Dragging type staged fracturing pipe column and construction technology

Abstract

The invention belongs to the technical field of oil and gas development, and particularly relates to a dragging type staged fracturing pipe column and a construction technology. According to the dragging type staged fracturing tubular column construction technology, when a fracturing tubular column tool string meets resistance, releasing is conducted on the fracturing tubular column tool string. The dragging type staged fracturing pipe column is used for implementing the dragging type staged fracturing pipe column construction technology and comprises a fracturing pipe column tool string and a releasing short section arranged on the upper side of the fracturing pipe column tool string.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas development, and in particular, relates to a drag-type segmented fracturing pipe string and a construction process of the drag-type segmented fracturing pipe string. Background Art

[0002] The drag-type fracturing string currently used mainly uses cement bridge plugs or packer expansion to stratify the oil and gas well sections. The cement bridge plug process requires a drill bit to drill out after fracturing to proceed to the next level of operation. This method consumes a lot of man-hours and is complicated to operate. The sealing effect is affected by the quality of cement solidification. If the cement solidification quality is insufficient, there is a risk of sealing failure. The packer expansion process uses a rubber tube expansion method to isolate. Compared with the cement bridge plug, the sealing time is short, the action speed is fast, and the construction operation is relatively easy.

[0003] However, the packer cannot be completely unsealed. During the dragging process, the rubber of the packer may be worn by the well wall, resulting in poor fracturing effect. At the same time, there are also problems such as failure to remove the pipe normally. After the pipe string is stuck, the entire pipe string can only be abandoned, affecting the economic benefits of the construction.

[0004] Therefore, it is necessary to design a staged fracturing pipe string and construction process that is easy to operate, high in operating efficiency and high in economic benefit. Summary of the invention

[0005] In view of the technical problems mentioned above, the present invention aims to propose a drag-type segmented fracturing string construction process, which can drop the fracturing string string after the string encounters an obstruction, thereby improving the economic benefits of the construction.

[0006] The present invention also proposes a drag-type segmented fracturing pipe string, which can drop the fracturing pipe string after encountering an obstacle, thereby improving the economic benefits of the construction.

[0007] According to the present invention, a drag-type segmented fracturing string construction process is provided, and when the fracturing string tool string encounters resistance, the fracturing string tool string is released.

[0008] In a specific embodiment, the fracturing string tool string is released by lifting.

[0009] In a specific embodiment, the fracturing string tool string is released by throwing a ball.

[0010] In a specific embodiment, after the fracturing tubing tool string is released, the fracturing tubing tool string is fished out by a fishing spear.

[0011] In a specific embodiment, after the fracturing string tool string is released, the fracturing string tool string is buried underground.

[0012] According to the present invention, a drag-type segmented fracturing string is also provided, which is used to implement the drag-type segmented fracturing string construction process provided by the present invention, including a fracturing string tool string and a drop-out short section arranged on the upper side of the fracturing string tool string.

[0013] In a specific embodiment, the drop-out sub includes a first connecting tube and a second connecting tube connected by a first shear pin.

[0014] In a specific embodiment, the drop section comprises:

[0015] A third connecting tube, wherein an elastic claw is provided at the lower end of the third connecting tube;

[0016] A fourth connecting tube is coaxially arranged at the lower end of the third connecting tube, and the elastic claw is engaged with the inner wall of the fourth connecting tube;

[0017] A throw-away ball seat is arranged in the third connecting cylinder through a second shear pin;

[0018] In the first state, the outer wall of the throw-away ball seat abuts against the inner wall of the elastic claw;

[0019] In the second state, the ball is thrown into the throwing ball seat and pressure is applied to cause the throwing ball seat to move relative to the elastic claw until it no longer abuts against the elastic claw.

[0020] In a specific embodiment, the hand-losing ball seat comprises:

[0021] The tee part used for holding the ball;

[0022] A connecting section disposed at the lower portion of the ball seat portion;

[0023] An abutment section disposed at the lower part of the connecting section, wherein the outer diameter of the abutment section is larger than the outer diameter of the connecting section;

[0024] In the first state, the outer wall of the abutment section abuts against the inner wall of the elastic claw;

[0025] In the second state, the abutment section moves to no longer abut against the inner wall of the elastic claw.

[0026] In a specific embodiment, the fracturing tubing tool string includes a plurality of tool string sections coaxially connected in sequence, the tool string sections include an upper packer, a fracturing sleeve and a lower packer connected in sequence from top to bottom, the starting pressure chambers of the upper packer and the lower packer are connected to each other through a control pipeline, and the starting pressure chambers of the packers of adjacent tool string sections are connected through a control pipeline.

[0027] Compared with the prior art, the advantages of the present application are as follows.

[0028] The drag-type staged fracturing string provided by the present invention can meet the requirements of staged fracturing technology. In addition, the drag-type staged fracturing string is provided with a drop-out short section, which can drop the string when the fracturing string tool string encounters an obstruction, thereby avoiding discarding the entire string, thereby improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be described below with reference to the accompanying drawings.

[0030] Figure 1 A schematic diagram showing an embodiment of a drag-type staged fracturing string according to the present invention;

[0031] Figure 2 A schematic diagram showing an embodiment of a first connecting tube and a second connecting tube of a drop section according to the present invention;

[0032] Figure 3 A schematic diagram showing an embodiment of a third connecting tube and a fourth connecting tube of a release nipple according to the present invention;

[0033] Figure 4 A schematic diagram of an embodiment of a tool string segment according to the present invention is shown.

[0034] The reference numerals in the figures are as follows:

[0035] 1. Fracturing string tool string; 10. Tool string section; 11. Upper packer; 12. Fracturing sleeve; 13. Lower packer; 14. Control pipeline; 15. Clamp;

[0036] 2. Hand-release short joint; 21. First connecting tube; 22. Second connecting tube; 23. First shear pin; 24. Third connecting tube; 241. Elastic claw; 25. Fourth connecting tube; 26. Second shear pin; 27. Hand-release ball seat; 271. Ball seat portion; 272. Connecting section; 273. Abutting section; 28. Upper joint;

[0037] 100. Drag-type segmented fracturing string.

[0038] 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

[0039] The present invention will be described below with reference to the accompanying drawings.

[0040] It should be noted that, in the present application, the direction of the drag-type segmented fracturing string according to the present invention closer to the wellhead after entering the well is described as "up" or similar terms, and the direction of the drag-type segmented fracturing string according to the present invention away from the wellhead after entering the well is described as "down" or similar terms.

[0041] Figure 1 The structure of the drag-type staged fracturing string 100 according to the present invention is shown. Figure 1 As shown, the drag-type staged fracturing string 100 comprises a coaxially connected fracturing string tool string 1 and a drop-out short section 2. The drop-out short section 2 is coaxially arranged on the upper part of the fracturing string tool string 1.

[0042] When implementing the staged fracturing process, the upper part of the release sub 2 is connected to the oil pipe (not shown in the figure), and the release sub 2 and the fracturing string tool string 1 are lowered into the well through the oil pipe. When the fracturing string tool string 1 encounters an obstacle, the release sub 2 can be used to release the fracturing string tool string 1 below the release sub 2, leaving the fracturing string tool string 1 below the release sub 2 in the well, and the oil pipe above the release sub 2 is lifted out, thereby improving economic benefits.

[0043] In a specific embodiment, Figure 2 As shown, the release sub 2 includes a first connecting tube 21 and a second connecting tube 22 connected by a first shear pin 23. The lower end of the first connecting tube 21 is coaxially sleeved inside the upper end of the second connecting tube 22, and the first shear pin 23 is penetrated through the overlapping portion of the first connecting tube 21 and the second connecting tube 22. Under this arrangement, when the axial tension between the first connecting tube 21 and the second connecting tube 22 exceeds the load limit of the first shear pin 23, the first shear pin 23 is sheared, thereby separating the first connecting tube 21 and the second connecting tube 22, and completing the release.

[0044] In a specific embodiment, the release short section 2 includes a third connecting tube 24 , a fourth connecting tube 25 and a release ball seat 27 .

[0045] like Figure 3 As shown, an elastic claw 241 is provided at the lower end of the third connecting cylinder 24. The elastic claw 241 is made of elastic material and can expand or contract radially under the action of external force. The fourth connecting cylinder 25 is coaxially arranged at the lower end of the third connecting cylinder 24, and the elastic claw 241 is located inside the fourth connecting cylinder 25. The elastic claw 241 clamps the inner wall of the fourth connecting cylinder 25, so that the fourth connecting cylinder 25 is fixedly connected to the third connecting cylinder 24.

[0046] The throw-away ball seat 27 is coaxially arranged inside the third connecting tube 24 .

[0047] In the first state, the throw-away ball seat 27 is fixedly connected to the third connecting tube 24 through the second shear pin 26, and the outer wall of the throw-away ball seat 27 abuts against the inner wall of the elastic claw 241. At this time, the elastic claw 241 is located between the inner wall of the fourth connecting tube 25 and the outer wall of the throw-away ball seat 27. The elastic claw 241 cannot shrink radially, so the elastic claw 241 can maintain a clamped state with the fourth connecting tube 25, thereby maintaining the third connecting tube 24 and the fourth connecting tube 25 in a fixed connection state.

[0048] In the second state, the ball is thrown and pressed against the throw-away ball seat 27, so that the throw-away ball seat 27 moves downward relative to the elastic claw 241, until the throw-away ball seat 27 no longer abuts against the elastic claw 241, so that the elastic claw 241 can contract radially. At this time, when the third connecting tube 24 moves upward relative to the fourth connecting tube 25, the elastic claw 241 can contract radially, so that it is no longer engaged with the fourth connecting tube 25, so that the third connecting tube 24 is separated from the fourth connecting tube 25, and the throw-away is completed.

[0049] In a specific embodiment, the throw-away ball seat 27 mainly includes a ball seat portion 271 , a connecting section 272 and an abutting section 273 .

[0050] The ball seat 271 is used to match the pressure-holding ball. The connecting section 272 is coaxially arranged at the lower end of the ball seat 271 . The abutting section 273 is coaxially arranged at the lower end of the connecting section 272 .

[0051] The outer diameter of the abutting section 273 is larger than the outer diameter of the connecting section 272. In the first state, the outer wall of the abutting section 273 abuts against the inner wall of the elastic claw 241, thereby preventing the elastic claw 241 from radially contracting. In the second state, the abutting section 273 moves downward relative to the elastic claw 241 to below the elastic claw 241, and the outer diameter of the connecting section 272 is smaller than the outer diameter of the abutting section 273, so the elastic claw 241 can be radially contracted to complete the release.

[0052] like Figure 1 As shown, the lower end of the second connecting tube 22 of the release short section 2 is coaxially connected to the upper end of the fracturing string tool string 1, the upper end of the first connecting tube 21 of the release short section 2 is coaxially connected to the lower end of the fourth connecting tube 25, and the upper end of the third connecting tube 24 of the release short section 2 is coaxially connected with an upper joint 28 for connecting to the oil pipe.

[0053] In a specific embodiment, the fracturing string tool string 1 includes a plurality of tool string sections 10 coaxially connected in sequence.

[0054] like Figure 4As shown, the tool string section 10 includes an upper packer 11, a fracturing sleeve 12 and a lower packer 13 connected in sequence from top to bottom. The start-up pressure chambers of the upper packer 11 and the lower packer 13 are connected to each other through a control pipeline 14, and the start-up pressure chambers of the packers of adjacent tool string sections 10 are connected through a control pipeline 14.

[0055] The specific structures of the upper packer 11 and the lower packer 13 are well known to those skilled in the art. When the starting pressure chambers of the upper packer 11 and the lower packer 13 receive pressure, the upper packer 11 and the lower packer 13 can complete the expansion and sealing. The present invention connects the driving pressure chambers of the upper packer 11 and the lower packer 13 of each tool string section 10 through a control pipeline 14, and all the packers can be expanded and sealed by one pressurization, thereby improving work efficiency.

[0056] In a specific embodiment, the upper packer 11 of the uppermost tool string section 10 is connected to the wellhead via a control pipeline 14. In this setting, by controlling the pressure in the control pipeline 14 through the wellhead, the expansion and release of each packer can be controlled to meet the needs of subsequent production.

[0057] In a specific embodiment, clips 15 for fixing the control pipeline 14 are provided between the upper packer 11 and the fracturing sleeve 12 and between the lower packer 13 and the fracturing sleeve 12 .

[0058] According to the present invention, a drag-type staged fracturing string construction process is provided. In this embodiment, using the drag-type staged fracturing string 100 provided according to the present invention, when performing the staged fracturing process, the drag-type staged fracturing string 100 is sent into the well by connecting the upper joint 28 of the release short section 2 through the oil pipe. When the fracturing string tool string 1 encounters an obstacle, the fracturing string tool string 1 is released through the release short section 2.

[0059] In a specific embodiment, an upward pulling force is provided to the first connecting tube 21 by lifting the oil pipe, so that the first shear pin 23 between the first connecting tube 21 and the second connecting tube 22 is sheared off, and the fracturing string tool string 1 is released.

[0060] In a specific embodiment, the fracturing string tool string 1 can also be released by throwing a ball. Specifically, a ball is thrown into the ball seat portion 271 of the release ball seat 27 to hold pressure, thereby pushing the release ball seat 27 to cut off the second shear pin 26 and move downward, so that the abutment section 273 of the release ball seat 27 no longer abuts the elastic claw 241, and at this time, the oil pipe is moved upward to separate the third connecting tube 24 from the fourth connecting tube 25, and the fracturing string tool string 1 is released.

[0061] In a specific embodiment, after the fracturing tubing tool string 1 is released, the fracturing tubing tool string 1 is fished out by a drill pipe with a fishing spear.

[0062] In a specific embodiment, after the fracturing string tool string 1 is released, the fracturing string tool string 1 may not be salvaged, and the fracturing string tool string 1 may be directly buried underground.

[0063] In a specific embodiment, before the drag-type staged fracturing string 100 provided by the present invention is run into the well, a grinding shoe is used to scrape the open hole well wall to prevent the upper packer 11 and the lower packer 13 of the tool string section 10 from being scratched during the running-in process.

[0064] In a specific embodiment, a round plug (not shown in the figure) is provided at the lower end of the fracturing string tool string 1. By providing the round plug, foreign matter in the well can be effectively prevented from entering the inner cavity during the tool lowering process, making it easier to lower the tool.

[0065] In a specific embodiment, the sizes of the ball seats of the fracturing sleeves 12 of each tool string section 10 of the fracturing string tool string 1 increase in order from bottom to top, and staged pressure holding is achieved during the fracturing operation by successively inserting balls from small to large.

[0066] In a specific embodiment, a release nipple 2 may be provided between any adjacent tool string sections 10 to cope with obstructions at different locations.

[0067] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0068] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0069] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0070] 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 drag-type staged fracturing string construction process, characterized in that: When the fracturing tubing string tool string encounters an obstruction, the fracturing tubing string tool string is released.

2. The drag-type staged fracturing pipe string construction process according to claim 1 is characterized in that: The fracturing string tool string is released by lifting.

3. The drag-type staged fracturing pipe string construction process according to claim 1 is characterized in that: The fracturing tubing tool string is released by throwing a ball.

4. The drag-type staged fracturing pipe string construction process according to claim 1 is characterized in that: After the fracturing tubing string tool string is released, the fracturing tubing string tool string is salvaged by a salvaging spear.

5. The drag-type staged fracturing pipe string construction process according to claim 1 is characterized in that: After the fracturing tubing string tool string is released, the fracturing tubing string tool string is buried underground.

6. A drag-type staged fracturing string, characterized in that: The method is used for implementing the drag-type segmented fracturing pipe string construction process according to any one of claims 1 to 5, comprising a fracturing pipe string tool string (1) and a drop-out short section (2) arranged on the upper side of the fracturing pipe string tool string (1).

7. The drag-type staged fracturing pipe string construction process according to claim 6 is characterized in that: The drop-out short section (2) comprises a first connecting tube (21) and a second connecting tube (22) connected via a first shear pin (23).

8. The drag-type staged fracturing pipe string construction process according to claim 6 is characterized in that: The release short section (2) comprises: A third connecting tube (24), wherein an elastic claw (241) is provided at the lower end of the third connecting tube (24); A fourth connecting tube (25) is coaxially arranged at the lower end of the third connecting tube (24), and the elastic claw (241) is engaged with the inner wall of the fourth connecting tube (25); and A throw-away ball seat (27) is arranged in the third connecting tube (24) via a second shear pin (26); In the first state, the outer wall of the throw-away ball seat (27) abuts against the inner wall of the elastic claw (241); In the second state, the ball is thrown into the throwing ball seat (27) and pressure is applied, so that the throwing ball seat (27) moves relative to the elastic claw (241) until it no longer abuts against the elastic claw (241).

9. The drag-type staged fracturing pipe string construction process according to claim 8, characterized in that: The hand-losing ball seat (27) comprises: A ball seat (271) for holding the ball during pitching; A connecting section (272) disposed at the lower portion of the ball seat portion (271); and an abutment section (273) disposed at the lower part of the connection section (272), wherein the outer diameter of the abutment section (273) is greater than the outer diameter of the connection section (272); In the first state, the outer wall of the abutment section (273) abuts against the inner wall of the elastic claw (241); In the second state, the abutment section (273) moves to a point where it no longer abuts against the inner wall of the elastic claw (241).

10. The drag-type staged fracturing pipe string construction process according to claim 6, characterized in that: The fracturing string tool string (1) comprises a plurality of tool string sections (10) coaxially connected in sequence, the tool string section (10) comprising an upper packer (11), a fracturing sleeve (12) and a lower packer (13) connected in sequence from top to bottom, the starting pressure chambers of the upper packer (11) and the lower packer (13) are connected to each other via a control pipeline (14), and the starting pressure chambers of the packers of adjacent tool string sections (10) are connected via a control pipeline (14).

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