Electric heating device connection device for well pattern and connection method thereof

Abstract

The present invention discloses an electric heating device connection device for a well network and a connection method thereof, which relates to the technical field of coalbed methane mining. The electric heating device connection device for a well network comprises: a main branch positioning pipe string, comprising a positioning mechanism that can be fixed with a casing, a first positioning and guiding connector, the first positioning and guiding connector can be positioned at the window of the main wellbore casing connected to the branch wellbore; at least one main branch and branch connecting pipe string, comprising: a main branch pipe string section and a branch pipe string section connected to the main branch pipe string section, the branch pipe string section comprises a guide at the lowest end, the lowest end of the main branch pipe string section has a first connecting mechanism, the first connecting mechanism can be matched and connected with the first positioning and guiding connector, and the upper end of the main branch pipe string section has a second positioning and guiding connector; and so on. The present application can realize the convenient, fast and safe lowering of electric heating equipment in the main wellbore and the branch wellbore of the coal seam.

Description

Technical Field

[0001] The invention relates to the technical field of coalbed methane mining, and in particular to an electric heating device connection device for a well network and a connection method thereof. Background Art

[0002] The exploration and development of coalbed methane in China is mainly concentrated in the shallow and medium-shallow areas below 1500m. The coalbed methane resources at a burial depth of 1500-2000m are 11.93×10 12 m 3 The coalbed methane resources at a depth of 2000 to 3000 m are 18.47×10 12 m 3 , coalbed methane resources are rich but the overall development level is relatively low. Unlike conventional oil and gas reservoirs, coal rock is a methane-rich reservoir, and methane gas is mainly stored in the microscopic pore structure of coal rock in the form of adsorption. During the drainage and depressurization process of coalbed methane wells, methane molecules desorb from the microscopic pores of coal rock, diffuse through microscopic cracks to larger cracks, and further seep into the wellbore, and are produced on the ground by the wellbore drainage equipment. Heating coal rock reservoirs is conducive to promoting the desorption and desorption of methane gas molecules. Relevant experimental studies have shown that the permeability of coal rock increases after heating, which can effectively increase the seepage rate of coalbed methane. The microwave heating method is different from the conventional heating method dominated by heat transfer alone, and it is an overall heating method that makes the coal rock itself a heat source. Electromagnetic energy is absorbed to the greatest extent and converted into thermal energy, which has the advantages of small environmental impact and adaptability to a variety of different storage characteristics. There is an interference effect between wells when the well network is used for electric heating mining. The edge temperature of the temperature field of adjacent wells is superimposed, which can effectively increase the upper limit of the temperature in the edge low-temperature area, promote the desorption and desorption of coalbed methane, and increase the overall gas production of the well network. Electric heating has high efficiency, but the heating range in the coal seam is limited. In order to effectively increase the production of coalbed methane, it is necessary to drill multiple wells to form a well network. Figure 1 As shown, multiple dense well patterns are drilled in the lower part 200 of the coal seam and casing is run in to complete the wells. Each well may include a branch wellbore and a main wellbore. The branch wellbore and the main wellbore are respectively run with branch wellbore casing 6 and main wellbore casing 5. Electric heating equipment 3 needs to be run in both the branch wellbore and the main wellbore. Subsequently, the electric heating equipment 3 can be powered by the cable 9 built into the continuous oil pipe 10, thereby forming a dense heating well pattern. Coalbed methane in the coal reservoir is accelerated to desorb under high temperature and migrate to the production horizontal wells in the upper part 100 of the coal seam, enters the interior of the horizontal wellbore through the sieve holes of the branch wellbore screen 400 and the main wellbore screen 300 in the production horizontal well, and is produced to the ground through the gas production wellhead device 500, thereby achieving the goal of increasing the production of a single well. However, electric heating equipment needs to be lowered into the main wellbore and multiple branch wellbores in a well with an electric heating wellhead device 600 in a dense well network at the bottom of the coal seam 200. Therefore, a device is urgently needed to conveniently and quickly lower multiple electric heating devices into the main wellbore and multiple branch wellbores. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present invention is to provide an electric heating device connection device for a well network and a connection method thereof, which can realize the convenient, fast and safe lowering of electric heating equipment into the main wellbore and branch wellbore of the coal seam.

[0004] The specific technical solution of the embodiment of the present invention is:

[0005] An electric heating device connection device for a well pattern, the electric heating device connection device for a well pattern comprising:

[0006] A main branch positioning string, comprising a positioning mechanism capable of being fixed to the casing, and a first positioning and guiding connector, wherein the first positioning and guiding connector can be positioned at a window of the main wellbore casing connected to the branch wellbore;

[0007] At least one main branch and branch connecting pipe string, comprising: a main branch pipe string section and a branch pipe string section connected to the main branch pipe string section, the branch pipe string section comprising a guide at the lowest end capable of guiding from the main wellbore casing into the branch wellbore, the lowest end of the main branch pipe string section having a first connecting mechanism, the first connecting mechanism being capable of being matched and connected with the first positioning and guiding connector, and the upper end of the main branch pipe string section having a second positioning and guiding connector;

[0008] The main branch connecting pipe column comprises a second connecting mechanism located at the lowermost end, wherein the second connecting mechanism can be matched and connected with the second positioning and guiding connector;

[0009] At least one electric heating device, the electric heating device is connected to at least one of the following positions: in the main branch positioning pipe string, in the branch pipe string section, in the main branch pipe string section, and in the main branch connecting pipe string.

[0010] Preferably, when there are multiple main and branch connecting tubings, the first connecting mechanism in the upper main and branch connecting tubings can be matched and connected with the second positioning and guiding connector in the adjacent lower main and branch connecting tubings; the second positioning and guiding connector in the adjacent lower main and branch connecting tubings can be positioned at the window of the main wellbore casing connecting the branch wellbore.

[0011] Preferably, at least one of the electric heating devices is connected to the main branch positioning column, and the positioning mechanism includes a guide shoe that can be locked with the casing by itself; the upper end of the guide shoe is connected to the electric heating device, and the upper end of the electric heating device is connected to the first positioning and guiding connector; the first positioning and guiding connector includes: a first connector body, a plurality of first elastic sealing sheets, a first slider, a first spring, a first quick connector, a first joint seal and a cable; a first opening is formed inside the upper end of the first connector body, the first joint seal is arranged in the first opening, a first opening is formed at the upper end of the first joint seal, and a plurality of first elastic sealing sheets partially clamp the Between the first joint seal and the first connector body, parts of the plurality of first elastic sealing sheets can cover the upper end of the first opening, the upper end of the cable is located in the first opening and connected to the first quick connector, a first slider is fixedly mounted on the cable, and the first spring is arranged between the first slider and the first joint seal so that the first quick connector can move along the axial direction in the first opening; the first connecting mechanism can be inserted into the first opening through the first elastic sealing sheet through the first opening and connected to the first quick connector; the other end of the cable is electrically connected to the electric heating device in the main support positioning column.

[0012] Preferably, a first positioning block capable of extending and retracting in a radial direction is disposed on the outer side wall of the first connector body, and a first elastic member is disposed between the first positioning block and the first connector body.

[0013] Preferably, a rotatable first roller is provided on the outer side wall of the first connector body, and the first roller can roll in the axial direction of the first connector body.

[0014] Preferably, the first connecting mechanism includes: a second quick connector; a plurality of second elastic sealing sheets covering the second quick connector, the second quick connector can be inserted into the first opening through the first elastic sealing sheet through the first opening, and the first quick connector can pass through the second elastic sealing sheet to be connected to the second quick connector.

[0015] Preferably, a branch connector is connected to the main branch pipe column section, and the branch connector includes a branch connector upper body and a branch connector lower body. The branch pipe column section is connected to the branch connector lower body, and a rotating mechanism is connected between the branch connector upper body and the branch connector lower body, which can make the branch connector upper body and the branch connector lower body rotate relative to each other, and the rotating mechanism includes an outer ring raceway, an inner ring raceway and a roller arranged between the outer ring raceway and the inner ring raceway.

[0016] Preferably, at least one of the electric heating devices is connected between the branch connector and the second positioning and guiding connector; at least one of the electric heating devices is connected in the branch pipe string section.

[0017] Preferably, the cable in the second positioning and guiding connector is electrically connected to the second quick connector, and the cable in the second positioning and guiding connector is electrically connected to at least one of the electric heating devices in the branch pipe string section.

[0018] A method for connecting an electric heating device for a well network using any of the above-mentioned electric heating device connecting devices for a well network, the method for connecting an electric heating device for a well network comprising:

[0019] The main branch positioning string is lowered into the main wellbore casing guide shoe at the bottom of the main wellbore casing, the positioning mechanism is fixed to the main wellbore casing guide shoe, and the first positioning and guiding connector is fixed and positioned at the window of the main wellbore casing connected to the branch wellbore;

[0020] After the main branch positioning pipe string is lowered, the main branch and branch connecting pipe strings are lowered into the main wellbore casing, and the branch pipe string section is made to enter the branch wellbore casing through the guide of the branch pipe string section, and then the first connecting mechanism of the main branch pipe string section is matched and connected with the first positioning and guiding connector;

[0021] After the main branch and branch connecting pipe strings are lowered, the main branch connecting pipe strings are lowered into the main wellbore casing, and the second connecting mechanism is matched and connected with the second positioning and guiding connector of the main branch and branch connecting pipe strings. The upper end of the main branch connecting pipe string is connected to a continuous oil pipe with a built-in cable, and power is supplied to the electric heating device in the electric heating device connecting device through the built-in cable.

[0022] The technical solution of the present invention has the following significant beneficial effects:

[0023] The electric heating device connection device and connection method for the well network in the present application can realize the safe lowering of the electric heating equipment in the main wellbore and branch wellbore of the coal seam, and can also realize the cable connection and sealing problem of the electric heating equipment in the main wellbore and branch wellbore, solving the problem of connection and power supply of the electric heating equipment in the dense well network of the coal seam. The present application can realize the lowering of the electric heating equipment in one or more branch wellbores, which can effectively increase the range of the dense well network electric heating coal seam, improve the heating efficiency, thereby reducing the number of drilling, thereby reducing the workload, reducing the development cost, and finally realizing the efficient and green mining of coalbed methane.

[0024] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope. Features described and / or shown for one embodiment can be used in one or more other embodiments in the same or similar manner, combined with features in other embodiments, or replace features in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0026] Figure 1 Schematic diagram of coal seam gas development for electric heating of dense well patterns in coal seams;

[0027] Figure 2 This is a schematic diagram of the structure of the electric heating device connection device for the well pattern in the embodiment of the present application after being assembled underground;

[0028] Figure 3 This is a schematic diagram of the structure of the main support positioning column in the embodiment of the present application;

[0029] Figure 4 This is a schematic diagram of the structure of the main branch and branch connection pipe string in the embodiment of the present application;

[0030] Figure 5 This is a schematic diagram of the structure of the main-branch connection pipe string in the embodiment of the present application;

[0031] Figure 6 It is a cross-sectional schematic diagram of a first positioning and guiding connector in an embodiment of the present application;

[0032] Figure 7 for Figure 6 Sectional view at AA in the middle;

[0033] Figure 8 This is a schematic diagram of the structure of the branch connector in the embodiment of the present application;

[0034] Fig. 9 It is a structural schematic diagram of the main wellbore and the first branch wellbore of a horizontal well;

[0035] Fig.10 A schematic diagram of the main support positioning string after the positioning mechanism and the casing guide shoe are locked;

[0036] Fig.11Schematic diagram after the main support positioning string is run in;

[0037] Fig.12 A schematic diagram of the main branch and branch connecting pipe strings being lowered into the main wellbore casing;

[0038] Fig.13 A schematic diagram of a branch pipe string section connecting a main branch and a branch pipe string being lowered into a branch wellbore casing;

[0039] Fig.14 Schematic diagram after the main branch and branch connection strings are lowered;

[0040] Fig.15 This is a schematic diagram after the second main branch and branch connecting pipe string are lowered;

[0041] Fig.16 Schematic diagram after the main branch connecting pipe string is lowered and connected.

[0042] Reference numerals of the above drawings:

[0043] 1. Main branch positioning string; 2. Main branch and branch connection string; 3. Electric heating equipment; 4. Main branch connection string; 5. Main wellbore casing; 6. Branch wellbore casing; 7. Branch wellbore casing guide shoe; 8. Main wellbore casing guide shoe; 9. Cable; 10. Continuous oil pipe; 101. Inverted joint; 11. Positioning mechanism; 12. First positioning and guiding connector; 121. First connector body; 1211. First opening; 122. First elastic sealing sheet; 123. First joint sealing member; 1231. First opening; 124. First slider; 125. First spring; 126. First quick connector; 127. Third elastic sealing sheet; 128. First positioning block; 129. First elastic member; 1210. The first roller; 21. the guide; 22. the second positioning and guiding connector; 23. the first connecting mechanism; 231. the second elastic sealing sheet; 232. the second quick connector; 24. the branch connector; 241. the upper body of the branch connector; 242. the lower body of the branch connector; 243. the rotating mechanism; 2431. the outer ring raceway; 2432. the inner ring raceway; 2433. the roller; 2434. the second roller; 41. the second connecting mechanism; 42. the centralizer; 43. the third positioning and guiding connector; 51. the fourth quick connector; 100. the upper part of the coal seam; 200. the lower part of the coal seam; 300. the main wellbore screen; 400. the branch wellbore screen; 500. the gas production wellhead device; 600. the electric heating wellhead device. DETAILED DESCRIPTION

[0044] The details of the present invention can be more clearly understood by combining the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only used for the purpose of explaining the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be regarded as belonging to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on another element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the communication between the two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation method.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0046] In order to realize the convenient, fast and safe lowering of electric heating equipment in the main wellbore and branch wellbore of the coal seam, an electric heating device connection device for a well network is proposed in the present application. Figure 2 This is a schematic diagram of the structure of the electric heating device connection device for the well pattern in the embodiment of the present application after being assembled underground. Figure 3 This is a schematic diagram of the structure of the main support positioning column in the embodiment of the present application. Figure 4 This is a schematic diagram of the structure of the main branch and branch connection pipe string in the embodiment of the present application. Figure 5 Schematic diagram of the structure of the main and branch connection pipe string in the embodiment of the present application. Figures 2 to 5 As shown, the electric heating device connection device for the well network may include: a main branch positioning string 1, at least one main branch and branch connection string 2, a main branch connection string 4, and at least one electric heating device 3.

[0047] like Figure 2 and Figure 3As shown, the main branch positioning string 1 may include a positioning mechanism 11 that can be fixed with the casing, and a first positioning and guiding connector 12. The positioning mechanism 11 can be connected to the first positioning and guiding connector 12 through a continuous tubing 10, and the electric heating device 3 can be connected to the continuous tubing 10. The first positioning and guiding connector 12 can be positioned at the window of the main wellbore casing 5 connected to the branch wellbore.

[0048] like Figure 3 As shown, the positioning mechanism 11 may include a guide shoe that can be locked with the casing by itself, for example, the guide shoe can be locked with the casing guide shoe at the bottom of the casing. The upper end of the guide shoe is directly or indirectly connected to the electric heating device 3, and the upper end of the electric heating device 3 is connected to the first positioning and guiding connector 12.

[0049] like Figure 4 As shown, the main branch and branch connecting pipe string 2 may include: a main branch pipe string section and a branch pipe string section connected to the main branch pipe string section. The branch pipe string section may include a guide 21 located at the lowermost end that can be guided from the main wellbore casing 5 into the branch wellbore, and the guide 21 is connected to the main branch pipe string section through a coiled tubing 10. The coiled tubing 10 may be connected to an electric heating device 3.

[0050] like Figure 4 As shown, the lowermost end of the main branch pipe string section has a first connection mechanism 23, and the first connection mechanism 23 can be matched and connected with the first positioning and guiding connector 12. The matching connection here includes electrical connection and physical connection. The uppermost end of the main branch pipe string section has a second positioning and guiding connector 22. The first connection mechanism 23 can be connected to the second positioning and guiding connector 22 through a continuous tubing 10, and an electric heating device 3 can be connected between the first connection mechanism 23 and the second positioning and guiding connector 22. The first connection mechanism 23 may include a continuous tubing 10 and a second quick connector 232.

[0051] like Figure 5 As shown, the main branch connection string 4 may include a second connection mechanism 41 at the lowermost end, and the second connection mechanism 41 can be connected with the second positioning and guiding connector 22. The main branch connection string 4 may be connected with an electric heating device 3, and the electric heating device 3 is located above the second connection mechanism 41. The second connection mechanism 41 may include a coiled tubing 10 and a third quick connector.

[0052] like Figures 2 to 5As shown, the electric heating device connection device for the well network may include at least one electric heating device 3, and the electric heating device 3 is connected to at least one of the following positions: in the main branch positioning pipe string 1, in the branch pipe string section, in the main branch pipe string section, and in the main branch connecting pipe string 4. The electric heating device 3 may be a device that can heat the coal seam using electric energy, for example, converting electric energy into microwaves to heat the coal seam, and of course, other methods of using electricity to generate heat energy to heat the coal seam may also be used.

[0053] like Figure 2 As shown, when there are multiple main and branch connection pipe strings 2, the first connection mechanism 23 in the upper main and branch connection pipe string 2 can be matched and connected with the second positioning and guiding connector 22 in the adjacent lower main and branch connection pipe string 2; the second positioning and guiding connector 22 in the adjacent lower main and branch connection pipe string 2 can be positioned at the window of the main wellbore casing 5 connected to the branch wellbore. Through the above structure, multiple electric heating devices 3 in the electric heating device connection device can be respectively extended into multiple branch wellbores in a well, thereby increasing the range of dense well pattern electric heating coal seam through the electric heating device connection device and improving heating efficiency.

[0054] Figure 6 is a cross-sectional schematic diagram of a first positioning and guiding connector in an embodiment of the present application, Figure 7 for Figure 6 The cross-sectional view at AA in the middle is as follows: Figure 6 to Figure 7As shown, the first positioning and guiding connector 12 may include: a first connector body 121, a plurality of first elastic sealing sheets 122, a first slider 124, a first spring 125, a first quick connector 126, a first joint seal 123 and a cable 9. A first opening 1211 is formed inside the upper end of the first connector body 121, the first joint seal 123 is disposed in the first opening 1211, and a first opening 1231 is formed at the upper end of the first joint seal 123. Parts of the plurality of first elastic sealing sheets 122 are clamped between the first joint seal 123 and the first connector body 121, and parts of the plurality of first elastic sealing sheets 122 are distributed circumferentially, so as to cover the upper end of the first opening 1231. The upper end of the cable 9 is located in the first opening 1231 and connected to the first quick connector 126. The first slider 124 is fixedly mounted on the cable 9. A first spring 125 is arranged between the first slider 124 and the first connector seal 123, so that the first quick connector 126 can move in the axial direction in the first opening 1231. The first connection mechanism 23 can be inserted into the first opening 1231 through the first elastic sealing sheet 122 through the first opening 1211 and connected to the first quick connector 126. The other end of the cable 9 passes through the lower end of the first connector body 121 and enters the inside of the coiled tubing 10, and finally electrically connects with the electric heating device 3 in the main branch positioning string 1. The inner wall of the upper end of the first opening 1211 can have an internal thread, so as to be physically connected with the first connection mechanism 23, such as being threadedly connected with the lower end of the coiled tubing 10 in the first connection mechanism 23. The plurality of first elastic sealing sheets 122 can prevent water from entering the first opening 1231, thereby preventing the first quick connector 126 from short-circuiting. The first spring 125 can be used to make the first quick connector 126 have a tendency to move upward, thereby ensuring the firmness and sufficiency of the connection between the first quick connector 126 and the first connecting mechanism 23, avoiding a loose connection due to a small distance difference between the two, or when the distance between the two is too large, the first quick connector 126 can move backward a little to ensure a perfect fit between the two.

[0055] Furthermore, a plurality of third elastic sealing sheets 127 distributed circumferentially are provided at the entrance of the first opening 1211 at the upper end of the first connector body 121, and the third elastic sealing sheets 127 can shield the entrance of the first opening 1211 to prevent external water from entering the first opening 1211. When the first connecting mechanism 23 passes through the entrance of the first opening 1211, it needs to pass through the third elastic sealing sheet 127.

[0056] like Figure 3As shown, a first positioning block 128 capable of being extended and retracted in the radial direction is provided at the outer wall of the first connector body 121, and a first elastic member 129 is provided between the first positioning block 128 and the first connector body 121. A groove is provided at the upper end of the outer wall of the first connector body 121, and the first positioning block 128 and the first elastic member 129 are provided in the groove. There can be multiple first positioning blocks 128 and matching first elastic members 129, which are distributed along the circumferential direction of the first connector body 121. The first positioning block 128 will open under the action of the first elastic member 129 after the window of the main wellbore casing 5 connecting the branch wellbore, and will be fixed at the bottom end of the window of the main wellbore casing 5. The upper ends of the first connector body 121 and the first positioning block 128 have guiding slopes, so that the guide 21 of the branch pipe string section can smoothly enter the branch wellbore casing 6.

[0057] like Figure 3 As shown, a rotatable first roller 1210 is provided at the outer side wall of the first connector body 121, which can roll in the axial direction of the first connector body 121. There can be multiple first rollers 1210, which can be distributed along the circumference of the first connector body 121, or arranged along the axial direction of the first connector body 121. The first roller 1210 can reduce the axial friction resistance between the first connector body 121 and the sleeve.

[0058] like Figure 4 As shown, the first connection mechanism 23 may further include: a plurality of second elastic sealing sheets 231 covering the second quick connector 232. The second elastic sealing sheets 231 are used to prevent external water from contacting the second quick connector 232. The second quick connector 232 can be inserted into the first opening 1231 through the first elastic sealing sheet 122 through the first opening 1211, and the first quick connector 126 can pass through the second elastic sealing sheet 231 to be connected to the second quick connector 232.

[0059] like Figure 4 As shown, a branch connector 24 is connected to the main branch pipe string section. Figure 8 Schematic diagram of the structure of the branch connector in the embodiment of the present application. Figure 8As shown, the branch connector 24 includes a branch connector upper body 241 and a branch connector lower body 242. The branch pipe string section is connected to the branch connector lower body 242, and a rotating mechanism 243 is connected between the branch connector upper body 241 and the branch connector lower body 242, which can make the branch connector upper body 241 and the branch connector lower body 242 rotate relative to each other. The rotating mechanism 243 includes an outer ring raceway 2431, an inner ring raceway 2432, and a roller 2433 arranged between the outer ring raceway 2431 and the inner ring raceway 2432. The outer ring raceway 2431 is connected to the lower end of the branch connector upper body 241, the inner ring raceway 2432 is connected to the upper end of the branch connector lower body 242, and the outer ring raceway 2431 is sleeved outside the inner ring raceway 2432. Through the rotating mechanism 243, the branch connector lower body 242 and the branch pipe string section can be rotated, so that the branch pipe string section can enter the branch wellbore casing 6 at a suitable angle.

[0060] Further, such as Figure 8 As shown, a rotatable second roller 2434 may be provided on the side wall of the branch connector 24 , and the second roller 2434 may roll in the axial direction of the branch connector 24 .

[0061] like Figure 4 As shown, at least one electric heating device 3 is connected between the branch connector 24 and the second positioning and guiding connector 22. The electric heating device 3 and the second positioning and guiding connector 22 and the branch connector 24 can be connected through the continuous tubing 10. At least one electric heating device 3 is connected in the branch pipe string section.

[0062] like Figure 4 As shown, the structure of the second positioning and guiding connector 22 can be similar to that of the first positioning and guiding connector 12, and will not be repeated here. The lower end of the continuous tubing 10 of the second connecting mechanism 41 can be threadedly connected with the first opening 1211 of the first connector body 121 in the second positioning and guiding connector 22. The third quick connector can be matched and connected with the first quick connector 126 in the second positioning and guiding connector 22 to achieve electrical connection. The guide 21 can adopt a self-adjusting guide shoe so that the lowermost end of the branch pipe string section can quickly enter the casing of the branch wellbore and lock with the guide shoe of the branch wellbore casing 6. The cable 9 in the second positioning and guiding connector 22 passes through the continuous tubing 10 and is electrically connected to the electric heating device 3 on the main branch pipe string section, and then passes through the branch connector 24 and is electrically connected to the second quick connector 232. At the same time, the cable 9 passes through the branch connector 24 and enters the continuous tubing 10 in the branch pipe string section. Finally, the cable 9 is electrically connected to at least one electric heating device 3 in the branch pipe string section.

[0063] like Figure 5As shown, as feasible, a centralizer 42 and a third positioning and guiding connector 43 may also be connected to the main branch connecting pipe column 4. The structure of the third positioning and guiding connector 43 may be similar to that of the first positioning and guiding connector 12, and will not be repeated here. The third positioning and guiding connector 43 is connected to the uppermost end of the main branch connecting pipe column 4, and the centralizer 42 is located above the second connecting mechanism 41. The third positioning and guiding connector 43 is connected to the electric heating device 3 through the continuous tubing 10, and the electric heating device 3 is connected to the centralizer 42 through the continuous tubing 10, and the lower end of the centralizer 42 is connected to the continuous tubing 10 in the second connecting mechanism 41. The cable 9 in the third positioning and guiding connector 43 passes through the continuous tubing 10 to be electrically connected to the electric heating device 3, and then passes through the continuous tubing 10, the centralizer 42, and the continuous tubing 10 to be electrically connected to the third quick connector in the second connecting mechanism 41. The centralizer 42 may include an upper body of the centralizer 42 and a lower body of the centralizer 42, and a rotating mechanism 243 is connected between the upper body of the centralizer 42 and the lower body of the centralizer 42, which enables the upper body of the centralizer 42 and the lower body of the centralizer 42 to rotate relative to each other. The structure of the rotating mechanism 243 is similar to that of the rotating mechanism 243 in the branch connector 24, and will not be described in detail here. The side wall of the centralizer 42 may have a rotatable third roller, which can roll in the axial direction of the centralizer 42.

[0064] When the main branch connection string 4 is lowered into the main wellbore casing 5, the main branch connection string 4 can be lowered by connecting the coiled tubing 10 with the fourth quick connector 51. The cable 9 passes through the coiled tubing 10 and is connected to the fourth quick connector 51. The fourth quick connector 51 can be electrically connected to the first quick connector 126 at the upper end of the third positioning and guiding connector 43, and the coiled tubing 10 is threadedly connected to the first opening 1211 at the upper end of the third positioning and guiding connector 43.

[0065] The present application also proposes a method for connecting an electric heating device for a well network. The method may use the above-mentioned electric heating device connection device for a well network. The method for connecting an electric heating device for a well network may include the following steps:

[0066] Fig. 9 It is a structural schematic diagram of the main wellbore and the first branch wellbore of the horizontal well. Fig. 9 As shown, after casing is run into the main wellbore and completed, the first branch wellbore is side-drilled and casing is run into. The main wellbore can be a horizontal wellbore. The bottom of the main wellbore casing 5 is the main wellbore casing guide shoe 8. The bottom of the branch wellbore casing 6 is the branch wellbore casing guide shoe 7.

[0067] Fig.10 The schematic diagram of the main support positioning string after the positioning mechanism and the casing guide shoe are locked. Fig.10As shown, the main branch positioning pipe string 1 is lowered into the main wellbore casing guide shoe 8 at the bottom of the main wellbore casing 5, the positioning mechanism 11 is fixed to the main wellbore casing guide shoe 8, and the first positioning and guiding connector 12 is fixedly positioned at the window of the main wellbore casing 5 connecting the branch wellbore.

[0068] In the above steps, the length of the main branch positioning string 1 is determined according to the length between the main wellbore casing guide shoe 8 and the side drilling point of the first branch wellbore, and the oil pipe string with the reverse joint 101 with the straightening block is connected to the first opening 1211 in the first positioning and guiding connector 12 at the top of the main branch positioning string 1, and the main branch positioning string 1 is sent to the main wellbore casing 5 through the oil pipe. During the lowering process, the positioning mechanism 11 of the main branch positioning string 1 remains in a retracted state in the casing. After entering the main wellbore casing guide shoe 8, the side wings of the positioning mechanism 11 are opened and fixed in the groove inside the main wellbore casing guide shoe 8 under the action of the spring, completing the fixed connection between the self-locking guide shoe and the main wellbore casing guide shoe 8. The first positioning block 128 of the first positioning and guiding connector 12 of the main branch positioning string 1 is in a retracted state in the casing. When the window opening position of the main wellbore casing 5 is reached, the first positioning block 128 is opened and fixed to the bottom of the window of the main wellbore casing 5 under the action of the first elastic member 129 to prevent the main branch positioning string 1 from continuing to descend. At the same time, the first roller 1210 of the first positioning and guiding connector 12 can reduce the friction resistance during the lowering of the main branch positioning string 1. Then, the lowered oil pipe string and the reverse joint 101 are rotated clockwise to complete the separation from the first opening 1211 of the first positioning and guiding connector 12, and the oil pipe string and the reverse joint 101 are pulled out after separation. Fig.11 Schematic diagram after the main support positioning string is lowered.

[0069] Fig.12 The schematic diagram of the main branch and branch connecting pipe string being lowered into the main wellbore casing is as follows: Fig.12 As shown, if it is necessary to run a plurality of main branches and branch connection pipe strings 2, a guide drilling tool can be run to drill a second branch wellbore inside the main wellbore casing 5, and a casing is run into the branch wellbore to complete the well. The second branch wellbore is located at the end of the first branch wellbore closer to the wellhead.

[0070] like Fig.12 As shown, after the main branch positioning string 1 is lowered, the main branch and branch connecting string 2 is lowered into the main wellbore casing 5, and the branch pipe string section is allowed to enter the branch wellbore casing 6 through the guide 21 of the branch pipe string section. Thereafter, the first connecting mechanism 23 of the main branch pipe string section is matched and connected with the first positioning and guiding connector 12.

[0071] In the above steps, the length of the main branch pipe string section in the main branch and branch connecting pipe string 2 is determined according to the length between the first sub-sidetracking point and the second sub-sidetracking point. The oil pipe string is connected to the second positioning and guiding connector 22 at the top of the main branch and branch connecting pipe string 2 through the reverse joint 101 with the straightening block, and the main branch and branch connecting pipe string 2 is sent to the main wellbore casing 5 through the oil pipe string. Fig.12 As shown, the guide 21 of the branch pipe string section can be guided by an inclined surface at the top of the first positioning and guiding connector 12, which can be a cone, and adjusted to a suitable angle under guidance to enter the branch wellbore casing 6. Fig.13 The schematic diagram of the branch pipe string section connecting the main branch and the branch pipe string being lowered into the branch wellbore casing is as follows: Fig.13 As shown, the second roller 2434 on the branch connector 24 can reduce the axial friction resistance, and the rotating mechanism 243 can make the lower body 242 of the branch connector rotate in the circumferential direction to adjust the position and angle of the first connecting mechanism 23 at the bottom of the main branch pipe string section, so that the second quick connector 232 of the first connecting mechanism 23 enters the first opening 1211 of the first connector body 121 of the first positioning and guiding connector 12, and then enters the first opening 1231, pushing the first slider 124 to move and complete the connection with the first quick connector 126, and locks in the first opening 1231. The first elastic sealing sheet 122 fills the gap at the connection to achieve sealing. Rotate the tubing string clockwise, and after the reverse joint 101 and the second positioning and guiding connector 22 are separated, lift out the tubing string and the reverse joint 101, Fig.14 Schematic diagram after the main branch and branch connecting pipe strings are lowered.

[0072] If it is necessary to connect multiple main branches and branch connection strings 2, repeat the above steps. Fig.15 This is a schematic diagram of the second main branch and branch connection string after it is lowered. Fig.15 As shown, the first connection mechanism 23 in the upper main branch and branch connection string 2 can be matched and connected with the second positioning and guiding connector 22 in the adjacent lower main branch and branch connection string 2. The second positioning and guiding connector 22 in the adjacent lower main branch and branch connection string 2 can be positioned at the window above the second connected branch wellbore of the main wellbore casing 5.

[0073] After the main branch and branch connection string 2 are lowered, Fig.16 The schematic diagram of the main branch connecting string after the connection is completed. Fig.16 As shown, the main-branch connecting string 4 is lowered into the main wellbore casing 5, and the second connecting mechanism 41 is matched and connected with the second positioning and guiding connector 22 of the main-branch and branch connecting strings 2. The upper end of the main-branch connecting string 4 is connected to a continuous oil pipe 10 with a built-in cable 9, and the built-in cable 9 is used to supply power to the electric heating device 3 in the electric heating device connection device.

[0074] In the above steps, the length of the main branch connection string 4 and the continuous tubing 10 with built-in cable 9 is determined according to the position of the second positioning and guiding connector 22 at the top of the last main branch and branch connection string 2. The second positioning and guiding connector 22 at the top of the main branch and branch connection string 2 is connected to the second connection mechanism 41 at the lower end of the main branch connection string 4, including the third quick connector of the second connection mechanism 41 being electrically connected to the first quick connector 126 of the second positioning and guiding connector 22, and the continuous tubing 10 of the second connection mechanism 41 being threadedly connected to the first opening 1211 of the first connector body 121 of the second positioning and guiding connector 22. The main branch connection string 4 is sent to the second positioning and guiding connector 22 at the top of the last group of main branch and branch connection strings 2 through the continuous tubing 10 with built-in cable 9 to complete the connection. The cable 9 inside the coiled tubing 10 is electrically connected to the first quick connector 126 in the third positioning and guiding connector 43 at the upper end of the main branch connecting string 4, and the coiled tubing 10 is threadedly connected to the opening of the connector body in the third positioning and guiding connector 43 at the upper end of the main branch connecting string 4. The cable 9 inside the coiled tubing 10 extends to the ground and is connected to the ground equipment, thereby realizing power supply to all the electric heating devices 3 in the electric heating device connection device for the well network.

[0075] The electric heating device connection device and connection method for the well network in the present application can realize the safe lowering of the electric heating device 3 in the main wellbore and the branch wellbore of the coal seam, and can also realize the connection and sealing problem of the cable 9 of the electric heating device 3 in the main wellbore and the branch wellbore, solving the connection and power supply problem of the electric heating device 3 in the dense well network of the coal seam. The present application can realize the lowering of the electric heating device 3 in any branch wellbore, which can effectively increase the range of the dense well network electric heating coal seam, improve the heating efficiency, thereby reducing the number of drilling, thereby reducing the workload, reducing the development cost, and finally realizing the efficient and green mining of coalbed methane.

[0076] All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for various purposes. The term "consisting essentially of ... " describing a combination should include determined elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel features of the combination. The use of the terms "comprising" or "including" to describe the combination of elements, ingredients, parts or steps here also contemplates the implementation method consisting essentially of these elements, ingredients, parts or steps. Here, by using the term "may", it is intended to illustrate that any attribute described that "may" includes is optional. Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "one" used to describe an element, ingredient, part or step is not said to exclude other elements, ingredients, parts or steps.

[0077] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An electric heating device connection device for a well pattern, characterized in that: The electric heating device connection device for the well pattern comprises: A main branch positioning string, comprising a positioning mechanism capable of being fixed to the casing, and a first positioning and guiding connector, wherein the first positioning and guiding connector can be positioned at a window of the main wellbore casing connected to the branch wellbore; At least one main branch and branch connecting pipe string, comprising: a main branch pipe string section and a branch pipe string section connected to the main branch pipe string section, the branch pipe string section comprising a guide at the lowest end capable of guiding from the main wellbore casing into the branch wellbore, the lowest end of the main branch pipe string section having a first connecting mechanism, the first connecting mechanism being capable of being matched and connected with the first positioning and guiding connector, and the upper end of the main branch pipe string section having a second positioning and guiding connector; The main branch connecting pipe column comprises a second connecting mechanism located at the lowermost end, wherein the second connecting mechanism can be matched and connected with the second positioning and guiding connector; At least one electric heating device, the electric heating device is connected to at least one of the following positions: in the main branch positioning pipe string, in the branch pipe string section, in the main branch pipe string section, and in the main branch connecting pipe string; At least one of the electric heating devices is connected to the main branch positioning column, and the positioning mechanism includes a guide shoe that can be locked with the casing by itself; the upper end of the guide shoe is connected to the electric heating device, and the upper end of the electric heating device is connected to the first positioning and guiding connector; the first positioning and guiding connector includes: a first connector body, a plurality of first elastic sealing sheets, a first slider, a first spring, a first quick connector, a first joint seal and a cable; a first opening is formed inside the upper end of the first connector body, the first joint seal is arranged in the first opening, a first opening is formed at the upper end of the first joint seal, and parts of the plurality of first elastic sealing sheets are clamped in the Between the first joint seal and the first connector body, a portion of the plurality of first elastic sealing sheets can cover the upper end of the first opening, the upper end of the cable is located in the first opening and connected to the first quick connector, a first slider is fixedly mounted on the cable, and the first spring is arranged between the first slider and the first joint seal so that the first quick connector can move along the axial direction in the first opening; the first connecting mechanism can be inserted into the first opening through the first elastic sealing sheet through the first opening and connected to the first quick connector; the other end of the cable is electrically connected to the electric heating device in the main support positioning column.

2. The electric heating device connection device for a well pattern according to claim 1, characterized in that: When there are multiple main and branch connection pipe columns, the first connection mechanism in the upper main and branch connection pipe column can be matched and connected with the second positioning and guiding connector in the adjacent lower main and branch connection pipe column; The second positioning and guiding connector in the adjacent lower main and branch connecting pipe strings can be positioned at the window of the main wellbore casing connected to the branch wellbore.

3. The electric heating device connection device for a well pattern according to claim 1, characterized in that: A first positioning block capable of extending and retracting in a radial direction is arranged on the outer side wall of the first connector body, and a first elastic member is arranged between the first positioning block and the first connector body.

4. The electric heating device connection device for a well pattern according to claim 1, characterized in that: A rotatable first roller is disposed on the outer side wall of the first connector body and can roll in the axial direction of the first connector body.

5. The electric heating device connection device for a well pattern according to claim 1, characterized in that: The first connecting mechanism includes: a second quick connector; a plurality of second elastic sealing sheets covering the second quick connector, the second quick connector can be inserted into the first opening through the first elastic sealing sheet through the first opening, and the first quick connector can pass through the second elastic sealing sheet to be connected to the second quick connector.

6. The electric heating device connection device for a well pattern according to claim 5, characterized in that: A branch connector is connected to the main branch pipe column section, and the branch connector includes a branch connector upper body and a branch connector lower body. The branch pipe column section is connected to the branch connector lower body, and a rotating mechanism is connected between the branch connector upper body and the branch connector lower body, which can make the branch connector upper body and the branch connector lower body rotate relative to each other, and the rotating mechanism includes an outer ring raceway, an inner ring raceway and a roller arranged between the outer ring raceway and the inner ring raceway.

7. The electric heating device connection device for a well pattern according to claim 6, characterized in that: At least one of the electric heating devices is connected between the branch connector and the second positioning and guiding connector; at least one of the electric heating devices is connected in the branch pipe string section.

8. The electric heating device connection device for a well pattern according to claim 7, characterized in that: The cable in the second positioning and guiding connector is electrically connected to the second quick connector, and the cable in the second positioning and guiding connector is electrically connected to at least one of the electric heating devices in the branch pipe string section.

9. A method for connecting an electric heating device for a well pattern using the electric heating device connecting device for a well pattern as claimed in any one of claims 1 to 8, characterized in that: The method for connecting the electric heating device for the well pattern comprises: The main branch positioning string is lowered into the main wellbore casing guide shoe at the bottom of the main wellbore casing, the positioning mechanism is fixed to the main wellbore casing guide shoe, and the first positioning and guiding connector is fixed and positioned at the window of the main wellbore casing connected to the branch wellbore; After the main branch positioning pipe string is lowered, the main branch and branch connecting pipe strings are lowered into the main wellbore casing, and the branch pipe string section is made to enter the branch wellbore casing through the guide of the branch pipe string section, and then the first connecting mechanism of the main branch pipe string section is matched and connected with the first positioning and guiding connector; After the main branch and branch connecting pipe strings are lowered, the main branch connecting pipe strings are lowered into the main wellbore casing, and the second connecting mechanism is matched and connected with the second positioning and guiding connector of the main branch and branch connecting pipe strings. The upper end of the main branch connecting pipe string is connected to a continuous oil pipe with a built-in cable, and power is supplied to the electric heating device in the electric heating device connecting device through the built-in cable.

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