Double-branch drilling method based on multi-target deep oil and gas development

Abstract

The invention belongs to the technical field of oil and gas drilling, and particularly relates to a double-branch drilling method based on multi-target deep oil and gas development. The double-branch well drilling method based on multi-target deep oil and gas development comprises the following steps that S1, first branch well drilling is conducted in a well, and a first branch well hole is formed; s2, a first well completion pipe string is put into the first branch borehole; s3, a recoverable windowing system is put into a preset position in the well, and second branch well drilling is carried out to form a second branch well hole; and S4, the recoverable windowing system is recovered, and a second well completion pipe string is put into the second branch borehole.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas drilling, and in particular, relates to a dual-branch drilling method based on multi-target deep oil and gas development. Background Art

[0002] With the continuous exploration and development of oil and gas resources, the remaining oil and gas are scattered. How to realize the one-time use of multiple target reservoirs and reduce the cost of oil and gas development engineering technology has become the key to improving the benefits of oil and gas exploration and development. In the implementation of existing engineering technology, oil and gas reservoirs in the same orientation can be effectively communicated and used through technical means such as directional wells and horizontal wells. However, in different orientations, especially when the orientations are greatly different, the use of conventional technical means will lead to particularly complex wellbore trajectories in the construction wells, making drilling construction difficult and not conducive to later completion operations.

[0003] At present, the branch drilling method used for multi-target oil and gas development is mainly aimed at high-level branch wells. The tools and process technologies developed are relatively complex and the application costs are high, which is not conducive to the promotion and application of the technology.

[0004] Chinese patent document CN111878021A discloses a branch well tool system and method, which meets the technical requirements of four-level branch wells and provides a wellbore foundation for realizing five-level branch wells, but the process is complicated and the application scenarios are relatively limited.

[0005] Chinese patent document CN104912479B discloses a method for drilling and completing a coalbed methane horizontal branch well. The main technical means is to use casing drilling in the third opening to avoid underground complexity. It is not applicable in the process of deep oil and gas development.

[0006] In summary, multi-target oil and gas development requires a relatively simple and low-cost branch drilling method to achieve drilling of oil and gas targets in different directions in the same wellbore and increase the scale and output of oil and gas in a single well. Summary of the invention

[0007] In view of the technical problems mentioned above, the present invention aims to propose a dual-branch drilling method based on multi-target deep oil and gas development, which has a simple process and low cost and can achieve drilling of oil and gas targets in different directions in the same wellbore.

[0008] According to the present invention, a dual-branch drilling method based on multi-objective deep oil and gas development is provided, comprising the following steps:

[0009] Step S1, drilling a first branch well in a well to form a first branch wellbore;

[0010] Step S2, lowering a first completion string into the first branch wellbore;

[0011] Step S3, lowering a recyclable window opening system into a predetermined position in the well, drilling a second branch well, and forming a second branch wellbore;

[0012] Step S4, recovering the recoverable window opening system, and lowering a second completion string into the second branch wellbore.

[0013] According to the present invention, in a specific embodiment, in step S2, the first completion string includes an anchor packer, a rupture disk and a first support pipe that are connected to each other.

[0014] According to the present invention, in a specific embodiment, after the first completion string is lowered to a predetermined position, an anchor packer is set by pressure.

[0015] According to the present invention, in a specific embodiment, in step S3, after the recoverable window opening system is lowered, anchoring, window opening, and blind drilling are completed by the recoverable window opening system, and finally a second branch wellbore is formed.

[0016] According to the present invention, in a specific embodiment, a first drilling tool is sent into a recoverable window opening system. After the first drilling tool completes a blind drilling section through the recoverable window opening system, the first drilling tool is pulled out, the guide drilling tool is replaced, and drilling is performed to form a second branch wellbore.

[0017] According to the present invention, in a specific embodiment, the recyclable window opening system includes a whipstock, and the entire recyclable window opening system is anchored by the whipstock.

[0018] According to the present invention, in a specific embodiment, in the step S4, the recyclable window opening system is recycled using a recycling component.

[0019] According to the present invention, in a specific embodiment, the recovery assembly unseals the whipstock by shocking.

[0020] According to the present invention, in a specific embodiment, in step S4, the second completion string includes a window hanger and a second support pipe.

[0021] According to the present invention, in a specific embodiment, a bottom elbow is provided at the lower end of the second support pipe, and the bottom elbow is lowered into the wall and enters the second branch wellbore by rebounding.

[0022] Compared with the prior art, the advantages of the present application are as follows.

[0023] The present invention proposes a dual-branch drilling method based on deep multi-target oil and gas development, which realizes the drilling of oil and gas target reservoirs in different directions in the same wellbore, and improves the scale and output of oil and gas in a single well. The present invention follows the method of constructing the lower branch first and then constructing the upper branch. After drilling the lower branch, the anchor packer, rupture disk, and support pipe are lowered to realize the open hole support and plugging of the lower branch wellbore, and the integrity of the lower branch wellbore is guaranteed. Then the drill is pulled out and the recyclable window opening system is lowered, and the drill is pulled out after hanging, opening the window, and drilling a certain distance. After that, according to the requirements of the dogleg degree of the wellbore track design, the guide drilling tool combination is assembled, and the upper branch construction is completed by drilling. Then, the completion string is lowered by re-entry, positioning, hanging, etc., and the window positioning guide tool cooperates with the pre-opening window hanger to be lowered to the casing window opening position, so that the preset window is aligned with the main wellbore, and the pressure is pressed to realize the hanging of the hanger, and the construction of the upper branch is completed, so as to realize the mobilization of oil and gas reservoirs in different directions.

[0024] Compared with the prior art, the present invention has a simple process and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be described below with reference to the accompanying drawings.

[0026] Figure 1 A schematic diagram showing the running of a dual-branch drilling string according to the present invention is shown;

[0027] Figure 2 A schematic diagram showing an embodiment of a dual-branch drilling wellbore structure according to the present invention is shown.

[0028] In the figure:

[0029] 1. The first branch wellbore;

[0030] 2. Second branch wellbore;

[0031] 3. First completion string; 31. Anchor packer; 32. Rupture disk; 33. First support pipe;

[0032] 5. Main shaft;

[0033] 6. Second completion string;

[0034] 61. Pre-opening window hanger; 611. Packer; 612. Guide tool;

[0035] 62. Second supporting tube; 621. Bottom elbow.

[0036] 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

[0037] The present invention will be described below with reference to the accompanying drawings.

[0038] It should be noted that the directional terms or qualifiers "upper", "lower", "left", "right", etc. used in this application are all relative to the referenced Figure 1 They are not intended to define the absolute positions of the components involved, but may vary depending on the specific circumstances.

[0039] According to the present invention, a dual-branch drilling method based on multi-objective deep oil and gas development is provided, comprising the following steps.

[0040] Step S1, drilling a first branch well in a well to form a first branch wellbore 1.

[0041] Step S2 , lowering the first completion string 3 into the first branch wellbore 1 to achieve open hole support and plugging of the first branch wellbore 1 , thereby ensuring the integrity of the first branch wellbore 1 .

[0042] According to the present invention, in a specific embodiment, in step S2, the first completion string 3 includes an anchor packer 31, a rupture disk 32 and a first support pipe 33 which are connected to each other.

[0043] like Figure 2 As shown, after the first completion string 3 is lowered into the first branch wellbore 1 to a predetermined position by a downhole tool, the anchor packer 31 is set by pressure.

[0044] The first support pipe 33 is sealed and fixed at the lower end of the anchor packer 31 and extends into the first branch wellbore 1. The first support pipe 33 can support the first branch wellbore 1.

[0045] The rupture disk 32 is located in the first support tube 33, temporarily sealing the first support tube 33. The rupture disk 22 can be mechanically crushed. When the first branch wellbore 1 needs to be connected with the main wellbore 5 after the well is completed, the rupture disk 22 can be crushed by applying pressure or other methods, mechanical collision, etc. to the rupture disk 22, so that the first branch wellbore 1 can be connected with the main wellbore 5.

[0046] In a specific embodiment, after the anchor packer 31 is set, the downhole tool used to run into the first completion string 3 is dropped, and after the downhole tool is pulled up, step S3 is performed.

[0047] Step S3 , lowering the recoverable window opening system into a predetermined position in the well, drilling a second branch well, and forming a second branch wellbore 2 , wherein the second branch wellbore 2 is located above the first branch wellbore 1 .

[0048] According to the present invention, in S3, after the recoverable window opening system is lowered, anchoring, window opening, and blind drilling are completed by the recoverable window opening system, and finally the second branch wellbore is formed.

[0049] Furthermore, the recyclable window opening system includes a whipstock, and the entire recyclable window opening system is anchored by the whipstock. The first drilling tool is sent into the recyclable window opening system to achieve sitting, hanging, pressing down and releasing, and the whipstock anchoring, window opening, and blind drilling are completed in one drilling trip.

[0050] Specifically, in step S2, after lifting the downhole tool used to lower the first completion string 3, it is replaced with a drill tool assembly (first drill tool) for lowering the recyclable window opening system. The first drill tool can cooperate with the recyclable window opening system to perform a series of downhole work. The first drill tool can lower the recyclable window opening system to the predetermined position where the second branch wellbore 2 needs to be established, and then anchor the recyclable window opening system in the well by pressure or other means. Afterwards, the recyclable window opening system opens a window on the side wall to provide an inclined guide for the first drill tool, so that the first drill tool can drill on the well wall and complete the blind drilling section.

[0051] Furthermore, according to the wellbore trajectory design requirements, the drill is started, the first drilling tool is lifted up, and then the first drilling tool is replaced with a guide drilling tool assembly, and the drilling is completed to complete the construction of the second branch wellbore 2.

[0052] After the drilling of the second branch wellbore 2 is completed, the drill is started and then step S4 is performed.

[0053] Step S4 , recover the recoverable window opening system, and lower the second completion string 6 into the second branch wellbore 2 .

[0054] In a specific embodiment, in step S4, the recyclable window opening system is recovered using a recovery component, and the recovery component has dual salvaging functions of a fishing hook and a mother cone.

[0055] Furthermore, the recovery component includes a drilling jar tool, which unseals the whipstock by jarring. Then, the drill is pulled up to lift the recovery component and retrieve the recoverable window opening component.

[0056] According to the present invention, in step S4 , the second completion string 6 includes a pre-window hanger 61 and a second support pipe 62 .

[0057] like Figure 1 As shown, a pre-window hanger 61 and a second support pipe 62 are lowered into the second branch wellbore 2, and the second support pipe 62 enters the second branch wellbore 2 through re-entry, positioning, and hanging, and the pre-window hanger 61 is anchored on the pipe wall.

[0058] In a specific embodiment, the lower end of the second support pipe 62 includes a bottom elbow 621. In this embodiment, the bottom elbow 621 is 3 to 5 meters long and has an angle of about 3 degrees. When the second support pipe 62 is lowered into the well from top to bottom, the inclined portion of the bottom elbow 621 points to the direction where the second branch wellbore 2 is located. During the lowering of the second support pipe 62, the bottom elbow 4 is lowered against the wall. When the bottom elbow 4 descends to the window, the bottom elbow 621 rebounds and calibrates to enter the second branch wellbore 2.

[0059] Then continue to lower the second completion string 6 until the top of the second completion string 6 is 10m above the window, and stop drilling. The pre-window hanger 61 includes a packer 611 and a guide tool 612. The guide tool 612 is located below the packer 611. The top of the second completion string 6 is 10m above the window, that is, the top of the packer 611 is 10m above the window, so as to ensure that the pre-guide tool 612 covers the window. The pre-window hanger 61 is adjusted according to the orientation of the directional joint, so that the preset window of the pre-window hanger 61 is opposite to the casing window orientation, and slowly lowered. Continue to lower it so that the preset window of the pre-window hanger 61 is aligned with the main wellbore 5. Then pressurize 15MPa to seat the pre-window hanger 61, and verify the seat by pressing up / lifting up. Then pressurize 20~25MPa to achieve the release of the pre-window hanger 61, and then slowly lift the drilling tool to pull out the guide tool 612, so as to establish a channel between the upper and lower wellbores.

[0060] 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.

[0061] 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.

[0062] 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 dual-branch drilling method based on multi-objective deep oil and gas development, characterized in that: The steps include: Step S1, drilling a first branch well in a well to form a first branch wellbore; Step S2, lowering a first completion string into the first branch wellbore; Step S3, lowering a recyclable window opening system into a predetermined position in the well, drilling a second branch well, and forming a second branch wellbore; Step S4, recovering the recoverable window opening system, and lowering a second completion string into the second branch wellbore.

2. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 1 is characterized in that: In step S2, the first completion string includes an anchor packer, a rupture disk and a first support pipe that are connected to each other.

3. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 2 is characterized in that: After the first completion string is lowered to a predetermined position, the anchor packer is set by pressure.

4. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 1, characterized in that: In step S3, after the recoverable window opening system is lowered, anchoring, window opening, and blind drilling are completed by the recoverable window opening system, and finally a second branch wellbore is formed.

5. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 4 is characterized in that: The first drilling tool is sent into the recyclable window opening system. After the first drilling tool completes the blind drilling section through the recyclable window opening system, the first drilling tool is pulled out, the guide drilling tool is replaced, and the second branch wellbore is formed by drilling.

6. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 1 is characterized in that: The recyclable window opening system comprises a bevel, and the entire recyclable window opening system is anchored by the bevel.

7. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 6 is characterized in that: In the step S4, the recyclable window opening system is recycled using a recycling component.

8. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 7 is characterized in that: The recovery assembly unseals the whipstock by shocking.

9. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 1, characterized in that: In step S4, the second completion string includes a window hanger and a second support pipe.

10. The dual-branch drilling method based on multi-objective deep oil and gas development according to claim 9, wherein The feature is that a bottom elbow is provided at the lower end of the second support tube, and the bottom elbow is inserted into the wall. Enter the second branch wellbore by rebounding.

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