Heavy oil development underground steam electric heating lifting and testing process

Abstract

The invention discloses an underground steam electric heating lifting and testing process for heavy oil development. The underground steam electric heating lifting and testing process for heavy oil development specifically comprises the following steps: S10, tubular column preparation: putting a first heat insulation tubular column into a steam injection channel, and putting a testing tubular column into a testing channel; s20, preparing a continuous pipe electric heater, wherein the continuous pipe electric heater is put down into the first heat insulation pipe column, and the continuous pipe electric heater is put down and sealed through a first sealing device; s30, heavy oil thermal recovery steam injection and drying, wherein underground steam is directly heated and dried through high-power electric heating; and when the step S30 is executed, the electric heating lifting test is synchronously carried out. The technical scheme has the beneficial effects that heated and lifted steam can directly enter the stratum, heat loss is greatly reduced, efficient electric heating is achieved, and therefore the dryness of underground steam is greatly improved, and the development problem of medium-deep layer SAGD and steam flooding is effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of heavy oil exploitation by steam injection in oil and gas fields, and in particular to a downhole steam electric heating and drying and testing process for heavy oil development. Background Art

[0002] At present, there are three main methods of thermal recovery of heavy oil in oil fields: steam stimulation, steam flooding and SAGD. The development of medium-deep heavy oil (<1000m) has entered the middle and late stages. In order to ensure the stable production of tens of millions of tons, it is necessary to convert deep and ultra-deep heavy oil reservoirs (1000-1700m) to steam flooding, SAGD and other methods to achieve reserve replacement. Among them, there are many technical difficulties in further developing the oil field through deep SAGD and steam drive, which makes it difficult to achieve effective development of SAGD and steam drive in deep blocks: on the one hand, the heat loss along the way is large: the dryness loss of the steam injection pipeline or pipeline network along the way is 5% to 15%, and the dryness loss of the wellbore is as high as 20% per kilometer. The comprehensive utilization rate of thermal energy is less than 60%, which makes it difficult to ensure the comprehensive utilization rate of deep SAGD bottom hole thermal energy> 70% index requirement; on the other hand, under conventional steam injection volume, the injection-production pressure difference is larger, the formation and expansion of the steam cavity are more difficult, and the steam thermal efficiency is low. According to the steam drive production mechanism of ultra-heavy oil, the mobility ratio of ultra-heavy oil and steam is greatly different, which is easy to cause steam channeling between injection and production wells. Therefore, low pressure difference operation is required during the development process, and the steam injection speed should be reduced as much as possible, but this will cause the bottom hole steam dryness to fail to reach 50%; and if the steam injection displacement is increased to ensure the bottom hole steam dryness, it will cause low heat utilization rate, large displacement resistance, and difficulty in establishing an effective displacement system.

[0003] In order to deal with the above-mentioned difficulties, some literatures mention the use of underground steam secondary electric heating technology. This technology is to lower a continuous tube electric heater into the steam wellhead, and the bottom electric heater performs secondary heating on the low-dryness steam at the bottom of the well. However, this technology adopts an eccentric wellhead heating method, that is, the heating string and the steam injection string are separated. This heating method causes more heat loss during the movement of steam, resulting in waste of heat energy and low heat utilization rate. In order to achieve the purpose of heating, the well must use an eccentric wellhead to insert a steam injection string and a heating string combination or a steam injection string and an electric heater combination, which are not concentric and co-pipe. This places high requirements on the development of underground space, casing size, and well conditions, and cannot be promoted and applied on a large scale in the later stage. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a downhole steam electric heating drying and testing process for heavy oil development. The technical solution is as follows:

[0005] A heavy oil development underground steam electric heating drying and testing process, the heavy oil development underground steam electric heating drying process method specifically includes:

[0006] S10 column preparation:

[0007] A steam injection-electric heating-testing integrated wellhead is used in an oil layer casing well, and a first heat-insulating pipe string is lowered through a steam injection channel at the steam injection-electric heating-testing integrated wellhead until the bottom end of the first heat-insulating pipe string reaches the upper part of the oil layer section or a preset first lowering depth, and then a test pipe string is lowered through a test channel at the steam injection-electric heating-testing integrated wellhead until the bottom end of the test pipe string reaches a preset second lowering depth;

[0008] S20 Continuous Tube Electric Heater Preparation:

[0009] The coiled tubing electric heater is lowered into the first thermally insulated pipe string until the heating section of the coiled tubing electric heater reaches the upper part of the oil layer section or a preset third lowering depth, so that the coiled tubing electric heater and the first thermally insulated pipe string together form a steam injection heating concentric pipe string, and the coiled tubing electric heater is connected to the steam injection-electric heating-testing integrated wellhead through a first sealing device for tripping and sealing;

[0010] S30 Heavy Oil Thermal Recovery Steam Stripping Dry:

[0011] The ground boiler is used to heat and generate steam, which is then injected into the first insulated pipe string through the steam injection valve on the integrated steam injection-electric heating-testing wellhead. The power of the coiled tube electric heater is adjusted through the high-pressure ground power regulating device, thereby performing high-power electric heating and directly heating the underground steam until the extraction is completed.

[0012] Furthermore, a test instrument is lowered into the test string, and an electric heating and drying test is performed simultaneously when executing step S30. The electric heating and drying test method specifically includes:

[0013] The test instrument is started to perform single-point or continuous testing through the test instrument, so as to dynamically monitor relevant parameters downhole, wherein the relevant parameters include temperature, pressure, dryness and steam absorption profile.

[0014] Furthermore, a test blowout preventer is installed at the upper end of the test channel, and the test instrument is lowered into the test pipe string through the test blowout preventer.

[0015] Furthermore, the steam injection-electric heating-testing integrated wellhead comprises a steam injection channel, a test channel, a hanging step, a casing valve and a steam injection valve. The steam injection channel is provided with a steam injection channel valve, the test channel is provided with a test channel valve, a hanging step is provided inside the test channel, one end of the first thermal insulation pipe string passes through the steam injection channel and is lowered into the well, and the other end of the first thermal insulation pipe string is threadedly connected to the inner wall of the steam injection channel, so that the first thermal insulation pipe string is suspended; one end of the test pipe string passes through the test channel and is lowered into the well, and the other end of the test pipe string is provided with a hanger, the hanger is overlapped on the hanging step, and the test pipe string is suspended under the action of gravity.

[0016] Furthermore, the test pipe string includes an integrally jointed oil pipe, a high-strength screen pipe and a wire plug; the lower end of the integrally jointed oil pipe passes through the test channel and is lowered into the well; one end of the high-strength screen pipe is fixedly connected to the lower end of the integrally jointed oil pipe, and the other end of the high-strength screen pipe is fixedly provided with the wire plug; the upper end of the integrally jointed oil pipe is overlapped on the suspension step through the hanger.

[0017] Furthermore, a suspension fixing screw for tightening or loosening the hanger is provided on the side wall of the test channel, and the setting direction of the suspension fixing screw is perpendicular to the depth direction of the well. The suspension fixing screw is threadedly connected to the side wall of the test channel, and the length of the suspension fixing screw inserted into the interior of the test channel can be adjusted by rotating the suspension fixing screw.

[0018] Further, the coiled tube electric heater comprises a first electric heater and a first heating cable, the first heating cable and the first electric heater are equal-diameter integrated devices, wherein the first electric heater is a heating section of the coiled tube electric heater, the first electric heater is arranged at the lower end of the first heating cable, and the first electric heater is electrically connected to the first heating cable.

[0019] Further, the first sealing device includes a sealing body, a cable sealing cover, a high-temperature sealing assembly, a pressure pad, a wear-resistant straightening sleeve, a pressing cap and a cable locking buckle, the sealing body is threadedly connected to the top of the steam injection channel, the top of the sealing body is provided with a sealing groove, the high-temperature sealing assembly and the pressure pad are placed in the sealing groove in sequence, the cable sealing cover is sleeved and threadedly connected to the top of the sealing body, a sealing adjustment handle for adjusting the rotation of the cable sealing cover is provided on the side wall of the cable sealing cover, the inner wall of the cable sealing cover presses the pressure pad, the wear-resistant straightening sleeve is provided on the top of the cable sealing cover, the pressing cap is threadedly connected to the top of the cable sealing cover and presses the wear-resistant straightening sleeve, and the cable locking buckle is provided on the top of the pressing cap; the first heating cable passes through the pressing cap, the wear-resistant straightening sleeve, the cable sealing cover, the pressure pad, the high-temperature sealing assembly and the sealing body in sequence, and is lowered into the first thermal insulation pipe column, and the cable locking buckle clamps and fixes one end of the first heating cable close to the pressing cap.

[0020] Furthermore, the high temperature sealing assembly comprises a plurality of multi-stage conical sealing rings. When the cable sealing cover is sleeved and threadedly connected to the top of the sealing body, the plurality of multi-stage conical sealing rings are stacked step by step and compressed by the pressure pad.

[0021] Furthermore, the heavy oil development underground steam electric heating drying process method applies a working system that combines grid electricity and green electricity, and consumes green electricity according to the principle of "using more green electricity and less grid electricity".

[0022] The beneficial effects of the present invention are:

[0023] The downhole steam electric heating and drying and testing process technology described in the present application directly lowers the first electric heater into the steam injection string, heats the steam at the outlet of the downhole steam injection string by the high-power first electric heater, and the heated and dried steam directly enters the formation, greatly reducing heat loss and achieving efficient electric heating, thereby greatly improving the downhole steam dryness and effectively solving the above-mentioned deep SAGD and steam drive development problems.

[0024] In order to scientifically control the steam injection parameters, electric heating power parameters, and electric heating methods (intermittent heating, continuous high-dryness heating), a parallel double-tube string for steam injection heating and testing is designed. During the steam injection heating process, the test and recording of downhole steam dryness, temperature, pressure and other parameters are simultaneously realized. The steam injection-electric heating-testing integrated wellhead developed in this application, as well as the matching first sealing device and test blowout prevention device, can fully ensure that steam injection electric heating and testing are carried out simultaneously. After the test understands the production rules of electric heating and drying in the block, it can be implemented in accordance with the scientific production system, and the steam injection heating concentric single string can be directly lowered to implement the technology in SAGD and steam drive for promotion and application, and realize efficient development. Ultimately, through the rational use of the working system combining green electricity and grid electricity, the electrification rate of heavy oil thermal recovery development can be improved, the energy consumption structure adjustment can be completed, and green transformation and development can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the steam injection heating-testing double-column development process in Example 1 of the present application.

[0026] Figure 2 This is a schematic diagram of the structure of the hanger in Example 1 of the present application.

[0027] Figure 3 This is a schematic diagram of the structure of the sealing device in Example 1 of the present application.

[0028] Figure 4 This is a schematic diagram of the deep steam flooding / SAGD electric heating dry development process in Example 2 of the present application;

[0029] Figure 5 This is a process flow chart of downhole steam electric heating and drying for heavy oil development in Example 3 of the present application.

[0030] Description of reference numerals:

[0031] 1. Steam injection-electric heating-testing integrated wellhead; 2. Steam injection channel; 3. Test channel; 31. Suspension step; 32. Hanger; 33. Suspension fixing screw; 4. First thermal insulation pipe string; 5. Integral joint oil pipe; 6. High-strength screen pipe; 7. Plug; 8. Oil layer section; 9. First electric heater; 10. First heating cable; 11. First sealing device; 12. Test blowout prevention device; 13. Steam injection channel valve; 14. Test channel valve; 15. Casing valve; 16. Steam injection valve; 17. Sealing body; 18. Cable sealing cover; 19. High-temperature sealing assembly; 20. Pressure pad; 21. Sealing adjustment handle; 22. Wear-resistant straightening sleeve; 23. Pressing cap; 24. Oil guide channel; 25. Steam leakage observation hole; 26. Cable locking buckle;

[0032] 3-1. High-pressure ground power regulating device; 3-2. Second heating cable; 3-3. Second sealing device; 3-4. Thermal recovery steam injection wellhead; 3-5. Second thermal insulation pipe string; 3-6. Thermosensitive packer; 3-7. Second electric heater; 3-8. Oil layer section; 3-9. Grid electricity; 3-10. Green electricity. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1-5 This application is described in further detail.

[0034] The present application provides a steam injection heating-testing dual-string development process, a deep steam drive / SAGD electric heating and drying development process and a complete heavy oil downhole electric heating and drying process system, which can significantly improve the traditional heavy oil steam injection thermal recovery development effect. The process is applicable to both vertical wells and horizontal wells, and the vertical well operation mode is mainly described here.

[0035] Example 1

[0036] The application designs and forms a steam injection heating-testing dual-pipeline development process, which can realize downhole electric heating and drying while performing dynamic testing.

[0037] refer to Figure 1 and Figure 2 The present application discloses a steam injection-electric heating-testing integrated wellhead 1. The steam injection-electric heating-testing integrated wellhead 1 comprises a steam injection channel 2, a test channel 3, a casing valve 15 and a steam injection valve 16. The steam injection channel 2 is provided with a steam injection channel valve 13, the test channel 3 is provided with a test channel valve 14, a hanging step 31 is provided in the test channel 3, and the side wall of the hanging step 31 is inclined. One end of the first insulation pipe string 4 passes through the steam injection channel 2 and goes down into the well, and the other end of the first insulation pipe string 4 is threadedly connected to the inner wall of the steam injection channel 2, so that the first insulation pipe string 4 is suspended, and the first insulation pipe string 4 and the steam injection channel 2 are connected. After the packer is set, the first insulated pipe string 4 is used to lower the continuous pipe electric heater to perform underground steam electric heating and drying; one end of the test pipe string passes through the test channel 3 and is lowered into the well, and the other end of the test pipe string is provided with a hanger 32, one end of the hanger 32 has an inclined surface, and the end of the hanger 32 with the inclined surface is used in conjunction with the inclined side wall of the hanging step 31, so as to overlap the hanging step 31, and the test pipe string is suspended by gravity, and the test pipe string and the test channel are sealed by the packer, and the test pipe string can provide a channel for the wireline lifting and lowering test operation.

[0038] refer to Figure 1In other implementations, a hanging screw 33 may be provided on the side wall of the test channel 3. The setting direction of the hanging screw 33 is perpendicular to the depth direction of the corresponding well and is threadedly connected to the side wall of the test channel. By rotating the hanging screw 33, the length of the hanging screw 33 inserted into the test channel can be adjusted. When the test pipe string needs to be further reinforced, the hanging screw 33 is rotated to increase the length of the hanging screw 33 inserted into the test channel until the hanging screw 33 is pressed against the hanger 32, which can effectively prevent the test pipe string from moving.

[0039] refer to Figure 1 The present application discloses a coiled tubing electric heater, which comprises a first electric heater 9 and a first heating cable 10. The first heating cable 10 and the first electric heater 9 are equal-diameter integrated devices, wherein the first electric heater 9 is the heating section of the coiled tubing electric heater, the first electric heater 9 is arranged at the lower end of the first heating cable 10, and the first electric heater 9 is electrically connected to the first heating cable 10. The electric heating outer tube of the first heating cable 10 is selected by optimizing the material and process structure, and the material that can resist high temperature and corrosion is selected. The electric heating outer tube of this material can work continuously for 3 years in the environment of high-temperature steam corrosion and scouring inside the first insulation pipe string 4, and is used in conjunction with the above-mentioned steam injection-electric heating-testing integrated wellhead 1, which greatly reduces the limitations of the traditional technology in the underground electric heating process and achieves a breakthrough in the underground electric heating process of the steam injection well.

[0040] refer to Figure 1 The present application discloses a test pipe string, which includes an integral joint oil pipe 5, a high-strength screen pipe 6 and a wire plug 7. The lower end of the integral joint oil pipe 5 passes through a test channel 3 and is lowered into the well. One end of the high-strength screen pipe 6 is fixedly connected to the lower end of the integral joint oil pipe 5, and the other end of the high-strength screen pipe 6 is fixedly provided with a wire plug 7; the upper end of the integral joint oil pipe 5 is sleeved with a hanger 32, and is overlapped on a suspension step 31 through the hanger 32 to complete the suspension sealing.

[0041] For the electric heating dry-lift test, the test instrument is about 1.5 meters long and 38 mm in outer diameter. The traditional test method is to put the test instrument into the test string and then contact it with the downhole steam for testing, and then lift up to recover the test instrument. Due to the limitation of the inner diameter of the test string, it is difficult to lift up and recover the test instrument, which can easily cause accidents such as the test instrument falling or getting stuck in the well, resulting in test interruption.

[0042] In the present application, a test string is formed by a combination of a thread plug 7, a high-strength screen tube 6 and an integral joint oil pipe 5. The integral joint oil pipe 5 can reduce the limitation of the overall maximum outer diameter of the test string, ensuring the smooth lifting and lowering of the test string as a whole; the high-strength screen tube 6 determines the lowering depth and the use length according to the test requirements, and the several air holes on the high-strength screen tube 6 can ensure the flow of steam after heating, so that the test instrument can fully contact with the steam, and then realize the recording of parameters such as dryness, temperature, and pressure. The high-strength screen tube 6 and the integral joint oil pipe 5 can provide a test passage for the tester, ensuring that the above-mentioned test instrument can reach the outlet position of the steam heated by the continuous tube electric heater. The test instrument performs lifting and lowering tests in the above-mentioned test string. Under the premise of ensuring the test effect, the test success rate can be greatly improved, and the bottom of the combined string is supported by a thread plug 7, so even if the test instrument falls, the test can still proceed normally.

[0043] The present application discloses a first sealing device 11 and a test blowout preventer 12 , both of which are used in conjunction with a steam injection-electric heating-testing integrated wellhead 1 .

[0044] refer to Figure 1 and Figure 3 The first sealing device 11 includes a sealing body 17, a cable sealing cover 18, a high-temperature sealing assembly 19, a pressure pad 20, a sealing adjustment handle 21, a wear-resistant straightening sleeve 22, a pressing cap 23, an oil guide channel 24, a steam leakage observation hole 25, and a cable locking buckle 26. The sealing body 17 is fixed to the top of the steam injection channel 2 by threaded connection. A sealing groove is provided on the top of the sealing body 17. The high-temperature sealing assembly 19 and the pressure pad 20 are placed in the sealing groove in sequence. The high-temperature sealing assembly 19 includes a plurality of multi-stage conical sealing rings, which are stacked step by step. The cable sealing cover 18 is sleeved and threadedly connected to the top of the sealing body 17. A sealing adjustment handle 21 for adjusting the rotation of the cable sealing cover 18 is provided on the side wall of the cable sealing cover 18. The inner wall of the cable sealing cover 18 compresses the pressure pad 20, thereby compressing the multi-stage conical sealing rings stacked together; the wear-resistant straightening sleeve 22 is arranged on the top of the cable sealing cover 18, the pressing cap 23 is threadedly connected to the top of the cable sealing cover 18 and compresses the wear-resistant straightening sleeve 22, the oil guide channel 24 is arranged on the pressing cap 23, and the cable locking buckle 26 is arranged on the top of the pressing cap 23; the first heating cable 10 passes through the pressing cap 23, the wear-resistant straightening sleeve 22, the cable sealing cover 18, the pressure pad 20, the high-temperature sealing assembly 19 and the sealing body 17 in sequence, and is lowered into the first thermal insulation pipe column 4, and the cable locking buckle 26 clamps and fixes the end of the first heating cable 10 close to the pressing cap 23 to ensure the smooth lifting and sealing of the continuous tube electric heater.

[0045] During implementation, the wear-resistant straightening sleeve 22 and the compression cap 23 are used to straighten the first electric heater 9 when it is lowered, and lubricating oil is added through the oil guide channel 24 to effectively prevent the continuous tube electric heater from wearing eccentrically when it is lowered. After the first electric heater 9 is lowered to the designed depth, the cable sealing cover 18 is tightened by the sealing adjustment handle 21 to push the pressure pad 20 downward, thereby compressing the high-temperature sealing component 19. The high-temperature sealing component 19 is composed of a multi-stage conical sealing ring stacked together. This structure can enhance the sealing ability of multiple sealing contact surfaces and realize the wellhead sealing of the first heating cable 10. Finally, the first electric heater 9 is fixed by the cable locking buckle 26. During the steam injection process, the sealing state can be observed and judged through the steam leakage observation hole 25.

[0046] refer to Figure 1 The test blowout preventer 12 is installed at the top of the test channel 3 by threaded connection. In this embodiment, the test blowout preventer 12 adopts a blowout preventer. There is pressure during the process of steam injection into the well. The blowout preventer can control the pressure so that the test during the steam injection electric heating process can be carried out smoothly. In other embodiments, other devices for controlling pressure can also be used instead. Installing the test blowout preventer 12 above the test channel 3 is conducive to ensuring dynamic monitoring of the test instrument during the steam injection and drying process, mastering the changes in the bottom hole dryness, and adjusting the power of the coiled tube electric heater in real time, thereby establishing a scientific block heating and drying system.

[0047] refer to Figure 1 On the basis of disclosing the above-mentioned devices and components, the present application also specifically discloses a downhole steam electric heating drying and testing process for heavy oil development.

[0048] The heavy oil development downhole steam electric heating drying process specifically includes the following steps:

[0049] S10 column preparation:

[0050] An integrated steam injection-electric heating-test wellhead 1 is used in the oil layer casing well. Specifically, in the embodiment of the present application, the oil layer casing is selected as a 9-5 / 8" casing or a larger casing well. The first insulation pipe string 4 is lowered into the steam injection channel 2 at the steam injection-electric heating-test integrated wellhead 1 by the operating machine until the bottom end of the first insulation pipe string 4 reaches the upper part of the oil layer section 8 or the preset first lowering depth. Then, the test pipe string is lowered into the test channel 3 at the steam injection-electric heating-test integrated wellhead 1 until the bottom end of the test pipe string reaches the preset second lowering depth. The second lowering depth is greater than the first lowering depth. In the embodiment of the present application, the second lowering depth corresponding to the test pipe string is about 18 meters more than the first lowering depth corresponding to the first insulation pipe string 4. Figure 1 The extra length of the test string compared to the first insulation string 4 is the pipe body of the high-strength screen tube 6 .

[0051] S20 Continuous Tube Electric Heater Preparation:

[0052] The coiled tubing electric heater is lowered into the first insulated pipe string 4 until the heating section of the coiled tubing electric heater reaches the upper part of the oil layer section 8 or the third lowering depth set in advance, so that the coiled tubing electric heater 9 and the first insulated pipe string 4 together form a steam injection heating concentric pipe string, and the coiled tubing electric heater is lowered and sealed by the first sealing device 11. The third lowering depth is set based on the first lowering depth.

[0053] S30 Heavy Oil Thermal Recovery Steam Stripping Dry:

[0054] The ground boiler is used to heat and generate steam, which is injected into the first insulated pipe string 4 through the steam injection valve 16 and the steam injection channel valve 13 on the integrated steam injection-electric heating-testing wellhead 1. The power of the coiled tube electric heater is adjusted through the high-pressure ground power regulating device 3-1, so as to perform high-power electric heating, realize direct heating of the underground steam, and use the principle of conservation of energy to improve the dryness of the injected steam until the dryness is completed.

[0055] S40 electric heating drying test:

[0056] A test instrument is placed in the test string in advance, and a test blowout prevention device 12 is installed. When executing step S30, an electric heating and drying test is performed at the same time. The electric heating and drying test method specifically includes:

[0057] Start the test instrument and perform single-point or continuous testing through the test instrument to dynamically monitor relevant parameters downhole, including temperature, pressure, dryness and steam absorption profile.

[0058] Since the technical solution described in this application adopts direct contact heating in steam, and through the steam injection-heating concentric pipe column structure, the heated steam can directly enter the production oil layer to heat the heavy oil, with almost no subsequent heat loss, so efficient electric heating can be achieved. The test results show that under the conditions of 5t / h ground steam injection rate and 350kW heating power, the bottom hole dryness is increased by 12.5%; under the conditions of 7t / h ground steam injection rate and 400kW heating power, the bottom hole dryness is increased by 11%, further verifying the technical feasibility of underground high-power electric heating to improve dryness.

[0059] Through the above technical solution, it is possible to achieve a breakthrough from the traditional steam injection-heating string separated to the steam injection-heating concentric string, which solves the previous restrictions on the downhole space, casing size, and well conditions of the development wells, and can realize large-scale promotion and application in the future.

[0060] Example 2

[0061] Example 2 of the present application is a further application of the heating and drying method based on Example 1.

[0062] refer to Figure 4 After continuous verification of the technical solution described in Example 1, after gradually mastering the production rules of electric heating in the block during implementation, the conventional thermal recovery steam injection wellhead 3-4 method is adopted. By inserting a steam injection-heating concentric single pipe string into the well, it is promoted and applied in steam throughput, steam drive and SAGD, realizing underground steam electric heating to dry out, and achieving the purpose of improving the recovery rate of steam injection development.

[0063] For deep steam drive / SAGD development wells, a second electric heater 3-7 is lowered into the second insulation pipe string 3-5, the second heating cable 3-2 is sealed by the second sealing device 3-3, steam is injected into the second insulation pipe string 3-5 through the thermal recovery steam injection wellhead 3-4, and the thermosensitive packer 3-6 is used for insulation. The heating power of the downhole second electric heater 3-7 is adjusted by the high-pressure ground power regulating device 3-1, and the downhole steam is heated according to the electric heating and drying production system. The steam after heating and drying directly enters the deep oil layer section 3-8, thereby effectively improving the recovery rate of deep steam drive / SAGD development.

[0064] Example 3

[0065] Example 3 of the present application is a power grid transformation for heavy oil steam injection thermal recovery development based on Example 2.

[0066] The traditional heavy oil steam injection thermal recovery method will produce a large amount of carbon emissions. In order to achieve the national "carbon peak and carbon neutrality" goals, it is urgent to optimize and adjust the energy consumption structure, and effectively implement a series of measures such as clean energy substitution and carbon emission reduction.

[0067] refer to Figure 5 For steam drive and SAGD long-term steam injection electric heating development, the technical scheme of this application carries out power grid transformation, combines the use of grid electricity 3-9 and green electricity 3-10, and reasonably adjusts the power of the second underground electric heater 3-7 through the high-voltage ground power regulation device 3-1 according to the power supply source. In accordance with the principle of "using more green electricity 3-10 and less grid electricity 3-9", the existing green electricity 3-10 in the oil field is fully utilized. By reasonably utilizing green electricity 3-10 and grid electricity 3-9 in combination with the working system, the second electric heater 3-7 is powered by green electricity 3-10, and the consumption of green electricity 3-10 is realized, which comprehensively improves the electrification rate of heavy oil development, thereby achieving the purpose of clean energy substitution and carbon emission reduction.

[0068] The implementation principle of a downhole steam electric heating drying and testing process for heavy oil development in the present application embodiment is as follows:

[0069] The technical solution described in this application directly lowers the coiled tube electric heater into the first insulated pipe string 4, and the high-power first electric heater 9 heats the steam at the outlet of the first insulated pipe string 4 underground. The steam that has been heated and dried directly enters the formation, maximizing the efficiency of electric heating, which can greatly improve the steam dryness underground, and effectively solve the above-mentioned deep SAGD and steam drive development problems. In order to scientifically control the steam injection parameters, electric heating power parameters, and electric heating methods (intermittent heating, continuous high-dryness heating), a parallel double-tube pipe string for steam injection heating-testing is designed. During the steam injection heating process, dynamic test recording of underground steam dryness, temperature, pressure and other parameters is simultaneously achieved. The steam injection-electric heating-testing integrated wellhead 1 for the steam injection well developed in this application, as well as the matching first sealing device 11 and test blowout prevention device 12, can fully ensure that steam injection electric heating and testing are carried out simultaneously.

[0070] Through dynamic testing, we can find out the production rules of electric heating and dry pumping in the block, and then form a scientific electric heating and dry pumping production and development system for the block. After that, we can implement it according to this production system, directly put in steam injection heating concentric single pipe string, implement the technology and promote its application in SAGD and steam drive, and realize efficient development.

[0071] Ultimately, through the rational use of the working system that combines green electricity 3-10 with grid electricity 3-9, the electrification rate of heavy oil thermal recovery will be increased, and while improving the downhole dryness, electricity will be used instead of steam, reducing the energy consumption of heavy oil steam injection, completing the energy consumption structure adjustment and achieving green transformation and development.

[0072] In addition, the same technical features after "first" and "second" in this application have exactly the same meaning. The use of "first" and "second" is only for the convenience of description and understanding, and does not impose additional restrictions on the technical features after "first" and "second".

[0073] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A downhole steam electric heating drying and testing process for heavy oil development, characterized by: The downhole steam electric heating and drying process for heavy oil development specifically includes: S10 column preparation: A steam injection-electric heating-testing integrated wellhead (1) is used in an oil layer casing well, and a first heat-insulating pipe string (4) is lowered through a steam injection channel (2) at the steam injection-electric heating-testing integrated wellhead (1) until the bottom end of the first heat-insulating pipe string (4) reaches the upper part of the oil layer section (8) or a preset first lowering depth, and then a test pipe string is lowered through a test channel (3) at the steam injection-electric heating-testing integrated wellhead (1) until the bottom end of the test pipe string reaches a preset second lowering depth; S20 Continuous Tube Electric Heater Preparation: The coiled tubing electric heater is lowered into the first heat-insulated pipe string (4) until the heating section of the coiled tubing electric heater reaches the upper part of the oil layer section (8) or a preset third lowering depth, so that the coiled tubing electric heater and the first heat-insulated pipe string (4) together form a steam injection heating concentric pipe string, and the coiled tubing electric heater is connected to the steam injection-electric heating-testing integrated wellhead (1) through a first sealing device (11) for tripping and sealing; S30 Heavy Oil Thermal Recovery Steam Stripping Dry: The ground boiler is heated to generate steam, and the steam is injected into the first insulated pipe string (4) through the steam injection valve (16) on the steam injection-electric heating-testing integrated wellhead (1). The power of the coiled tube electric heater is adjusted through the high-pressure ground power regulating device (3-1), thereby performing high-power electric heating to directly heat the underground steam until the extraction is completed.

2. The heavy oil development downhole steam electric heating drying and testing process according to claim 1, characterized in that: A test instrument is lowered into the test string, and an electric heating and drying test is performed simultaneously when executing step S30. The electric heating and drying test method specifically includes: The test instrument is started to perform single-point or continuous testing through the test instrument, so as to dynamically monitor relevant parameters downhole, wherein the relevant parameters include temperature, pressure, dryness and steam absorption profile.

3. The heavy oil development downhole steam electric heating drying and testing process according to claim 2, characterized in that: A test blowout prevention device (12) is installed at the upper end of the test channel (3), and the test instrument is lowered into the test pipe string through the test blowout prevention device (12).

4. The heavy oil development downhole steam electric heating drying and testing process according to claim 1, characterized in that: The steam injection-electric heating-testing integrated wellhead (1) comprises a steam injection channel (2), a test channel (3), a hanging step (31), a casing valve (15) and a steam injection valve (16); the steam injection channel (2) is provided with a steam injection channel (2) valve, the test channel (3) is provided with a test channel (3) valve, one end of the first thermal insulation pipe string (4) passes through the steam injection channel (2) and is lowered into the well, the other end of the first thermal insulation pipe string (4) is threadedly connected to the inner wall of the steam injection channel (2), so that the first thermal insulation pipe string (4) is suspended; one end of the test pipe string passes through the test channel (3) and is lowered into the well, the other end of the test pipe string is provided with a hanger (32), the hanger (32) is overlapped on the hanging step (31), and the test pipe string is suspended under the action of gravity.

5. The heavy oil development downhole steam electric heating drying and testing process according to claim 4, characterized in that: The test pipe string comprises an integral joint oil pipe (5), a high-strength screen pipe (6) and a thread plug (7); the lower end of the integral joint oil pipe (5) passes through the test channel (3) and is lowered into the well; one end of the high-strength screen pipe (6) is fixedly connected to the lower end of the integral joint oil pipe (5), and the other end of the high-strength screen pipe (6) is fixedly provided with the thread plug (7); the upper end of the integral joint oil pipe (5) is overlapped on the suspension step (31) through the hanger (32).

6. The heavy oil development downhole steam electric heating drying and testing process according to claim 4, characterized in that: A hanging fixing screw (33) for tightening or loosening the hanger (32) is provided on the side wall of the test channel (3); the setting direction of the hanging fixing screw (33) is perpendicular to the depth direction of the well; the hanging fixing screw (33) is threadedly connected to the side wall of the test channel; the length of the hanging fixing screw (33) inserted into the interior of the test channel (3) is adjusted by rotating the hanging fixing screw (33).

7. The heavy oil development downhole steam electric heating drying and testing process according to claim 1, characterized in that: The coiled tube electric heater comprises a first electric heater (9) and a first heating cable (10), wherein the first heating cable (10) and the first electric heater (9) are equal-diameter integrated devices, wherein the first electric heater (9) is a heating section of the coiled tube electric heater, the first electric heater (9) is arranged at the lower end of the first heating cable (10), and the first electric heater (9) is electrically connected to the first heating cable (10).

8. The heavy oil development downhole steam electric heating drying and testing process according to claim 7, characterized in that: The first sealing device (11) comprises a sealing body (17), a cable sealing cover (18), a high-temperature sealing assembly (19), a pressure pad (20), a wear-resistant straightening sleeve (22), a compression cap (23) and a cable locking buckle (26); the sealing body (17) is threadedly connected to the top of the steam injection channel (2); a sealing groove is provided on the top of the sealing body (17); the high-temperature sealing assembly (19) and the pressure pad (20) are placed in the sealing groove in sequence; the cable sealing cover (18) is sleeved and threadedly connected to the sealing body (17); The top of the main body (17), the side wall of the cable sealing cover (18) is provided with a sealing adjustment handle (21) for adjusting the rotation of the cable sealing cover (18), the inner wall of the cable sealing cover (18) presses the pressure pad (20), the wear-resistant straightening sleeve (22) is arranged on the top of the cable sealing cover (18), the pressing protective cap (23) is threadedly connected to the top of the cable sealing cover (18) and presses the wear-resistant straightening sleeve (22), and the cable locking buckle (26) is arranged on the top of the pressing protective cap (23); The first heating cable (10) passes through the compression cap (23), the wear-resistant straightening sleeve (22), the cable sealing cover (18), the pressure pad (20), the high-temperature sealing assembly (19) and the sealing body (17) in sequence, and is lowered into the first thermal insulation pipe column (4), and the cable locking buckle (26) clamps and fixes one end of the first heating cable (10) close to the compression cap (23).

9. The heavy oil development downhole steam electric heating drying and testing process as claimed in claim 8, characterized in that: The high temperature sealing assembly (19) comprises a plurality of multi-stage conical sealing rings. When the cable sealing cover (18) is sleeved and threadedly connected to the top of the sealing body (17), the plurality of multi-stage conical sealing rings are stacked step by step and compressed by the pressure pad (20).

10. The heavy oil development downhole steam electric heating drying and testing process according to claim 1, characterized in that: The heavy oil development underground steam electric heating drying process method uses a working system combining grid electricity (3-9) and green electricity (3-10), and consumes green electricity (3-10) according to the principle of "using more green electricity (3-10) and less grid electricity (3-9)".

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