubber tubes (22) are separated by spacer rings (23). The top rubber tube abuts against the bottom of the backwash piston seat (21).

10. The electrically heated test column for heavy oil testing according to claim 8, characterized in that: The hydraulic drive mechanism includes an upper cylinder (26), a lower central tube (27), and a lower cylinder (28). The upper cylinder (26) is connected below the lower backwash sleeve (25) and its upper part is sealed to the outer wall of the central tube (16). The lower central tube (27) is connected to the lower end of the central tube (16), and the lower cylinder (28) is connected below the upper cylinder (26) and its upper part is sealed to the outer wall of the lower central tube (27). The central tube (16) has a through hole that communicates with the hydraulic chamber of the upper cylinder (26), and the lower central tube (27) has a through hole that communicates with the hydraulic chamber of the lower cylinder (28).

Images