A downhole connecting device for horizontal well and operation method thereof

Abstract

The present invention relates to a downhole communicating device for a horizontal well and an operation method. The downhole communicating device for a horizontal well comprises a communicating device female joint and a communicating device male joint; the communicating device female joint comprises an upper joint, an outer sleeve, a sealing sleeve, and a guide shoe plug; the connector male joint comprises a connector and a plug; the communicating device female joint sealing sleeve and the plug of the connector male joint form an axial plug-in sealing fit, and the communicating device female joint and the connector male joint form an axial locking fit. The operation method comprises: installing the communicating device female joint at the bottom of the first wellbore completion string and lowering it to a predetermined position, and dissolving the guide shoe plug in the drilling fluid; installing the communicating device male joint at the bottom of the second wellbore completion string and lowering it into the completion string; inserting the male joint plug into the female joint sealing sleeve while the female joint and the male joint are docked and locked. The docking of the two completion strings of the horizontal well connecting well is achieved, which effectively solves the problems caused by formation sanding and formation collapse, and provides convenience for later production and maintenance.

Description

Technical Field

[0001] The invention relates to a downhole communicating device for a horizontal well and an operating method in the field of well completion tools. Background Art

[0002] Connecting wells are an important means of exploiting underground brine, coal seams, geothermal energy and other resources. Currently, connecting wells are mainly connected by horizontal wells and vertical wells. This type of connecting well can only connect the formation channels of the two wells, and cannot achieve direct connection between the completion strings. Therefore, there are problems such as sand production affecting production, poor connectivity, formation collapse and connection failure.

[0003] Chinese patent CN206246093U discloses "An oil-casing communicating device". It mainly solves the problems of the existing oil receiving device that many equipments are used, the operation is complicated, the workload is large, it is unsafe and the anti-pollution effect is poor. Its technical solution is: the upper joint and the lower joint are connected with an outer tube, the outer tube is equipped with an inner sleeve, the upper part of the outer tube wall has an oil drain hole, and there is a long hole on the outer tube wall below the oil drain hole, the long hole is connected with a support block, and the support block is horizontally connected with a knife-edge pin, the knife-edge pin has a groove at one end placed in the knife edge, the knife edge is placed in the groove of the outer wall of the inner sleeve, and there is a sealing ring in the outer groove of the inner sleeve. However, the oil-casing communicating device still cannot effectively solve the problem of docking the horizontal well and the vertical well pipe string.

[0004] Connecting horizontal wells is a new mode of connecting wells. By directly connecting and docking two horizontal wells in the formation, better connection effects can be achieved. The docking of two completion strings of the horizontal well connecting wells can effectively solve the problems caused by formation sanding and formation collapse, and provide convenience for later production and maintenance. Summary of the invention

[0005] In view of the current lack of tools for connecting horizontal wells, the present invention proposes a horizontal well downhole connector to solve the rigid connection and sealing of the downhole tubing of the horizontal well connecting well, which can avoid the adverse effects of sand production, formation collapse and other problems on the horizontal well connecting well; the present invention also relates to a method for using the tool to achieve horizontal well connection operations.

[0006] One of the technical solutions of the present invention is a downhole communicating joint for a horizontal well, comprising a communicating joint female joint and a communicating joint male joint;

[0007] The communicating vessel female joint comprises an upper joint, an outer sleeve, a sealing sleeve and a shoe plug; wherein, the upper joint of the communicating vessel female joint has a connecting thread, the outer sleeve is located at the lower part of the upper joint, the sealing sleeve is sealed and fixed inside the outer sleeve, the upper joint and the sealing sleeve are hollow structures, the shoe plug is sealed and fixed at the lower part of the outer sleeve, and the hollow structures of the upper joint and the sealing sleeve are blocked, and the shoe plug is made of a soluble material;

[0008] The male connector of the connector includes a connector and a plug; wherein the upper part of the connector has a connecting thread, the plug and the connector are hollow structures, the lower part of the plug is blocked, and a circulation space is provided in the circumference, and the plug seals and fixes the lower part of the connector;

[0009] The sealing sleeve of the communicating vessel female joint and the plug of the connector male joint form an axial plug-in sealing fit, and the communicating vessel female joint and the connector male joint form an axial locking fit.

[0010] The second technical solution of the present invention is the above-mentioned operation method using the downhole communicating vessel of the horizontal well, comprising:

[0011] After the first wellbore A of the horizontal well connection well is drilled, a female connector is installed at the bottom of the completion string a, and the completion string a is lowered to the predetermined position;

[0012] The guide shoe plug on the female connector of the connecting device is dissolved in the drilling fluid. After the guide shoe plug is completely dissolved, the completion string a enters a state ready for docking;

[0013] After the second wellbore B in the horizontal well connecting well is drilled and connected with wellbore A, a male connector is installed at the bottom of the completion string b;

[0014] The completion string b is lowered, and the completion string b is lifted up before being connected, and the original lifting weight of the completion string b is recorded, and then the completion string b is continued to be lowered for connection;

[0015] Insert the plug of the male connector of the communicating vessel into the sealing sleeve of the female connector of the communicating vessel at the bottom of the completion string a, and at the same time, the female connector of the communicating vessel and the male connector of the communicating vessel are butt-jointed and locked;

[0016] When the completion string b is lifted up and exceeds the original lifting weight, and the string hanging weight continues to increase, it means that the connecting vessel is successfully docked to form the completion string c.

[0017] The further optimization scheme of the present invention for the first downhole communicating vessel of the horizontal well includes:

[0018] The communicating vessel female joint and the connector male joint are axially locked and matched by means of a retaining spring and a retaining spring groove arranged on the contact surface of the outer sleeve and the plug.

[0019] The shoe guide plug is connected and fixed to the lower part of the outer shell through a retaining spring.

[0020] A wear-resistant sealing layer is arranged inside the sealing sleeve.

[0021] The wear-resistant sealing layer of the sealing sleeve is a vulcanized rubber layer.

[0022] The upper joint and the outer sleeve, the connecting head and the plug are all split assembly mechanisms connected by threads.

[0023] A sealing member is provided at the threaded connection between the upper joint and the outer sleeve.

[0024] The present invention provides an operation method for further optimizing a downhole communicating vessel of a horizontal well, comprising:

[0025] After the first wellbore A of the horizontal well connection well is drilled, a female connector is installed at the bottom of the completion string a, and the completion string a is lowered to the predetermined position;

[0026] The guide shoe plug on the female connector of the connecting device is dissolved in the drilling fluid. After the guide shoe plug is completely dissolved, the completion string a enters a state ready for docking;

[0027] After the second wellbore B in the horizontal well connecting well is drilled and connected with wellbore A, a male connector is installed at the bottom of the completion string b;

[0028] The completion string b is lowered, and the completion string b is lifted up before being connected, and the original lifting weight of the completion string b is recorded, and then the completion string b is continued to be lowered for connection;

[0029] Insert the plug of the male connector of the communicating device into the sealing sleeve of the female connector of the communicating device at the bottom of the completion string a, and insert the retaining spring of the female connector of the communicating device into the retaining spring groove of the male connector of the communicating device to achieve docking and locking;

[0030] When the completion string b is lifted up and exceeds the original lifting weight, and the string hanging weight continues to increase, it means that the connecting vessel is successfully docked to form the completion string c.

[0031] The present invention provides a special tool for connecting downhole tubulars in horizontal wells, which has the advantage of realizing effective connection of completion tubulars in horizontal wells and connecting wells, and can realize rigid connection and sealing of two completion tubulars in the horizontal wells and connecting wells, and effectively solve the problems of sand production and formation collapse in the horizontal wells and connecting wells for production, and meets the needs and characteristics of the completion of horizontal wells and connecting wells, improves the development effect of the connecting wells, and fills the gap of the completion tools for horizontal wells and connecting wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of female connector of connecting vessel;

[0033] Figure 2 Schematic diagram of the male connector of the connecting vessel;

[0034] Figure 3 Schematic diagram of the structure of the underground connecting device docking completion;

[0035] Figure 4 Schematic diagram of the wellbore [A] and completion string [a] structure;

[0036] Figure 5 Schematic diagram of the wellbore [B] and completion string [b] structure;

[0037] Figure 6 Schematic diagram of the completion string after docking [c]. DETAILED DESCRIPTION

[0038] The invention will now be further described with reference to the accompanying drawings.

[0039] Embodiment 1:

[0040] A downhole communicating device for a horizontal well, comprising a communicating device female joint and a communicating device male joint; the communicating device female joint comprises an upper joint 101, an outer sleeve 102, a sealing sleeve 104, and a guide shoe plug 106; wherein, the upper part of the upper joint 101 of the communicating device female joint has a connecting thread, the outer sleeve 102 is located at the lower part of the upper joint 101, the sealing sleeve 104 is sealed and fixed inside the outer sleeve 102, the upper joint 101 and the sealing sleeve 104 are hollow structures, the guide shoe plug 106 is sealed and fixed at the lower part of the outer sleeve 102, and the hollow structures of the upper joint 101 and the sealing sleeve 104 are blocked, and the guide shoe plug 106 is made of a soluble material;

[0041] The male connector of the connector includes a connector 201 and a plug 203; wherein the upper portion of the connector 201 has a connecting thread, the plug 203 and the connector 201 are hollow structures, the lower portion of the plug 203 is blocked, and a circulation space 204 is provided in the circumferential direction, and the plug 203 seals and fixes the lower portion of the connector 201;

[0042] The sealing sleeve 104 of the communicating vessel female joint and the plug 203 of the connector male joint form an axial plug-in sealing fit, and the communicating vessel female joint and the connector male joint form an axial locking fit.

[0043] Embodiment 2:

[0044] An operation method using a downhole communicating vessel in a horizontal well comprises:

[0045] After the first wellbore A of the horizontal well connection well is drilled, a female connector is installed at the bottom of the completion string a, and the completion string a is lowered to the predetermined position;

[0046] The guide shoe plug 106 on the female connector of the communicating vessel dissolves in the drilling fluid. After the guide shoe plug 106 is completely dissolved, the completion string a enters a state ready for docking.

[0047] After the second wellbore B in the horizontal well connecting well is drilled and connected with wellbore A, a male connector is installed at the bottom of the completion string b;

[0048] The completion string b is lowered, and the completion string b is lifted up before being connected, and the original lifting weight of the completion string b is recorded, and then the completion string b is continued to be lowered for connection;

[0049] Insert the plug 203 of the male connector of the communicating vessel into the sealing sleeve 104 of the female connector of the communicating vessel at the bottom of the completion string a, and at the same time, the female connector of the communicating vessel and the male connector of the communicating vessel are docked and locked;

[0050] When the completion string b is lifted up and exceeds the original lifting weight, and the string hanging weight continues to increase, it means that the connecting vessel is successfully docked to form the completion string c.

[0051] Embodiment 3:

[0052] A downhole communicating device for a horizontal well is further optimized on the basis of Example 1 and includes:

[0053] The female connector of the communicating vessel and the male connector of the connector are axially locked together by means of a retaining spring 105 and a retaining spring groove 205 arranged on the contact surfaces of the outer sleeve 102 and the plug 203 .

[0054] The shoe guide plug 106 is connected and fixed to the lower part of the outer sleeve 102 through a retaining spring 105 .

[0055] The sealing sleeve 104 is provided with a wear-resistant sealing layer.

[0056] The wear-resistant sealing layer of the sealing sleeve 104 is a vulcanized rubber layer 107 .

[0057] The upper joint 101 and the outer sleeve 102, the connector 201 and the plug 203 are all separate assembly structures connected by threads.

[0058] A sealing member 103 is provided at the threaded connection between the upper joint 101 and the outer sleeve 102 .

[0059] Embodiment 4:

[0060] The method for operating a downhole communicating vessel in a horizontal well according to the third embodiment includes:

[0061] After the first wellbore A of the horizontal well connection well is drilled, a female connector is installed at the bottom of the completion string a, and the completion string a is lowered to the predetermined position;

[0062] The guide shoe plug 106 on the female connector of the communicating vessel dissolves in the drilling fluid. After the guide shoe plug 106 is completely dissolved, the completion string a enters a state ready for docking.

[0063] After the second wellbore B in the horizontal well connecting well is drilled and connected with wellbore A, a male connector is installed at the bottom of the completion string b;

[0064] The completion string b is lowered, and the completion string b is lifted up before being connected, and the original lifting weight of the completion string b is recorded, and then the completion string b is continued to be lowered for connection;

[0065] Insert the plug 203 of the male connector 2 into the sealing sleeve 104 of the female connector 1 at the bottom of the completion string a, and insert the retaining spring 105 of the female connector 1 into the retaining spring groove 205 of the male connector 2 to achieve docking and locking;

[0066] When the completion string b is lifted up and exceeds the original lifting weight, and the string hanging weight continues to increase, it means that the connecting vessel is successfully docked to form the completion string c.

[0067] Embodiment 5:

[0068] A downhole communicating joint for a horizontal well is composed of a communicating joint female joint and a communicating joint male joint. The communicating joint female joint and the communicating joint male joint are butt-jointed to form a complete downhole communicating joint for a horizontal well.

[0069] like Figure 1 As shown, the communicating vessel female joint is mainly composed of an upper joint 101, an outer sleeve 102, a sealing sleeve 104, a guide shoe plug 106 and the like; the specific structure is as follows: the main function of the sealing sleeve 104 and the rubber layer 107 is to wrap the plug 203 of the communicating vessel male joint to achieve the sealing function of the tool as a whole after docking; the guide shoe plug 106 is made of soluble metal and is installed on the outer sleeve 102 through a retaining spring connection. Its function is to provide guidance for the completion pipe string a when it is lowered, and at the same time prevent foreign matter from entering the tool during the lowering process. After the tool is lowered, the guide shoe plug 106 can be gradually dissolved in the drilling fluid. After the guide shoe plug 106 is completely dissolved, the internal structure of the communicating vessel female joint 1 is opened and enters a state to be docked.

[0070] like Figure 2 As shown, the male connector of the connector is mainly composed of several parts such as a connector head 201 and a plug 203. The male connector of the connector can guide the completion string b to be lowered. The plug 203 has a retaining spring groove 205 which can be embedded in the retaining spring 105 on the female connector of the communicating device to connect the male connector 2 with the female connector of the communicating device; at the same time, the plug 203 can also cooperate with the sealing sleeve 104 and the rubber layer 107 on the female connector of the communicating device to achieve the sealing of the inside and outside of the tool after the two parts of the downhole communicating device of the horizontal well are connected; the circulation hole 204 on the plug 203 can achieve the internal connection between the two parts of the downhole communicating device of the horizontal well.

[0071] like Figure 3 As shown, the horizontal well connecting vessel is in a complete state after the connecting vessel female joint and the connector male joint are connected.

[0072] Embodiment 6:

[0073] The following describes a horizontal well downhole communicating device and a completion operation method for a horizontal well connecting well completed with a 139.7 mm diameter casing, which includes the following steps:

[0074] Step 1: Tool assembly, assemble the female connector and the male connector of the connector in advance.

[0075] Step 2: After the wellbore A of the horizontal well connecting well is drilled, preparations are made for well cleaning, casing operation and cementing, and then casing operation is started. The female joint of the connecting device, several pieces of casing, blind plate, packer and grading hoop are sequentially lowered, and then the casing is connected to the wellhead. This pipe string is the completion pipe string a.

[0076] Step 3: After the casing operation of the completion string a is completed, pressure is applied from the wellhead into the completion string a to complete the expansion seal of the packer and the opening of the grading collar.

[0077] Step 4: Start cementing operation of completion string a. After injecting cement slurry, insert impact rubber plug into completion string a to displace impact.

[0078] Step 5: The guide shoe plug 106 of the communicating female joint begins to dissolve gradually after the casing operation begins, and dissolution is completed before the wellbore B of the horizontal well connecting well is drilled, and the communicating female joint enters a state ready for docking.

[0079] Step 6: After drilling the borehole B of the horizontal well connecting well, make preparations for well cleaning, casing lowering and cementing, and ensure that the drilling bit can enter the borehole A of the horizontal well connecting well until the bottom of the female joint of the connecting device.

[0080] Step 7: Start the casing operation, and sequentially put in the connecting pipe male joint, several pieces of casing, blind plate, packer, and grading hoop, and then run the casing. This pipe string is the completion pipe string b.

[0081] Step 8: When the male connector of the communicating device on the completion string b is lowered to 3m before the docking position, lift the completion string b and record the hanging weight of the completion string b. Then, lower the completion string b to the docking position, insert the plug 203 of the communicating device male connector into the sealing sleeve 204 of the communicating device female connector, and embed the retaining spring 107 of the communicating device female connector into the retaining spring groove 205 of the communicating device male connector.

[0082] Step 9: If the completion string b is lifted up and exceeds the original lifting weight, and the hanging weight of the string continues to increase, it means that the downhole connecting device of the horizontal well is successfully connected.

[0083] Step 10: Start cementing operation of completion string b. After injecting cement slurry, insert impact rubber plug into completion string a to displace the impact.

[0084] Step 11: Insert a grinding shoe through a small drill pipe into the completion string a and the completion string b respectively, and drill out the graded collar and blind plate in the two completion strings.

[0085] Step 12: After the two tubing strings are drilled, the horizontal wellbores are connected to form a complete horizontal well connected well completion string c.

Claims

1. A downhole communicating device for a horizontal well, comprising a communicating device female joint and a communicating device male joint; characterized in that: The communicating vessel female joint comprises an upper joint [101], an outer sleeve [102], a sealing sleeve [104], and a shoe plug [106]; wherein the upper part of the communicating vessel female joint has a connecting thread, the outer sleeve [102] is located at the lower part of the upper joint [101], the sealing sleeve [104] is sealed and fixed inside the outer sleeve [102], the upper joint [101] and the sealing sleeve [104] are hollow structures, the shoe plug [106] is sealed and fixed at the lower part of the outer sleeve [102], and blocks the hollow structures of the upper joint [101] and the sealing sleeve [104], and the shoe plug [106] is made of a soluble material; the communicating vessel male joint comprises a connector [201] and a plug [203]; wherein the upper part of the connector [201] has a connecting thread, the plug [203] and the connector [201] are connected to each other. The structure is hollow, the lower part of the plug [203] is blocked, and a circulation space [204] is provided in the circumferential direction. The plug [203] seals and fixes the lower part of the connector [201]. The female connector sealing sleeve [104] and the plug [203] of the male connector form an axial plug-in sealing fit, and the female connector and the male connector form an axial locking fit. The female connector and the male connector form an axial locking fit through a retaining ring [105] and a retaining ring groove [205] provided on the contact surface of the outer sleeve [102] and the plug [203]. The wear-resistant sealing layer of the sealing sleeve [104] is a vulcanized rubber layer [107]. The upper connector [101] and the outer sleeve [102], the connector [201] and the plug [203] are all split assembly mechanisms connected by threads.

2. The downhole communicating vessel for a horizontal well according to claim 1, characterized in that: The shoe guide plug [106] is connected and fixed to the lower part of the outer sleeve [102] through a retaining spring [105].

3. The downhole communicating vessel for a horizontal well according to claim 1 or 2, characterized in that: The sealing sleeve [104] is provided with a wear-resistant sealing layer.

4. The downhole communicating vessel for a horizontal well according to claim 3, characterized in that: A sealing member [103] is provided at the threaded connection between the upper joint [101] and the outer sleeve [102].

5. An operation method using the downhole communicating vessel of a horizontal well according to claim 1, characterized in that include: After the first wellbore [A] of the horizontal well connecting well is drilled, a female connector is installed at the bottom of the completion string [a], and the completion string [a] is lowered to a predetermined position; the guide shoe plug [106] on the female connector is dissolved in the drilling fluid, and after the guide shoe plug [106] is completely dissolved, the completion string [a] enters a state ready for docking; after the second wellbore [B] of the horizontal well connecting well is drilled and connected with the wellbore [A], a male connector is installed at the bottom of the completion string [b]; the completion string [b] is lowered, Before the completion string [b] is to be docked, the string is lifted up, and the original lifting weight of the completion string [b] is recorded, and then the completion string [b] is continued to be lowered for docking; the plug [203] of the male connector of the connecting pipe is inserted into the sealing sleeve [104] of the female connector of the connecting pipe at the bottom of the completion string [a], and the female connector of the connecting pipe and the male connector of the connecting pipe are docked and locked; the completion string [b] is lifted up to exceed the original lifting weight, and the string hanging weight continues to increase, indicating that the connecting pipe is successfully docked, forming the completion string [c].

6. An operation method using the downhole communicating vessel of a horizontal well according to claim 3, characterized in that include: After the first borehole [A] of the horizontal well connecting well is drilled, a female connector is installed at the bottom of the completion string [a], and the completion string [a] is lowered to a predetermined position; the guide plug [106] on the female connector is dissolved in the drilling fluid, and after the guide plug [106] is completely dissolved, the completion string [a] enters a state ready for docking; after the second borehole [B] of the horizontal well connecting well is drilled and connected with the borehole [A], a male connector is installed at the bottom of the completion string [b]; the completion string [b] is lowered, and the completion string [b] is prepared for docking. The tubular column is lifted up, and the original lifting weight of the completion tubular column [b] is recorded. Then, the completion tubular column [b] is lowered for docking. The plug [203] of the male connector [2] of the connecting pipe is inserted into the sealing sleeve [104] of the female connector [1] of the connecting pipe at the bottom of the completion tubular column [a]. The retaining spring [105] of the female connector [1] of the connecting pipe is inserted into the retaining spring groove [205] of the male connector [2] of the connecting pipe to achieve docking and locking. The completion tubular column [b] is lifted up to exceed the original lifting weight. If the hanging weight of the tubular column continues to increase, it means that the connecting pipe is successfully docked, and the completion tubular column [c] is formed.

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