Steering device and construction method for multi-branch completion string

Abstract

The present invention provides a guiding device for a multi-branch completion string, comprising: a guide, wherein the upper end surface of the guide is provided with a guiding inclined surface; a guide delivery pipe string, which comprises a delivery oil pipe, a gyroscopic positioning short section connected to the delivery oil pipe, and a guide delivery short section, wherein the gyroscopic positioning short section is used to determine the relative orientation of the guide inclined surface of the guide and the window, and the guide delivery short section is used to connect the guide and lower it into the wellbore, and the guide can be driven to rotate by rotating the delivery oil pipe so that the guiding inclined surface is aligned with the window; wherein the guide delivery pipe string is constructed so that the guide delivery short section can be separated from the guide by pressing down the delivery oil pipe and pressing and lifting, so that the guide delivery pipe string can be taken out. The present invention also provides a guiding construction method for a multi-branch completion string.

Description

Technical Field

[0001] The present invention belongs to the technical field of petroleum completion and production, and specifically relates to a guiding device for a multi-branch completion string. The present invention also relates to a construction method for a multi-branch completion string. Background Art

[0002] Branch well technology refers to a branch wellbore that is drilled from the side of a main wellbore to enter the reservoir for oil production. Since its branches share a common wellhead and upper well section, the drilling cost is greatly reduced. It can realize the production of multiple oil and gas layers on one main wellbore, realize multi-target and three-dimensional production in one well, and is an important technical means to achieve economical and efficient development of oil and gas wells.

[0003] At present, branch well technology has been applied to major oil fields at home and abroad, but most of them belong to level 4 and below completion. Level 4 and below branch well completion technology has reliable mechanical tie-back and branch re-entry capabilities, but the window sealing cannot be guaranteed, which leads to serious well construction risks.

[0004] With the continuous development of oilfield exploitation technology, branch well technology of level five and above has good window hydraulic sealing and low well construction risk, and is gradually becoming the forefront and hot spot of branch well development technology in oil and gas fields. In the prior art, there are also cases of using five-level branch completion technology. However, the current five-level branch completion technology is prone to still have some problems. For example, in the prior art, the pipe string guidance efficiency in the five-level branch completion technology is low, the guidance accuracy is poor, and the window sealing and the back-connection sealing of the pipe string cannot be effectively guaranteed. In addition, the cost, process, etc. of the five-level completion technology in the prior art are relatively complicated. This also greatly increases the cost of downhole operations. Summary of the invention

[0005] In response to the technical problems mentioned above, the present invention aims to propose a guiding device for a multi-branch completion string, which can accurately locate the window and achieve the back-connection sealing of the main wellbore and the branch wellbore, effectively ensuring the reliable guiding and long-term sealing of the multi-branch completion string, which is very beneficial to reducing the risk of well construction.

[0006] The invention also provides a guiding construction method for a multi-branch completion pipe string.

[0007] To this end, according to a first aspect of the present invention, there is provided a guiding device for a multi-branch completion tubing, comprising: a guide, wherein the upper end surface of the guide is provided with a guiding slope; a guide delivery pipe string, which comprises an oil delivery pipe, a gyroscopic positioning short section connected to the oil delivery pipe, and a guide delivery short section, wherein the gyroscopic positioning short section is used to determine the relative orientation of the guiding slope of the guide and the window, and the guide delivery short section is used to connect the guide and lower it into the wellbore, and the guide can be driven to rotate by rotating the oil delivery pipe so that the guiding slope is aligned with the window; wherein the guide delivery pipe string is constructed to be able to separate the guide delivery short section from the guide by pressing down the oil delivery pipe and pressing up, so that the guide delivery pipe string can be removed.

[0008] In one embodiment, the guide delivery short section includes a core shaft and an elastic claw sleeved on the core shaft, the end of the core shaft is provided with a head whose diameter gradually increases toward the axial end, and the guide is provided with an annular inner groove, and the head can form radial support for the elastic claw so that the elastic claw is adapted to the inner groove, thereby connecting the guide and the guide delivery short section.

[0009] In one embodiment, the guide delivery short section also includes a pressing sleeve fixedly connected to the upper end of the core shaft and an elastic member arranged axially between the pressing sleeve and the elastic claw, the core shaft is provided with a flow channel extending from the axial upper end face to the interior, the outer periphery of the core shaft is provided with an annular protrusion, the upper end inner wall of the elastic claw is provided with a step with the end face facing downward, and a sealed annular liquid cavity is formed between the upper end face of the annular protrusion and the end face of the step, the core shaft is provided with a pressure transmission hole connecting the flow channel and the annular liquid cavity, wherein, by pressing down the delivery oil pipe, the pressing sleeve can axially compress the elastic member and push the core shaft to move axially downward relative to the elastic claw, so that the head releases its support for the elastic claw, and then the pressure in the flow channel acts on the step through the pressure transmission hole by pressing, thereby separating the elastic claw from the inner groove of the guide.

[0010] In one embodiment, the guide is provided with a plurality of axially extending long grooves, which are evenly distributed circumferentially, and the head is provided with a plurality of axially evenly distributed ribs, which can be adapted to the long grooves, so that torque can be transmitted by rotating the upper oil pipe to drive the guide to rotate.

[0011] According to a second aspect of the present invention, a guiding construction method for a multi-branch completion string is provided, comprising the following construction steps:

[0012] Providing a guide device as described above;

[0013] A main completion string and a branch completion string are respectively lowered into the main wellbore and the branch wellbore;

[0014] The guide is lowered into the main wellbore and anchored so that the guide slope of the guide is aligned with the window and the lower end of the guide is connected to the main completion pipe string;

[0015] A window brancher is lowered, the lower end of which is respectively connected to a main return pipe string and a branch return pipe string which are independent of each other. During the lowering process, the branch return pipe string contacts the guide slope on the guide and is introduced into the branch wellbore until it is adapted to be connected with the branch completion pipe string, and the main return pipe string is adapted to be connected with the guide, thereby completing the connection of the pipe string and realizing the completion;

[0016] Carry out production operations.

[0017] In one embodiment, the lower end of the guide is connected to the main completion pipe string using a bent oil pipe.

[0018] In one embodiment, a first sealing tie-back cylinder is provided at the top of the main completion pipe string, and a first main sealing plug is provided at the lower end of the bent oil pipe. During the process of lowering the guide, the first main sealing plug can be adapted to be inserted into the first sealing tie-back cylinder, so that the guide and the main completion pipe string form a sealed connection.

[0019] In one embodiment, a second main return connection plug is provided at the lower end of the main return connection pipe string. During the process of lowering the main return connection pipe string, the second main return connection plug can be adapted to be inserted into a sealing hole provided inside the guide, so that the main return connection pipe string forms a sealed connection with the main completion pipe string.

[0020] In one embodiment, a second sealing return tube is provided at the top of the branch completion pipe string, and a branch sealing plug is provided at the lower end of the branch return pipe string. During the process of lowering the branch return pipe string, the branch sealing plug can be adapted to be inserted into the second sealing return tube, so that the branch return pipe string forms a sealed connection with the branch completion pipe string.

[0021] In one embodiment, the window brancher uses hydraulic sealing at the branch.

[0022] Compared with the prior art, the advantages of this application are:

[0023] The guiding device for the multi-branch completion string according to the present invention can accurately locate the window, which is very beneficial to improving the directional positioning efficiency of the guide, and can realize the back-connection sealing of the main wellbore and the branch wellbore, effectively ensuring the reliable guidance and long-term sealing of the multi-branch completion string, which is very beneficial to reducing the risk of well construction. The present invention realizes a five-level branch completion pipe string guiding technology through the above-mentioned guiding construction method for the multi-branch completion string, which is equipped with a special guide to send the pipe string into the guide, improves the directional efficiency of the guide, and enhances the directional accuracy. At the same time, the window brancher is used to realize the back-connection sealing of the main wellbore and the branch wellbore through the guidance of the guide, effectively ensuring the sealing performance of the connection between the upper back-connection pipe string and the lower completion pipe string. This is very beneficial to enhance the window hydraulic sealing of the branch well technology of level five and above, and is beneficial to reducing the risk of well construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described below with reference to the accompanying drawings.

[0025] Figure 1 The figure shows the state of the guiding device for the multi-branch completion string according to the present invention after being lowered into the wellbore.

[0026] Figure 2 Shows Figure 1 The structure of the guide in the guide device shown.

[0027] Figure 3 and Figure 4 Shows Figure 1 The guide in the guide device shown is fed into the structure of the short section.

[0028] Figures 5 to 7 The process of the guide being fed into the short section and then being separated from the guide is shown.

[0029] Figure 8 It shows the status of the wellbore after completion.

[0030] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0031] The present invention will be described below with reference to the accompanying drawings.

[0032] In the present application, it should be noted that the end of the guiding device for multi-branch completion tubing according to the present invention lowered into the wellbore close to the wellhead is defined as the "upper end" or similar terms, and the end away from the wellhead is defined as the "lower end" or similar terms.

[0033] Figure 1The figure shows the state of the guide device 100 for the multi-branch completion string according to the present invention after being lowered into the wellbore. The guide device 100 will be described in detail below in conjunction with the accompanying drawings. Figure 1 As shown, the guide device 100 includes a guide 1 and a guide delivery pipe string, and the guide delivery pipe string is used to connect the guide 1 to deliver the guide 1 to a predetermined position in the wellbore. The upper end surface of the guide 1 is constructed with a guide slope 10 for guiding the return pipe string. The guide delivery pipe string includes an oil delivery pipe 2, a gyro positioning short section 3 connected to the oil delivery pipe 2, and a guide delivery short section 4. The gyro positioning short section 3 is used to determine the relative orientation of the guide slope 10 of the guide 1 and the window of the branch wellbore. The guide delivery short section 4 is used to connect the guide 1 and lower it into the wellbore. The guide delivery short section 4 is constructed to be able to drive the guide 1 to rotate by rotating the oil delivery pipe 2, so as to adjust the guide slope 10 to align with the window.

[0034] like Figure 2 As shown, the guide 1 is roughly cylindrical, and the upper end surface of the guide 1 is formed as a guide slope 10. A through hole is provided inside the guide 1, which axially penetrates the guide 1. The through hole is eccentrically arranged and biased toward the high side of the guide slope. A long groove 12 partially extending in the axial direction is provided on the inner wall surface of the guide 1, and the long groove 12 extends axially inward from the guide slope 10 to the inside of the guide 1. At the same time, an inner groove 11 extending radially outward is also provided on the inner wall surface of the guide 1. The functions of the inner groove 11 and the long groove 12 will be introduced below.

[0035] like Figure 3 As shown, the guide delivery short section 4 includes a core shaft 41, an elastic claw 42, a pressing sleeve 43 and an elastic member 44. The elastic claw 42 is sleeved on the core shaft 41 and can move axially along the core shaft 41. A head 411 is provided at the end of the core shaft 41, and the head 411 is configured as a conical structure with a gradually increasing diameter along the axial direction outward. The head 411 can form radial support for the elastic claw 42 corresponding to the claw position of the elastic claw 42, so that the elastic claw 42 can be adapted and installed in the inner groove 11 of the guide 1 to form a lock. Thus, the guide 1 is connected to the lower end of the guide delivery short section 4.

[0036] According to one embodiment of the present invention, Figure 4As shown, a rib 415 is provided on the outer peripheral surface of the head 411 of the mandrel 41, and the rib 415 can be adapted to the long groove 12 in the guide 1. Therefore, the torque can be transmitted by rotating the upper oil pipe 2, thereby driving the guide 1 to rotate. Preferably, a plurality of axially extending long grooves 12 are provided in the guide 1, and the plurality of long grooves 12 are evenly distributed circumferentially, and a plurality of ribs 415 that can be adapted to be inserted into the long grooves 12 are also provided on the head 411 of the mandrel 41. In this way, the guide delivery pipe string can adjust the orientation of the guide slope 10 of the guide 1 by rotating the upper oil pipe 2, thereby realizing the orientation of the guide 1, which is very convenient and quick, and significantly improves the positioning, orientation and anchoring efficiency of the guide 1.

[0037] In this embodiment, the gyro positioning subsection 3 includes a gyro 9 (not shown), and the relative position of the gyro positioning subsection 3 and the window of the branch well can be known by inserting the gyro. Since the position of the gyro positioning subsection 3 and the position of the guiding slope 10 of the guide 1 have been determined on the ground, the relative position of the guiding slope 10 of the guide 1 and the window can be known. Therefore, the position of the guiding slope 10 of the guide 1 can be adjusted by rotating the delivery pipe string, and the orientation of the guide 1 can be achieved.

[0038] like Figure 3 As shown, the pressing sleeve 43 is fixedly connected to the upper end of the mandrel 41. For example, the pressing sleeve 43 is fixedly connected to the mandrel 41 through a thread. The upper end of the pressing sleeve 43 is configured as a connecting buckle for connecting with the oil delivery pipe 2. The upper end portion of the mandrel 41 extends to the inside of the pressing sleeve 43, so that the pressing sleeve 43 is sleeved on the mandrel 41. The inside of the pressing sleeve 43 is provided with a shoulder with the end face facing downward. The upper end of the elastic claw 42 extends between the pressing sleeve 43 and the mandrel 41, so that an annular installation space is formed between the mandrel 41, the pressing sleeve 43, and the upper end face of the shoulder and the elastic claw 42. The elastic member 44 is installed in the installation space, and the upper end of the elastic member 44 abuts against the shoulder, and the lower end abuts against the upper end face of the elastic claw 42. The elastic member 44 can be, for example, a spring.

[0039] like Figure 3 As shown, a flow channel 412 is provided inside the core shaft 41. The flow channel 412 extends axially inward from the axial upper end surface of the core shaft 41 and ends inside the core shaft 41. Figure 3In the illustrated embodiment, the flow channel 412 extends to a position close to the axial middle of the core shaft 41. An annular protrusion 413 is provided on the outer peripheral surface of the core shaft 41, and the annular protrusion 413 is arranged at the axial lower end position of the end of the flow channel 412. At the same time, a step 421 with the end face facing downward is provided on the inner wall surface of the upper end of the elastic claw 42. As a result, a closed annular liquid cavity 45 is formed between the upper end face of the annular protrusion 413 and the end face of the step 421. The core shaft 41 is also provided with a pressure transmission hole 414 connected to the flow channel 412, and the pressure transmission hole 414 is arranged near the end position of the flow channel 412, and the pressure transmission hole 414 connects the flow channel 412 and the annular liquid cavity 45.

[0040] Figures 5 to 7 The figure shows the connection and disconnection process between the guide delivery sub 4 and the guide 1. Figure 5 As shown, the guide 1 is connected to the lower end of the guide delivery sub 4. In this state, the guide 1 can be lowered into the guide delivery pipe string. The elastic claws 42 are radially expanded under the action of the head 411, and are adapted to engage with the inner groove 11 of the guide 1, so that the guide 1 is connected to the lower end of the guide delivery sub 4. After the guide 1 reaches the predetermined position in the wellbore, and the orientation and anchoring of the guide 1 are completed.

[0041] like Figure 6 As shown, by pressing down the oil pipe 2, the pressing sleeve 43 axially compresses the elastic member 44 downward, and pushes the core shaft 41 to move axially downward relative to the elastic claw 42, so that the head 411 of the core shaft 41 is offset from the elastic claw 42, thereby releasing the radial support for the elastic claw 42.

[0042] like Figure 7 As shown, further, by pressing to increase the pressure in the pipe string, the liquid pressure in the flow channel 412 of the core shaft 41 is transmitted to the annular liquid chamber 45 through the pressure transmission hole 414, so that the pressure in the annular liquid chamber 45 increases, so that the liquid pressure acts on the end surface of the step 421 of the elastic claw 42. As the pressure continues to increase, the elastic claw 42 is separated from the inner groove 11 of the guide 1, and then the guide is lifted up to send the pipe string, so that the guide is sent into the pipe string and the guide 1 is separated, so that the guide is sent out of the wellbore. In this way, the introduction and directional anchoring of the guide 1 are completed.

[0043] The present invention also proposes a guiding construction method for a multi-branch completion pipe string, in which the guiding device 100 is used for guiding.

[0044] First, lower completion pipe strings are lowered into the drilled main wellbore and branch wellbore. The lower completion pipe string includes a main completion pipe string 5 and a branch well completion pipe string 6. The main completion pipe string 5 is lowered into the main wellbore, and the branch well completion pipe string 6 is lowered into the branch well completion pipe string 6. After the main completion pipe string 5 and the branch well completion pipe string 6 are respectively lowered into the appropriate positions in the main wellbore and the branch wellbore, the main completion pipe string 5 and the branch well completion pipe string 6 can be hung by corresponding hangers and cemented. In this way, the main completion pipe string 5 and the branch well completion pipe string 6 can be left in the main wellbore and the branch wellbore, and the main completion pipe string 5 and the branch well completion pipe string 6 are kept in the appropriate positions in the wellbore by corresponding hangers.

[0045] According to the present invention, a first sealing tie-back tube is provided at the top of the main completion string 5, and a second sealing tie-back tube is provided at the top of the branch completion string 6. The first sealing tie-back tube and the second sealing tie-back tube are used to adapt and connect the upper completion string.

[0046] After that, the guide 1 is lowered into the main wellbore. The guide 1 is connected to the guide delivery pipe string, and then the guide 1 is delivered to the window position in the wellbore. First, the delivery pipe 2, the gyro positioning short section 3, and the guide delivery short section 4 are connected in sequence, and the guide 1 is connected to the lower end of the guide delivery short section 4. At the same time, ensure that the rib 415 on the head 411 of the guide delivery short section 4 is adapted to be inserted into the long groove 12 of the guide 1. As a result, the guide 1 and the guide delivery short section 4 form a Figure 5 The connection state shown. Then, the guide 1 is lowered by lowering the oil pipe 2. During the lowering process, when the pipe string is sent to a position about one oil pipe above the window, the relative position of the gyro positioning short section 3 and the window can be known by inserting a gyro. Since the position of the gyro positioning short section and the position of the guide slope of the guide have been determined before the wellhead is lowered, the relative position of the guide slope 10 of the guide and the window can be known. After that, the position of the guide slope 10 of the guide 1 is aligned with the position of the window by rotating the feeding pipe string. After that, the guide feeding pipe string is further lowered to connect the lower end of the guide 1 with the main completion pipe string 5. At this time, the guide slope 10 of the guide 1 is aligned with the window.

[0047] According to the present invention, the lower end of the guide 1 is connected to the main completion pipe string 5 by using a bent oil pipe 8. The bent oil pipe 8 is fixedly connected to the lower end of the guide 1, and a first main sealing plug 81 is provided at the lower end of the bent oil pipe 8. In the process of lowering the guide 1, the bent oil pipe 8 is adapted to be inserted into the first sealing return tube at the upper end of the main completion pipe string 5 through the first main sealing plug 81, so that the guide 1 is sealed and connected to the main completion pipe string 5. The bent oil pipe 8 can ensure that the main completion pipe string 5 at the lower end is in a concentric position with the upper casing, which facilitates the subsequent insertion of the first main sealing plug 81 into the first sealing return tube.

[0048] In one embodiment, a toothed male buckle (not shown) is provided on the outer side of the first main sealing plug 81, which is used to cooperate with the toothed female buckle in the first sealing tie-back tube at the upper end of the main completion pipe string 5. After the first main sealing plug 81 is inserted, the pipe string can be locked, and the first main sealing plug 81 and the first sealing tie-back tube can be sealed. Thus, the guide 1 can be connected to the main completion pipe string 5 as a whole through the bent oil pipe 8, and the guide can be sealed with the main wellbore pipe string 5.

[0049] After the guiding slope 10 of the guide 1 is aligned with the window and the tie-back is completed, the guide 1 is anchored to the inner wall of the main wellbore. Figure 6 and Figure 7 As shown, by pressing down the oil delivery pipe 2, the elastic claw 42 is separated from the head 411 of the mandrel 41, and the elastic claw 42 loses the radial support of the head 411 of the mandrel 41. Further, by pressing inside the pipe string, the pressure acts on the end face of the step 421 of the elastic claw 42 through the pressure transmission hole 414. Under the action of the pressure, the elastic claw 42 is pulled out of the inner groove 11 of the guide 1, so that the elastic claw 42 is separated from the inner groove 11 of the guide 1. At this time, the guide delivery short section 4 is separated from the guide 1, and then the entire guide delivery pipe string can be lifted up. In this way, the delivery and anchoring of the guide 1 are completed.

[0050] After that, it goes down into the window brancher 7 and goes down into the upper return pipe string through the window brancher 7. Figure 8 As shown, the upper end of the window branch 7 is connected to the upper oil pipe 9, and the window branch 7 is lowered by lowering the upper oil pipe 9. The return pipe string includes a main return pipe string 71 and a branch return pipe string 72, and the main return pipe string 71 and the branch return pipe string 72 are independently connected to the lower end of the window branch 7. The length of the branch return pipe string 72 is greater than the length of the main return pipe string 71. During the lowering process, the branch return pipe string 72 first contacts the guide slope 10 at the upper end of the guide 1, so that under the action of the guide 1, the branch return pipe string 72 is guided into the branch wellbore, and the pipe string is continuously lowered until the lower end of the branch return pipe string 72 is adapted to be connected with the branch completion pipe string 6. At the same time, the lower end of the shorter main return pipe string 71 is also adapted to be connected with the main completion pipe string 5.

[0051] In one embodiment, the window brancher 7 uses hydraulic sealing at the branching point. Therefore, the fluid can flow from the wellhead through the upper oil pipe into the window brancher 7, and then be divided into the main return pipe string 71 and the branch return pipe string 72 without leakage at the connection point. This is very helpful to ensure the sealing performance of the completion pipe string.

[0052] According to the present invention, a second main return plug 711 is provided at the lower end of the main return pipe string 71. During the process of lowering the main return pipe string 71, the second main return plug 711 can be adapted to be inserted into the sealing hole provided inside the guide 1, so that the main return pipe string 71 forms a sealed connection with the guide 1, thereby forming a sealed connection between the main return pipe string 71 and the main completion pipe string 5. In one embodiment, the sealing hole is constructed as a sealing combination structure located on the axial inner side of the long groove 12, which can be adapted to the second main return plug 711 to form a sealed connection. Similarly, a branch sealing plug 721 is provided at the lower end of the branch return pipe string 72. During the process of lowering the branch return pipe string 72, the branch sealing plug 721 can be adapted to be inserted into the second sealing return tube provided at the upper end of the branch completion pipe string 6, so that the branch return pipe string 72 forms a sealed connection with the branch completion pipe string 6.

[0053] In one embodiment, the second main tie-back plug 711 and the branch sealing plug 721 have the same structure as the first main sealing plug 81, and can also be connected by a male buckle (not shown). Thus, the second main tie-back plug 711 can be inserted into the guide 1 to lock the main tie-back pipe string 71, and the branch sealing plug 721 can be inserted into the second sealing tie-back tube to lock the branch tie-back pipe string 72. At the same time, the sealing between the second main tie-back plug 711 and the guide 1, and between the branch sealing plug 721 and the second sealing tie-back tube, is achieved. Thus, the tie-back of the pipe string is completed and the well is completed.

[0054] Afterwards, production operations can be carried out through the tubing string.

[0055] The guiding device 100 for the multi-branch completion string according to the present invention can accurately locate the window, which is very beneficial to improving the directional positioning efficiency of the guide 1, and can realize the back-connection sealing of the main wellbore and the branch wellbore, effectively ensuring the reliable guidance and long-term sealing of the multi-branch completion string, which is very beneficial to reducing the risk of well construction. The present invention realizes a five-level branch completion pipe string guiding technology through the above-mentioned guiding construction method for the multi-branch completion string, which is sent into the pipe string through the guide 1 with a special guide, which improves the directional efficiency of the guide and enhances the directional accuracy. At the same time, the window brancher 7 is used to guide the guide 1 to realize the accurate guidance of the pipe string to the main wellbore and the branch wellbore respectively, and realize the back-connection sealing of the main wellbore and the branch wellbore, effectively ensuring the sealing performance of the connection between the upper back-connection pipe string and the lower completion pipe string. This is very beneficial to enhancing the hydraulic sealing of the window of the branch well technology of level 5 and above, and is beneficial to reducing the risk of well construction. In addition, the construction method is simple in process and low in construction cost.

[0056] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A guiding device for a multi-branch completion string, comprising: A guide (1), wherein the upper end surface of the guide is provided with a guide slope (10); A guide delivery pipe string, comprising an oil delivery pipe (2), a gyroscopic positioning short section (3) connected to the oil delivery pipe, and a guide delivery short section (4), wherein the gyroscopic positioning short section is used to determine the relative orientation of the guide inclined surface of the guide and the window, and the guide delivery short section is used to connect the guide and lower it into the wellbore, and the guide can be driven to rotate by rotating the oil delivery pipe so that the guide inclined surface is aligned with the window; The guide delivery pipe string is configured to be able to separate the guide delivery nipple from the guide by pressing down the delivery oil pipe and pressing and lifting it, so that the guide delivery pipe string can be taken out. The guide delivery nipple comprises a core shaft (41) and an elastic claw (42) sleeved on the core shaft, the end of the core shaft is provided with a head (411) whose diameter gradually increases towards the axial end, and the guide is provided with an annular inner groove (11). The head can form radial support for the elastic claw so that the elastic claw is adapted to the inner groove, thereby connecting the guide with the guide feeding nipple. The guide delivery nipple further comprises a pressing sleeve (43) fixedly connected to the upper end of the core shaft, and an elastic member (44) arranged axially between the pressing sleeve and the elastic claw. The core shaft is provided with a flow channel (412) extending from the axial upper end surface to the interior, the outer periphery of the core shaft is provided with an annular protrusion (413), the inner wall of the upper end of the elastic claw is provided with a step (421) with the end surface facing downward, a sealed annular liquid cavity (45) is formed between the upper end surface of the annular protrusion and the end surface of the step, and the core shaft is provided with a pressure transmission hole (414) connecting the flow channel and the annular liquid cavity. Among them, by pressing down the oil delivery pipe, the pressing sleeve can axially compress the elastic part and push the core shaft to move axially downward relative to the elastic claw, so that the head releases the support for the elastic claw, and then by pressing down, the pressure in the flow channel acts on the step through the pressure transmission hole, thereby separating the elastic claw from the inner groove of the guide.

2. The guide device according to claim 1, characterized in that: The guide is provided with a plurality of axially extending long grooves (12), the plurality of long grooves being evenly distributed in the circumference, and the head is provided with a plurality of axially evenly distributed ribs (415), the ribs being able to fit with the long grooves, so that torque can be transmitted by rotating the oil delivery pipe to drive the guide to rotate.

3. A guiding construction method for a multi-branch completion string includes the following construction steps: Providing a guide device according to claim 1 or 2; Lowering a main completion pipe string (5) and a branch completion pipe string (6) into the main wellbore and the branch wellbore respectively; The guide is lowered into the main wellbore and anchored so that the guide slope of the guide is aligned with the window and the lower end of the guide is connected to the main completion pipe string; A window brancher (7) is lowered, wherein the lower end of the window brancher is respectively connected to a main return pipe string (71) and a branch return pipe string (72) which are independent of each other. During the lowering process, the branch return pipe string contacts the guide slope on the guide and is guided into the branch wellbore until it is adapted to be connected with the branch completion pipe string, and the main return pipe string is adapted to be connected with the guide, thereby completing the connection of the pipe string and achieving completion; Carry out production operations.

4. The guiding construction method according to claim 3, characterized in that: The lower end of the guide is connected to the main completion pipe string by a bent oil pipe (8).

5. The guiding construction method according to claim 4, characterized in that: A first sealing tie-back cylinder is provided at the top of the main completion pipe string, and a first main sealing plug (81) is provided at the lower end of the bent oil pipe. During the process of lowering the guide, the first main sealing plug can be adapted to be inserted into the first sealing tie-back sleeve, so that the guide forms a sealed connection with the main completion pipe string.

6. The guiding construction method according to claim 3, characterized in that: A second main return plug (711) is provided at the lower end of the main return pipe string. During the process of lowering the main return pipe string, the second main return plug can be adapted to be inserted into the sealing hole provided inside the guide, so that the main return pipe string and the main completion pipe string form a sealed connection.

7. The guiding construction method according to claim 3, characterized in that: A second sealing tie-back tube is provided at the top of the branch completion pipe string, and a branch sealing plug (721) is provided at the lower end of the branch tie-back pipe string. During the process of lowering the branch return pipe string, the branch sealing plug can be adapted to be inserted into the second sealing return pipe, so that the branch return pipe string forms a sealed connection with the branch completion pipe string.

8. The guiding construction method according to any one of claims 3 to 7, characterized in that: The window brancher adopts hydraulic sealing at the branching position.

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