Thickened oil vertical well and horizontal well electric heating communication method and tubular column structure

Abstract

The invention relates to the technical field of oil exploitation, in particular to an electric heating communication method for a heavy oil vertical well and a horizontal well and a tubular column structure, and the electric heating communication method comprises the following steps: step 1, drilling an infilled horizontal well in the middle of a vertical well row in a heavy oil old area; the vertical well heating assembly and the horizontal well heating assembly are arranged in the vertical well and the infilled horizontal well respectively, the vertical well oil layer section and the horizontal section of the infilled horizontal well are heated respectively, steam is replaced for heating the oil layer, and the communicating speed of the vertical well and the infilled horizontal well is increased through periodic heating and crude oil extraction; uniform communication of the vertical well and the infilled horizontal well is achieved, efficient utilization of the vertical well oil layer section and the horizontal section of the infilled horizontal well is achieved, and the recovery efficiency is improved. By means of the method, the problems that after development of conversion from the old thickened oil area to VHSD (vertical well and horizontal well combined steam drive), a steam channeling channel develops, effective communication cannot be established between the vertical well and the infilled horizontal well, the oil layer production is poor, the yield is low, and the oil-steam ratio is low can be solved, and the recovery efficiency of the old thickened oil area can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum extraction, and relates to an electric heating connection method for a thick oil vertical well and a horizontal well, and a pipe string structure. Background Art

[0002] Steam injection for thermal recovery is widely used in heavy oil reservoirs both domestically and internationally. However, due to steam overburden and reservoir heterogeneity, vertical wells typically only utilize the upper reservoir, leaving the middle and lower reservoirs largely unused for extended periods. In horizontal wells, steam channeling occurs along areas with good physical properties, leading to severely uneven production over long horizontal sections. The resulting steam sweep volume is small, making it difficult to utilize the large amount of remaining oil in the reservoir. This ultimately results in low production, a low oil-to-gas ratio, high water cuts, and low recovery factors. Steam huff-and-puff recovery factors are approximately 20%, while steam flooding recovery factors are around 40%. In recent years, development in older heavy oil fields has shifted to VHSD (combined vertical and horizontal well steam flooding). This involves drilling new horizontal wells between existing vertical well rows to infill the existing rows. This combined steam flooding strategy utilizes both existing and horizontal wells, with continuous steam injection in the older wells and continuous production in the horizontal wells, further improving recovery factors in these older heavy oil fields. Because the newly drilled horizontal well is located in a reservoir that has been subjected to continuous steam stimulation for many years, extremely developed steam channeling channels have formed in the reservoir. After steam is injected into the old well (vertical well), the steam cannot directly act on the horizontal well, but flows along the original steam channeling channels. No connecting channel can be established between the old well (vertical well) and the horizontal well, resulting in extremely low production of the horizontal well and failure to achieve the purpose of improving the recovery rate. Summary of the Invention

[0003] The present invention provides a method and a tubing structure for electrically heating and connecting heavy oil vertical wells and horizontal wells, which overcomes the shortcomings of the above-mentioned existing technologies and can effectively solve the problem of extremely low production of the infilled horizontal wells due to the inability to establish a connecting channel between the old wells and the infilled horizontal wells after the existing heavy oil old areas are converted to VHSD (combined steam drive of vertical wells and infilled horizontal wells).

[0004] One of the technical solutions of the present invention is achieved by the following measures: a method for electrically heating and connecting a vertical well and a horizontal well of heavy oil, comprising the following steps: Step 1: Drill infill horizontal wells in the middle of the vertical well row in the old heavy oil area; Step 2: Run a vertical well heating assembly and a horizontal well heating assembly into the vertical well and the infilled horizontal well respectively; Step 3: injecting solvent into the vertical well and the infilled horizontal well simultaneously until the wellbore is full; Step 4: Continuously heat the vertical wells and infilled horizontal wells to control the downhole temperature within the set range; Step 5: Stop heating the vertical wells and infilled horizontal wells, and start pumping to extract crude oil and water from the wellbore simultaneously; Step 6: Repeat steps 3 to 5 and determine whether the vertical well is connected to the infill horizontal well. If so, proceed to step 7. Step seven: heat the vertical wells and continuously inject solvent, while heating the infilled horizontal wells and continuously pumping out oil.

[0005] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: In the above step 1, the infill horizontal well is located in the center of two rows of vertical wells in the old heavy oil area. The distance between the vertical well and the infill horizontal well is 10 to 35 meters. The vertical well oil layer is completed by perforation. The number of casing perforations in the upper section of the oil layer is less than the number of casing perforations in the lower section of the oil layer. The horizontal section of the infill horizontal well is drilled along the bottom of the oil layer, 1 to 2 meters away from the bottom of the oil layer.

[0006] The above-mentioned infill horizontal wells are single-branch horizontal wells or multi-branch horizontal wells. The branches are drilled laterally and upward along the main wellbore of the horizontal section. The length of the branch section is 50 to 100 meters. The angle between the branch and the main wellbore is 0 to 90 degrees. The distance between the branch and the top boundary of the oil layer is greater than 1 meter. The branch wellbore is completed or not.

[0007] The horizontal section of the above-mentioned infill horizontal wells was completed with screen pipes, and the number of screen pipe slits in the physical interlayers with permeability lower than 100mD and the mudstone distribution section was increased to 1.5 times.

[0008] As a preferred embodiment, in the above step 2, a second long oil pipe and a second production oil pipe arranged in parallel are lowered into the dense horizontal well, the second long oil pipe is lowered to 5 to 10 meters from the end of the horizontal section, the lower end of the second production oil pipe is connected to a second oil pump and lowered to an inclined well section with a well inclination angle of 40 to 60 degrees, the horizontal well heating assembly includes a second temperature measuring cable and a second heating cable, the second temperature measuring cable and the second heating cable are both installed in the second long oil pipe, and are lowered from the second long oil pipe to 5 to 10 meters from the tail end of the second long oil pipe.

[0009] As another preferred embodiment, the above-mentioned first heating cable is lowered from the first long oil pipe to the bottom of the oil layer, the first temperature measuring cable is installed on the outside of the first long oil pipe, and the lower end of the first temperature measuring cable is located 10 meters below the bottom of the oil layer.

[0010] As a preferred embodiment, in the above step 2, a second long oil pipe and a second production oil pipe arranged in parallel are lowered into the dense horizontal well, the second long oil pipe is lowered to 5 to 10 meters from the end of the horizontal section, the second production oil pipe is connected to the second oil pump and lowered to the inclined well section with a well inclination angle of 40 to 60 degrees, the horizontal well heating assembly includes a second temperature measuring cable and a second heating cable, the second temperature measuring cable and the second heating cable are both installed in the second long oil pipe, and are lowered from the second long oil pipe to 5 to 10 meters from the tail end of the second long oil pipe.

[0011] As another preferred embodiment, in the above-mentioned step 2, a third long oil pipe and a third production oil pipe arranged in parallel are lowered into the intensified horizontal well, and both the third long oil pipe and the third production oil pipe are lowered to 5 to 10 meters from the end of the horizontal section. A third oil pump is installed on the upper part of the third production oil pipe, and the third oil pump is located in the inclined well section with a well inclination angle of 40 to 60 degrees. The horizontal well heating assembly includes a third temperature measuring cable and a third heating cable. The third heating cable is installed in the third long oil pipe and lowered from the third long oil pipe to 5 to 10 meters from the tail end of the third long oil pipe. The upper part of the third temperature measuring cable is fixed on the outside of the third production oil pipe, and the lower end of the third temperature measuring cable penetrates through the hole on the third production oil pipe below the third oil pump and extends to 5 to 10 meters from the end of the horizontal section.

[0012] The solvent in the above step 3 is at least one of clean water, liquefied petroleum gas, C3-C8 light hydrocarbons, and a slug of clean water and a viscosity reducer. If the solvent is a slug of clean water and a viscosity reducer, the viscosity reducer is injected first, and then the clean water is injected.

[0013] In step 4 above, the wellbore temperature is controlled between 100 and 350°C; In the above step 5, the pumping production time is gradually extended from the first round. If the oil content in the return fluid in the wellbore during the pumping production round is less than 5%, the next round is entered; The above step seven is: continuously injecting solvent into the vertical well to heat the vertical well so that the temperature of the oil layer is 150 to 250°C, and at the same time heating the infilled horizontal well to make the oil layer temperature 120 to 170°C, and continuously pumping out oil.

[0014] Step 6 is to check whether the vertical well is connected to the infilled horizontal well. If so, the connectivity between the infilled horizontal well and the surrounding vertical wells is tested in sequence. When the infilled horizontal well is connected to the surrounding vertical wells for more than 4 times, the process proceeds to step 7. If not, repeat steps 3 to 5. The method for detecting the connectivity between a vertical well and an infilled horizontal well includes the following steps: When normal-temperature deoiled water is continuously injected from the vertical wells to heat the remaining vertical wells and infill the horizontal wells for production, if the temperature of the horizontal section of the infilled horizontal well continues to drop by more than 10°C or the wellhead pressure of the infilled horizontal well increases by more than 0.2 MPa, the vertical well and the infilled horizontal well are connected; When the wellbore temperature of the vertical well is between 95 and 105°C, room-temperature deoiled water is continuously injected from the infilled horizontal well. If the temperature in the vertical well continues to drop by more than 10°C or the wellhead pressure of the vertical well increases by more than 0.2 MPa, the vertical well is connected to the infilled horizontal well.

[0015] The second technical solution of the present invention is achieved by the following measures: a thick oil vertical well and horizontal well electric heating connecting pipe string structure, including a vertical well heating assembly arranged in the vertical well and a horizontal well heating assembly arranged in the dense horizontal well, a first production oil pipe and a first long oil pipe are arranged in parallel in the vertical well, a first oil pump is installed at the lower end of the first production oil pipe, the vertical well heating assembly includes a first temperature measuring cable and a first heating cable, the first heating cable is installed in the first long oil pipe, the first temperature measuring cable is installed outside the first long oil pipe, or the first temperature measuring cable and the heating cable are both installed in the first long oil pipe; The horizontal well heating assembly includes a second temperature measuring cable and a second heating cable. A second long oil pipe and a second production oil pipe are arranged in parallel in the infilled horizontal well. A second oil pump is installed at the lower end of the second production oil pipe. The second temperature measuring cable and the second heating cable are both installed in the second long oil pipe. Alternatively, the horizontal well heating assembly includes a third temperature measuring cable and a third heating cable, a third long oil pipe and a third production oil pipe are arranged in parallel in the dense horizontal well, a third oil pump is installed on the upper part of the third production oil pipe, the third heating cable is installed in the third long oil pipe, the upper part of the third temperature measuring cable is fixed to the outside of the third production oil pipe, and the lower end of the third temperature measuring cable is inserted through the hole on the third production oil pipe below the third oil pump and installed on the inner side of the lower part of the third production oil pipe.

[0016] The following is a further optimization and / or improvement of the second technical solution of the above invention: The first heating cable, the second heating cable and the third heating cable are all resistive heating structures, and the maximum heating temperatures of the first heating cable, the second heating cable and the third heating cable are all less than 380°C.

[0017] This invention involves inserting vertical well heating assemblies and horizontal well heating assemblies into vertical wells and infilled horizontal wells, respectively, to heat the oil reservoir section of the vertical well and the horizontal section of the infilled horizontal well, replacing steam heating of the oil reservoir. Cyclic heating and crude oil production accelerates the connection between the vertical well and the infilled horizontal well, achieving uniform connectivity between the vertical well and the infilled horizontal well, efficient utilization of the oil reservoir section and the horizontal section of the infilled horizontal well, and improving oil recovery. This invention addresses the issues of developing steam channeling channels, lack of effective connectivity between the vertical well and the infilled horizontal well, poor oil reservoir utilization, low production, and low oil-to-gas ratio after transitioning to VHSD (combined vertical and horizontal well steam flooding) in old heavy oil fields, and can improve oil recovery in old heavy oil fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attachment Figure 1 This is a schematic diagram of the well pattern structure between vertical wells and infill horizontal wells in the present invention.

[0019] Attachment Figure 2 It is a schematic diagram of the vertical structure of the oil reservoir between the old wells and the infilled horizontal wells in the present invention.

[0020] Attachment Figure 3 The structure of the vertical well heating assembly in the present invention is shown as follows Figure 1 .

[0021] Attachment Figure 4 The structure of the vertical well heating assembly in the present invention is shown as follows Figure 2 .

[0022] Attachment Figure 5 The structure of the horizontal well heating assembly in the present invention is shown as follows Figure 1 .

[0023] Attachment Figure 6 The structure of the horizontal well heating assembly in the present invention is shown as follows Figure 2 .

[0024] The codes in the accompanying drawings are: 1 for a vertical well, 2 for an infilled horizontal well, 3 for the first production tubing, 4 for the first long tubing, 5 for the first oil well pump, 6 for the first temperature measuring cable, 7 for the first heating cable, 8 for the second production tubing, 9 for the second long tubing, 10 for the second oil well pump, 11 for the second temperature measuring cable, 12 for the second heating cable, 13 for the third production tubing, 14 for the third long tubing, 15 for the third oil well pump, 16 for the third temperature measuring cable, 17 for the third heating cable, 18 for the first clamp, 19 for the second clamp, 20 for the perforation section, 21 for the screen pipe, and 22 for the heating belt. DETAILED DESCRIPTION

[0025] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions.

[0026] In the present invention, for the convenience of description, the relative position relationship of each component is described based on the Figure 1 For example, the positional relationships of front, back, up, down, left, and right are determined according to the layout directions of the drawings in the specification.

[0027] The present invention will be further described below in conjunction with the embodiments and accompanying drawings: Example 1: As shown in the attached Figures 1 to 6 As shown, the method for electrically heating and connecting a heavy oil vertical well and a horizontal well comprises the following steps: Step 1: Drill infill horizontal well 2 in the middle of vertical well row 1 in the old heavy oil area; Step 2: Run the vertical well heating assembly and the horizontal well heating assembly into the vertical well 1 and the infilled horizontal well 2 respectively; Step 3: inject solvent into the vertical well 1 and the infilled horizontal well 2 simultaneously until the wellbores are full; Step 4: Continuously heat the vertical well 1 and the infilled horizontal well 2 to control the downhole temperature within the set range; Step 5: Stop heating the vertical well 1 and the infilled horizontal well 2, and start pumping to extract the crude oil and water from the wellbore simultaneously; Step 6: Repeat steps 3 to 5 and determine whether vertical well 1 is connected to infill horizontal well 2. If so, proceed to step 7. Step seven: heat the vertical well 1 and continuously inject solvent, while heating the infilled horizontal well 2 and continuously pumping oil for production.

[0028] Targeting the combined development of vertical and horizontal wells in legacy heavy oil production areas, the present invention employs a vertical well heating assembly and a horizontal well heating assembly, respectively, in vertical well 1 and infilled horizontal well 2. This heating assembly heats the oil reservoir section of vertical well 1 and the horizontal section of infilled horizontal well 2, replacing steam heating of the oil reservoir. Cyclic heating and crude oil production accelerates the connection between vertical well 1 and infilled horizontal well 2, achieving uniform connection between vertical well 1 and infilled horizontal well 2, efficient production of the oil reservoir section of vertical well 1 and the horizontal section of infilled horizontal well 2, and improving oil recovery. The electrical heating connection method for heavy oil vertical and horizontal wells provided by the present invention addresses the issues of developing steam channeling channels, the inability to establish effective connection between vertical well 1 and infilled horizontal well 2, poor oil reservoir production, low production, and a low oil-to-gas ratio after transitioning to VHSD (combined vertical and horizontal well steam flooding) in legacy heavy oil production areas, and can improve oil recovery in legacy heavy oil production areas.

[0029] The above-mentioned method of connecting vertical and horizontal heavy oil wells with electrical heating can be further optimized and / or improved according to actual needs: Example 2: As an optimization of the above example, as shown in the attached Figure 1 、 2 As shown, in step 1, the infill horizontal well 2 is located in the center of two rows of vertical wells 1 in the old heavy oil area. The distance between the vertical well 1 and the infill horizontal well 2 is 10 to 35 meters. The vertical well 1 is completed by perforation in the oil layer. The number of casing perforations in the upper section of the oil layer is less than the number of casing perforations in the lower section of the oil layer. The horizontal section of the infill horizontal well 2 is drilled along the bottom of the oil layer, 1 to 2 meters away from the bottom of the oil layer.

[0030] In this embodiment, the vertical wells 1 are multiple wells with an inter-well distance of 70 meters. The oil reservoir portion of the vertical wells 1 is completed using perforation, and the oil reservoir casing diameter is preferably φ177.8 mm. The perforation density of the upper 10 m of the perforation section 20 is 10 holes / m, and the perforation density of the lower 10 m is 20 holes / m. The infilled horizontal well 2 is located in the center of the two rows of vertical wells 1 in the old heavy oil zone. This facilitates subsequent control of wellbore heating and facilitates determination of connection between the vertical wells 1 in the old heavy oil zone and the infilled horizontal wells 2. Based on the continuous distribution of the reservoir, the horizontal section length is 200 to 1000 meters.

[0031] Example 3: As an optimization of the above embodiment, as shown in the attached Figure 2As shown, in step 1, the infill horizontal well 2 is a single-branch horizontal well or a multi-branch horizontal well, and the branch is drilled sideways and upwards along the main wellbore of the horizontal section. The length of the branch section is 50 to 100 meters, and the angle between the branch and the main wellbore is 0 to 90 degrees. The distance between the branch and the top boundary of the oil layer is greater than 1 meter, and the branch wellbore is completed or not.

[0032] In this embodiment, the branch wellbore can be completed with casing or open hole. Cyclic heating and crude oil production accelerates the connection between vertical well 1 and infilled horizontal well 2, achieving uniform connection between vertical well 1 and infilled horizontal well 2, and efficiently utilizing the oil reservoir section of vertical well 1 and the horizontal section of infilled horizontal well 2, thereby improving the recovery rate.

[0033] Example 4: As an optimization of the above embodiment, as shown in the attached Figure 5 、 6 As shown, in step 1, the horizontal section of the infill horizontal well 2 is completed using screen pipe 21, and the number of screen pipe 21 seams in the physical interlayers and mudstone distribution sections with permeability lower than 100 mD is increased to 1.5 times.

[0034] In this example, the medium-depth of the heavy oil reservoir is 220 meters. The reservoir lithology is primarily medium-fine sandstone, the oil layer is 20 meters thick, the formation crude oil viscosity is 20,000 mPa.s (50°C), the porosity is 30%, the permeability is 1,000 mD, and the oil saturation is 50%. The horizontal section of infill horizontal well 2 was completed using screen 21. The diameters of the reservoir casing are φ244.5 mm / φ273 mm, and the diameters of screen 21 are φ177.8 mm / φ168.3 mm. To increase the oil drainage rate in low-permeability areas, the number of slits in screen 21 was increased by 1.5 times in the interlayers and mudstone sections with poor permeability (i.e., permeability below 100 mD).

[0035] Example 5: As an optimization of the above embodiment, as shown in the attached Figure 3 As shown, in step 2, the first production oil pipe 3 and the first long oil pipe 4 arranged in parallel are lowered into the vertical well 1. The lower end of the first production oil pipe 3 is connected to the first oil pump 5 and then lowered to the upper part of the oil layer. The lower end of the first long oil pipe 4 is lowered to 10 meters below the bottom boundary of the oil layer. The vertical well heating assembly includes a first temperature measuring cable 6 and a first heating cable 7. The first heating cable 7 is lowered from the first long oil pipe 4 to the bottom boundary of the oil layer. The first temperature measuring cable 6 is installed on the outside of the first long oil pipe 4, and the lower end of the first temperature measuring cable 6 is located 10 meters below the bottom boundary of the oil layer.

[0036] In this embodiment, in vertical well 1, a first temperature-measuring cable 6 is bundled outside a first long oil pipe 4 and lowered 10 meters below the reservoir bottom. This allows accurate wellbore temperature measurement. A first heating cable 7 heats the entire wellbore. The lower end of the first production tubing 3 is connected to a first oil pump 5 and lowered to the upper reservoir to begin oil production. This allows for simultaneous electrical heating and oil production, or electrical heating and solvent injection, meeting the multifunctional requirements of heating, injection, and temperature measurement. The process is simple, operation is convenient, and it can be used in conjunction with a Christmas tree.

[0037] Example 6: The difference between this example and the fifth example is that the installation method of the vertical well heating assembly is different. Figure 4 As shown, in step 2, a first production oil pipe 3 and a first long oil pipe 4 arranged in parallel are lowered into the vertical well 1. The lower end of the first production oil pipe 3 is connected to the first oil pump 5 and then lowered to the upper part of the oil layer. The lower end of the first long oil pipe 4 is lowered to 10 meters below the bottom boundary of the oil layer. The vertical well heating assembly includes a first temperature measuring cable 6 and a first heating cable 7. The first temperature measuring cable 6 and the first heating cable 7 are both installed in the first long oil pipe 4 and lowered from the first long oil pipe 4 to the bottom boundary of the oil layer.

[0038] In this embodiment, parallel double oil pipes are lowered into the vertical well 1, the first temperature measuring cable 6 and the first heating cable 7 are integrated in the first long oil pipe 4, and are lowered from the first long oil pipe 4 to the bottom boundary of the oil layer. The first heating cable 7 heats the entire well section, and the lower end of the first production oil pipe 3 is connected to the first oil pump 5 and then lowered to the upper part of the oil layer to start oil pumping production. The first production oil pipe 3 and the first long oil pipe 4 can be installed according to the on-site wellhead equipment, which is convenient for the installation of the vertical well heating component.

[0039] Example 7: As an optimization of the above embodiment, as shown in the attached Figure 5 As shown, in step 2, a second long oil pipe 9 and a second production oil pipe 8 arranged in parallel are lowered into the dense horizontal well 2, and the second long oil pipe 9 is lowered to 5 to 10 meters from the end of the horizontal section. The lower end of the second production oil pipe 8 is connected to a second oil pump 10 and lowered to an inclined well section with a well inclination angle of 40 to 60 degrees. The horizontal well heating assembly includes a second temperature measuring cable 11 and a second heating cable 12. The second temperature measuring cable 11 and the second heating cable 12 are both installed in the second long oil pipe 9 and lowered from the second long oil pipe 9 to 5 to 10 meters from the tail end of the second long oil pipe 9.

[0040] A parallel double oil pipe is lowered into the infilled horizontal well 2, and the second temperature measuring cable 11 and the second heating cable 12 are integrated in the second long oil pipe 9. The cables are lowered from the second long oil pipe 9 to a distance of 5 to 10 meters from the tail end of the second long oil pipe 9. The second heating cable 12 only heats the horizontal section of the infilled horizontal well 2. In this way, electric heating and oil production or electric heating and solvent injection can be carried out simultaneously, meeting the multifunctional requirements of heating, injection and production, and temperature measurement. The process is simple, the operation is convenient, and it is used in conjunction with the oil production tree device.

[0041] Example 8: The difference between this example and example 7 is that the horizontal well heating assembly is set differently. Figure 6 As shown, in step 2, a third long oil pipe 14 and a third production oil pipe 13 arranged in parallel are lowered into the dense horizontal well 2, and the third long oil pipe 14 and the third production oil pipe 13 are both lowered to 5 to 10 meters from the end of the horizontal section. A third oil pump 15 is installed on the upper part of the third production oil pipe 13, and the third oil pump 15 is located in the inclined well section with a well inclination angle of 40 to 60 degrees. The horizontal well heating assembly includes a third temperature measuring cable 16 and a third heating cable 17. The third heating cable 17 is installed in the third long oil pipe 14 and lowered from the third long oil pipe 14 to 5 to 10 meters from the tail end of the third long oil pipe 14. The upper part of the third temperature measuring cable 16 is fixed to the outside of the third production oil pipe 13, and the lower end of the third temperature measuring cable 16 penetrates from the hole on the third production oil pipe 13 below the third oil pump 15 and extends to 5 to 10 meters from the end of the horizontal section.

[0042] The third oil pump 15 is installed on the upper part of the third oil production pipe 13. The third oil pump 15 is located in the inclined well section with an inclination angle of 40 to 60 degrees. In this way, the horizontal well heating assembly can be installed according to different well equipment. The third heating cable 17 is installed in the third long oil pipe 14 and is lowered from the third long oil pipe 14 to 5 to 10 meters from the tail end of the third long oil pipe 14. In this way, the third heating cable 17 only heats the horizontal section of the infilled horizontal well 2. The upper part of the third temperature measuring cable is tied to the outside of the third production oil pipe 13. The lower end of the third temperature measuring cable 16 is inserted through the hole on the third production oil pipe 13 below the third oil pump 15 and extends to 5 to 10 meters from the end of the horizontal section. In this way, the temperature of the horizontal section of the infilled horizontal well 2 can be accurately measured, which is convenient for controlling the heating power of the third heating cable 17. In this way, electric heating and oil pumping or electric heating and solvent injection can be carried out simultaneously, meeting the multifunctional requirements of heating, injection and production, and temperature measurement. The process is simple, the operation is convenient, and it is used in conjunction with the oil production tree device.

[0043] Example 9: As an optimization of the above example, the solvent in step 3 is at least one of clean water, liquefied petroleum gas, C3-C8 light hydrocarbons, and a slug of clean water and a viscosity reducer. If the solvent is a slug of clean water and a viscosity reducer, the viscosity reducer is injected first, and then the clean water is injected.

[0044] If the solvent is a plug composed of clean water and viscosity reducer, the viscosity reducer is injected first, and then the clean water. In vertical well 1, 10 cubic meters of viscosity reducer is injected, and then clean water is injected until the wellbore is full; in infilled horizontal well 2, 30 cubic meters of viscosity reducer is injected, and then clean water is injected until the wellbore is full.

[0045] As attached Figure 2 、 Figure 3 、 Figure 6As shown, solvents are simultaneously injected into the vertical well 1 from the first production tubing 3 and the first long tubing 4, and into the infilled horizontal well 2 from the third long tubing 14 and the third production tubing 13. The solvents can be slugs of water, liquefied petroleum gas, C3-C8 light hydrocarbons, or a combination of water and viscosity reducer. The type of solvent can be selected according to actual needs and can be injected separately in stages or one or more of them can be injected in combination.

[0046] As attached Figure 4 、 Figure 5 As shown, clean water is simultaneously injected into the vertical well 1 from the first production oil pipe 3 and the first long oil pipe 4, and into the infilled horizontal well 2 from the second long oil pipe 9 and the second production oil pipe 8. The clean water is continuously heated by the heating cable, and the clean water is converted into high-dryness steam and enters the oil layer. The viscosity of the crude oil is reduced through heat exchange, and the crude oil flows into the wellbore to fill the volume space of the water. The heating cable evenly heats the entire well section, so that the oil layer around the wellbore can be evenly mobilized.

[0047] After liquefied petroleum gas and C3-C8 light hydrocarbons are injected into the wellbore, they are continuously heated by the heating cable. The liquefied petroleum gas and C3~C8 light hydrocarbons enter the oil layer in a gaseous state and expand over a large area. Through heat exchange and extraction, the viscosity of the crude oil is greatly reduced, and light hydrocarbon components are produced. The oil layers in a larger area around the wellbore can be utilized more effectively, thereby increasing the production of a single well.

[0048] Example 10: As an optimization of the above example, in step 4, the wellbore temperature is controlled between 100 and 350°C.

[0049] The heating cable heats the vertical well 1 and the infilled horizontal well 2 simultaneously. When clean water is used in the wellbore, the salinity is lower than 1000 mg / L and the wellbore temperature is controlled below 350°C; when liquefied petroleum gas is used in the wellbore, the wellbore temperature is controlled above 100°C; when C3-C8 light hydrocarbons are used in the wellbore, the wellbore temperature is controlled below 350°C; the continuous heating time is set as needed, and during the wellbore heating process, solvent can be added to the wellbore as needed.

[0050] Example 11: As an optimization of the above example, in step 5, the oil pumping production time is gradually extended from the first round. If the oil content in the return fluid in the wellbore during this round of oil pumping production is less than 5%, the next round is entered.

[0051] After the first round, as the heating range increases, the time of each round of oil pumping production needs to be gradually extended. When the oil content in the return fluid in the wellbore is less than 5%, the next round of oil pumping production will be started. During the oil pumping production process, if there is still crude oil in the wellbore, but the crude oil cannot be extracted from the ground due to the decrease in wellbore temperature and the increase in crude oil viscosity, the wellbore can be heated by a heating cable to assist oil pumping production. Specifically, after heating the wellbore, the wellhead temperature is greater than 70°C and the bottomhole temperature is less than 150°C.

[0052] Example 12: As an optimization of the above example, as shown in the attached Figure 1 、 2 As shown, step seven is: continuously injecting solvent into vertical well 1 to heat vertical well 1 so that the temperature of the oil layer is 150 to 250°C, and at the same time heating the infilled horizontal well 2 so that the temperature of the oil layer is 120 to 170°C, and continuously pumping out oil.

[0053] In this embodiment, a solvent, preferably clean water, is continuously injected into vertical well 1 at a daily rate of 5 to 20 t / d. A heating cable heats vertical well 1, raising the reservoir temperature to 150 to 250°C. The heating cable also heats vertical well 1 to a reservoir temperature of 120 to 170°C, while infilled horizontal well 2 continues pumping oil. Continuous heating via the heating cable converts the clean water into high-dryness steam, which enters the reservoir. Heat exchange reduces the crude oil's viscosity, allowing it to flow into the wellbore, filling the water's volumetric space. The heating cable uniformly heats the entire wellbore.

[0054] Example 13: As an optimization of the above example, as shown in the attached Figure 1 、 2 As shown, step six is: check whether the vertical well 1 is connected to the infilled horizontal well 2. If so, test the connectivity between the infilled horizontal well 2 and the surrounding vertical wells 1 in sequence. When the infilled horizontal well 2 is connected to the surrounding vertical wells 1 for more than 4 times, proceed to step seven; if not, repeat steps three to five. The method for detecting the connection between the vertical well 1 and the infilled horizontal well 2 includes the following steps: When normal-temperature deoiled water is continuously injected from vertical well 1 to heat the remaining vertical well 1 and infill horizontal well 2 for production, if the temperature of the horizontal section of infill horizontal well 2 continues to drop by more than 10°C or the wellhead pressure of infill horizontal well 2 increases by more than 0.2 MPa, then vertical well 1 and infill horizontal well 2 are connected; When the wellbore temperature of vertical well 1 is between 95 and 105°C, room-temperature deoiled water is continuously injected from the infilled horizontal well 2. If the temperature in vertical well 1 continues to drop by more than 10°C or the wellhead pressure of vertical well 1 increases by more than 0.2 MPa, then vertical well 1 is connected to the infilled horizontal well 2.

[0055] In this embodiment, steps 3 to 5 are repeated 4 to 8 times. After multiple rounds of continuous heating and oil pumping, the heating zone 22 around the wellbore will gradually expand until the heating zones 22 of the vertical well 1 and the infilled horizontal well 2 are interconnected. The number of repeated rounds of steps 3 to 5 can also be reduced or increased according to actual needs.

[0056] The method for detecting the connectivity between the vertical well 1 and the infill horizontal well 2 includes: The first method is to continuously inject room-temperature deoiled water from vertical well 1, keep the remaining vertical wells 1 electrically heated, and infill the horizontal well 2 for production. Observe the wellhead pressure and horizontal section temperature of the infilled horizontal well 2. If the temperature continuously drops by more than 10°C or the wellhead pressure increases by more than 0.2 MPa, it indicates that the vertical well 1 is connected to the infilled horizontal well 2. Test the connectivity between the infilled horizontal well 2 and the surrounding vertical wells 1 in sequence. If the number of connected vertical wells 1 is greater than 4, proceed to step 7. The second method: The wellbore temperature of vertical well 1 is 100°C. Normal-temperature deoiled water is continuously injected from the infilled horizontal well 2. The temperature and wellhead pressure changes in vertical well 1 are observed. If the temperature continues to drop by more than 10°C or the wellhead pressure increases by more than 0.2 MPa, it indicates that vertical well 1 is connected to the infilled horizontal well 2. The connectivity between the infilled horizontal well 2 and the surrounding vertical wells 1 is tested in sequence. When the number of surrounding vertical wells 1 connected is greater than 4, proceed to step 7.

[0057] Example 14: As shown in the attached Figure 1 、 2 As shown in Figures 3 and 5, the electric heating connecting pipe string structure of the heavy oil vertical well and the horizontal well includes a vertical well heating component arranged in the vertical well 1 and a horizontal well heating component arranged in the dense horizontal well 2. A first production oil pipe 3 and a first long oil pipe 4 are arranged in parallel in the vertical well 1. A first oil pump 5 is installed at the lower end of the first production oil pipe 3. The vertical well heating component includes a first temperature measuring cable 6 and a first heating cable 7. The first heating cable 7 is installed in the first long oil pipe 4, and the first temperature measuring cable 6 is installed on the outside of the first long oil pipe 4.

[0058] The horizontal well heating assembly includes a second temperature measuring cable 11 and a second heating cable 12. A second long oil pipe 9 and a second production oil pipe 8 are arranged in parallel in the dense horizontal well 2. A second oil pump 10 is installed at the lower end of the second production oil pipe 8. The second temperature measuring cable 11 and the second heating cable 12 are both installed in the second long oil pipe 9.

[0059] During use, the first temperature measuring cable 6 in the vertical well 1 is bundled with the outside of the first long oil pipe 4 through several existing well-known first clamps 18. The process is simple and the operation is convenient. It is used in conjunction with the oil tree device. The first heating cable 7 can heat the entire well section of the vertical well 1. The first temperature measuring cable 6 can collect the oil layer temperature, which is convenient for controlling the power of the first heating cable 7. In this way, the oil layer is directly heated with high thermal efficiency, which can greatly reduce steam consumption and reduce carbon emissions. The power supply for the first heating cable 7 can use green electricity, such as solar power generation and photovoltaics, to achieve low-carbon development of heavy oil.

[0060] A second long oil pipe 9 and a second production oil pipe 8 are arranged in parallel in the infilled horizontal well 2. The second temperature measuring cable 11 and the second heating cable 12 are integrated in the second long oil pipe 9. The second heating cable 12 only heats the horizontal section of the infilled horizontal well 2. In this way, electric heating and oil production or electric heating and solvent injection can be carried out simultaneously, meeting the multifunctional requirements of heating, injection and temperature measurement. The process is simple, the operation is convenient, and it is used in conjunction with the oil tree device.

[0061] Example 15: The difference between this example and example 14 is that the installation method of the first temperature measuring cable 6 and the first heating cable 7 in the vertical well heating assembly is different. Figure 1 、 2 As shown in Figures 4 and 5, the electric heating connecting pipe string structure of the heavy oil vertical well and the horizontal well includes a vertical well heating component arranged in the vertical well 1 and a horizontal well heating component arranged in the dense horizontal well 2. A first production oil pipe 3 and a first long oil pipe 4 are arranged in parallel in the vertical well 1. A first oil pump 5 is installed at the lower end of the first production oil pipe 3. The vertical well heating component includes a first temperature measuring cable 6 and a first heating cable 7. The first temperature measuring cable 6 and the first heating cable 7 are both installed in the first long oil pipe 4.

[0062] The horizontal well heating assembly includes a second temperature measuring cable 11 and a second heating cable 12. A second long oil pipe 9 and a second production oil pipe 8 are arranged in parallel in the dense horizontal well 2. A second oil pump 10 is installed at the lower end of the second production oil pipe 8. The second temperature measuring cable 11 and the second heating cable 12 are both installed in the second long oil pipe 9.

[0063] During use, the first temperature measuring cable 6 and the first heating cable 7 are integrated in the first long oil pipe 4. The first heating cable 7 heats the entire well section. The lower end of the first production oil pipe 3 is connected to the first pumping pump 5 and then lowered into the upper part of the oil layer to start oil pumping production. The first production oil pipe 3 and the first long oil pipe 4 can be installed according to the on-site wellhead equipment, which is convenient for the installation of the vertical well heating component. The first heating cable 7 can heat the entire well section of the vertical well 1. The first temperature measuring cable 6 can collect the oil layer temperature, which is convenient for controlling the power of the first heating cable 7. In this way, the oil layer is directly heated with high thermal efficiency, which can greatly reduce steam consumption and reduce carbon emissions. The power supply used to power the first heating cable 7 can use green electricity, such as solar power generation and photovoltaics, to achieve low-carbon development of heavy oil, make the oil layer utilization more uniform, and improve the recovery rate of old heavy oil areas.

[0064] A second long oil pipe 9 and a second production oil pipe 8 are arranged in parallel in the infilled horizontal well 2. The second temperature measuring cable 11 and the second heating cable 12 are integrated in the second long oil pipe 9. The second heating cable 12 only heats the horizontal section of the infilled horizontal well 2. In this way, electric heating and oil production or electric heating and solvent injection can be carried out simultaneously, meeting the multifunctional requirements of heating, injection and temperature measurement. The process is simple, the operation is convenient, and it is used in conjunction with the oil tree device.

[0065] Example 16: The difference between this example and Example 14 is only the different arrangement of the horizontal well heating assembly. Figure 1 、 2 As shown in Figures 3 and 6, the electric heating connecting pipe string structure of the heavy oil vertical well and the horizontal well includes a vertical well heating component arranged in the vertical well 1 and a horizontal well heating component arranged in the dense horizontal well 2. A first production oil pipe 3 and a first long oil pipe 4 are arranged in parallel in the vertical well 1. A first oil pump 5 is installed at the lower end of the first production oil pipe 3. The vertical well heating component includes a first temperature measuring cable 6 and a first heating cable 7. The first heating cable 7 is installed in the first long oil pipe 4, and the first temperature measuring cable 6 is installed on the outside of the first long oil pipe 4.

[0066] The horizontal well heating assembly includes a third temperature measuring cable 16 and a third heating cable 17. The third long oil pipe 14 and the third production oil pipe 13 are arranged in parallel in the dense horizontal well 2. A third oil pump 15 is installed on the upper part of the third production oil pipe 13. The third heating cable 17 is installed in the third long oil pipe 14. The upper part of the third temperature measuring cable 16 is fixed to the outside of the third production oil pipe 13. The lower end of the third temperature measuring cable 16 is inserted into the hole on the third production oil pipe 13 below the third oil pump 15 and is installed on the inner side of the lower part of the third production oil pipe 13.

[0067] During use, a third oil pump 15 is installed on the upper part of the third production oil pipe 13. The third oil pump 15 is located in the inclined well section with an inclination angle of 40 to 60 degrees. In this way, the horizontal well heating assembly can be installed according to different well equipment. The third heating cable 17 is installed in the third long oil pipe 14. The third heating cable 17 only heats the horizontal section of the encrypted horizontal well 2. The upper part of the third temperature measuring cable is bundled with the outside of the third production oil pipe 13 through several existing well-known second clamps 19. The lower end of the third temperature measuring cable 16 is inserted into the hole on the third production oil pipe 13 below the third oil pump 15 and is installed on the inner side of the lower part of the third production oil pipe 13. In this way, the temperature of the horizontal section of the encrypted horizontal well 2 can be accurately measured, which is convenient for controlling the heating power of the third heating cable 17.

[0068] After the first temperature measuring cable 6 in the vertical well 1 is bundled with the outside of the first long oil pipe 4 through several existing well-known first clamps 18, the process is simple and the operation is convenient. It is used in conjunction with the oil tree device. The first heating cable 7 can heat the entire well section of the vertical well 1. The first temperature measuring cable 6 can collect the oil layer temperature, which is convenient for controlling the power of the first heating cable 7. In this way, the oil layer is directly heated with high thermal efficiency, which can significantly reduce steam consumption and reduce carbon emissions. The power supply used to power the first heating cable 7 can use green electricity, such as solar power generation and photovoltaic power generation, to achieve low-carbon development of heavy oil.

[0069] Example 17: The difference between this example and Example 15 is the different arrangement of the horizontal well heating assembly. Figure 1 、 2 As shown in Figures 4 and 6, the electric heating connecting pipe string structure of the heavy oil vertical well and the horizontal well includes a vertical well heating component arranged in the vertical well 1 and a horizontal well heating component arranged in the dense horizontal well 2. A first production oil pipe 3 and a first long oil pipe 4 are arranged in parallel in the vertical well 1. A first oil pump 5 is installed at the lower end of the first production oil pipe 3. The vertical well heating component includes a first temperature measuring cable 6 and a first heating cable 7. The first temperature measuring cable 6 and the first heating cable 7 are both installed in the first long oil pipe 4.

[0070] The horizontal well heating assembly includes a third temperature measuring cable 16 and a third heating cable 17. The third long oil pipe 14 and the third production oil pipe 13 are arranged in parallel in the dense horizontal well 2. A third oil pump 15 is installed on the upper part of the third production oil pipe 13. The third heating cable 17 is installed in the third long oil pipe 14. The upper part of the third temperature measuring cable 16 is fixed to the outside of the third production oil pipe 13. The lower end of the third temperature measuring cable 16 is inserted into the hole on the third production oil pipe 13 below the third oil pump 15 and is installed on the inner side of the lower part of the third production oil pipe 13.

[0071] During use, a third oil pump 15 is installed on the upper part of the third production oil pipe 13. The third oil pump 15 is located in the inclined well section with an inclination angle of 40 to 60 degrees. In this way, the horizontal well heating assembly can be installed according to different well equipment. The third heating cable 17 is installed in the third long oil pipe 14. The third heating cable 17 only heats the horizontal section of the encrypted horizontal well 2. The upper part of the third temperature measuring cable is bundled with the outside of the third production oil pipe 13 through several existing well-known second clamps 19. The lower end of the third temperature measuring cable 16 is inserted into the hole on the third production oil pipe 13 below the third oil pump 15 and is installed on the inner side of the lower part of the third production oil pipe 13. In this way, the temperature of the horizontal section of the encrypted horizontal well 2 can be accurately measured, which is convenient for controlling the heating power of the third heating cable 17.

[0072] The first temperature measuring cable 6 and the first heating cable 7 are integrated in the first long oil pipe 4. The first heating cable 7 heats the entire well section. The lower end of the first production oil pipe 3 is connected to the first pumping pump 5 and then lowered into the upper part of the oil layer to start oil production. The first production oil pipe 3 and the first long oil pipe 4 can be installed according to the on-site wellhead equipment, which is convenient for the installation of the vertical well heating component. The first heating cable 7 can heat the entire well section of the vertical well 1. The first temperature measuring cable 6 can collect the oil layer temperature, which is convenient for controlling the power of the first heating cable 7. In this way, the oil layer is directly heated with high thermal efficiency, which can greatly reduce steam consumption and reduce carbon emissions. The power supply used to power the first heating cable 7 can use green electricity, such as solar power generation and photovoltaics, to achieve low-carbon development of heavy oil, make the oil layer utilization more uniform, and improve the recovery rate of old heavy oil areas.

[0073] The present invention directly heats the oil layer, has high thermal efficiency, and can significantly reduce steam consumption. The power supply for supplying power to the first heating cable 7 can adopt green electricity, such as solar power generation and photovoltaic power generation, to achieve low-carbon development of heavy oil, make the oil layer production more uniform, and improve the recovery rate of old heavy oil areas. Electric heating and oil pumping production or electric heating and solvent injection can be carried out simultaneously to meet the multifunctional requirements of heating, injection and production, and temperature measurement. The process is simple and the operation is convenient. It is used in conjunction with the oil tree device, and solves the problems of steam channeling development after the old heavy oil area is converted to VHSD (combined steam drive of vertical wells and infilled horizontal wells), the inability to establish effective connection between the vertical well 1 and the infilled horizontal well 2, poor oil layer production, low production, low oil-gas ratio, and low recovery rate.

[0074] The above-mentioned electric heating connecting string structure for vertical and horizontal heavy oil wells can be further optimized and / or improved according to actual needs: Example 18: As an optimization of the above embodiment, as shown in the attached Figures 3 to 6 As shown, the first heating cable 7, the second heating cable 12 and the third heating cable 17 are all resistive heating structures, and the maximum heating temperatures of the first heating cable 7, the second heating cable 12 and the third heating cable 17 are all less than 380°C.

[0075] During use, the first heating cable 7, the second heating cable 12 and the third heating cable 17 are all stainless steel armored mineral insulated cables, the insulation material of the heating cables are all magnesium oxide, and the maximum heating temperature of the heating cables is less than 380°C; the power of the first heating cable 7, the second heating cable 12 and the third heating cable 17 are all 500 to 2000W / m, and the outside of the cable is a stainless steel seamless steel pipe with a wall thickness greater than 2mm to ensure the safe operation of the cable. An existing well-known power control device is installed on the ground, and the wellbore temperature is adjusted to meet the design requirements by adjusting the power size, making operation more convenient.

[0076] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A method for connecting heavy oil vertical wells and horizontal wells with electrical heating, characterized in that The steps are as follows: Step 1: Drill infill horizontal wells in the middle of the vertical well row in the old heavy oil area; Step 2: Run a vertical well heating assembly and a horizontal well heating assembly into the vertical well and the infilled horizontal well respectively; Step 3: injecting solvent into the vertical well and the infilled horizontal well simultaneously until the wellbore is full; Step 4: Continuously heat the vertical wells and infilled horizontal wells to control the downhole temperature within the set range; Step 5: Stop heating the vertical wells and infilled horizontal wells, and start pumping to extract crude oil and water from the wellbore simultaneously; Step 6: Repeat steps 3 to 5 and determine whether the vertical well is connected to the infill horizontal well. If so, proceed to step 7. Step seven: heat the vertical wells and continuously inject solvent, while heating the infilled horizontal wells and continuously pumping out oil.

2. The method for electrically heating and connecting a vertical well and a horizontal well of heavy oil according to claim 1 is characterized in that In step 1, the infill horizontal well is located in the middle of two rows of vertical wells in the old heavy oil zone, with the vertical well and the infill horizontal well spaced 10 to 35 meters apart. The vertical well is completed by perforation in the oil reservoir, with the number of casing perforations in the upper section of the oil reservoir being less than that in the lower section. The horizontal section of the infill horizontal well is drilled along the bottom of the oil reservoir, 1 to 2 meters above the bottom of the oil reservoir. Or / and, the infill horizontal well is a single-branch horizontal well or a multi-branch horizontal well, with the branches drilled laterally and upward along the main wellbore of the horizontal section, the branch section length is 50 to 100 meters, the angle between the branch and the main wellbore is 0 to 90 degrees, the distance between the branch and the top of the oil layer is greater than 1 meter, and the branch wellbore is completed or incomplete; Or / and, screen pipe completion is used for the horizontal section of infill horizontal wells, and the number of screen pipe slits in the physical interlayers with permeability less than 100mD and mudstone distribution sections is increased to 1.5 times.

3. The method for electrically heating and connecting a vertical well and a horizontal well of heavy oil according to claim 2 is characterized in that In step 2, a first production tubing and a first long tubing arranged in parallel are lowered into the vertical well. The lower end of the first production tubing is connected to a first oil pump and then lowered to the upper part of the oil layer. The lower end of the first long tubing is lowered to 10 meters below the bottom of the oil layer. The vertical well heating assembly includes a first temperature measuring cable and a first heating cable. The first temperature measuring cable and the first heating cable are both installed in the first long tubing and lowered from the first long tubing to the bottom of the oil layer. Alternatively, the first heating cable is lowered from the first long oil pipe to the bottom of the oil layer, the first temperature measuring cable is installed on the outside of the first long oil pipe, and the lower end of the first temperature measuring cable is located 10 meters below the bottom of the oil layer.

4. The method for electrically heating and connecting a vertical well and a horizontal well of heavy oil according to claim 3 is characterized in that In step 2, a second long oil pipe and a second production oil pipe arranged in parallel are lowered into the infill horizontal well. The second long oil pipe is lowered to 5 to 10 meters from the end of the horizontal section. The lower end of the second production oil pipe is connected to a second oil pump and lowered to an inclined well section with a well inclination angle of 40 to 60 degrees. The horizontal well heating assembly includes a second temperature measuring cable and a second heating cable. The second temperature measuring cable and the second heating cable are both installed in the second long oil pipe and lowered from the second long oil pipe to 5 to 10 meters from the tail end of the second long oil pipe.

5. The method for electrically heating and connecting a vertical well and a horizontal well of heavy oil according to claim 3 is characterized in that In step 2, a third long oil pipe and a third production oil pipe arranged in parallel are lowered into the encrypted horizontal well. Both the third long oil pipe and the third production oil pipe are lowered to 5 to 10 meters from the end of the horizontal section. A third oil pump is installed on the upper part of the third production oil pipe. The third oil pump is located in the inclined well section with a well inclination angle of 40 to 60 degrees. The horizontal well heating assembly includes a third temperature measuring cable and a third heating cable. The third heating cable is installed in the third long oil pipe and lowered from the third long oil pipe to 5 to 10 meters from the tail end of the third long oil pipe. The upper part of the third temperature measuring cable is fixed on the outside of the third production oil pipe. The lower end of the third temperature measuring cable penetrates through the hole on the third production oil pipe below the third oil pump and extends to 5 to 10 meters from the end of the horizontal section.

6. The method for electrically heating and connecting a vertical well and a horizontal well of heavy oil according to claim 1, 2, 3, 4 or 5, characterized in that: The solvent in step 3 is at least one of water, liquefied petroleum gas, C3-C8 light hydrocarbons, and a slug of water combined with a viscosity reducer. If the solvent is a slug of water combined with a viscosity reducer, the viscosity reducer is injected first, followed by the water. or / and, in step 4, controlling the wellbore temperature between 100 and 350° C.; or / and, in step 5, the pumping production time is gradually extended from the first round, and if the oil content in the return fluid in the wellbore during the first round of pumping production is less than 5%, the pumping production is transferred to the next round; Or / and, step seven is: continuously injecting solvent into the vertical well to heat the vertical well so that the temperature at the oil layer is 150 to 250°C, and simultaneously heating the infilled horizontal well to make the oil layer temperature 120 to 170°C, and continuously pumping out oil.

7. The method for electrically heating and connecting a vertical well and a horizontal well of heavy oil according to claim 1, 2, 3, 4 or 5, characterized in that Step 6: Check whether the vertical well is connected to the infilled horizontal well. If so, test the connectivity between the infilled horizontal well and the surrounding vertical wells in sequence. When the infilled horizontal well is connected to the surrounding vertical wells for more than 4 times, proceed to step 7. If not, repeat steps 3 to 5. The method for detecting the connectivity between a vertical well and an infilled horizontal well includes the following steps: When normal-temperature deoiled water is continuously injected from the vertical wells to heat the remaining vertical wells and infill the horizontal wells for production, if the temperature of the horizontal section of the infilled horizontal well continues to drop by more than 10°C or the wellhead pressure of the infilled horizontal well increases by more than 0.2 MPa, the vertical well and the infilled horizontal well are connected; When the wellbore temperature of the vertical well is between 95 and 105°C, room-temperature deoiled water is continuously injected from the infilled horizontal well. If the temperature in the vertical well continues to drop by more than 10°C or the wellhead pressure of the vertical well increases by more than 0.2 MPa, the vertical well is connected to the infilled horizontal well.

8. The method for electrically heating and connecting a vertical well and a horizontal well of heavy oil according to claim 6 is characterized in that Step 6: Check whether the vertical well is connected to the infilled horizontal well. If so, test the connectivity between the infilled horizontal well and the surrounding vertical wells in sequence. When the infilled horizontal well is connected to the surrounding vertical wells for more than 4 times, proceed to step 7. If not, repeat steps 3 to 5. The method for detecting the connectivity between a vertical well and an infilled horizontal well includes the following steps: When normal-temperature deoiled water is continuously injected from the vertical wells to heat the remaining vertical wells and infill the horizontal wells for production, if the temperature of the horizontal section of the infilled horizontal well continues to drop by more than 10°C or the wellhead pressure of the infilled horizontal well increases by more than 0.2 MPa, the vertical well and the infilled horizontal well are connected; When the wellbore temperature of the vertical well is between 95 and 105°C, room-temperature deoiled water is continuously injected from the infilled horizontal well. If the temperature in the vertical well continues to drop by more than 10°C or the wellhead pressure of the vertical well increases by more than 0.2 MPa, the vertical well is connected to the infilled horizontal well.

9. A pipe string structure for connecting heavy oil vertical wells and horizontal wells with electric heating, used in the method for connecting heavy oil vertical wells and horizontal wells with electric heating according to any one of claims 1 to 8, characterized in that The vertical well heating assembly comprises a vertical well heating assembly arranged in a vertical well and a horizontal well heating assembly arranged in an infilled horizontal well. A first production oil pipe and a first long oil pipe are arranged in parallel in the vertical well. A first oil pump is installed at the lower end of the first production oil pipe. The vertical well heating assembly comprises a first temperature measuring cable and a first heating cable. The first heating cable is installed in the first long oil pipe and the first temperature measuring cable is installed outside the first long oil pipe, or both the first temperature measuring cable and the first heating cable are installed in the first long oil pipe. The horizontal well heating assembly includes a second temperature measuring cable and a second heating cable. A second long oil pipe and a second production oil pipe are arranged in parallel in the infilled horizontal well. A second oil pump is installed at the lower end of the second production oil pipe. The second temperature measuring cable and the second heating cable are both installed in the second long oil pipe. Alternatively, the horizontal well heating assembly includes a third temperature measuring cable and a third heating cable, a third long oil pipe and a third production oil pipe are arranged in parallel in the dense horizontal well, a third oil pump is installed on the upper part of the third production oil pipe, the third heating cable is installed in the third long oil pipe, the upper part of the third temperature measuring cable is fixed to the outside of the third production oil pipe, and the lower end of the third temperature measuring cable is inserted through the hole on the third production oil pipe below the third oil pump and installed on the inner side of the lower part of the third production oil pipe.

10. The electrically heated connecting pipe string structure for heavy oil vertical wells and horizontal wells according to claim 9 is characterized in that The first heating cable, the second heating cable and the third heating cable all have resistive heating structures, and the maximum heating temperatures of the first heating cable, the second heating cable and the third heating cable are all less than 380°C.

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