Ground directional hole advanced fault exploration method

Abstract

The invention discloses a ground directional hole advanced fault exploration method which comprises the steps that a first limestone layer upward from the lower boundary of a coal seam is a first limestone layer, and a first limestone layer downward from the lower boundary of the coal seam is a second limestone layer; the upper boundary of the coal seam is a coal seam top F1, the lower boundary of the coal seam is a coal seam bottom F2, the upper boundary of the first limestone layer is a first limestone top A1, the lower boundary of the first limestone layer is a first limestone bottom A2, the upper boundary of the second limestone layer is a second limestone top B1, and the lower boundary of the second limestone layer is a second limestone bottom B2; determining the fault type, calculating the fault fracture zone width, judging the fault trend and determining the fault inclination angle. According to geological parameters obtained through rock debris logging, gamma logging, logging during drilling, drilling fluid consumption logging and a horizontal coring device coring experiment in the drilling process of all the drill holes and coordinates of all the key control points, fault parameters such as fault types, fault positions, fault trends and fault fall are obtained, and the fault exploration efficiency and precision are improved.

Description

Technical Field

[0001] The present invention relates to the field of coal mine fault exploration. It adopts ground directional horizontal holes to advance fault exploration, and accurately determines the fault type and fault parameters by side drilling multiple horizontal branch holes, providing a scientific basis for coal mine water prevention and control work, and ensuring the safe excavation and recovery of coal mines. Background Art

[0002] With the gradual increase in the scale, depth and complexity of coal mining, the safety production threats faced by mines are becoming more and more serious. According to incomplete statistics, among the major accidents in coal mines, various major accidents related to geological structures account for 80%. Faults, as the main geological structures in coal mines, have a direct or indirect relationship with the occurrence of disasters. Therefore, doing a good job in the exploration of faults in coal mines will, to a certain extent, play a role in protecting the safety production of mines. At present, domestic fault exploration technology is still in the development stage. At present, coal mines often use geophysical exploration methods such as three-dimensional seismic, electrical method, geological radar, conventional drilling methods and underground directional hole methods to explore faults. Among them, geophysical exploration methods mainly have the following disadvantages:

[0003] ① The horizontal position error is usually between -30 and +30m;

[0004] ② Multiple solutions for geological anomalies;

[0005] ③ The conclusion of the investigation lacks physical comparison and is not intuitive enough;

[0006] Conventional drilling methods have the following main disadvantages:

[0007] ① The angle and orientation of conventional drilling are not fixed during drilling, and the actual drilling trajectory often has a large error with the designed trajectory;

[0008] ② It is impossible to monitor and adjust the drilling trajectory during drilling;

[0009] ③ The exploration depth of a single hole is relatively small, generally 150m, and the maximum does not exceed 200m;

[0010] ④Multi-branch hole drilling cannot be achieved;

[0011] Downhole directional drilling methods mainly have the following disadvantages:

[0012] ① Relying on underground tunnels, it is impossible to truly achieve regional advanced exploration;

[0013] ② Due to the limitations of underground construction conditions, rotary drilling and directional drilling cannot be well combined, and the drilling speed is slow;

[0014] ③ The azimuth change of the drilling trajectory is small and the exploration area is small.

[0015] Since 2003, China has gradually introduced the screw motor measurement while drilling directional drilling technology widely used in the field of ground oil drilling into the coal system drilling construction. Although it has been successfully applied to the water hazard control and gas extraction in the coal seam floor area of ​​coal mines, there is no systematic research on the use of ground directional horizontal holes to achieve advanced fault detection. However, the use of ground directional holes for exploration has high accuracy, long distance, short cycle, and can be used for fault control, which can provide new technical means for the prevention of coal mine disasters and accidents, and has important research significance. Summary of the invention

[0016] Therefore, the technical problem to be solved by the present invention is to provide a method for advanced fault exploration using a ground directional borehole.

[0017] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0018] A method for advanced fault detection through a ground directional borehole, wherein the first limestone layer upward from the lower boundary of a coal seam is the first limestone layer, and the first limestone layer downward from the lower boundary of the coal seam is the second limestone layer; the upper boundary of the coal seam is the coal seam top F 1 , the lower boundary is the bottom of the coal seam F 2 The upper boundary of the first limestone layer is the first limestone top A 1 , the lower boundary is the first limestone bottom A 2 The upper boundary of the second limestone layer is the second limestone top B 1 , the lower boundary is the second limestone bottom B 2 ;

[0019] Determine the fault type: According to the first limestone top A 1 and the first limestone bottom A 2 The thickness of the first limestone H is calculated by the difference in burial depth 1 ; Then through the second limestone top B 1 and the second limestone bottom B 2 The thickness of the second limestone H is calculated by the difference in burial depth 2 , when H 1 With H 2 When approaching, determine the type of fault; through the coal seam top F 1 and coal seam bottom F 2 The thickness L of the coal seam is calculated by the difference in buried depth 1 , when the coal seam thickness L 1 The thickness of the coal seam revealed by the drilling is L 2 When approaching, the type of fault is confirmed again;

[0020] At depth h 1 At, horizontally and along the fault thickness direction: the left boundary of the fault is the lower disk point C of the first fault 1 The right boundary is the first fault upper point C 2; at depth h 2 At, horizontally and along the fault thickness direction: the left boundary of the fault is the lower disk point E of the second fault 1 The right boundary is the upper point E of the second fault. 2 ;h 1 Less than h 2 ;

[0021] Calculate the width of the fault zone: Point C below the first fault 1 and the first fault upper point C 2 Corrected horizontal distance d 1 is the depth h 1 Calculate the width of the fault segment at the second fault point E 1 and the second fault upper point E 2 Corrected horizontal distance d 2 is the depth h 2 The width of the fault crushing zone is calculated at different depths, and the width of the fault crushing zone is accurately calculated.

[0022] Determine the direction of the fault: Place the first fault at point C 1 and the second fault E 1 Draw the fault direction X 1 , and then count the first fault C 2 and the first fault point E 2 Draw the fault direction X 2 , then X 1 and X 2 The two are coupled to accurately determine the direction of the fault;

[0023] Determine the fault dip: Use the first fault bottom point C 1 and the second fault bottom point E 1 Coordinates, calculate the fault dip angle γ 1 ; Then use the first fault to count C 2 and the second fault upper point E 2 Coordinate calculation of fault dip angle γ 2 ; by γ 1 and γ 2 Compare the corrected fault dip γ.

[0024] The above-mentioned method of advanced fault detection by ground directional drilling is to 3 At, horizontally and along the fault thickness direction: the left boundary of the fault is the lower disk point D of the third fault 1 The right boundary is the upper point D of the third fault. 2 ;h 2 >h 3 >h 1 ;

[0025] Calculate the width of the fault zone: Point C below the first fault 1 and the first fault upper point C 2 Corrected horizontal distance d 1 is the depth h 1 Calculate the width of the fault segment at the third fault point D 1 and the third fault upper point D 2 Corrected horizontal distance d 3 is the depth h 3 Calculate the width of the fault segment at the second fault point E 1 and the second fault upper point E 2 Corrected horizontal distance d 2 is the depth h 2 The width of the fault crushing zone is calculated at different depths, and the width of the fault crushing zone is accurately calculated.

[0026] Determine the direction of the fault: Place the first fault at point C 1 、The third fault bottom inventory D 1 and the second fault E 1 Draw the fault direction X 1 , and then count the first fault C 2 , the third fault upper point D 2 and the second fault E 2 Draw the fault direction X 2 , then X 1 and X 2 The two are coupled to accurately determine the direction of the fault;

[0027] Determine the fault dip: Use the first fault bottom point C 1 And the third fault bottom inventory D 1 Coordinates, calculate the upper fault dip angle ɑ 1 ; Then use the first fault to count C 2 and the third fault upper point D 2 Coordinates, calculate the upper fault dip angle ɑ 2 , through 1 and 2 Compare and correct the upper fault dip angle ɑ;

[0028] Using the fault to count the first D 1 and the second fault bottom point E 1 Coordinates, calculate the lower fault dip angle β 1 ; Then use the third fault to count D 2 and the second fault upper point E 2 Coordinates, calculate the lower fault dip angle β 2 , through β 1 and β 2Compare and correct the lower fault dip angle β;

[0029] Using the first fault to count C 1 and the second fault bottom point E 1 Coordinates, calculate the fault dip angle γ 1 ; Then use the first fault to count C 2 and the second fault upper point E 2 Coordinate calculation of fault dip angle γ 2 ; Correct the fault dip angle γ by comparing ɑ and β.

[0030] The above-mentioned method of advanced fault detection by ground directional drilling, the coal seam top F 1 、Coal seam bottom F 2 、The first limestone top A 1 、First limestone bottom A 2 、Second limestone top B 1 、Second limestone bottom B 2 、The first fault bottom inventory C 1 、First fault upper point C 2 、Second fault bottom inventory E 1 and the second fault on the inventory E 2 The method to obtain is as follows:

[0031] At least a first borehole and a second borehole are drilled respectively, wherein the first borehole is at a depth h 1 The fault is horizontal and passes through the fault along the fault thickness direction. The left boundary of the fault here is the lower disk point C of the first fault. 1 The right boundary is the upper point C of the first fault. 2 The second borehole is at a depth of h 2 The fault is crossed horizontally at the left boundary of the fault, where the lower point E of the second fault is 1 The right boundary is the upper point E of the second fault. 2 ;h 1 Less than h 2 ;

[0032] At least one of the first borehole and the second borehole passes through the coal seam roof F 1 and coal seam bottom F 2 ,

[0033] At least one of the first borehole and the second borehole passes through the first limestone roof A of the first limestone layer adjacent to the coal seam. 1 and the first limestone bottom A 2 ,

[0034] At least one of the first borehole and the second borehole passes through the second limestone roof B of the second limestone layer below the coal seam. 1 and the second limestone bottom B 2 .

[0035] In the above-mentioned method for advanced fault detection by ground directional boreholes, when both the first borehole and the second borehole cannot penetrate the top of the coal seam of the coal seam, 1 and the coal seam bottom F 2 When any one of the above is performed, at least a third borehole is drilled, and the third borehole at least passes through the coal seam top F 1 and the coal seam bottom F 2 that one of the boreholes that is not penetrated by the first borehole and the second borehole;

[0036] or when the first borehole and the second borehole cannot penetrate the first limestone top A 1 and the first limestone bottom A 2 When any one of the above is performed, at least a third borehole is drilled, and the third borehole at least passes through the first limestone top A 1 and the first limestone bottom A 2 that one of the boreholes that is not penetrated by the first borehole and the second borehole;

[0037] or when the first borehole and the second borehole cannot penetrate the second limestone top B of the second limestone layer 1 and the second limestone bottom B 2 When any one of the above is performed, at least a third borehole is drilled, and the third borehole at least passes through the second limestone top B 1 and the second limestone bottom B 2 The one that is not penetrated by the first bore hole and the second bore hole.

[0038] In the above-mentioned method of advance fault exploration using ground directional holes, the portion of the first limestone layer and the coal seam that is on the same horizontal plane is called the limestone-coal seam; the first borehole passes through the fault along the limestone-coal seam.

[0039] In the above-mentioned method for advanced fault exploration using a ground directional borehole, the second borehole passes through the fault along the second limestone layer.

[0040] In the above-mentioned method for advanced fault detection by ground directional drilling, the portion of the first limestone layer and the coal seam on the same horizontal plane is called the limestone-coal parallel layer, the first borehole passes through the fault along the limestone-coal parallel layer, and the bottom of the first borehole passes through the top of the coal seam. 1 The second borehole passes through the fault along the second limestone layer; the third borehole passes through the bottom of the coal seam F 2 、The second limestone top B 1 and the second limestone bottom B 2 (This drilling method is easier to drill, more efficient and less costly.).

[0041] The above-mentioned method for advanced fault exploration with a ground directional borehole includes drilling at least a fourth borehole, wherein the fourth borehole is horizontally provided at a depth of h 3 The fault is crossed horizontally at the left boundary of the fault, where the lower point D of the third fault is 1 The right boundary is the upper point D of the third fault. 2 ;h 2 >h 3 >h 1 .

[0042] The above-mentioned method for advanced fault exploration through ground directional boreholes includes performing cuttings logging, natural gamma logging, drilling logging and drilling fluid consumption logging during the drilling process, using a horizontal coring device for coring verification in special borehole sections, and performing multi-factor coupling analysis to accurately determine the location of the fault zone.

[0043] For the returning cuttings during the horizontal hole drilling process, it is necessary to ensure that they are collected at least once every 1m, and for special layers, they must be collected once every 0.5m. The lag time of returning cuttings is calculated through field experiments to invert the real stratigraphic sequence;

[0044] The wireless directional measurement while drilling instrument is equipped with a natural gamma probe. During the horizontal hole drilling process, the natural gamma probe is used at any time to detect the intensity of gamma rays emitted by the decay process of radioactive nuclides in the rock to distinguish the lithology of the rock formation and verify the formation inversion of the cuttings.

[0045] Taking advantage of the different hardness and softness of rocks of different properties, during the drilling of the horizontal hole section, the thickness of the rock layer drilled through within 1 hour is used to determine the lithology of the underground rock formation and verify the formation inversion from the rock cuttings;

[0046] During the drilling of the horizontal hole section, the drilling fluid consumption is increased due to the change of lithology and the fault fracture zone. The drilling fluid consumption is regularly observed, usually once every hour. If it is less than one hour but more than 30 minutes, the drilling fluid consumption should also be observed to verify the formation inversion of the cuttings.

[0047] For areas where cuttings change, gamma value changes, drilling time changes, and drilling fluid consumption increases, a horizontal coring device is used for coring verification;

[0048] During the drilling process of the horizontal hole section, multi-factor coupling is carried out on the cuttings logging, gamma logging, drilling time logging, drilling fluid consumption logging and coring experiment of the horizontal coring device to accurately determine the location of the fault zone.

[0049] In the above-mentioned method of using ground directional holes to advance fault exploration, the first borehole, the second borehole and the third borehole are branch holes of the same ground borehole (to reduce construction costs), and the ground borehole includes a straight hole section and an inclined section, and the starting points of the first borehole, the second borehole and the third borehole are all directly connected to the inclined section.

[0050] The technical scheme of the present invention has achieved the following beneficial technical effects: through the geological parameters obtained by cuttings logging, gamma logging, drilling logging, drilling fluid consumption logging and horizontal coring device coring experiments during the drilling of each borehole, combined with the coordinates of each key control point, it is possible to ensure the fault type, fault position, fault direction, fault drop and other fault parameters, and then effectively provide accurate geological data for mine excavation and water control design, so that the mine excavation design and water control design are more in line with reality, which can ensure the safe production of the mine and improve the economic benefits of the mine. The present invention uses ground directional hole construction technology to improve the efficiency and accuracy of fault exploration. Compared with underground directional hole means, long-distance advance exploration can be achieved, which is not limited by underground construction conditions and the exploration area is increased; compared with conventional drilling means, multi-branch drilling can be achieved, the efficiency is increased, and the real-time monitoring and adjustment of the borehole trajectory can be achieved. The error between the actual trajectory and the designed trajectory of drilling is greatly reduced, and the drilling depth exceeds 200m; compared with geophysical exploration means, the data obtained is more intuitive and accurate, and the error is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A structural schematic diagram of a drilling structure schematic diagram in the present invention;

[0052] Figure 2 The plan layout of the drilling holes in the present invention;

[0053] Figure 3 Drilling profile arrangement diagram in the present invention.

[0054] The reference numerals in the figure are as follows: 1. second limestone layer; 2. coal seam; 3. fault zone; 4. side drilling point; 5. first borehole; 6. second borehole; 7. third borehole; 8. fourth borehole; 9. first limestone layer; 10. straight hole section; 11. deflection section; 12. horizontal hole section; 13. drilling rig;

[0055] A1. Top of the first limestone; A2. Bottom of the first limestone; B1. Top of the second limestone; B2. Bottom of the second limestone; F1. Top of the coal seam; F2. Bottom of the coal seam; C1. Lower point of the first fault; C2. Upper point of the first fault; D1. Lower point of the third fault; D2. Upper point of the third fault; E1. Lower point of the second fault; E2. Upper point of the second fault. DETAILED DESCRIPTION

[0056] like Figure 2 and Figure 3 As shown, the method for advanced fault detection by ground directional boreholes in this embodiment is as follows:

[0057] The first limestone layer upward from the lower boundary of the coal seam 2 is the first limestone layer 9, and the first limestone layer downward from the lower boundary of the coal seam 2 is the second limestone layer 1; the upper boundary of the coal seam 2 is the coal seam top F 1 , the lower boundary is the bottom of the coal seam F 2 The upper boundary of the first limestone layer 9 is the first limestone top A 1 , the lower boundary is the first limestone bottom A 2 The upper boundary of the second limestone layer 1 is the second limestone top B 1 , Lower boundary second limestone bottom B 2 ;

[0058] Determine the fault type: According to the first limestone top A 1 and the first limestone bottom A 2 The thickness of the first limestone H is calculated by the difference in burial depth 1 ; Then through the second limestone top B 1 and the second limestone bottom B 2 The thickness of the second limestone H is calculated by the difference in burial depth 2 , when H 1 With H 2 When approaching, the type of fault can be determined; through the top of the coal seam F 1 and coal seam bottom F 2 The thickness L of the coal seam is calculated by the difference in buried depth 1 , when the coal seam thickness L 1 The thickness of the coal seam revealed by the drilling is L 2 When approaching, the type of fault can be confirmed again;

[0059] At depth h 1 At, horizontally and along the fault thickness direction: the left boundary of the fault is the lower disk point C of the first fault 1 The right boundary is the upper point C of the first fault. 2 ; at depth h 2 At, horizontally and along the fault thickness direction: the left boundary of the fault is the lower disk point E of the second fault 1 The right boundary is the upper point E of the second fault. 2 ;h 1 Less than h 2 ;

[0060] Calculate the width of the fault zone: Point C below the first fault 1 and the first fault upper point C 2 Corrected horizontal distance d 1 is the depth h 1 Calculate the width of the fault segment at the second fault point E 1and the second fault upper point E 2 Corrected horizontal distance d 2 is the depth h 2 The width of the fault crushing zone is calculated at different depths, and the width of the fault crushing zone is accurately calculated.

[0061] Determine the direction of the fault: Place the first fault at point C 1 and the second fault E 1 Draw the fault direction X 1 , and then count the first fault C 2 and the second fault E 2 Draw the fault direction X 2 , then X 1 and X 2 The two are coupled to accurately determine the direction of the fault;

[0062] Determine the fault dip: Use the first fault bottom point C 1 and the second fault bottom point E 1 Coordinates, calculate the fault dip angle γ 1 ; Then use the first fault to count C 2 and the second fault upper point E 2 Coordinate calculation of fault dip angle γ 2 ; by γ 1 and γ 2 Compare the corrected fault dip γ.

[0063] In some other embodiments, in order to more accurately detect the fault, at the depth h 3 At, horizontally and along the fault thickness direction: the left boundary of the fault is the lower disk point D of the third fault 1 The right boundary is the upper point D of the third fault. 2 ;h 2 >h 3 >h 1 ;

[0064] Calculate the width of the fault zone: Point C below the first fault 1 and the first fault upper point C 2 Corrected horizontal distance d 1 is the depth h 1 Calculate the width of the fault segment at the third fault point D 1 and the third fault upper point D 2 Corrected horizontal distance d 3 is the depth h 3 Calculate the width of the fault segment at the second fault point E 1 and the second fault upper point E 2 Corrected horizontal distance d 2 is the depth h2 The width of the fault crushing zone is calculated at different depths, and the width of the fault crushing zone is accurately calculated.

[0065] Determine the direction of the fault: First, count the fault down to point C 1 、The third fault bottom inventory D 1 and the second fault E 1 Draw the fault direction X 1 , and then count the first fault C 2 , the third fault upper point D 2 and the second fault E 2 Draw the fault direction X 2 , then X 1 and X 2 The two are coupled to accurately determine the direction of the fault;

[0066] Determine the fault dip: Use the first fault bottom point C 1 And the third fault bottom inventory D 1 Coordinates, calculate the upper fault dip angle ɑ 1 ; Then use the first fault to count C 2 and the third fault upper point D 2 Coordinates, calculate the upper fault dip angle ɑ 2 , through 1 and 2 Compare and correct the upper fault dip angle ɑ;

[0067] Using the third fault to count D 1 and the second fault bottom point E 1 Coordinates, calculate the lower fault dip angle β 1 ; Then use the third fault to count D 2 and the second fault upper point E 2 Coordinates, calculate the lower fault dip angle β 2 , through β 1 and β 2 Compare and correct the lower fault dip angle β;

[0068] Using the first fault to count C 1 and the third fault bottom point E 1 Coordinates, calculate the fault dip angle γ 1 ; Then use the fault to count C 2 And fault upper inventory E 2 Coordinate calculation of fault dip angle γ 2 ; Correct the fault dip angle γ by comparing ɑ and β.

[0069] The above coal seam top F 1 、Coal seam bottom F 2 、The first limestone top A 1、First limestone bottom A 2 、Second limestone top B 1 、Second limestone bottom B 2 、The first fault bottom inventory C 1 、First fault upper point C 2 、Second fault bottom inventory E 1 and the second fault E 2 The method to obtain is as follows:

[0070] At least a first borehole 5 and a second borehole 6 are drilled respectively, wherein the first borehole 5 is at a depth h 1 It is horizontal and passes through fault 3 along the thickness direction of fault 3. The left boundary of the fault here is the lower disk point C of the first fault. 1 The right boundary is the first fault upper point C 2 The second borehole 6 is at a depth of h 2 The left side of the fault is the lower point E of the second fault. 1 The right boundary is the upper point E of the second fault. 2 ;h 1 Less than h 2 At least one of the first borehole 5 and the second borehole 6 passes through the top of the coal seam 2 F 1 and coal seam bottom F 2 At least one of the first borehole 5 and the second borehole 6 passes through the first limestone roof A of the first limestone layer 9 adjacent to the coal seam 2. 1 and the first limestone bottom A 2 At least one of the first borehole 5 and the second borehole 6 passes through the second limestone top B of the second limestone layer 1 below the coal seam 2. 1 and the second limestone bottom B 2 .

[0071] When the first borehole 5 and the second borehole 6 cannot penetrate the coal seam top F of the coal seam 2 1 and the coal seam bottom F 2 When any one of the above is performed, at least a third borehole 7 is drilled, and the third borehole 7 at least passes through the coal seam top F 1 and the coal seam bottom F 2 The one not penetrated by the first bore hole 5 and the second bore hole 6;

[0072] Or when the first borehole 5 and the second borehole 6 cannot pass through the first limestone top A 1 and the first limestone bottom A 2 When any one of the above is performed, at least a third borehole 7 is drilled, and the third borehole 7 at least passes through the first limestone top A 1 and the first limestone bottom A 2The one not penetrated by the first bore hole 5 and the second bore hole 6;

[0073] Or when the first borehole 5 and the second borehole 6 cannot penetrate the second limestone top B of the second limestone layer 1 1 and the second limestone bottom B 2 When any one of the above is performed, at least a third borehole 7 is drilled, and the third borehole 7 at least passes through the second limestone top B 1 and the second limestone bottom B 2 The one that is not penetrated by the first bore hole 5 and the second bore hole 6.

[0074] The portion of the first limestone layer 9 and the coal seam 2 on the same horizontal plane is called the limestone-coal parallel layer. The first borehole 5 passes through the fault 3 along the limestone-coal parallel layer. The bottom of the first borehole 5 passes through the top of the coal seam. 1 The second borehole 6 passes through the fault 3 along the second limestone layer 1; the third borehole 7 passes through the bottom F of the coal seam 2 、The second limestone top B 1 and the second limestone bottom B 2 .

[0075] A fourth borehole 8 is also drilled, which is horizontal at a depth h 3 The left side of the fault is the lower point D of the third fault. 1 The right boundary is the upper point D of the third fault. 2 ;h 2 >h 3 >h 1 .

[0076] During the drilling process, cuttings logging, natural gamma logging, drilling logging and drilling fluid consumption logging are performed. For special hole sections (broken bottom layer or water-gushing formation, etc.), horizontal coring devices are used for coring verification, and multi-factor coupling analysis is performed to accurately determine the location of the fault zone.

[0077] For the returning cuttings during the horizontal hole drilling process, it is necessary to ensure that they are collected at least once every 1m, and for special layers, they must be collected once every 0.5m. The lag time of returning cuttings is calculated through field experiments to invert the real stratigraphic sequence;

[0078] The wireless directional measurement while drilling instrument is equipped with a natural gamma probe. During the horizontal hole drilling process, the natural gamma probe is used at any time to detect the intensity of gamma rays emitted by the decay process of radioactive nuclides in the rock to distinguish the lithology of the rock formation and verify the formation inversion of the cuttings.

[0079] Taking advantage of the different hardness and softness of rocks of different properties, during the drilling of the horizontal hole section, the thickness of the rock layer drilled through within 1 hour is used to determine the lithology of the underground rock formation and verify the formation inversion from the rock cuttings;

[0080] During the drilling of the horizontal hole section, the drilling fluid consumption is increased due to the change of lithology and the fault fracture zone. The drilling fluid consumption is regularly observed, usually once every hour. If it is less than one hour but more than 30 minutes, the drilling fluid consumption should also be observed to verify the formation inversion of the cuttings.

[0081] For areas where cuttings change, gamma value changes, drilling time changes, and drilling fluid consumption increases, a horizontal coring device is used for coring verification;

[0082] During the drilling process of the horizontal hole section, multi-factor coupling is carried out on the cuttings logging, gamma logging, drilling time logging, drilling fluid consumption logging and coring experiment of the horizontal coring device to accurately determine the location of the fault zone.

[0083] After the construction of the first horizontal branch hole is completed, 2 to 3 more horizontal branch holes are constructed, and combined with the comprehensive stratigraphic column chart of the area, the purpose of accurately determining the fault type and fault parameters is achieved.

[0084] like Figure 1 As shown, this figure is a ground directional horizontal hole drilling structure diagram. A suitable site is selected on the ground as the drilling site, and a suitable matching drilling rig is selected according to the buried depth of the target layer in the exploration area; first, the straight hole section is constructed, the diameter of the straight hole section is Ф311mm, and the Ф244.5×8.94mm casing is lowered to the bedrock section, 5 to 10m into the bedrock section, and the pipe is fixed with a single-liquid cement slurry with a water-cement ratio of ≤0.60; secondly, the inclined section is constructed, the diameter of the inclined section is Ф215.9mm, and the Ф177.8×8.05mm casing is lowered to the top of the target layer 1 to 2m, and the pipe is fixed with a single-liquid cement slurry with a water-cement ratio of ≤0.60; finally, the horizontal hole section is constructed, the diameter of the horizontal hole section is Ф152.4mm, and it is a bare hole section. Directional drilling is carried out according to the purpose of fault exploration. The construction of this hole section is a key factor in fault exploration. Figure 2 and Figure 3 As shown, in this embodiment, the first borehole 5, the second borehole 6 and the third borehole 7 are branch holes of the same ground borehole, and the ground borehole includes a straight hole section 10 and an inclined section 11, and the starting points of the first borehole 5, the second borehole 6 and the third borehole 7 are directly connected to the inclined section 11.

[0085] According to the preliminary results of fault exploration by ground 3D seismic, a suitable site is selected as the drilling site and a fault exploration drilling arrangement scheme is designed. The present invention first constructs the straight hole section and the deflection section, and then constructs the first horizontal hole 5 from the side drilling point 4. First, the first limestone top A is determined by cuttings logging and natural gamma logging technology. 1 After the drilling trajectory enters the limestone, ensure that the first horizontal hole 5 is drilled along the limestone layer. If the drilling fluid consumption increases, the drilling time becomes faster, or the natural gamma or rock cuttings lithology changes during the drilling process, the drill tool is pulled out of the wellhead and a horizontal coring device is used for coring verification. After multi-factor coupling analysis, the fault bottom inventory C is determined. 1 and fault upper point C 2 The accurate position of the coal seam is determined by adjusting the well inclination to detect the top boundary F of the coal seam. 1 After the first horizontal hole 5 is sealed with grouting, the second horizontal hole 6 is constructed, and the well inclination is adjusted to explore the bottom boundary F of the coal seam. 2 and the second limestone top B 1 、Second limestone bottom B 2 After the second horizontal hole 6 was grout-sealed, the third horizontal hole 7 was constructed, and the well inclination and azimuth were adjusted for drilling. The first limestone bottom A was determined based on the cuttings logging and natural gamma logging technology. 2 When drilling fluid consumption increases, drilling time increases, natural gamma or cuttings lithology changes, the drilling tool is pulled out of the wellhead and coring is verified using a horizontal coring device. The third fault lower point D is determined through multi-factor coupling analysis. 1 and the third fault upper point D 2 After the third horizontal hole 7 was sealed with grouting, the fourth horizontal hole 8 was constructed, and the well inclination and azimuth were adjusted for drilling. During the drilling process, if the drilling fluid consumption increased, the drilling time became faster, or the natural gamma or rock cuttings lithology changed, the drill tool was pulled out of the wellhead, and the horizontal coring device was used for coring verification. After multi-factor coupling analysis, the second fault lower inventory point E was determined. 1 and the second fault upper point E 2 The exact location.

[0086] During the implementation of the present invention, the first horizontal branch hole, the second horizontal branch hole, the third horizontal branch hole and the fourth horizontal branch hole need to be drilled for advance fault exploration. The geological parameters obtained through cuttings logging, gamma logging, drilling time logging, drilling fluid consumption logging and horizontal coring device coring experiment during the drilling of each horizontal branch hole, combined with the coordinates of each key control point, can ensure the fault parameters such as fault type, fault position, fault direction, fault drop, etc., and thus can effectively provide accurate geological data for mine excavation and water control design, make the mine excavation design and water control design more in line with reality, ensure the safe production of the mine, and improve the economic benefits of the mine.

[0087] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for advanced fault detection using a ground directional borehole, characterized in that: The first limestone layer upward from the lower boundary of the coal seam (2) is the first limestone layer (9), and the first limestone layer downward from the lower boundary of the coal seam (2) is the second limestone layer (1); the upper boundary of the coal seam (2) is the coal seam top F1, and the lower boundary is the coal seam bottom F2; the upper boundary of the first limestone layer (9) is the first limestone top A1, and the lower boundary is the first limestone bottom A2; the upper boundary of the second limestone layer (1) is the second limestone top B1, and the lower boundary is the second limestone bottom B2; Determine the fault type: calculate the first limestone thickness H1 according to the burial depth difference between the first limestone top A1 and the first limestone bottom A2; calculate the second limestone thickness H2 according to the burial depth difference between the second limestone top B1 and the second limestone bottom B2. When H1 is close to H2, determine the fault type; calculate the thickness L1 of the coal seam according to the burial depth difference between the coal seam top F1 and the coal seam bottom F2. When the coal seam thickness L1 is close to the coal seam thickness L2 revealed by the drilling, confirm the fault type again; At depth h1, horizontally and along the fault thickness direction: the left boundary of the fault is the lower point C1 of the first fault, and the right boundary is the upper point C2 of the first fault; at depth h2, horizontally and along the fault thickness direction: the left boundary of the fault is the lower point E1 of the second fault, and the right boundary is the upper point E2 of the second fault; h1 is smaller than h2; Calculate the width of the fault crushing zone: The horizontal distance d1 corrected by the first fault lower point C1 and the first fault upper point C2 is the width of the fault crushing section calculated at the depth h1. The horizontal distance d2 corrected by the second fault lower point E1 and the second fault upper point E2 is the width of the fault crushing section calculated at the depth h2. By calculating the width of the fault crushing zone at different depths, the width of the fault crushing zone can be accurately calculated. Determine the fault direction: Draw the fault direction X1 by connecting the lower point C1 of the first fault and the lower point E1 of the second fault, and then draw the fault direction X2 by connecting the upper point C2 of the first fault and the upper point E2 of the first fault. Then couple X1 and X2 to accurately determine the fault direction. Determine the fault dip: Use the coordinates of the lower point C1 of the first fault and the lower point E1 of the second fault to calculate the fault dip γ1; then use the coordinates of the upper point C2 of the first fault and the upper point E2 of the second fault to calculate the fault dip γ2; and correct the fault dip γ by comparing γ1 and γ2.

2. The method for advanced fault detection using a ground directional borehole according to claim 1, characterized in that: At depth h3, horizontally and along the fault thickness direction: the left boundary of the fault is the lower point D1 of the third fault, and the right boundary is the upper point D2 of the third fault; h2>h3>h1; Calculate the width of the fault crushing zone: the first fault lower point C1 and the first fault upper point C2 correct the horizontal distance d1 to calculate the width of the fault crushing section at depth h1, the third fault lower point D1 and the third fault upper point D2 correct the horizontal distance d3 to calculate the width of the fault crushing section at depth h3, the second fault lower point E1 and the second fault upper point E2 correct the horizontal distance d2 to calculate the width of the fault crushing section at depth h2. By calculating the width of the fault crushing zone at different depths, the width of the fault crushing zone can be accurately calculated; Determine the fault direction: Draw the fault direction X1 by connecting the lower point C1 of the first fault, the lower point D1 of the third fault, and the lower point E1 of the second fault. Draw the fault direction X2 by connecting the upper point C2 of the first fault, the upper point D2 of the third fault, and the upper point E2 of the second fault. Then couple X1 and X2 to accurately determine the fault direction. Determine the fault dip: Use the coordinates of the lower point C1 of the first fault and the lower point D1 of the third fault to calculate the upper fault dip ɑ1; then use the coordinates of the upper point C2 of the first fault and the upper point D2 of the third fault to calculate the upper fault dip ɑ2, and correct the upper fault dip ɑ by comparing ɑ1 and ɑ2; The lower fault dip angle β1 is calculated using the coordinates of the first fault lower point D1 and the second fault lower point E1; the lower fault dip angle β2 is calculated using the coordinates of the third fault upper point D2 and the second fault upper point E2, and the lower fault dip angle β is corrected by comparing β1 and β2; The fault dip angle γ1 is calculated using the coordinates of the lower point C1 of the first fault and the lower point E1 of the second fault; the fault dip angle γ2 is calculated using the coordinates of the upper point C2 of the first fault and the upper point E2 of the second fault; the fault dip angle γ is corrected by comparing α and β.

3. A method for advanced fault detection using a ground directional borehole according to claim 1 or 2, characterized in that: The method for obtaining the coal seam top F1, coal seam bottom F2, first limestone top A1, first limestone bottom A2, second limestone top B1, second limestone bottom B2, first fault lower point C1, first fault upper point C2, second fault lower point E1 and second fault upper point E2 is as follows: At least a first borehole (5) and a second borehole (6) are drilled respectively, wherein the first borehole (5) is horizontally disposed at a depth h1 and passes through the fault (3) along the thickness direction of the fault (3), wherein the left boundary of the fault is the lower point C1 of the first fault and the right boundary is the upper point C2 of the first fault; the second borehole (6) passes through the fault (3) horizontally at a depth h2, wherein the left boundary of the fault is the lower point E1 of the second fault and the right boundary is the upper point E2 of the second fault; and h1 is smaller than h2; At least one of the first borehole (5) and the second borehole (6) passes through the coal seam top F1 and the coal seam bottom F2 of the coal seam (2). At least one of the first borehole (5) and the second borehole (6) passes through a first limestone top A1 and a first limestone bottom A2 of a first limestone layer (9) adjacent to the coal seam (2). At least any one of the first borehole (5) and the second borehole (6) passes through the second limestone top B1 and the second limestone bottom B2 of the second limestone layer (1) below the coal seam (2).

4. The method for advanced fault detection using a ground directional borehole according to claim 3, characterized in that: When the first borehole (5) and the second borehole (6) are both unable to penetrate any one of the coal seam top F1 and the coal seam bottom F2 of the coal seam (2), at least a third borehole (7) is drilled, and the third borehole (7) penetrates at least the one of the coal seam top F1 and the coal seam bottom F2 that is not penetrated by the first borehole (5) and the second borehole (6); or when the first borehole (5) and the second borehole (6) cannot pass through any one of the first limestone top A1 and the first limestone bottom A2, at least a third borehole (7) is drilled, and the third borehole (7) passes through at least the one of the first limestone top A1 and the first limestone bottom A2 that is not passed through by the first borehole (5) and the second borehole (6); Alternatively, when both the first borehole (5) and the second borehole (6) are unable to penetrate any one of the second limestone top B1 and the second limestone bottom B2 of the second limestone layer (1), at least a third borehole (7) is drilled, and the third borehole (7) at least penetrates the one of the second limestone top B1 and the second limestone bottom B2 that is not penetrated by the first borehole (5) and the second borehole (6).

5. The method for advanced fault detection using a ground directional borehole according to claim 3, characterized in that: The portion of the first limestone layer (9) and the coal seam (2) that is on the same horizontal plane is called a limestone-coal seam; the first borehole (5) passes through the fault (3) along the limestone-coal seam.

6. The method for advanced fault detection using a ground directional borehole according to claim 3, characterized in that: The second borehole (6) passes through the fault (3) along the second limestone layer (1).

7. The method for advanced fault detection using a ground directional borehole according to claim 3, characterized in that: The portion of the first limestone layer (9) and the coal seam (2) that is on the same horizontal plane is called a limestone-coal seam. The first borehole (5) passes through the fault (3) along the limestone-coal seam, and the bottom of the first borehole (5) passes through the coal seam top F1; the second borehole (6) passes through the fault (3) along the second limestone layer (1); and the third borehole (7) passes through the coal seam bottom F2, the second limestone top B1 and the second limestone bottom B2.

8. The method for advanced fault detection using a ground directional borehole according to claim 3, characterized in that: At least a fourth borehole (8) is drilled, and the fourth borehole (8) horizontally passes through the fault (3) at a depth h3, where the left boundary of the fault is the lower point D1 of the third fault and the right boundary is the upper point D2 of the third fault; h2>h3>h1.

9. A method for advanced fault detection using ground directional boreholes according to claim 8, characterized in that: During the drilling process, cuttings logging, natural gamma logging, drilling logging and drilling fluid consumption logging are performed. In special hole sections, horizontal coring devices are used for coring verification, and multi-factor coupling analysis is performed to accurately determine the location of the fault zone. For the returning cuttings during the horizontal hole drilling process, it is necessary to ensure that they are collected at least once every 1m, and for special layers, they must be collected once every 0.5m. The lag time of returning cuttings is calculated through field experiments to invert the real stratigraphic sequence; The wireless directional measurement while drilling instrument is equipped with a natural gamma probe. During the horizontal hole drilling process, the natural gamma probe is used at any time to detect the intensity of gamma rays emitted by the decay process of radioactive nuclides in the rock to distinguish the lithology of the rock formation and verify the formation inversion of the cuttings. Taking advantage of the different hardness and softness of rocks of different properties, during the drilling of the horizontal hole section, the thickness of the rock layer drilled through within 1 hour is used to determine the lithology of the underground rock formation and verify the formation inversion from the rock cuttings; During the drilling of the horizontal hole section, the drilling fluid consumption is increased due to the change of lithology and the fault fracture zone. The drilling fluid consumption is regularly observed, usually once every hour. If it is less than one hour but more than 30 minutes, the drilling fluid consumption should also be observed to verify the formation inversion of the cuttings. For areas where cuttings change, gamma value changes, drilling time changes, and drilling fluid consumption increases, a horizontal coring device is used for coring verification; During the drilling process of the horizontal hole section, multi-factor coupling is carried out on the cuttings logging, gamma logging, drilling time logging, drilling fluid consumption logging and coring experiment of the horizontal coring device to accurately determine the location of the fault zone.

10. The method for advanced fault detection using ground directional boreholes according to claim 1, characterized in that: The first borehole (5), the second borehole (6) and the third borehole (7) are branch holes of the same ground borehole, and the ground borehole comprises a straight hole section (10) and an inclined section (11), and the starting points of the first borehole (5), the second borehole (6) and the third borehole (7) are all directly connected to the inclined section (11).

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