Method and system for determining track of fractured section of ground horizontal well of steeply inclined coal seam based on directional target spot

Abstract

The invention provides a method and a system for determining a track of a fractured section of a ground horizontal well of a steeply inclined coal seam based on a directional target spot, and relates to the technical field of ground fracture prevention and control of rock burst of the steeply inclined coal seam. The method comprises the following steps: determining coal seam elevation, thickness and inclination angle, constructing a section line set containing initial and added section lines, and drawing a coal seam section map; a fracturing section target spot is arranged on a target fracturing level, the position of the target spot is calculated according to coal seam parameters, directional drilling of a fracturing well is guided, accurate matching of a fracturing section and coal seam occurrence conditions is achieved, the fracturing effect is improved, and engineering risks are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ground fracturing prevention and control of rock burst in steeply inclined coal seams, and particularly relates to a method and system for determining the trajectory of a fracturing section of a ground horizontal well in a steeply inclined coal seam based on a directional target point. BACKGROUND

[0002] Steeply inclined coal seams have complex occurrence conditions, and the angle and thickness of the coal seams vary greatly in the mining area. Moreover, under different inclination angles and thicknesses, the overburden rock breaking characteristics are different, which further affects the selection of the key prevention and control horizon of ground fracturing, that is, the vertical distance between the fracturing well and the coal seam needs to be adjusted accordingly. The current traditional ground fracturing well arrangement method does not consider the special and complex conditions of steeply inclined coal seams, and the fracturing prevention and control horizon remains unchanged, which cannot guarantee the effect of ground fracturing pressure relief and there is a risk of the wellbore penetrating the coal seam. SUMMARY

[0003] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a method and system for determining the trajectory of a fracturing section of a ground horizontal well in a steeply inclined coal seam based on a directional target point, which sets a plurality of target points in the control area according to the occurrence conditions of the coal seam, so that the wellbore is drilled along the target points and arranged, ensuring the fracturing effect and reducing the engineering risk.

[0004] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0005] A method for determining the trajectory of a fracturing section of a ground horizontal well in a steeply inclined coal seam based on a directional target point, comprising:

[0006] determining the upper elevation, lower elevation and average thickness of the steeply inclined coal seam in the proposed mining area;

[0007] in the proposed control area, a plurality of initial profile lines in the north-south direction are set at a predetermined interval from the left boundary of the proposed control area;

[0008] determining the number of profile lines that need to be added between each adjacent initial profile line according to the absolute difference of the tangent slope of the intersection point of the coal seam floor contour at the target fracturing level of each adjacent initial profile line, and arranging the added profile lines at the same interval to form the added profile lines, obtaining a profile line set including the initial profile lines and the added profile lines;

[0009] drawing a corresponding coal seam profile based on the coal seam parameters at each profile line in the profile line set; wherein the coal seam parameters include the coal seam inclination angle and the coal seam thickness; the coal seam inclination angle is determined by the coal seam floor contour at each profile line, and the coal seam thickness is determined by the borehole columnar chart near each profile line;

[0010] In each of the coal seam profile maps, a fracturing section target point is arranged at the target fracturing level, and a vertical distance from each of the fracturing section target points to the upper surface of the coal seam is calculated according to the corresponding coal seam dip angle and the coal seam thickness, so that each of the fracturing section target points is matched with the occurrence conditions of the coal seam;

[0011] A vertical section of the fracturing well is drilled vertically downward from the ground and arranged, and when the vertical section of the fracturing well reaches the target fracturing level, a fracturing section is drilled and arranged along the strike of the coal seam with each of the fracturing section target points as a directional target point.

[0012] Preferably, the determining step of the preset interval is:

[0013] The control length of the target control area along the strike direction of the coal seam is obtained, the control length is divided into several equal intervals according to the number of the initial profile lines to be arranged, and the length of adjacent intervals is taken as the preset interval, so that each of the initial profile lines is uniformly distributed along the strike direction of the coal seam.

[0014] Preferably, the determining step of the target fracturing level is:

[0015] In combination with the rock burst prevention and control requirement of the steeply inclined coal seam, a design vertical distance between the fracturing prevention and control horizon and the coal seam is determined, a horizontal elevation corresponding to the design vertical distance is inversely calculated along the coal floor contour based on the upper elevation, the lower elevation and the average thickness of the coal seam in the target mining area of the steeply inclined coal seam, and the horizontal elevation is taken as the target fracturing level.

[0016] Preferably, the way of determining the number of profile lines to be added between each of the adjacent initial profile lines is:

[0017] The absolute difference of the tangent slope of the intersection point of the coal floor contour of two adjacent initial profile lines at the target fracturing level is obtained;

[0018] The absolute difference of the tangent slope is compared with a preset tangent slope difference interval, and the number of profile lines to be added between two adjacent initial profile lines is determined according to the interval in which the absolute difference of the tangent slope is located, so that the greater the change of the tangent slope, the more the number of profile lines to be added.

[0019] Preferably, the obtaining step of the coal seam dip angle is:

[0020] A plurality of representative points are selected near the intersection point of each of the profile lines and the coal floor contour;

[0021] The spatial strike and tendency of the coal floor contour are determined based on the spatial positions of the representative points, and the coal seam dip angle at each of the profile lines is calculated according to the spatial strike and tendency, which is taken as the coal seam dip angle when the coal seam profile map is drawn.

[0022] Preferably, the coal seam thickness obtaining step is:

[0023] At least one borehole column chart is selected near each of the profile lines;

[0024] The difference between the coal seam roof elevation and the coal seam floor elevation in the borehole column chart is read as the coal seam thickness at the profile line;

[0025] When there are multiple borehole column charts, the average of each of the differences is taken as the coal seam thickness.

[0026] Preferably, the vertical distance from each of the fracturing segment targets to the coal seam upper surface calculating step is:

[0027] In the coal seam profile map, the coal seam upper surface and the coal seam floor are drawn according to the coal seam dip angle and the coal seam thickness;

[0028] The fracturing segment targets are arranged on the target fracturing level, and a perpendicular line is drawn from the fracturing segment target to the coal seam upper surface in the vertical direction in the coal seam profile map;

[0029] The length of the perpendicular line is measured as the vertical distance from the fracturing segment target to the coal seam upper surface.

[0030] Preferably, the application of the vertical distance from the fracturing segment target to the coal seam upper surface includes:

[0031] The vertical distance from the fracturing segment target to the coal seam upper surface at the initial profile line and the vertical distance from the fracturing segment target to the coal seam upper surface at the additional profile line are respectively measured in the corresponding coal seam profile map;

[0032] Each of the vertical distances is combined with the coal seam dip angle, the coal seam thickness, and the target fracturing level for analysis to evaluate whether the arrangement of each of the fracturing segment targets relative to the coal seam upper surface meets the fracturing prevention and control requirements and to determine the fracturing segment target for arranging the fracturing segment.

[0033] Preferably, the upper elevation of the steeply inclined coal seam proposed mining area is nine hundred and seventy meters, the lower elevation is nine hundred and twenty meters, the average coal seam thickness is twenty-five meters, the preset interval is seventy-five meters, the target fracturing level is nine hundred and fifty meters, the initial profile line is four, and the additional profile line is four.

[0034] A steeply inclined coal seam ground horizontal well fracturing segment trajectory determination system based on directional targets, comprising:

[0035] A coal seam parameter identification unit for determining the upper elevation, the lower elevation, and the average coal seam thickness of a steeply inclined coal seam proposed mining area;

[0036] an initial profile line arrangement unit, configured to arrange a plurality of initial profile lines in a preset interval along the north-south direction from the left boundary of the target control area to the right boundary of the target control area;

[0037] a profile line optimization and addition unit, configured to determine the number of profile lines to be added between each pair of adjacent initial profile lines according to the absolute difference of the tangent slope of the intersection point of the coal seam floor contour at the target fracturing level, and arrange the added profile lines in the same interval to obtain a profile line set comprising the initial profile lines and the added profile lines;

[0038] a coal seam profile drawing unit, configured to draw a corresponding coal seam profile based on the coal seam parameters at each profile line in the profile line set, wherein the coal seam dip angle is determined by the coal seam floor contour at each profile line, and the coal seam thickness is determined by the borehole columnar chart near each profile line;

[0039] a fracturing segment target point matching unit, configured to arrange fracturing segment target points on the target fracturing level in each coal seam profile, and calculate the vertical distance from each fracturing segment target point to the coal seam upper surface according to the corresponding coal seam dip angle and coal seam thickness, so that each fracturing segment target point is matched with the coal seam occurrence conditions;

[0040] a directional drilling arrangement unit, configured to drill vertically downward from the ground and arrange a vertical segment of a fracturing well, and when the vertical segment of the fracturing well reaches the target fracturing level, drill and arrange a fracturing segment along the coal seam trend with each fracturing segment target point as a directional target point.

[0041] The present application discloses the following technical effects:

[0042] The present application can truly reflect the change of the dip angle and thickness of the steeply inclined coal seam along the trend and dip by arranging initial profile lines according to the change of the coal seam floor contour in the target control area and adaptively adding profile lines based on the absolute difference of the tangent slope of adjacent initial profile lines at the target fracturing level, and solves the problem that the fixed horizon is often used for fracturing well arrangement in the background technology and the spatial change of the coal seam cannot be reflected. The present application constructs a profile line set, so that the non-uniformity of the coal seam occurrence conditions is completely expressed, and provides a basis for fracturing segment arrangement, and improves the accuracy of the wellbore trajectory design.

[0043] This invention generates coal seam profiles based on the dip angle and thickness of each profile line. At the target fracturing level, fracturing target points are individually arranged for each profile line, and the vertical distance from each target point to the upper coal seam surface is calculated. This allows the fracturing segment arrangement to be dynamically adjusted according to the coal seam occurrence conditions, overcoming the problem of unstable fracturing effects caused by the fixed relationship between the fracturing layer and the coal seam in the prior art. This invention achieves precise matching of the "fracturing target point - coal seam spatial structure," effectively reducing the risk of wellbore penetration into coal and improving the rationality of fracturing control layers.

[0044] This invention, after the vertical section of the fracturing well reaches the target fracturing level, uses multiple fracturing segment target points as directional drilling targets. This allows the wellbore to be arranged with horizontal and fracturing segments along the corresponding target point directions, overcoming the shortcomings of prior art that cannot simultaneously consider fracturing effectiveness, safety, and geological changes. Through this multi-target directional layout, the invention enables the fracturing well trajectory to adapt to the complex geometry of steeply inclined coal seams, ensuring that the fracturing segments are within the effective pressure relief zone while improving the safety of the wellbore structure. This achieves a comprehensive improvement in fracturing control effectiveness, wellbore stability, and engineering feasibility. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A flowchart of the method provided in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the technical route provided in the embodiments of the present invention;

[0048] Figure 3 This is a schematic diagram of the cross-sectional line arrangement provided for an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of the target point arrangement in the cross-sectional view at the initial cross-section line provided in an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of the target point arrangement in the cross-sectional view at the location where the cross-sectional line is added, provided in an embodiment of the present invention.

[0051] Figure 6 This is a schematic diagram of the trajectory of the horizontal well fracturing section provided in an embodiment of the present invention. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] The purpose of this invention is to provide a method and system for determining the trajectory of the fracturing section in a surface horizontal well of a steeply inclined coal seam based on directional target points, so as to ensure that the arrangement of the fracturing section meets the requirements of fracturing control and reduce engineering risks.

[0054] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Figure 1 The method flowchart provided in the embodiments of the present invention is as follows: Figure 1 As shown, this invention provides a method for determining the trajectory of the fracturing section in a surface horizontal well of a steeply inclined coal seam based on a directional target point, comprising:

[0056] Step 100: Determine the upper and lower elevations and the average thickness of the coal seam in the proposed mining area of ​​the steeply inclined coal seam;

[0057] Step 200: Within the proposed control area, set several initial north-south oriented profile lines starting from the left boundary of the proposed control area at preset intervals;

[0058] Step 300: Based on the absolute difference of the tangent slopes at the intersection points of the contour lines of the coal seam floor at the target fracturing level of each adjacent initial profile line, determine the number of profile lines that need to be added between each adjacent initial profile line, and arrange them at the same interval to form additional profile lines, thus obtaining a set of profile lines including the initial profile lines and the additional profile lines.

[0059] Step 400: Draw the corresponding coal seam profile based on the coal seam parameters at each profile line in the profile line set; wherein the coal seam dip angle is determined by the coal seam floor contour lines at each profile line, and the coal seam thickness is determined by the borehole columnar section near each profile line;

[0060] Step 500: In each coal seam profile, arrange the fracturing target points at the target fracturing level, and calculate the vertical distance from each fracturing target point to the upper surface of the coal seam according to the corresponding coal seam dip angle and coal seam thickness, so that each fracturing target point matches the coal seam occurrence conditions.

[0061] Step 600: Drill vertically downwards from the ground and arrange the vertical sections of the fracturing well. When the vertical sections of the fracturing well reach the target fracturing level, drill along the coal seam with the target points of each fracturing section as directional target points and arrange the fracturing sections.

[0062] like Figure 2 As shown, the technical approach of this embodiment includes:

[0063] The upper and lower elevations of the proposed mining area for the steeply inclined coal seam are determined to be b and a, respectively, and the average thickness is H.

[0064] Within the proposed control area, starting from the left boundary of the proposed control area, an initial north-south oriented profile line is set at intervals of S, and each initial profile line is denoted as X. i ,in, n is the number of initial profile lines within the proposed control area;

[0065] Let K be the absolute difference in the slope of the tangent lines at the intersection points of two adjacent initial profile lines and the contour lines of the horizontal coal seam floor at point Z. Based on the magnitude of K, add a additional profile lines at equal intervals between the two adjacent profile lines, and denote each additional profile line as X'. j ,, m is the number of profile lines to be added within the proposed control area;

[0066] A coal seam profile T is drawn based on the coal seam parameters at the initial profile line. i Coal seam profile T' is drawn based on the coal seam parameters at the added profile lines. j The coal seam dip angle parameter is obtained from the contour lines of the coal seam floor at each profile line, and the coal seam thickness parameter is obtained from the borehole columnar section at the nearest profile line;

[0067] In coal seam profile T i In the middle, the dip angle of the coal seam is θ i The coal seam thickness is H i Fracturing section target point S i The target point is located at a horizontal level of Z, and the vertical distance between the target point and the upper surface of the coal seam is L. i ;

[0068] In the coal seam profile T` j In the middle, the coal seam dip angle is θ` j The coal seam thickness is H` j Fracturing section target point S' j The target point is located at a horizontal level of Z, and the vertical distance between the target point and the upper surface of the coal seam is L'. j ;

[0069] Drilling vertically downwards from the ground and deploying vertical fracturing well sections, upon reaching horizontal Z, along the coal seam strike, with the target point S of the fracturing section... i and S` j Drilling is carried out at the target point and fracturing sections are arranged.

[0070] Specifically, the main steps of this embodiment are as follows:

[0071] a. Determine the upper and lower elevations of the proposed mining area 1 of the steeply inclined coal seam as b and a, respectively, and the average thickness as H;

[0072] b. Within the proposed control area 1, starting from the left boundary of the proposed control area 1, set an initial north-south oriented profile line 2 at intervals of S, and denote each initial profile line 2 as X. i ,in, n is the number of initial profile lines 2 within the proposed control area 1;

[0073] c. Let K be the absolute difference in the slope of the tangent line at the intersection point 4 of two adjacent initial profile lines 2 and the contour line 3 of the coal seam floor at the Z level. Based on the magnitude of K, add a additional profile lines 5 at equal intervals between two adjacent profile lines 2, and denote each additional profile line 5 as X`. j ,, m represents the number of 5 additional profile lines to be added within the proposed control area 1;

[0074] d. Draw coal seam profile Ti based on the coal seam parameters at the two initial profile lines, and draw coal seam profile T` based on the coal seam parameters at the five additional profile lines. j The coal seam dip angle parameter is obtained from the contour lines of the coal seam floor at each profile line, and the coal seam thickness parameter is obtained from the borehole columnar section at the nearest profile line;

[0075] e. In the coal seam profile T i In the middle, the dip angle of coal seam 7 is θ i The thickness of coal seam 7 is H. i The horizontal position of target point Si in the fracturing section is Z, and the vertical distance between target point 6 and the upper surface of coal seam 7 is L. i ;

[0076] f. In the coal seam profile T` j In the middle, the dip angle of coal seam 7 is θ` j The thickness of coal seam 7 is H` j Fracturing section target point S` j The target point is located at level Z, and the vertical distance between target point 6 and the upper surface of coal seam 7 is L'. j ;

[0077] g. Drill vertically downwards from the ground and arrange vertical sections of the fracturing well. When reaching horizontal Z, follow the coal seam strike with the target point S of the fracturing section. i and S` j Drilling was carried out at target point 6 and fracturing section 8 was arranged.

[0078] in, , , , , .

[0079] The following example uses the determination of the fracturing trajectory of a horizontal well in a steeply inclined coal seam at a mine in Gansu Province based on directional target points, combined with... Figures 3 to 6The present invention will be further described below. The specific technical steps of this embodiment are as follows:

[0080] The upper and lower elevations of the proposed mining area 1 for the steeply inclined coal seam are determined to be +970m and +920m, respectively, with an average thickness of 25m.

[0081] Within the proposed control area 1, starting from the left boundary of the proposed control area 1, an initial profile line 2 running north-south is set at intervals of 75m. Each initial profile line 2 is denoted as X. i ,in, The number of initial profile lines 2 within the proposed control area is 4;

[0082] Let K be the absolute difference in the slope of the tangent line at the intersection point 4 of two adjacent initial profile lines 2 and the contour line 3 of the horizontal coal seam floor at +950m. Based on the magnitude of K, add a additional profile lines 5 at equal intervals between the two adjacent profile lines 2, and denote each additional profile line 5 as X`. j ,, The number of sections 5 to be added within the proposed control area 1 is 4;

[0083] Based on the parameters of coal seam 2 at the initial profile line, a coal seam profile diagram T is drawn. i Based on the parameters of five coal seams with added profile lines, a coal seam profile diagram T` was drawn. j The coal seam dip angle parameter is obtained from the contour lines of the coal seam floor at each profile line, and the coal seam thickness parameter is obtained from the borehole columnar section at the nearest profile line;

[0084] In coal seam profile T i In the middle, the dip angle of coal seam 7 is θ i The thickness of coal seam 7 is H. i Fracturing section target point S i The target point is located at a horizontal level of +950m, and the vertical distance between target point 6 and the upper surface of coal seam 7 is L. i ;

[0085] In the coal seam profile T` j In the middle, the dip angle of coal seam 7 is θ` j The thickness of coal seam 7 is H` j Fracturing section target point S` j The target point is located at level Z, and the vertical distance between target point 6 and the upper surface of coal seam 7 is L'. j ;

[0086] Drilling vertically downwards from the ground and deploying vertical sections of the fracturing well, reaching a horizontal depth of +950m, and then proceeding along the coal seam with the target point S of the fracturing section... i and S` j Drilling was carried out at target point 6 and fracturing section 8 was arranged.

[0087] in, , .

[0088] No coal penetration occurred in the wellbore during drilling, and mine pressure monitoring showed that the mine pressure intensity during the working face recovery process was significantly reduced after surface fracturing. This validated a method for determining the trajectory of the fracturing section in a horizontal well in a steeply inclined coal seam based on directional target points. The adoption of this fracturing section layout method in the inclined well is of great significance for ensuring the safe and efficient mining of steeply inclined coal seams.

[0089] Corresponding to the above method, this embodiment also provides a system for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, including:

[0090] The coal seam parameter identification unit is used to determine the upper and lower elevations and the average thickness of the coal seam in the proposed mining area of ​​the steeply inclined coal seam.

[0091] An initial profile line arrangement unit is used to set several north-south oriented initial profile lines at preset intervals, starting from the left boundary of the area to be controlled.

[0092] The profile line optimization and addition unit is used to determine the number of profile lines to be added between adjacent initial profile lines based on the absolute difference of the tangent slope at the intersection point of the coal seam floor contour lines at the target fracturing level, and to arrange the added profile lines at the same interval to obtain a profile line set including the initial profile lines and the added profile lines.

[0093] The coal seam profile drawing unit is used to draw the corresponding coal seam profile based on the coal seam parameters at each profile line in the profile line set; wherein the coal seam dip angle is determined by the coal seam bottom contour line at each profile line, and the coal seam thickness is determined by the borehole columnar section near each profile line.

[0094] The fracturing segment target matching unit is used to arrange fracturing segment target points at the target fracturing level in each of the coal seam profile diagrams, and calculate the vertical distance from each of the fracturing segment target points to the upper surface of the coal seam according to the corresponding coal seam dip angle and coal seam thickness, so that each of the fracturing segment target points matches the coal seam occurrence conditions.

[0095] A directional drilling layout unit is used to drill vertically downwards from the ground and arrange vertical sections of the fracturing well. When the vertical section of the fracturing well reaches the target fracturing level, the fracturing section is drilled and arranged along the coal seam strike with each fracturing section target point as the directional target point.

[0096] The beneficial effects of this invention are as follows:

[0097] (1) This invention takes into account the complex occurrence conditions of steeply inclined coal seams and arranges the target points of the fracturing section based on the occurrence characteristics of coal seams at each profile line. It can accurately determine the fracturing control layer and obtain the target point position to ensure the fracturing effect.

[0098] (2) The method for determining the trajectory of the horizontal well fracturing section in this invention is simple and has strong applicability. Compared with the traditional method for determining the trajectory of the fracturing section, it can effectively control rockburst in steeply inclined coal seams and has broad application prospects.

[0099] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0100] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0101] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for determining the trajectory of the fracturing section in a horizontal well in a steeply inclined coal seam based on a directional target point, characterized in that, include: Determine the upper and lower elevations and the average thickness of the coal seam in the proposed mining area of ​​the steeply inclined coal seam; Within the proposed control area, several initial north-south oriented profile lines are set starting from the left boundary of the proposed control area at preset intervals; Based on the absolute difference in the slope of the tangent at the intersection of the contour lines of the coal seam floor at the target fracturing level of each adjacent initial profile line, the number of additional profile lines to be added between each adjacent initial profile line is determined, and the additional profile lines are arranged at the same interval to form an additional profile line set including the initial profile line and the additional profile lines. Based on the coal seam parameters at each profile line in the profile line set, a corresponding coal seam profile is drawn; wherein, the coal seam parameters include the coal seam dip angle and the coal seam thickness; the coal seam dip angle is determined by the coal seam floor contour lines at each profile line, and the coal seam thickness is determined by the borehole columnar section near each profile line; In each of the coal seam profile diagrams, fracturing target points are arranged at the target fracturing level, and the vertical distance from each fracturing target point to the upper surface of the coal seam is calculated according to the corresponding coal seam dip angle and coal seam thickness, so that each fracturing target point matches the coal seam occurrence conditions. Drill vertically downwards from the ground and arrange vertical sections of the fracturing well. When the vertical section of the fracturing well reaches the target fracturing level, drill along the coal seam with each fracturing section target point as the directional target point and arrange the fracturing sections.

2. The method for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, as described in claim 1, is characterized in that... The steps for determining the preset spacing are as follows: The control length of the area to be controlled along the coal seam direction is obtained. Based on the required number of initial profile lines, the control length is divided into several equal intervals. The length of adjacent intervals is taken as the preset spacing, so that each initial profile line is evenly distributed along the coal seam direction.

3. The method for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, as described in claim 1, is characterized in that... The steps for determining the target fracturing level are as follows: In accordance with the requirements for rockburst prevention and control in steeply inclined coal seams, the design vertical distance between the fracturing prevention and control layer and the coal seam is determined. Based on the upper and lower elevations of the proposed mining area of ​​the steeply inclined coal seam and the average thickness of the coal seam, the horizontal elevation corresponding to the design vertical distance is inverted along the contour lines of the coal seam floor, and the horizontal elevation is taken as the target fracturing level.

4. The method for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, as described in claim 1, is characterized in that... The method for determining the number of additional section lines needed between adjacent initial section lines is as follows: Obtain the absolute difference in the tangent slope of the intersection point of two adjacent initial profile lines and the contour lines of the coal seam floor at the target fracturing level; The absolute difference of the tangent slope is compared with the preset tangent slope difference grading interval. Based on the grading interval where the absolute difference of the tangent slope is located, the number of profile lines to be added between two adjacent initial profile lines is determined, so that the greater the change in the tangent slope, the more profile lines are added.

5. The method for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, as described in claim 1, is characterized in that... The steps for obtaining the dip angle of the coal seam are as follows: Select multiple representative points near the intersections of the aforementioned profile lines and the contour lines of the coal seam floor; Based on the spatial location of the representative points, the spatial orientation and dip of the contour lines of the coal seam floor are determined, and the dip angle of the coal seam at each of the profile lines is calculated according to the spatial orientation and dip, which is used as the dip angle of the coal seam when drawing the coal seam profile.

6. The method for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, as described in claim 1, is characterized in that... The steps for obtaining the coal seam thickness are as follows: Select at least one borehole column near each of the aforementioned profile lines; Read the difference between the elevation of the coal seam roof and the elevation of the coal seam floor in the borehole columnar section, and use the difference as the coal seam thickness at the profile line; When there are multiple borehole columnar sections, the average value of the differences is taken as the coal seam thickness.

7. The method for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, as described in claim 1, is characterized in that... The calculation steps for the vertical distance from the target point of each fracturing section to the upper surface of the coal seam are as follows: In the coal seam profile, the upper coal seam surface and the bottom coal seam are drawn according to the coal seam dip angle and the coal seam thickness; Arrange the target point of the fracturing section on the target fracturing level, and draw a vertical line from the target point of the fracturing section to the upper surface of the coal seam in the vertical direction in the coal seam profile diagram; The length of the vertical line is measured as the vertical distance between the target point of the fracturing section and the upper surface of the coal seam.

8. The method for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, as described in claim 1, is characterized in that... The application steps for the vertical distance between the target point of the fracturing section and the upper surface of the coal seam include: The vertical distance between the target point of the fracturing section located on the initial profile line and the upper surface of the coal seam, and the vertical distance between the target point of the fracturing section located on the additional profile line and the upper surface of the coal seam, are respectively measured in the corresponding coal seam profile diagram. The vertical distances are analyzed in conjunction with the dip angle of the coal seam, the thickness of the coal seam, and the target fracturing level to evaluate whether the arrangement of each fracturing segment target point relative to the upper surface of the coal seam meets the fracturing control requirements, and to determine the fracturing segment target points used for arranging the fracturing segments.

9. The method for determining the trajectory of the fracturing section in a steeply inclined coal seam surface horizontal well based on a directional target point, as described in claim 1, is characterized in that... The upper elevation of the proposed mining area of ​​the steeply inclined coal seam is 970 meters, the lower elevation is 920 meters, the average thickness of the coal seam is 25 meters, the preset spacing is 75 meters, the target fracturing level is 950 meters, the initial profile lines are four, and the additional profile lines are four.

10. A system for determining the trajectory of the fracturing section in a horizontal well in a steeply inclined coal seam based on a directional target point, characterized in that, include: The coal seam parameter identification unit is used to determine the upper and lower elevations and the average thickness of the coal seam in the proposed mining area of ​​the steeply inclined coal seam. An initial profile line arrangement unit is used to set several north-south oriented initial profile lines at preset intervals, starting from the left boundary of the area to be controlled. The profile line optimization and addition unit is used to determine the number of profile lines to be added between adjacent initial profile lines based on the absolute difference of the tangent slope at the intersection point of the coal seam floor contour lines at the target fracturing level, and to arrange the added profile lines at the same interval to obtain a profile line set including the initial profile lines and the added profile lines. The coal seam profile drawing unit is used to draw the corresponding coal seam profile based on the coal seam parameters at each profile line in the profile line set; wherein the coal seam dip angle is determined by the coal seam bottom contour line at each profile line, and the coal seam thickness is determined by the borehole columnar section near each profile line. The fracturing segment target matching unit is used to arrange fracturing segment target points at the target fracturing level in each of the coal seam profile diagrams, and calculate the vertical distance from each of the fracturing segment target points to the upper surface of the coal seam according to the corresponding coal seam dip angle and coal seam thickness, so that each of the fracturing segment target points matches the coal seam occurrence conditions. A directional drilling layout unit is used to drill vertically downwards from the ground and arrange vertical sections of the fracturing well. When the vertical section of the fracturing well reaches the target fracturing level, the fracturing section is drilled and arranged along the coal seam strike with each fracturing section target point as the directional target point.

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