Combined well spacing method for ground vertical well and underground horizontal well

Abstract

The invention discloses a combined well spacing method for a ground vertical well and an underground horizontal well, which comprises the following steps of: determining estimated fracturing information of the vertical well and estimated fracturing information of the horizontal well according to acquired fracturing construction information of a surrounding mine; the width of the to-be-mined working face and the lateral mining-induced fracture range of the mined working face are obtained, vertical well construction information is determined according to the width of the to-be-mined working face, the lateral mining-induced fracture range and vertical well estimated fracturing information, fracturing construction is conducted on the thick and hard roof based on the vertical well construction information, and the vertical well fracturing range of a ground vertical well is obtained; and horizontal well construction information is determined according to the horizontal well estimated fracturing information and the vertical well fracturing range, and fracturing construction is conducted on the impact main control rock stratum based on the horizontal well construction information. According to the combined well spacing method for the ground vertical well and the underground horizontal well, the well spacing scheme that the ground vertical well and the underground horizontal well are matched with each other is adopted, sufficient fracturing and pressure relief can be conducted on a thick and hard top plate, and cooperative prevention and control over rock burst and mine earthquake disasters are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of mine roof fracturing and pressure relief methods, and in particular to a combined well arrangement method of ground vertical wells and underground horizontal wells. Background Art

[0002] Thick and hard roof is one of the main factors causing rock burst and mine tremors. Its high strength and complete structure lead to the formation of suspended roof in the middle and low roof of goaf, resulting in stress concentration, which can easily cause rock burst. The high roof forms a large-scale spatial structure, which can easily produce strong mine tremors after instability. According to statistics, 80% of rock burst and mine tremors in most mining areas are related to the instability of thick and hard roof. Single measures such as underground short-hole fracturing and roof pre-cracking blasting cannot achieve coordinated prevention and control of rock burst and mine tremors.

[0003] At present, ground vertical well fracturing measures have significant advantages in regional governance, advanced governance, and pre-cracking and weakening of multi-layer thick hard roofs, and have been widely promoted and applied in the field of mine earthquake control. However, for mines where both rock burst and mine earthquakes coexist, the use of ground vertical well fracturing measures is prone to forming fracturing blind zones at the edge of the region, making it difficult to completely eliminate the rock burst risk caused by the middle and low-level roof. Based on this, the present invention provides a combined well layout method of ground vertical wells and underground horizontal wells for the regional prevention and control of rock burst and mine earthquakes. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention proposes a method for jointly deploying ground vertical wells and underground horizontal wells. Through the well deployment scheme in which the ground vertical wells and underground horizontal wells cooperate with each other, the thick hard roof can be fully fractured and decompressed, and coordinated prevention and control of rock burst and mine earthquake disasters can be achieved.

[0006] The combined well layout method of surface vertical wells and underground horizontal wells of an embodiment of the present invention includes: S1: determining estimated vertical well fracturing information and horizontal well fracturing information for the thick hard roof based on acquired fracturing construction information of surrounding mines;

[0007] S2: Obtain the width of the working face to be mined and the range of lateral mining fractures of the mined working face, determine the vertical well construction information based on the width of the working face to be mined, the range of lateral mining fractures and the estimated fracturing information of the vertical well, perform fracturing construction on the mine earthquake main control rock layer and the impact main control rock layer based on the vertical well construction information, and obtain the vertical well fracturing range of the ground vertical well; S3: Determine the horizontal well construction information based on the estimated fracturing information of the horizontal well and the vertical well fracturing range, perform fracturing construction on the impact main control rock layer based on the horizontal well construction information, and the underground horizontal well is located between the ground vertical well and the tunnel.

[0008] In some embodiments, the tunnels located on both sides of the working face to be mined are auxiliary transport tunnels and rubber transport tunnels, respectively. The auxiliary transport tunnel is closer to the mined working face than the rubber transport tunnel. The vertical well construction information includes the vertical well inclination construction position along the inclination of the working face to be mined. The arrangement of the vertical well inclination construction position is as follows: if the lateral mining fracture range does not extend to the thick hard roof of the working face to be mined, the distance between the well axis of the ground vertical well and the positive side of the auxiliary transport tunnel is equal to half of the width of the working face to be mined; if the lateral mining fracture range extends to the thick hard roof of the working face to be mined, the distance between the well axis of the ground vertical well and the positive side of the auxiliary transport tunnel is greater than half of the width of the working face to be mined, so that the vertical well fracturing range and the lateral mining fracture range are arranged at intervals.

[0009] In some embodiments, the vertical well construction information also includes the vertical well construction positions along the direction of the working face to be mined. The arrangement of the vertical well construction positions is as follows: there are multiple ground vertical wells, and the multiple ground vertical wells are arranged along the direction of the working face.

[0010] In some embodiments, the estimated fracturing information of the vertical well includes an estimated width of the fracture network. The spacing between two adjacent vertical wells on the ground, the estimated width of the fracture network, and the periodic fracture step distance of the thick hard roof of the working face to be mined satisfy the following formula:

[0011] D=(b+d) / 2

[0012] D is the distance between two adjacent ground vertical wells, b is the estimated width of the fracture network, and d is the periodic fracture step distance of the thick hard roof of the working face to be mined.

[0013] In some embodiments, in step S2, obtaining the vertical well fracturing range includes:

[0014] The expansion of the fracture network of the surface vertical well is monitored by using a surface microseismic monitoring method to obtain the fracturing range of the vertical well.

[0015] In some embodiments, the underground horizontal wells are arranged in pairs, and the two underground horizontal wells arranged in pairs are respectively arranged close to the auxiliary transport tunnel and the rubber transport tunnel.

[0016] In some embodiments, the estimated fracturing information of the horizontal well includes an estimated fracturing range of the horizontal well. The estimated fracturing range of the horizontal well arranged near the auxiliary transportation roadway has a first boundary and a second boundary arranged along the inclination of the working face to be mined. The first boundary is arranged on a side of the auxiliary transportation roadway close to the working face to be mined, and the second boundary is arranged on a side of the auxiliary transportation roadway away from the working face to be mined. The distance between the first boundary and the main side of the auxiliary transportation roadway is six times the width of the auxiliary transportation roadway, and the distance between the second boundary and the secondary side of the auxiliary transportation roadway is twice the width of the auxiliary transportation roadway.

[0017] The estimated fracturing range of the horizontal well arranged close to the rubber transport tunnel has a third boundary and a fourth boundary arranged along the inclination of the working face to be mined. The third boundary is arranged on the side of the rubber transport tunnel close to the working face to be mined, and the fourth boundary is arranged on the side of the rubber transport tunnel away from the working face to be mined. The distance between the third boundary and the main side of the rubber transport tunnel is six times the width of the rubber transport tunnel, and the distance between the fourth boundary and the secondary side of the rubber transport tunnel is equal to the width of the rubber transport tunnel.

[0018] In some embodiments, the vertical well construction information includes the number of vertical well fracturing points, the vertical well fracturing points are grouped in two, and there are multiple groups of vertical well fracturing points, and the multiple groups of vertical well fracturing points are arranged in sequence along the extension direction of the ground vertical well; the horizontal well construction information includes the number of horizontal well fracturing points, the horizontal well fracturing points are grouped in two, and there are multiple groups of horizontal well fracturing points, and the multiple groups of horizontal well fracturing points are arranged in sequence along the extension direction of the horizontal well.

[0019] In some embodiments, the step S1: determining the estimated vertical well fracturing information and horizontal well fracturing information for the target mine based on the obtained fracturing construction information of the surrounding mines includes: determining the estimated vertical well fracturing information for the target mine based on the obtained vertical well fracturing construction information of the surrounding mines, and determining the estimated horizontal well fracturing information for the target mine based on the obtained horizontal well fracturing construction information of the surrounding mines.

[0020] The combined well arrangement method of ground vertical wells and underground horizontal wells in the embodiment of the present invention uses ground vertical wells to pre-crack the impact-controlled rock strata and mine-seismic main-controlled rock strata of the working face to be mined, so that the vertical well fracture network can be extended to the impact-controlled rock strata and mine-seismic main-controlled rock strata. At the same time, underground horizontal wells are used to pre-crack the impact-controlled rock strata near the tunnel area. In this way, all-round and sufficient fracturing and pressure relief can be achieved for the high, medium and low layers of the thick hard roof of the working face to be mined, and the occurrence of pressure relief blind spots can be prevented. It is therefore more suitable for mines where rock burst and mine seismic disasters coexist, and can achieve coordinated prevention and control of rock burst and mine seismic disasters. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a plan view schematic diagram of a surface vertical well and an underground horizontal well according to an embodiment of the present invention.

[0022] Figure 2 It is a cross-sectional view of a surface vertical well and an underground horizontal well according to an embodiment of the present invention.

[0023] Reference numerals:

[0024] 1. Mined working face;

[0025] 2. Working face to be mined; 21. Auxiliary transport tunnel; 22. Rubber transport tunnel;

[0026] 3. Surface vertical well; 31. Vertical well fracturing range; 32. Vertical well fracturing point;

[0027] 4. Downhole horizontal well; 41. Estimated fracturing range of horizontal well; 411. First boundary; 412. Second boundary; 413. Third boundary; 414. Fourth boundary; 42. Fracturing point of horizontal well. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0029] like Figure 1 and Figure 2 As shown, the combined well layout method of surface vertical wells and underground horizontal wells in an embodiment of the present invention is applicable to pre-splitting thick hard roof of a target mine. The target mine includes a mined working face 1, a working face 2 to be mined, and tunnels located on both sides of the working face 2 to be mined. The thick hard roof includes rock formations mainly controlled by impact and rock formations mainly controlled by mine seismic. The combined well layout method includes:

[0030] S1: Determine estimated fracturing information for vertical wells and horizontal wells for thick hard roof based on the obtained fracturing construction information of surrounding mines;

[0031] S2: Obtain the width of the working face to be mined and the range of lateral mining fractures of the mined working face 1. Determine the vertical well construction information based on the width of the working face to be mined, the range of lateral mining fractures, and the estimated fracturing information of the vertical well. Perform fracturing construction on the main rock formations controlled by mine earthquakes and the main rock formations controlled by impacts based on the vertical well construction information, and obtain the vertical well fracturing range 31 of the surface vertical well 3.

[0032] S3: Determine the horizontal well construction information based on the estimated fracturing information of the horizontal well and the vertical well fracturing range 31, and perform fracturing construction on the impact main control rock formation based on the horizontal well construction information. The underground horizontal well 4 is set between the ground vertical well 3 and the tunnel.

[0033] It is known that due to the limited fracturing coverage of the ground vertical well 3, a fracturing blind area is easily formed at the edge of the vertical well fracturing coverage (i.e., the area close to the tunnels on both sides of the working face 2 to be mined), resulting in insufficient pressure relief in the area close to the tunnels on both sides of the low-level roof of the working face 2 to be mined (i.e., the main controlling rock formation of the impact), making it difficult to completely eliminate the risk of impact ground pressure on the low-level roof.

[0034] The combined well arrangement method of ground vertical wells and underground horizontal wells in the embodiment of the present invention adopts the ground vertical well 3 to pre-crack the impact main controlling rock layer and the mine earthquake main controlling rock layer of the working face 2 to be mined, so that the vertical well fracture network can be extended to the impact main controlling rock layer and the mine earthquake main controlling rock layer. At the same time, the underground horizontal well 4 is used to pre-crack the impact main controlling rock layer near the tunnel area. In this way, all-round and sufficient fracturing and pressure relief can be achieved for the high, medium and low layers of the thick hard roof of the working face 2 to be mined, and the occurrence of pressure relief blind spots can be prevented. It is therefore more suitable for mines where rock burst and mine earthquake disasters coexist, and can achieve coordinated prevention and control of rock burst and mine earthquake disasters.

[0035] Specifically, if Figure 1 As shown, the direction of the working face 2 to be mined is the direction of coal mining advancement, and the working face 2 to be mined is inclined perpendicular to its direction; the tunnel located on the side of the working face 2 to be mined close to the mined working face 1 is the auxiliary transport tunnel 21, and the tunnel located on the side of the working face 2 to be mined away from the mined working face 1 is the rubber transport tunnel 22. The widths of the auxiliary transport tunnel 21 and the rubber transport tunnel 22 are equal, the mined working face 1 and the working face 2 to be mined are parallel and a coal pillar is provided between them, and the auxiliary transport tunnel 21 is closer to the mined working face 1 than the rubber transport tunnel 22.

[0036] The side wall of the auxiliary transport tunnel 21 close to the working face 2 to be mined is its main side, the side wall of the auxiliary transport tunnel 21 away from the working face 2 to be mined is its secondary side, the side wall of the rubber transport tunnel 22 close to the working face 2 to be mined is its main side, and the side wall of the rubber transport tunnel 22 away from the working face 2 to be mined is its secondary side.

[0037] The ground vertical well 3 and the underground horizontal well 4 of the embodiment of the present invention are arranged in the thick hard roof of the working face 2 to be mined of the target mine, and are used to pre-crack and relieve pressure on the thick hard roof to achieve coordinated prevention and control of rock burst and mine earthquake disasters.

[0038] like Figure 2 As shown, the target mine's thick, hard roof consists of multiple rock layers from bottom to top. First, the fracture zone height is calculated based on a combination of theoretical calculations and field measurements. The thick, intact, and strong roof below the fracture zone height range is the primary percussion-controlled rock layer, typically no less than 10 meters thick. The thick, intact, and strong roof above the fracture zone height range is the primary mine-seismic-controlled rock layer, typically no less than 30 meters thick. A surface vertical well 3 penetrates both the primary mine-seismic-controlled rock layer and the primary percussion-controlled rock layer. An underground horizontal well 4 is located in the primary percussion-controlled rock layer and extends along the strike of the working face 2 to be mined.

[0039] It is known that the mined working face 1 is a working face that has been mined, and lateral mining cracks will be generated laterally of the mined working face. Optionally, in step S2, the range of the lateral mining cracks of the mined working face 1 can be estimated based on the angle of rock formation movement, or detected through means such as geophysical exploration, thereby determining the range of the lateral mining cracks of the mined working face.

[0040] Optionally, the fracturing construction steps of the surface vertical well 3 and the underground horizontal well 4 in the embodiment of the present invention are: drilling first and then fracturing, wherein the drilling is carried out by a drilling rig and the fracturing is carried out by a fracturing pump truck.

[0041] In some embodiments, step S1: determining estimated vertical well fracturing information and estimated horizontal well fracturing information for a target mine based on acquired fracturing construction information of surrounding mines includes:

[0042] Based on the vertical well fracturing construction information obtained from the surrounding mines, the estimated vertical well fracturing information for the target mine is determined, and based on the horizontal well fracturing construction information obtained from the surrounding mines, the estimated horizontal well fracturing information for the target mine is determined.

[0043] It is understood that the geological conditions of the surrounding mines should be similar to those of the target mine.

[0044] Therefore, based on the vertical well fracturing construction information of surrounding mines with similar geological conditions, the expansion of the vertical well fracturing network of the target mine under the preset fracturing pressure and fracturing flow rate can be estimated to determine the vertical well estimated fracturing information such as the estimated width of the fracturing network and the estimated length of the fracturing network, which makes it easier for construction personnel to determine the construction position, spacing and other parameters of the ground vertical well 3, providing a basis for determining the vertical well construction information, thereby ensuring that the vertical well fracturing range 31 can cover the thick hard roof of the working face 2 to be mined, and reducing the pre-cracking blind area.

[0045] Based on the horizontal well fracturing construction information of surrounding mines with similar geological conditions, the expansion of the horizontal well fracturing network of the target mine under the preset fracturing pressure and fracturing flow rate can be estimated to determine the estimated horizontal well fracturing range 41 and other horizontal well estimated fracturing information, which makes it easier for construction personnel to determine the construction position, spacing and other parameters of the underground horizontal well 4, providing a basis for determining the horizontal well construction information, so that the blind area of ​​the ground vertical well 3 fracturing construction can be further fractured through the underground horizontal well 4 fracturing construction, ensuring the comprehensive unloading of the thick hard roof of the working face 2 to be mined, and realizing the coordinated prevention and control of rock burst and mine tremors.

[0046] In some embodiments, the tunnels located on both sides of the working face 2 to be mined are an auxiliary transport tunnel 21 and a rubber transport tunnel 22. The auxiliary transport tunnel 21 is closer to the mined working face 1 than the rubber transport tunnel 22. The vertical well construction information includes the inclined construction position of the vertical well along the inclination of the working face 2 to be mined. The arrangement of the inclined construction position of the vertical well is as follows:

[0047] If the lateral mining cracks do not extend to the thick hard roof of the working face 2 to be mined, the distance between the shaft of the ground vertical well 3 and the positive wall of the auxiliary transport roadway 21 is equal to half the width of the working face to be mined (e.g. Figure 1 shown);

[0048] If the lateral mining fracture range extends to the thick hard roof of the working face 2 to be mined, the distance between the well axis of the ground vertical well 3 and the front side of the auxiliary transport tunnel 21 is greater than half the width of the working face to be mined, so that the vertical well fracturing range 31 and the lateral mining fracture range are arranged at intervals.

[0049] It is known that if the vertical well fracturing range 31 intersects with the lateral mining fracture range, it will cause leakage, making the vertical well fracturing effect of the surface vertical well 3 worse.

[0050] If the mining cracks do not extend to the thick hard roof of the working face 2 to be mined, the ground vertical well 3 can be arranged in the middle position of the working face 2 to be mined along the inclination of the working face 2 to be mined, that is, the distance between the well axis of the ground vertical well 3 and the positive side of the auxiliary transport tunnel 21 is equal to half of the width of the working face to be mined. Therefore, when conducting fracturing construction of the ground vertical well 3, it can be fractured evenly from the middle area of ​​the working face 2 to both sides, so that the vertical well fracturing range 31 can completely cover the thick hard roof at the top of the working face 2 to be mined in the inclination direction, thereby improving the fracturing effect.

[0051] If the mining cracks extend to the thick hard roof of the working face 2 to be mined, it is necessary to move the ground vertical well 3 at the inclined position in the direction away from the auxiliary transport tunnel 21 according to the boundary position of the lateral mining crack range, that is, the distance between the well axis of the ground vertical well 3 and the positive side of the auxiliary transport tunnel 21 is greater than half of the width of the working face to be mined, so that the vertical well fracturing range 31 formed by the fracturing construction of the ground vertical well 3 is arranged at intervals from the lateral mining crack range (the two do not affect each other), thereby ensuring the fracturing effect of the ground vertical well 3.

[0052] Therefore, the thick hard roof of the working face 2 to be mined can be pre-cracked by the fracturing construction of the ground vertical well 3 to achieve a better anti-blowout effect.

[0053] It can be understood that the main side of the auxiliary transport lane 21 and the main side of the rubber transport lane 22 form the above-mentioned lane main side.

[0054] In some embodiments, as Figure 1 and Figure 2 As shown, the vertical well construction information also includes the vertical well construction positions along the direction of the working face 2 to be mined. The arrangement of the vertical well construction positions is as follows: there are multiple ground vertical wells 3, and the multiple ground vertical wells 3 are arranged along the direction of the working face.

[0055] In some embodiments, the estimated fracturing information of the vertical well includes the estimated width of the fracture network. The distance between two adjacent ground vertical wells 3, the estimated width of the fracture network, and the periodic fracturing step distance of the thick hard roof of the working face 2 to be mined satisfy the following formula:

[0056] D=(b+d) / 2

[0057] D is the distance between two adjacent ground vertical wells 3, b is the estimated width of the fracture network, and d is the periodic fracture step distance of the thick hard roof of the working face 2 to be mined.

[0058] Through the above settings, it can be ensured that the fracture networks of two adjacent ground vertical wells 3 are connected, so that the fracture networks of multiple ground vertical wells 3 can completely cover the thick hard roof of the working face 2 to be mined along the direction of the working face 2 to be mined, thereby achieving a better pre-cracking effect.

[0059] Optionally, the periodic breaking step distance of the thick hard roof of the working face 2 to be mined is obtained according to the limit breaking step distance formula.

[0060] like Figure 1 As shown, the estimated width b of the hydraulic fracturing network is the dimension of the hydraulic fracturing network along the direction of the working face 2 to be mined; the estimated length L of the hydraulic fracturing network is the dimension of the hydraulic fracturing network along the inclination of the working face 2 to be mined.

[0061] In some embodiments, in step S2, obtaining the vertical well fracturing range 31 includes:

[0062] The fracture network expansion of the surface vertical well 3 is monitored by surface microseismic monitoring to obtain the vertical well fracturing range 31.

[0063] After the fracturing construction of the ground vertical well 3 is completed, the ground microseismic monitoring method is used to obtain and determine the vertical well fracturing range 31, and then determine the fracturing blind area of ​​the ground vertical well 3, providing more accurate data support for the fracturing construction of the underground horizontal well 4.

[0064] In some embodiments, the underground horizontal wells 4 are arranged in pairs, and the two underground horizontal wells 4 arranged in pairs are respectively arranged close to the auxiliary transport tunnel 21 and the rubber transport tunnel 22.

[0065] After the fracturing construction of the ground vertical well 3 is completed, the vertical well fracturing network expands along the inclination of the working face 2 to be mined, and the vertical well fracturing network extends to the auxiliary transport tunnel 21 and the rubber transport tunnel 22 along the two edges of the inclination of the working face 2 to be mined. Fracturing blind spots are easily formed in the low-level roofs in the top areas of the auxiliary transport tunnel 21 and the rubber transport tunnel 22; by setting up two underground horizontal wells 4, the low-level thick and hard roofs in the top areas of the auxiliary transport tunnel 21 and the rubber transport tunnel 22 can be further fractured at the same time, reducing fracturing blind spots and ensuring anti-bumping effects.

[0066] Optionally, the length of the underground horizontal well 4 is 500m to 800m.

[0067] When the strike length of the working face 2 to be mined is greater than the length of the underground horizontal well 4, multiple underground horizontal wells 4 can be set along the strike length of the working face 2 to be mined, so that the horizontal well fracturing network can completely cover the strike length of the working face 2 to be mined, preventing the occurrence of fracturing blind spots.

[0068] In some embodiments, as Figure 1 As shown, the estimated fracturing information of the horizontal well includes an estimated fracturing range 41 of the horizontal well. The estimated fracturing range 41 of the horizontal well arranged near the auxiliary transportation roadway 21 has a first boundary 411 and a second boundary 412 arranged along the inclination of the working face 2 to be mined. The first boundary 411 is arranged on the side of the auxiliary transportation roadway 21 close to the working face 2 to be mined, and the second boundary 412 is arranged on the side of the auxiliary transportation roadway 21 away from the working face 2 to be mined. The distance D1 between the first boundary 411 and the main side of the auxiliary transportation roadway 21 is six times the width of the auxiliary transportation roadway 21, and the distance D2 between the second boundary 412 and the secondary side of the auxiliary transportation roadway 21 is twice the width of the auxiliary transportation roadway 21.

[0069] The estimated fracturing range 41 of the horizontal well arranged near the rubber transport tunnel 22 has a third boundary 413 and a fourth boundary 414 arranged along the inclination of the working face 2 to be mined. The third boundary 413 is arranged on the side of the rubber transport tunnel 22 close to the working face 2 to be mined, and the fourth boundary 414 is arranged on the side of the rubber transport tunnel 22 away from the working face 2 to be mined. The distance D3 between the third boundary 413 and the main side of the rubber transport tunnel 22 is six times the width of the rubber transport tunnel 22, and the distance D4 between the fourth boundary 414 and the secondary side of the rubber transport tunnel 22 is equal to the width of the rubber transport tunnel 22.

[0070] The tunnel is the key area for the prevention and control of rock burst. According to the distribution range of the tunnel surrounding rock stress concentration area and the tunnel roof cutting and unloading requirements, the prevention and control areas (i.e., pre-cracking areas) of the auxiliary transport tunnel 21 main wall, auxiliary transport tunnel 21 secondary wall, rubber transport tunnel 22 main wall and rubber transport tunnel 22 secondary wall can be determined; in addition, since the auxiliary transport tunnel 21 is an air-facing tunnel, it is affected by the lateral hanging roof of the mined working face 1, and the degree of stress concentration of the surrounding rock of the auxiliary transport tunnel 21 is greater than that of the rubber transport tunnel 22. Therefore, the prevention and control area of ​​the secondary wall of the auxiliary transport tunnel 21 is larger than that of the secondary wall of the rubber transport tunnel 22.

[0071] By making the above restrictions on the estimated fracturing range 41 of the horizontal well, the prevention and control area requirements of the auxiliary transport tunnel 21 main side, auxiliary transport tunnel 21 secondary side, rubber transport tunnel 22 main side and rubber transport tunnel 22 secondary side can be met, thereby fully pre-cracking the low-lying thick and hard roof near the tunnel area to ensure the anti-bumping effect.

[0072] Optionally, if a single horizontal well cannot cover the above-mentioned area through fracturing, the number of underground horizontal wells can be increased. In other words, multiple underground horizontal wells can be set at the top of the auxiliary transport tunnel 21 or the rubber transport tunnel 22 along the inclination of the working face to be mined, and the well axes of the multiple underground horizontal wells can be arranged in parallel to ensure that the fracturing network of the underground horizontal wells can completely cover the above-mentioned prevention and control area.

[0073] In some embodiments, the vertical well construction information includes the number of vertical well fracturing points 32, which are grouped in two. There are multiple groups of vertical well fracturing points 32, and the multiple groups of vertical well fracturing points 32 are arranged in sequence along the extension direction of the ground vertical well 3; the horizontal well construction information includes the number of horizontal well fracturing points 42, which are multiple. There are multiple horizontal well fracturing points 42, which are grouped in two. There are multiple groups of horizontal well fracturing points 42, and the multiple groups of horizontal well fracturing points 42 are arranged in sequence along the extension direction of the horizontal well.

[0074] Specifically, if Figure 2As shown, during the fracturing operation of a surface vertical well 3, a perforation process is first used to form a set of vertical well fracturing points 32 targeting the lowest stratum. A vertical fracturing segment is formed between the two vertical well fracturing points 32 in this set. Water injection fracturing is then performed on these two vertical well fracturing points 32. A bridge plugging process is then used to seal the vertical fracturing segment, completing the vertical well fracturing of the lowest stratum. The same method is then used to perform vertical well fracturing on multiple strata, including the primary impact control stratum and the primary mine seismic control stratum, from bottom to top.

[0075] Similarly, when performing fracturing construction of the underground horizontal well 4, a group of horizontal well fracturing points 42 away from the wellhead is first formed, and a horizontal fracturing section is formed between the two horizontal well fracturing points 42 of this group. Water injection fracturing is performed on the two horizontal well fracturing points 42 of this group, and then the horizontal fracturing section is sealed using a bridge plugging process, thus completing the fracturing construction of this section of the horizontal well; thereafter, the same construction method is used to construct multiple horizontal fracturing sections in sequence along the direction close to the wellhead, thereby realizing fracturing construction on the impact main controlling rock formation, reducing fracturing blind spots, and reducing the risk of impact ground pressure on the low-lying roof.

[0076] Optionally, the distance between two vertical well fracturing points 32 in the same group is 18 m to 25 m, preferably 20 m.

[0077] Optionally, the distance between two horizontal well fracturing points 42 in the same group of horizontal well fracturing points is 18 m to 25 m, preferably 20 m.

[0078] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0079] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0080] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0081] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0082] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean 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 expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0083] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for combining surface vertical wells and underground horizontal wells, characterized in that: The method is applicable to pre-splitting thick hard roof of a target mine, wherein the target mine includes a mined working face, a working face to be mined, and tunnels located on both sides of the working face to be mined. The thick hard roof includes rock strata mainly controlled by impact and rock strata mainly controlled by mine earthquakes. The combined well layout method includes: S1: Determining estimated fracturing information for vertical wells and horizontal wells for the thick hard roof based on the acquired fracturing construction information of surrounding mines; S2: Obtaining the width of the working face to be mined and the range of lateral mining-induced fissures of the mined working face, determining vertical well construction information based on the width of the working face to be mined, the range of lateral mining-induced fissures, and the estimated fracturing information of the vertical well, performing fracturing construction on the mine earthquake main control rock formation and the impact main control rock formation based on the vertical well construction information, and obtaining the vertical well fracturing range of the surface vertical well; S3: Determine horizontal well construction information according to the estimated fracturing information of the horizontal well and the fracturing range of the vertical well, and perform fracturing construction on the impact main control rock formation based on the horizontal well construction information. The underground horizontal well is located between the ground vertical well and the tunnel.

2. The method for combining surface vertical wells and underground horizontal wells according to claim 1, characterized in that: The tunnels located on both sides of the working face to be mined are auxiliary transport tunnels and rubber transport tunnels. The auxiliary transport tunnels are closer to the mined working face than the rubber transport tunnels. The vertical well construction information includes the inclined construction positions of the vertical wells along the inclination of the working face to be mined. The arrangement of the inclined construction positions of the vertical wells is as follows: If the lateral mining cracks do not extend to the thick hard roof of the working face to be mined, the distance between the shaft of the surface vertical well and the main wall of the auxiliary transport roadway is equal to half the width of the working face to be mined; If the range of the lateral mining cracks extends to the thick hard roof of the working face to be mined, the distance between the well axis of the ground vertical well and the main wall of the auxiliary transport tunnel is greater than half the width of the working face to be mined, so that the vertical well fracturing range and the lateral mining crack range are arranged at intervals.

3. The method for combining surface vertical wells and underground horizontal wells according to claim 2, characterized in that: The vertical well construction information also includes the vertical well construction positions along the direction of the working face to be mined. The vertical well construction positions are arranged as follows: there are multiple ground vertical wells, and the multiple ground vertical wells are arranged along the direction of the working face.

4. The method for combining surface vertical wells and underground horizontal wells according to claim 3 is characterized in that: The estimated fracturing information of the vertical wells includes the estimated width of the fracturing network. The spacing between two adjacent vertical wells on the ground, the estimated width of the fracturing network, and the periodic breaking step distance of the thick hard roof of the working face to be mined satisfy the following formula: D=(b+d) / 2 D is the distance between two adjacent ground vertical wells, b is the estimated width of the fracture network, and d is the periodic fracture step distance of the thick hard roof of the working face to be mined.

5. The method for combining surface vertical wells and underground horizontal wells according to claim 1, characterized in that: In step S2, obtaining the vertical well fracturing range includes: The expansion of the fracture network of the surface vertical well is monitored by using a surface microseismic monitoring method to obtain the fracturing range of the vertical well.

6. The method for combining surface vertical wells and underground horizontal wells according to claim 2, characterized in that: The underground horizontal wells are arranged in pairs, and the two underground horizontal wells arranged in pairs are respectively arranged close to the auxiliary transport lane and the rubber transport lane.

7. The method for combining surface vertical wells and underground horizontal wells according to claim 6, characterized in that: The estimated fracturing information of the horizontal well includes an estimated fracturing range of the horizontal well. The estimated fracturing range of the horizontal well arranged near the auxiliary transportation roadway has a first boundary and a second boundary arranged along the inclination of the working face to be mined. The first boundary is arranged on a side of the auxiliary transportation roadway close to the working face to be mined, and the second boundary is arranged on a side of the auxiliary transportation roadway away from the working face to be mined. The distance between the first boundary and the main side of the auxiliary transportation roadway is six times the width of the auxiliary transportation roadway, and the distance between the second boundary and the secondary side of the auxiliary transportation roadway is twice the width of the auxiliary transportation roadway. The estimated fracturing range of the horizontal well arranged close to the rubber transport tunnel has a third boundary and a fourth boundary arranged along the inclination of the working face to be mined. The third boundary is arranged on the side of the rubber transport tunnel close to the working face to be mined, and the fourth boundary is arranged on the side of the rubber transport tunnel away from the working face to be mined. The distance between the third boundary and the main side of the rubber transport tunnel is six times the width of the rubber transport tunnel, and the distance between the fourth boundary and the secondary side of the rubber transport tunnel is equal to the width of the rubber transport tunnel.

8. The method for combining surface vertical wells and underground horizontal wells according to any one of claims 1 to 7, characterized in that: The vertical well construction information includes the number of vertical well fracturing points, wherein the vertical well fracturing points are grouped in pairs, and the vertical well fracturing points are provided in multiple groups, and the multiple groups of vertical well fracturing points are sequentially spaced along the extension direction of the ground vertical well; The horizontal well construction information includes the number of horizontal well fracturing points. The horizontal well fracturing points form a group of two. There are multiple groups of horizontal well fracturing points. The multiple groups of horizontal well fracturing points are sequentially spaced along the extension direction of the horizontal well.

9. The method for combining surface vertical wells and underground horizontal wells according to any one of claims 1 to 7, characterized in that: The step S1: determining the estimated vertical well fracturing information and the estimated horizontal well fracturing information for the target mine based on the acquired fracturing construction information of the surrounding mines includes: Based on the vertical well fracturing construction information obtained from the surrounding mines, the estimated vertical well fracturing information for the target mine is determined, and based on the horizontal well fracturing construction information obtained from the surrounding mines, the estimated horizontal well fracturing information for the target mine is determined.

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