Mining method of tight reservoir

Abstract

The invention discloses a tight reservoir exploitation method, and belongs to the technical field of petroleum development. The mining method for the tight reservoir comprises the steps that S1, a well pattern is arranged, wherein the well pattern is a vertical well and horizontal well combined well pattern; s2, fracturing and gas injection are conducted on the vertical well; s3, fracturing and soaking the horizontal well; s4, all the horizontal wells are opened for production, and all the vertical wells are closed until the production effect does not meet the first set requirement; s5, the horizontal wells in even rows are controlled to be shut down, the horizontal wells in odd rows are controlled to be converted into injection wells and inject gas into the stratum, and the vertical wells are controlled to serve as the injection wells to inject gas into the stratum; s6, after gas injection is finished, all the vertical wells are shut in for soaking, and all the horizontal wells are shut in for soaking; s7, after soaking is finished, all the horizontal wells are controlled to be opened for production, and all the vertical wells are controlled to be closed until the production effect does not meet the second set requirement; and S8, repeatedly executing the steps S5 to S7 for a plurality of times. The method can provide help for the development of tight oil / shale oil reservoirs.

Description

Technical Field

[0001] The present invention relates to the technical field of oil development, and in particular to a method for exploiting a tight reservoir. Background Art

[0002] Shale / tight oil reservoirs have low matrix permeability, typically requiring fracturing to increase formation permeability. After horizontal well fracturing is put into production, depletion-based development can easily lead to insufficient formation energy. Improving or supplementing well formation energy and enhancing recovery rates are key challenges in the development of tight / shale oil reservoirs. Summary of the Invention

[0003] The present invention aims to provide a method for extracting tight reservoirs. This method employs a combined vertical and horizontal well pattern. Based on this pattern, a method for extracting oil by injecting gas to increase or supplement formation energy and improve oil recovery is developed, thereby facilitating the development of tight oil / shale oil reservoirs.

[0004] A method for mining a tight reservoir, comprising:

[0005] S1. Arranging a well pattern, wherein the well pattern is a combination of vertical wells and horizontal wells;

[0006] S2, performing fracturing and gas injection on the vertical well;

[0007] S3, fracturing and soaking the horizontal well;

[0008] S4, all the horizontal wells are started for production, and all the vertical wells are shut in, until the production effect does not meet the first set requirement;

[0009] S5. Control the horizontal wells in the even-numbered rows to be shut in, control the horizontal wells in the odd-numbered rows to be converted into injection wells and inject gas into the formation, and control the vertical wells to be used as injection wells to inject gas into the formation;

[0010] S6. After the gas injection is completed, all the vertical wells are shut in and soaked, and all the horizontal wells are shut in and soaked;

[0011] S7, after the soaking is completed, all the horizontal wells are controlled to start production, and all the vertical wells are controlled to shut in, until the production effect does not meet the second set requirement;

[0012] S8. Repeat steps S5 to S7 several times until the development effect does not meet the third setting requirement.

[0013] Optionally, in step S1, in the well pattern:

[0014] The total number of rows N of the well pattern is ≥3 and N is an odd number, and the vertical wells and the horizontal wells in each row are distributed at intervals.

[0015] Optionally, in the well pattern, the first well and the last well in each row are both vertical wells.

[0016] Optionally, in the well pattern, in the second row to the second-to-last row, a vertical well is provided in front of, behind, to the left of, and to the right of each horizontal well, respectively.

[0017] Optionally, in the well pattern, one vertical well is provided at the left, right and rear position of each horizontal well in the first row, respectively.

[0018] Optionally, in the well pattern, a vertical well is provided at the left, right and front position of each horizontal well in the last row, respectively.

[0019] Optionally, in step S2, fracturing and injecting gas into the vertical well includes:

[0020] S21, performing hydraulic fracturing on all the vertical wells;

[0021] S22, after completing the hydraulic fracturing of the vertical well, use the vertical well as an injection well to inject gas into the formation;

[0022] S23, after the gas injection into the vertical well is completed, the vertical well is shut in and soaked;

[0023] S24, the soaking of the vertical well is completed.

[0024] Optionally, in step S3, fracturing and soaking the horizontal well includes:

[0025] S31, after the vertical wells are soaked, all the horizontal wells are fracturing;

[0026] S32, after the hydraulic fracturing of the horizontal well is completed, the horizontal well is shut in and soaked;

[0027] S33, the soaking of the horizontal well is completed.

[0028] Optionally, the tight reservoir is a shale oil reservoir or a tight oil reservoir.

[0029] This invention proposes a method for extracting tight reservoirs. It designs a combined vertical and horizontal well pattern. Based on this pattern, a method for extracting oil by injecting gas to increase or supplement formation energy and improve oil recovery is developed, thereby facilitating the development of tight oil / shale oil reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of a method for mining a tight reservoir provided by an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the distribution positions of vertical wells and horizontal wells in the well pattern provided by an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of horizontal wells and adjacent vertical wells in the second to second-to-last rows of the well pattern provided by an embodiment of the present invention;

[0033] Figure 4 Schematic diagram of the first row of horizontal wells and adjacent vertical wells in the well pattern provided by an embodiment of the present invention;

[0034] Figure 5 It is a schematic diagram of the horizontal wells in the penultimate row and the adjacent vertical wells in the well pattern provided by an embodiment of the present invention.

[0035] In the picture:

[0036] 1. Vertical well; 2. Horizontal well. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0040] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0041] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0042] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0043] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0044] See also Figure 1-Figure 5 , this embodiment provides a method for mining a tight reservoir.

[0045] Specifically, in this embodiment, the tight reservoir is a shale oil reservoir or a tight oil reservoir.

[0046] Specifically, see Figure 1 In this embodiment, a method for mining a tight reservoir includes:

[0047] S1, arranging a well pattern, which is a combination of vertical well 1 and horizontal well 2;

[0048] S2, fracturing and gas injection into vertical well 1;

[0049] S3, fracturing and soaking the horizontal well 2;

[0050] S4: All horizontal wells 2 are put into production, and all vertical wells 1 are shut in until the production effect does not meet the first set requirement;

[0051] S5, shutting in horizontal well 2 in the even-numbered row, converting horizontal well 2 in the odd-numbered row into an injection well and injecting gas into the formation, and controlling vertical well 1 as an injection well to inject gas into the formation;

[0052] S6. After the gas injection is completed, all vertical wells are shut in and soaked, and all horizontal wells are shut in and soaked;

[0053] S7: After the soaking is completed, all horizontal wells 2 are controlled to start production, and all vertical wells 1 are controlled to shut in until the production effect does not meet the second set requirement;

[0054] S8. Repeat steps S5 to S7 several times until the development effect does not meet the third setting requirement.

[0055] The method for mining a tight reservoir provided in this embodiment has the following advantages:

[0056] This embodiment provides a method for producing tight reservoirs. This embodiment provides a combined vertical and horizontal well pattern, based on which a method for producing tight oil / shale oil reservoirs is designed to increase or supplement formation energy and improve oil recovery.

[0057] Specifically, in the actual mining process, steps S5 to S7 are repeatedly executed several times. When the development effect does not meet the third setting requirement, the mining method of this article ends.

[0058] Specifically, see Figure 2-Figure 5 In this embodiment, in step S1:

[0059] In the well pattern, the total number of rows N of the well pattern is ≥ 3 and N is an odd number, and in each row, vertical wells 1 and horizontal wells 2 are distributed alternately.

[0060] In the well pattern, the first well and the last well in each row are both vertical wells 1.

[0061] In the well pattern, in the second row to the second-to-last row, a vertical well 1 is provided in front of, behind, to the left of, and to the right of each horizontal well 2 .

[0062] In the well pattern, a vertical well 1 is provided at the left, right and rear positions of each horizontal well 2 in the first row.

[0063] In the well pattern, a vertical well 1 is provided at the left, right and front positions of each horizontal well 2 in the last row.

[0064] Furthermore, in this embodiment, in step S2, fracturing and gas injection into the vertical well 1 includes:

[0065] S21, fracturing all vertical wells 1;

[0066] S22, after the vertical well 1 is hydraulically fractured, the vertical well 1 is used as an injection well to inject gas into the formation;

[0067] S23, after the gas injection of vertical well 1 is completed, vertical well 1 is shut in and soaked;

[0068] S24, the soaking of vertical well 1 is completed.

[0069] In step S3, fracturing and soaking the horizontal well 2 includes:

[0070] S31, after the vertical well 1 is soaked, all horizontal wells 2 are fractured;

[0071] S32. After the fracturing of horizontal well 2 is completed, horizontal well 2 is shut in and soaked.

[0072] S33. The soaking of horizontal well 2 is completed.

[0073] For example, in this embodiment, there are five rows of well patterns, and in each row, vertical wells 1 and horizontal wells 2 are alternately distributed; the first well and the last well in each row are both vertical wells 1; a vertical well 1 is respectively provided at the left, right, and rear positions of each horizontal well 2 in the first row; in the second to fourth rows, a vertical well 1 is respectively provided at the front, rear, left, and right positions of each horizontal well 2; and a vertical well 1 is respectively provided at the left, right, and front positions of each horizontal well 2 in the fifth row.

[0074] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for mining a tight reservoir, characterized in that: include: S1, arranging a well pattern, wherein the well pattern is a combination of vertical wells (1) and horizontal wells (2); S2, fracturing and gas injection into the vertical well (1); S3, fracturing and soaking the horizontal well (2); S4, all the horizontal wells (2) are opened for production, and all the vertical wells (1) are shut in, until the production effect does not meet the first set requirement; S5, controlling the horizontal wells (2) in the even-numbered rows to be shut in, controlling the horizontal wells (2) in the odd-numbered rows to be converted into injection wells and to inject gas into the formation, and controlling the vertical wells (1) to be injection wells and to inject gas into the formation; S6. After the gas injection is completed, all the vertical wells (1) are shut in and soaked, and all the horizontal wells (2) are shut in and soaked; S7, after the soaking is completed, all the horizontal wells (2) are controlled to start production, and all the vertical wells (1) are controlled to shut in, until the production effect does not meet the second set requirement; S8. Repeat steps S5 to S7 several times until the development effect does not meet the third setting requirement.

2. The method for mining a tight reservoir according to claim 1, characterized in that: In the step S1, in the well pattern: The total number of rows of the well pattern N is greater than or equal to 3 and N is an odd number, and in each row the vertical wells (1) and the horizontal wells (2) are distributed at intervals.

3. The method for mining a tight reservoir according to claim 2, characterized in that: In the well network, the first well and the last well in each row are both vertical wells (1).

4. The method for mining a tight reservoir according to claim 2, characterized in that: In the well network, in the second row to the second-to-last row, one vertical well (1) is respectively arranged in front of, behind, to the left and to the right of each horizontal well (2).

5. The method for mining a tight reservoir according to claim 2, characterized in that: In the well network, one vertical well (1) is respectively arranged at the left, right and rear position of each horizontal well (2) in the first row.

6. The method for mining a tight reservoir according to claim 2, characterized in that: In the well network, one vertical well (1) is respectively arranged at the left, right and front position of each horizontal well (2) in the last row.

7. The method for mining a tight reservoir according to claim 1, characterized in that: In step S2, the fracturing and gas injection of the vertical well (1) includes: S21, fracturing all the vertical wells (1); S22, after the vertical well (1) is fracturing, the vertical well (1) is used as an injection well to inject gas into the formation; S23, after the gas injection of the vertical well (1) is completed, the vertical well (1) is shut down and soaked; S24, the soaking of the vertical well (1) is completed.

8. The method for mining a tight reservoir according to claim 1, characterized in that: In step S3, the fracturing and soaking of the horizontal well (2) includes: S31, after the soaking of the vertical well (1) is completed, all the horizontal wells (2) are subjected to fracturing; S32, after the hydraulic fracturing of the horizontal well (2) is completed, the horizontal well (2) is shut in and soaked; S33, the soaking of the horizontal well (2) is completed.

9. A method for mining a tight reservoir according to any one of claims 1 to 8, characterized in that: The tight reservoir is a shale oil reservoir or a tight oil reservoir.

Images