Steam electric heating and drying and testing technology for heavy oil development well

Abstract

The application discloses a steam electric heating and dry extraction technology for heavy oil development, and specifically comprises the following steps: S10, pipe column preparation: a first heat insulation pipe column is lowered into a steam injection channel, and a test pipe column is lowered into a test channel; S20, continuous pipe electric heater preparation: a continuous pipe electric heater is lowered into the first heat insulation pipe column, and the continuous pipe electric heater is lowered and sealed through a first sealing device; and S30, heavy oil thermal recovery steam injection and dry extraction: high-power electric heating is performed to directly heat and dry extract underground steam; and when S30 is performed, electric heating dry extraction testing is synchronously performed. The steam extracted by the heating and dry extraction can directly enter the stratum, heat loss is greatly reduced, efficient electric heating is realized, and therefore, the dryness of the underground steam is greatly improved, and the development problems of the above-mentioned medium-deep SAGD and steam drive are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steam injection for heavy oil exploitation, and in particular to a downhole steam electric heating and dryness extraction and testing process for heavy oil development. BACKGROUND

[0002] At present, there are three ways for thermal recovery of heavy oil in oilfields, namely, steam huff and puff, steam flooding and SAGD. The development of medium-deep heavy oil reservoirs (<1000m) has entered the middle and late stages. In order to ensure stable production of ten million tons, it is necessary to convert steam flooding, SAGD and other methods for deep and ultra-deep heavy oil reservoirs (1000-1700m) to realize reserve replacement. Among them, further development of oilfields through deep SAGD and steam flooding has many technical problems, making it difficult to effectively develop SAGD and steam flooding in deep blocks. On the one hand, there is a large heat loss along the way: the dryness loss of the steam injection pipeline or pipe network along the way is 5%-15%, the dryness loss of the wellbore per kilometer is as high as 20%, the comprehensive utilization rate of heat energy is less than 60%, and it is difficult to ensure that the comprehensive utilization rate of heat energy at the bottom of the deep SAGD well is greater than 70%; on the other hand, under the conventional steam injection rate, the injection-production pressure difference is larger, the steam cavity formation and expansion are more difficult, the steam heat efficiency is low, according to the super heavy oil steam flooding recovery mechanism, the difference between the super heavy oil and the steam mobility ratio is large, which is easy to cause steam channeling between injection and production wells, so low pressure difference operation is required during development, and the steam injection rate should be reduced as much as possible, but this will cause the bottom steam dryness to be unable to reach 50%; if the steam injection rate is increased to ensure the bottom steam dryness, it will cause low heat utilization rate, large displacement resistance, and difficulty in establishing an effective displacement system.

[0003] In order to solve the above problems, some documents mention the use of downhole steam secondary electric heating technology. This technology is to lower the continuous pipe electric heater into the steam wellhead, and the bottom electric heater performs secondary heating on the low dryness steam at the bottom. However, in this technology, the eccentric wellhead heating method is used, that is, the heating pipe string and the steam injection pipe string are separated. Such a heating method causes a lot of heat loss during the movement of the steam, resulting in waste of heat energy and low heat utilization rate. In order to achieve the purpose of heating, the downhole must use the eccentric wellhead to lower the combination of the steam injection pipe string and the heating pipe string or the combination of the steam injection pipe string and the electric heater, which is not concentric and the same pipe, which has high requirements for the development of downhole space, casing size and well conditions, and cannot be widely applied in the later stage. SUMMARY

[0004] In order to solve the above problems, the present application proposes a downhole steam electric heating and dryness extraction and testing process for heavy oil development, and the technical scheme is as follows:

[0005] A downhole steam electric heating and dryness extraction and testing process for heavy oil development, the downhole steam electric heating and dryness extraction process for heavy oil development specifically comprises:

[0006] S10 pipe column preparation:

[0007] In the oil layer casing well, the steam injection-electric heating-test integrated well head is used, the first heat insulation pipe column is lowered through the steam injection channel at the steam injection-electric heating-test integrated well head until the bottom end of the first heat insulation pipe column reaches the upper part of the oil layer section or the first preset lowering depth, then the test pipe column is lowered through the test channel at the steam injection-electric heating-test integrated well head until the bottom end of the test pipe column reaches the second preset lowering depth.

[0008] S20 continuous pipe electric heater preparation:

[0009] The continuous pipe electric heater is lowered into the first heat insulation pipe column until the heating section of the continuous pipe electric heater reaches the upper part of the oil layer section or the third preset lowering depth, so that the continuous pipe electric heater forms a steam injection heating concentric pipe column with the first heat insulation pipe column, and the continuous pipe electric heater is connected with the steam injection-electric heating-test integrated well head through the first sealing device for lowering and sealing.

[0010] S30 heavy oil thermal recovery steam injection and dryness extraction:

[0011] The ground boiler generates steam, and the steam is injected into the first heat insulation pipe column through the steam injection valve on the steam injection-electric heating-test integrated well head, and the power of the continuous pipe electric heater is adjusted through the high-pressure ground power adjusting device, so as to perform high-power electric heating to directly heat the downhole steam until the dryness extraction is completed.

[0012] Further, the test instrument is lowered into the test pipe column, and the electric heating dryness extraction test is performed at the same time when the step S30 is performed, and the electric heating dryness extraction test method specifically includes:

[0013] The test instrument is started, and single-point or continuous test is performed through the test instrument, so as to dynamically monitor the related parameters in the well, including temperature, pressure, dryness and steam absorption profile.

[0014] Further, the upper end of the test channel is provided with a test blowout preventer, and the test instrument is lowered into the test pipe column through the test blowout preventer.

[0015] Further, the steam injection-electric heating-test 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, the test channel is internally provided with a hanging step, one end of the first heat insulation pipe string passes through the steam injection channel and is lowered into the well, the other end of the first heat insulation pipe string is threadedly connected with the inner wall of the steam injection channel, so that the first heat insulation pipe string is hung; one end of the test pipe string passes through the test channel and is lowered into the well, 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 hung under the action of gravity.

[0016] Further, the test pipe string comprises a whole joint oil pipe, a high-strength screen pipe and a thread protector, the lower end of the whole joint 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 whole joint oil pipe, and the other end of the high-strength screen pipe is fixedly provided with the thread protector; the upper end of the whole joint oil pipe is overlapped on the hanging step through the hanger.

[0017] Further, a hanging fixing screw for abutting or loosening the hanger is provided on the side wall of the test channel, the setting direction of the hanging fixing screw is perpendicular to the depth direction of the well, the hanging fixing screw is threadedly connected with the side wall of the test channel, and the length of the hanging fixing screw penetrating into the test channel can be adjusted by rotating the hanging fixing screw.

[0018] Further, the continuous pipe 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 continuous pipe 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 with the first heating cable.

[0019] Further, the first sealing device comprises a sealing body, a cable sealing cover, a high-temperature sealing assembly, a pressure pad, a wear-resistant centralizer, a pressing cap and a cable locking buckle, the sealing body is threadedly connected at the top end 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 sequentially placed in the sealing groove, the cable sealing cover is sleeved and threadedly connected at the top of the sealing body, the side wall of the cable sealing cover is provided with a sealing adjusting handle for adjusting the rotation of the cable sealing cover, the inner wall of the cable sealing cover presses the pressure pad, the wear-resistant centralizer is arranged at the top of the cable sealing cover, the pressing cap is threadedly connected at the top of the cable sealing cover and presses the wear-resistant centralizer, and the cable locking buckle is arranged at the top of the pressing cap.

[0020] The first heating cable passes through the compression cap, the wear-resistant centralizer, the cable sealing cover, the compression pad, the high-temperature sealing assembly and the sealing body in sequence, and is lowered into the first heat-insulating pipe column, and the cable locking buckle clamps and fixes one end of the first heating cable close to the compression cap.

[0021] Further, the high-temperature sealing assembly comprises a plurality of multi-stage conical sealing rings, which are stacked step by step and compressed by the compression pad when the cable sealing cover is sleeved and threadedly connected on the top of the sealing body.

[0022] Further, the steam electric heating dryness extraction process for the heavy oil development well applies a working system combining grid electricity and green electricity, and absorbs green electricity according to the principle of "using more green electricity and less grid electricity".

[0023] The beneficial effects of the present application are as follows:

[0024] The downhole steam electric heating dryness extraction and testing process technology described in the present application directly lowers the first electric heater into the steam injection pipe column, heats the steam at the outlet of the downhole steam injection pipe column through the high-power first electric heater, and directly introduces the heated steam into the formation, greatly reducing the heat loss and realizing efficient electric heating, thereby greatly improving the downhole steam dryness and effectively solving the development problems of the above-mentioned deep SAGD and steam drive.

[0025] In order to scientifically control the steam injection parameters and the electric heating power parameters, the electric heating mode (intermittent heating, continuous high dryness heating), a parallel double pipe string for steam injection and heating is designed, and the downhole steam dryness, temperature, pressure and other parameters are tested and recorded during the steam injection and heating process. The steam injection-electric heating-testing integrated wellhead of the steam injection well developed in the present application, as well as the matched first sealing device and testing blowout preventer, can fully guarantee the simultaneous performance of steam injection and electric heating and testing. After the production rules of electric heating dryness extraction in the block are tested, the steam injection and heating concentric single pipe string can be directly lowered according to the scientific production system, and the technology can be applied to SAGD and steam drive to realize efficient development. Finally, through the reasonable use of the working system combining green electricity and grid electricity, the electric heating rate of heavy oil thermal recovery development is improved, the energy consumption structure is adjusted, and green transformation development is realized. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a steam injection and heating-testing double pipe string development process schematic diagram in the embodiment 1 of the present application.

[0027] Figure 2 It is a structure schematic diagram of the hanger in the embodiment 1 of the present application.

[0028] Figure 3Structure diagram of the sealing device in Example 1 of the present application.

[0029] Figure 4 Process diagram of the deep steam flooding / SAGD electric heating dry development process in Example 2 of the present application.

[0030] Figure 5 Process flow diagram of the heavy oil development downhole steam electric heating dry development process in Example 3 of the present application.

[0031] Legend of reference signs:

[0032] 1, steam injection-electric heating-testing integrated wellhead; 2, steam injection passage; 3, testing passage; 31, suspension step; 32, hanger; 33, hanger fixing screw; 4, first heat insulation pipe column; 5, integral joint tubing; 6, high-strength screen pipe; 7, plug; 8, oil layer section; 9, first electric heater; 10, first heating cable; 11, first sealing device; 12, testing blowout preventer; 13, steam injection passage valve; 14, testing passage valve; 15, casing valve; 16, steam injection valve; 17, sealing main body; 18, cable sealing cover; 19, high-temperature sealing assembly; 20, pressure pad; 21, sealing adjustment handle; 22, wear-resistant centralizing sleeve; 23, compression cap; 24, oil guide passage; 25, steam leakage observation hole; 26, cable locking buckle;

[0033] 3-1, high-pressure ground power adjustment device; 3-2, second heating cable; 3-3, second sealing device; 3-4, thermal recovery steam injection wellhead; 3-5, second heat insulation pipe column; 3-6, thermal sensitive packer; 3-7, second electric heater; 3-8, oil layer section; 3-9, grid electricity; 3-10, green electricity. DETAILED DESCRIPTION

[0034] The following will be described in detail below with reference to the accompanying Figures 1-5 The present application will be further described in detail.

[0035] The present application provides a steam injection heating-testing double pipe column development process, a deep steam flooding / SAGD electric heating dry development process and a complete heavy oil downhole electric heating dry development process system, which can significantly improve the development effect of traditional heavy oil steam injection thermal recovery. The process is applicable to both vertical wells and horizontal wells, and here the operation mode of vertical wells is mainly described. Example 1

[0036] The present application designs a steam injection heating-testing double pipe column development process, which can realize dynamic testing while downhole electric heating dry development.

[0037] Reference Figure 1 and Figure 2The application discloses a steam injection-electric heating-test integrated well head 1. The steam injection-electric heating-test integrated well head 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 arranged in the test channel 3, the side wall of the hanging step 31 is arranged in an inclined mode, one end of a first heat insulation pipe column 4 penetrates through the steam injection channel 2 and is lowered into a well, the other end of the first heat insulation pipe column 4 is threadedly connected with the inner wall of the steam injection channel 2, so that the first heat insulation pipe column 4 is hung, the first heat insulation pipe column 4 is packed by a packer with the steam injection channel 2, the first heat insulation pipe column 4 is used for lowering a continuous pipe electric heater, so that the downhole steam electric heating dry-up is carried out, one end of a test pipe column penetrates through the test channel 3 and is lowered into the well, the other end of the test pipe column is provided with a hanger 32, one end of the hanger 32 is provided with an inclined surface, the end of the hanger 32 provided with the inclined surface is used in cooperation with the inclined side wall of the hanging step 31, so as to be lapped on the hanging step 31, the test pipe column is hung under the action of gravity, the test pipe column is packed by a packer with the test channel, and the test pipe column can provide a channel for a wireline testing operation.

[0038] Reference Figure 1 In other embodiments, a hanging fixing screw 33 can also be arranged on the side wall of the test channel 3, the arrangement direction of the hanging fixing screw 33 is perpendicular to the depth direction of the corresponding well, and the hanging fixing screw 33 is threadedly connected with the side wall of the test channel, by rotating the hanging fixing screw 33, the length of the hanging fixing screw 33 penetrating into the test channel can be adjusted. When it is needed to further reinforce the test pipe column, the hanging fixing screw 33 is rotated, so that the length of the hanging fixing screw 33 penetrating into the test channel is increased, until the hanging fixing screw 33 abuts against the hanger 32, and the test pipe column can be effectively prevented from moving.

[0039] Reference Figure 1 The application discloses a continuous pipe electric heater, which comprises a first electric heater 9 and a first heating cable 10, and 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 continuous pipe 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 with the first heating cable 10. Wherein the electric heating outer pipe of the first heating cable 10 is selected by optimizing the material and process structure, and a material capable of resisting high temperature and corrosion is selected, the electric heating outer pipe of the material can continuously work for three years in the environment with high-temperature steam corrosion and scouring in the first heat insulation pipe column 4, and is used in cooperation with the steam injection-electric heating-test integrated well head 1, so that the limitation of the downhole electric heating process of the traditional technology is greatly reduced, and the downhole electric heating process of the steam injection well is broken through.

[0040] Reference Figure 1The application discloses a test pipe column which comprises a whole joint oil pipe 5, a high-strength screen pipe 6 and a thread plug 7, the lower end of the whole joint oil pipe 5 passes through a test channel 3 and is lowered into a well, one end of the high-strength screen pipe 6 is fixedly connected to the lower end of the whole 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 whole joint oil pipe 5 is sleeved with a hanger 32 which is lapped on a hanger step 31 to complete hanger setting.

[0041] For the electric heating dryness test, the length of a test instrument is about 1.5 meters, and the outer diameter is 38 millimeters; a traditional test mode is that the test instrument is lowered into the test pipe column to contact with downhole steam for test, and then the test instrument is recovered by being pulled up, so that the test instrument is difficult to be pulled up and recovered due to the limitation of the inner diameter of the test pipe column, and accidents such as falling and well sticking of the test instrument are easily caused, thereby leading to interruption of the test.

[0042] In the application, the test pipe column is formed by combination of the thread plug 7, the high-strength screen pipe 6 and the whole joint oil pipe 5, the whole joint oil pipe 5 can reduce the limitation of the maximum overall outer diameter of the test pipe column, and the smooth running of the whole test pipe column is guaranteed; the high-strength screen pipe 6 is determined according to the test requirement, the depth and the length of use, a plurality of air holes on the high-strength screen pipe 6 can guarantee the flow of steam after heating, so that the test instrument can be fully contacted with the steam, and then the parameters such as dryness, temperature and pressure can be recorded. The high-strength screen pipe 6 and the whole joint oil pipe 5 can provide a test passage for the test instrument, so that the above test instrument can reach the outlet position of the steam heated by the continuous pipe electric heater, the test instrument is tested in the above test pipe column, the test success rate can be greatly improved under the premise of guaranteeing the test effect, and the thread plug 7 is arranged at the bottom of the combined pipe column, even if the test instrument falls, the test can still be carried out normally.

[0043] The application discloses a first sealing device 11 and a test blowout preventer 12 which are used in combination with the steam injection-electric heating-test integrated wellhead 1.

[0044] Reference Figure 1 and Figure 3, the first sealing device 11 comprises a sealing body 17, a cable sealing cover 18, a high-temperature sealing assembly 19, a pressing pad 20, a sealing adjustment handle 21, a wear-resistant centralizer 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 at the top end of the steam injection channel 2 through threaded connection. A sealing groove is arranged at the top of the sealing body 17. The high-temperature sealing assembly 19 and the pressing pad 20 are sequentially arranged in the sealing groove. The high-temperature sealing assembly 19 comprises a plurality of multi-stage conical sealing rings which are stacked in stages. The cable sealing cover 18 is sleeved and threadedly connected at the top of the sealing body 17. The sealing adjustment handle 21 is arranged on the sidewall of the cable sealing cover 18 and used for adjusting the rotation of the cable sealing cover 18. The inner wall of the cable sealing cover 18 presses the pressing pad 20, and further presses the multi-stage conical sealing rings stacked together. The wear-resistant centralizer 22 is arranged at the top of the cable sealing cover 18. The pressing cap 23 is threadedly connected at the top of the cable sealing cover 18 and presses the wear-resistant centralizer 22. The oil guide channel 24 is arranged on the pressing cap 23. The cable locking buckle 26 is arranged at the top of the pressing cap 23. The first heating cable 10 sequentially passes through the pressing cap 23, the wear-resistant centralizer 22, the cable sealing cover 18, the pressing pad 20, the high-temperature sealing assembly 19 and the sealing body 17, and is lowered into the first heat-insulating string 4. The cable locking buckle 26 clamps and fixes the end of the first heating cable 10 close to the pressing cap 23, so as to ensure the smooth running and sealing of the continuous tube electric heater.

[0045] In the implementation, the wear-resistant centralizer 22 and the pressing cap 23 are used for centralizing the first electric heater 9 during running and pulling. The lubricating oil is added through the oil guide channel 24, so as to effectively prevent the continuous tube electric heater from being eccentrically worn. After the first electric heater 9 is lowered to the designed depth, the cable sealing cover 18 is screwed through the sealing adjustment handle 21, the pressing pad 20 is pushed to move downward, so as to press the high-temperature sealing assembly 19. The high-temperature sealing assembly 19 is composed of multi-stage conical sealing rings. This structure can strengthen the sealing capacity of multiple sealing contact surfaces, realize the wellhead sealing of the first heating cable 10, and finally complete the fixation of the first electric heater 9 through 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] Reference Figure 1 The test blowout preventer 12 is installed at the top end of the test channel 3 in a threaded connection mode. In this embodiment, the test blowout preventer 12 is a blowout preventer pipe. During the steam injection process, the pressure is controlled, so that the test is smoothly conducted during the steam injection and electric heating process. In other embodiments, other pressure control devices can also be used instead. The test blowout preventer 12 is installed above the test channel 3, which is beneficial to ensure that the testing instrument dynamically monitors during the steam injection and dryness extraction process, masters the change of the bottom hole dryness, adjusts the power of the continuous tube electric heater in real time, and further establishes a scientific block heating and dryness extraction system.

[0047] refer to Figure 1 In addition to disclosing the aforementioned device and components, this application also specifically discloses a downhole steam electric heating drying and testing process for heavy oil development.

[0048] The specific steps of the downhole steam electric heating and dehydration process for heavy oil development include:

[0049] S10 tubing preparation:

[0050] In the cased well of the oil layer, an integrated steam injection-electric heating-testing wellhead 1 is used. Specifically, in this embodiment, the oil layer casing is selected as 9-5 / 8" casing or larger. A first insulated tubing string 4 is lowered into the steam injection channel 2 at the integrated steam injection-electric heating-testing wellhead 1 using a workover rig until the bottom of the first insulated tubing string 4 reaches the upper part of the oil layer section 8 or a pre-set first lowering depth. Then, a test tubing string is lowered into the test channel 3 at the integrated steam injection-electric heating-testing wellhead 1 until the bottom of the test tubing string reaches a pre-set second lowering depth. The second lowering depth is greater than the first lowering depth. In this embodiment, the second lowering depth corresponding to the test tubing string is approximately 18 meters greater than the first lowering depth corresponding to the first insulated tubing string 4. Figure 1 The portion of the test tube column that is longer than the first insulation tube column 4 is the tube body of the high-strength screen tube 6.

[0051] Preparation of S20 continuous tube electric heater:

[0052] The coiled tube electric heater is lowered into the first insulated tube string 4 until the heating section of the coiled tube electric heater reaches the upper part of the oil layer section 8 or the pre-set third lowering depth, so that the coiled tube electric heater 9 and the first insulated tube string 4 together form a concentric tube string for steam injection heating. The coiled tube 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 injection drying:

[0054] Steam is generated by heating the surface boiler. The steam is injected into the first insulated tubing string 4 through the steam injection valve 16 and steam injection channel valve 13 on the integrated steam injection-electric heating-test wellhead 1. The power of the continuous tube electric heater is adjusted by the high-pressure surface power adjustment device 3-1 to achieve high-power electric heating and direct heating of the steam in the well. The dryness of the injected steam is increased by utilizing the principle of energy conservation until the dryness is achieved.

[0055] S40 electric heating drying test:

[0056] The tester is lowered into the test string in advance, and the test blowout preventer 12 is installed, and the electric heating dryness test is performed at the same time when the step S30 is performed, and the electric heating dryness test method specifically comprises the following steps:

[0057] The tester is started, and single-point or continuous testing is performed through the tester, so that the related parameters in the well are dynamically monitored, and the related parameters include temperature, pressure, dryness, and steam absorption profile.

[0058] In the technical solution described in the present application, direct contact heating in steam is adopted, and a steam injection-heating concentric string structure is adopted, the heated steam can directly enter the production oil layer to heat the heavy oil, and there is almost no subsequent heat loss, so that efficient electric heating can be realized. The test results show that under the conditions of 5 t / h ground steam injection speed and heating power of 350 kW, the bottom hole dryness is increased by 12.5%; under the conditions of 7 t / h ground steam injection speed and heating power of 400 kW, the bottom hole dryness is increased by 11%, which further verifies the technical feasibility of the downhole high-power electric heating dryness.

[0059] Through the above technical solution, the traditional steam injection-heating string separation type is broken through to the steam injection-heating concentric string, and the previous limitation of high requirements for downhole space, casing size and well condition of the development well is solved, and large-scale application in the later period can be realized. Example 2

[0060] Example 2 of the present application is further applied to the heating dryness method on the basis of example 1.

[0061] Reference Figure 4 After continuous verification of the technical solution described in example 1, and after gradually mastering the block electric heating production law in the implementation, the conventional thermal recovery steam injection wellhead 3-4 method is adopted, the steam injection-heating concentric single string is lowered into the downhole, the steam stimulation, steam flooding and SAGD are popularized and applied, the downhole steam electric heating dryness is realized, and the purpose of improving the steam injection development recovery efficiency is achieved.

[0062] For deep steam flooding / SAGD development wells, the second electric heater 3-7 is lowered into the second heat insulation string 3-5, the second heating cable 3-2 is sealed through the second sealing device 3-3, steam is injected into the second heat insulation string 3-5 through the thermal recovery steam injection wellhead 3-4, the heat-sensitive packer 3-6 is heat-insulated, the heating power of the second electric heater 3-7 in the downhole is adjusted through the high-pressure ground power regulating device 3-1, the downhole steam is heated according to the electric heating dryness production system, and the heated steam directly enters the deep oil layer section 3-8, so as to effectively improve the recovery efficiency of deep steam flooding / SAGD development. Example 3

[0063] The embodiment 3 of the present application is the power grid reconstruction for the steam injection thermal recovery development of heavy oil.

[0064] The traditional steam injection thermal recovery development method of heavy oil produces a large amount of carbon emissions, and it is urgent to carry out energy consumption structure optimization and adjustment, and effectively carry out a series of measures such as clean energy replacement and carbon emission reduction.

[0065] Reference Figure 5 For long-term steam injection and SAGD electric heating development, the technical scheme of the present application carries out power grid reconstruction, uses grid electricity 3-9 and green electricity 3-10 in combination, reasonably adjusts the power of the second electric heater 3-7 in the well according to the power supply source through the high-voltage ground power regulating device 3-1, and according to the principle of “using more green electricity 3-10 and less grid electricity 3-9”, fully utilizes the existing green electricity 3-10 in the oilfield, supplies power for the second electric heater 3-7 through the reasonable use of the working system of green electricity 3-10 and grid electricity 3-9 in combination, realizes the consumption of green electricity 3-10, comprehensively improves the electrification rate of heavy oil development, and thus achieves the purpose of clean energy replacement and carbon emission reduction.

[0066] The implementation principle of the embodiment of the present application for the downhole steam electric heating and dryness extraction and testing process of heavy oil development is:

[0067] The technical scheme of the present application directly lowers the continuous tube electric heater into the first heat insulation pipe column 4, the first electric heater 9 with high power heats the steam at the outlet of the first heat insulation pipe column 4 in the well, the steam extracted by heating directly enters the formation, the electric heating efficiency is maximized, the downhole steam dryness can be greatly improved, and the development problems of the above-mentioned deep SAGD and steam drive are effectively solved. In order to scientifically control the steam injection parameters and the electric heating power parameters and the electric heating mode (intermittent heating, continuous high dryness heating), a parallel double pipe column for steam injection heating and testing is designed, and the dynamic testing and recording of the downhole steam dryness, temperature, pressure and other parameters are realized at the same time during the steam injection heating process. The steam injection-electric heating-testing integrated wellhead 1 developed in the present application and the matching first sealing device 11 and testing blowout preventers 12 can fully guarantee the simultaneous steam injection electric heating and testing.

[0068] Through the dynamic testing, the production law of the electric heating dryness extraction in the block is found out, and then the scientific electric heating dryness extraction production development system of the block is formed. After that, the production system is executed, the steam injection heating concentric single pipe column is directly lowered, the implementation technology is applied to the SAGD and steam drive, and efficient development is realized.

[0069] Finally, by reasonably using the working system of the combination of green electricity 3-10 and grid electricity 3-9, the electrification rate of heavy oil thermal recovery development is improved, the downhole dryness is improved at the same time, the steam is replaced by electricity, the energy consumption of heavy oil steam injection is reduced, the energy consumption structure adjustment is completed, and the green transformation development is realized.

[0070] In addition, the same technical features represented after "first" and "second" in the present application have the same meaning, and "first" and "second" are used only for convenient description and understanding, and do not additionally limit the technical features after "first" and "second".

[0071] The above are preferred embodiments of the present application, and do not limit the protection scope of the present application, so: any equivalent changes made on the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A downhole steam electric heating and testing process for heavy oil development, characterized in that it comprises: S10 pipe column preparation: using a steam injection-electric heating-testing integrated wellhead (1) in a cased hole, a first heat-insulating pipe column (4) is lowered through a steam injection passage (2) of the steam injection-electric heating-testing integrated wellhead (1) until the bottom end of the first heat-insulating pipe column (4) reaches the upper part of an oil layer section (8) or a first preset depth of insertion, and then a testing pipe column is lowered through a testing passage (3) of the steam injection-electric heating-testing integrated wellhead (1) until the bottom end of the testing pipe column reaches a second preset depth of insertion; S20 continuous pipe electric heater preparation: a continuous pipe electric heater is lowered into the first heat-insulating pipe column (4) until the heating section of the continuous pipe electric heater reaches the upper part of the oil layer section (8) or a third preset depth of insertion, so that the continuous pipe electric heater forms a steam injection and heating concentric pipe column together with the first heat-insulating pipe column (4), and the continuous pipe electric heater is connected to the steam injection-electric heating-testing integrated wellhead (1) through a first sealing device (11) for lifting and sealing; S30 heavy oil thermal recovery steam injection and drying: steam is generated by a ground boiler and injected into the first heat-insulating pipe column (4) through a steam injection valve (16) on the steam injection-electric heating-testing integrated wellhead (1), and the power of the continuous pipe electric heater is adjusted through a high-pressure ground power adjusting device (3-1) to perform high-power electric heating and directly heat the downhole steam until the drying is completed; the continuous pipe electric heater comprises a first electric heater (9) and a first heating cable (10), and 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 continuous pipe 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 with the first heating cable (10).

2. The downhole steam electric heating and testing process for heavy oil development according to claim 1, characterized in that the first heat-insulating pipe column (4) comprises a first heat-insulating pipe (5) and a first heat-insulating sleeve (6), the first heat-insulating pipe (5) is arranged in the first heat-insulating sleeve (6), the first heat-insulating pipe (5) is connected with the first heat-insulating sleeve (6) through a first sealing device (7), and the first heat-insulating pipe (5) is connected with the first heat-insulating sleeve (6) through a second sealing device (12).

3. The downhole steam electric heating and testing process for heavy oil development according to claim 1, characterized in that the testing pipe column comprises a testing pipe (13) and a testing sleeve (14), the testing pipe (13) is arranged in the testing sleeve (14), the testing pipe (13) is connected with the testing sleeve (14) through a third sealing device (15), and the testing pipe (13) is connected with the testing sleeve (14) through a fourth sealing device (17).

4. The downhole steam electric heating and testing process for heavy oil development according to claim 1, characterized in that the first electric heater (9) is a heating section of the continuous pipe electric heater, the first electric heater (9) is arranged at the lower end of the first heating cable (10), the first electric heater (9) is electrically connected with the first heating cable (10), and the first electric heater (9) is connected with the first heating cable (10) through a fifth sealing device (18). ​ ​ ​ ​ ​ 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 centralizer (22), a compression cap (23) and a cable locking buckle (26), the sealing body (17) is threadedly connected at the top end of the steam injection channel (2), the top of the sealing body (17) is provided with a sealing groove, the high-temperature sealing assembly (19) and the pressure pad (20) are sequentially placed in the sealing groove, the cable sealing cover (18) is sleeved and threadedly connected at the top of the sealing body (17), the side wall of the cable sealing cover (18) is provided with a sealing adjusting handle (21) for adjusting the rotation of the cable sealing cover (18), the inner wall of the cable sealing cover (18) compresses the pressure pad (20), the wear-resistant centralizer (22) is arranged at the top of the cable sealing cover (18), the compression cap (23) is threadedly connected at the top of the cable sealing cover (18) and compresses the wear-resistant centralizer (22), and the cable locking buckle (26) is arranged at the top of the compression cap (23). The first heating cable (10) sequentially passes through the compression cap (23), the wear-resistant centralizer (22), the cable sealing cover (18), the pressure pad (20), the high-temperature sealing assembly (19) and the sealing body (17), and is lowered into the first heat-insulated string (4), and the cable locking buckle (26) clamps and fixes one end of the first heating cable (10) close to the compression cap (23).

2. The heavy oil production downhole steam electric heating and dryout and testing process of claim 1 wherein: The test instrument is lowered into the test string, and the electric heating drying test is simultaneously performed when the step S30 is executed, and the electric heating drying test method specifically comprises the following steps: The test instrument is started, and single-point or continuous testing is performed through the test instrument, so that the related parameters in the well are dynamically monitored, and the related parameters include temperature, pressure, dryness and steam absorption profile.

3. The heavy oil production downhole steam electric heating and dryout and testing process of claim 2 wherein: The upper end of the test channel (3) is provided with a test blowout preventer (12), and the test instrument is lowered into the test string through the test blowout preventer (12).

4. The heavy oil production downhole steam electric heating lift and test process of claim 1 wherein: The steam injection-electric heating-test integrated wellhead (1) comprises a steam injection channel (2), a test channel (3), a suspension 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 heat-insulated string (4) passes through the steam injection channel (2) and is lowered into the well, and the other end of the first heat-insulated string (4) is threadedly connected with the inner wall of the steam injection channel (2), so that the first heat-insulated string (4) is suspended; one end of the test string penetrates into the test channel (3) and is lowered into the well, the other end of the test string is provided with a hanger (32), the hanger (32) is overlapped on the suspension step (31), and the test string is suspended under the action of gravity.

5. The heavy oil production downhole steam electric heating and dryout and testing process of claim 4 wherein: The test pipe column comprises a whole joint oil pipe (5), a high-strength screen pipe (6) and a plug (7), the lower end of the whole joint oil pipe (5) passes through the test channel (3) and is lowered downhole, one end of the high-strength screen pipe (6) is fixedly connected to the lower end of the whole joint oil pipe (5), and the other end of the high-strength screen pipe (6) is fixedly provided with the plug (7); the upper end of the whole joint oil pipe (5) is lapped on the suspension step (31) through the hanger (32).

6. The heavy oil production downhole steam electric heating and dryout and testing process of claim 4 wherein: A suspension fixing screw (33) for abutting or loosening the hanger (32) is provided on the side wall of the test channel (3), the setting direction of the suspension fixing screw (33) is perpendicular to the depth direction of the well, the suspension fixing screw (33) is threadedly connected with the side wall of the test channel, and the length of the suspension fixing screw (33) penetrating into the inside of the test channel (3) is adjusted by rotating the suspension fixing screw (33).

7. The heavy oil production downhole steam electric heating lift and test process of claim 1 wherein: 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 on the top of the sealing main body (17), the plurality of multi-stage conical sealing rings are stacked and compressed by the compression pad (20) in stages.

8. The heavy oil production downhole steam electric heating lift and test process of claim 1 wherein: The steam electric heating dry extraction process method for thickened oil development downhole applies a working system combining grid electricity (3-9) and green electricity (3-10), and absorbs 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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