Long-distance accurate drilling method for ground directional drilling in thin limestone

Abstract

The invention discloses a long-distance accurate drilling method for ground directional drilling in thin limestone, which comprises the following steps of: firstly, collecting hydrogeological parameters of a treatment area, then constructing a probing hole on the ground, probing data of each stratum, acquiring accurate data of each stratum, and calculating the accurate data of each stratum; the continuity and the specific position of a drill hole in a target stratum are comprehensively judged by combining upward-returning rock debris, while-drilling natural gamma measurement data and logging record data during drilling in the drilling process, then the target stratum is drilled, drilling trajectories are formed by recording coordinate points in the drilling process, and a three-dimensional trajectory model is formed after multiple drilling trajectories are connected. And the change of the anticipated stratum fluctuation inclination angle is realized, and an actual drilling track can be guided. Through the technical means of comprehensively utilizing hydrogeological parameters, exploring hole construction, drilling continuity monitoring and three-dimensional track establishment, the accuracy and safety of drilling construction are ensured, and the method has wide application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of drilling thin limestone on coal mine floor, and more specifically to a method for drilling long distance and accurately in thin limestone by ground directional drilling. Background Art

[0002] With the development of ground directional drilling and grouting reinforcement technology, this technology has been increasingly widely used in mine water prevention and control projects, especially in the reinforcement and transformation of thin limestone layers in coal mine floors. The thickness of thin limestone is generally less than 6 meters, while the drilling section of horizontal holes can reach hundreds of meters to thousands of meters, which increases the difficulty of accurate positioning during drilling. At present, the distribution of thin limestone often alternates with mudstone, sandstone and other strata, with similar layer thickness and similar properties, which brings difficulties to the identification of strata. In addition, the undulations of the surface and the influence of faults make it an urgent problem to accurately identify the target stratum and ensure the accurate drilling of the borehole in the thin limestone. The existing technology has problems such as inaccurate positioning and difficult to control drilling trajectory in the application of this field. Summary of the invention

[0003] To this end, the technical problem to be solved by the present invention is to provide a method for ground directional drilling that can accurately judge and identify thin layers of limestone on the ground and realize long-distance drilling and long-distance precise drilling in thin layers of limestone.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for long-distance precision drilling of ground directional drilling holes in thin limestone, comprising the following steps:

[0005] Step A: Collect the hydrogeological parameters of the treatment area, including the thickness of the thin limestone layer in the treatment area, the interlayer distance between the thin limestone layer and the coal seam, and the properties of the top and bottom plates of the thin limestone layer;

[0006] Step B: construct a large-angle exploration hole on the ground into the treatment area, record and accurately determine the vertical depth, layer thickness and spacing of each rock layer in the treatment area;

[0007] Step C: After confirming the target thin limestone layer, the drill tool is lifted up, and then the drill tool is horizontally drilled into the target thin limestone layer and drilled along the target thin limestone layer;

[0008] Step D: During the drilling construction in the target thin limestone, the continuity and specific location of the borehole in the target thin limestone are comprehensively confirmed by combining the returned rock cuttings, the natural gamma measurement data while drilling, and the logging data during drilling;

[0009] Step E: During the horizontal drilling construction, the coordinate points of the current drilling tool are recorded at regular intervals. After the drilling is completed, the coordinate points are sequentially connected to form a drilling trajectory A;

[0010] Step F: construct branch drilling holes adjacent to the drilling trajectory A in the target thin layer of limestone. When drilling the branch drilling holes, the coordinate points of the current drilling tool are recorded at regular intervals. After the construction is completed, the coordinate points are sequentially connected to form the drilling trajectory B.

[0011] Step G: Connect the coordinate points corresponding to the drilling trajectory A and the drilling trajectory B to establish a three-dimensional trajectory model, so as to predict the change of the stratum undulation inclination angle;

[0012] Step H: When performing actual drilling construction on the target thin layer of limestone, the drilling trajectory is guided in combination with the situation of the three-dimensional trajectory model.

[0013] In the above-mentioned method of long-distance precise drilling of thin limestone by ground directional drilling, in step A, after collecting the hydrogeological parameters of the treatment area, a comprehensive column chart is drawn to record in detail the thickness and vertical depth of the coal seam, the thickness and vertical depth of each layer of limestone, and calculate the interlayer distance between the coal seam and each layer of limestone.

[0014] In the above-mentioned method for long-distance precise drilling of ground directional drilling in thin limestone, in step B, during the construction of the exploration hole, the inclination of the exploration hole inclination section is maintained at 60-70°.

[0015] In the above-mentioned method of long-distance precise drilling of thin limestone by ground directional drilling, in step B, the exploration hole is drilled through each rock layer in turn, and the relevant data is recorded and calculated to obtain the specific vertical depth, layer thickness, and distance between each layer of limestone and coal seam of each stratum, and compared and analyzed with the data in step A, so as to accurately determine the location of the target thin limestone layer.

[0016] In the above-mentioned method for long-distance precise drilling of thin-layer limestone by ground directional drilling, in step D, during the drilling of the exploration hole, the drilling fluid carries the rock cuttings back to the wellhead on the ground, collects the rock cutting samples, and uses dilute hydrochloric acid to titrate and analyze the rock cutting samples to determine the properties of the rock cutting samples.

[0017] In the above-mentioned method of long-distance precise drilling of ground directional drilling in thin limestone, in step E and step F, during the drilling construction process, the drill tool performs inclination measurement every 10 meters, and records the hole depth, well inclination, azimuth, and east-west displacement data of the current point to form a coordinate point.

[0018] In the above-mentioned method for long-distance precise drilling of a ground directional borehole in a thin layer of limestone, in step D, natural gamma measurement data while drilling is analyzed, the properties of the surrounding rock along the drilling trajectory are monitored in real time, and the continuity of the drilling of the borehole in the thin layer of limestone is judged by the different radioactive properties of different rocks.

[0019] In the above-mentioned method for long-distance precise drilling of thin limestone by ground directional drilling, in step D, the properties of the rock cut by the drill tool and the stratum in which the drill tool is located are determined based on the drilling logging data.

[0020] The technical solution of the present invention achieves the following beneficial technical effects:

[0021] 1. Through the comprehensive use of hydrogeological parameters, exploration hole construction, drilling continuity monitoring and three-dimensional trajectory establishment, the accuracy and safety of drilling construction are ensured, and it has broad application prospects.

[0022] 2. Use multiple judgment methods to ensure accurate directional horizontal drilling in the target rock layer. After practical verification, the average limestone layer-aligning rate in thin limestone drilling in actual applications is as high as 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the construction of the exploration hole of the present invention;

[0024] Figure 2 Schematic diagram of the three-dimensional stratum model of the present invention. DETAILED DESCRIPTION

[0025] This embodiment takes a directional horizontal hole thin layer limestone cement high pressure grouting project in a certain construction area as an application example, and adopts a ground directional drilling method for long-distance precision drilling in thin layer limestone, which specifically includes the following steps:

[0026] Step A: Collect the hydrogeological parameters of the treatment area, including the thickness of the thin limestone layer, the interlayer distance between the thin limestone layer and the coal seam, and the properties of the thin limestone roof and floor rocks in the treatment area, and draw a comprehensive columnar chart to record in detail the thickness and vertical depth of the coal seam, the thickness and vertical depth of each limestone layer, and calculate the interlayer distance between the coal seam and each limestone layer;

[0027] Step B: construct a large-angle exploration hole on the ground into the treatment area, and keep the inclination of the exploration hole in the inclined section at 60-70°. The exploration hole drills through each rock layer in turn, records and accurately determines the vertical depth, layer thickness and spacing of each rock layer in the treatment area, and compares and analyzes with the data in step A, so as to accurately determine the location of the target thin layer of limestone;

[0028] Step C: After confirming the target thin limestone layer, the drill tool is lifted up, and then the drill tool is horizontally drilled into the target thin limestone layer and drilled along the target thin limestone layer;

[0029] Step D: During the drilling construction in the target thin layer of limestone, the continuity and specific location of the drilling of the borehole in the thin layer of limestone are comprehensively confirmed by combining the returned rock cuttings, the natural gamma measurement data while drilling, and the logging data during drilling; the drilling fluid carries the rock cuttings back to the wellhead on the ground, collects the rock cutting samples, and uses dilute hydrochloric acid to titrate and analyze the rock cutting samples to determine the properties of the rock cutting samples. The chemical reaction formula of limestone and dilute hydrochloric acid is as follows: CaCO3+2HCL=CaCL2+CO2↑+H2O;

[0030] Analyze the natural gamma measurement data while drilling, monitor the properties of the surrounding rocks along the drilling trajectory in real time, and judge the continuity of drilling in thin limestone by the different radioactive properties of different rocks. The rock properties in different strata are quite different, and the drilling speeds of the boreholes in limestone, coal seams, sandstone, and mudstone are different. The drilling logging data can be used to determine the formation.

[0031] Table 1: Drilling logging parameters

[0032] rock name color Hydrochloric acid drop reaction Gamma Data Drilling time Limestone Gray, off-white Violent reaction 20～50 7~12min / m Sand, mudstone Deep black, gray Basically no reaction 51～300 4~6min / m Coal seam black No reaction 10～20 1~3min / m

[0033] Step E: During the drilling construction process, the drill tool is measured for inclination every 10 meters, and the hole depth, well inclination, azimuth, and east-west displacement data of the current point are recorded to form coordinate points, and the coordinate points of the current drill tool are recorded. After the drilling is completed, the coordinate points are connected in sequence to form a drilling trajectory A; then the adjacent branch drilling holes are constructed. After the adjacent branch drilling holes are constructed, the coordinate points recorded in the branch drilling holes are connected in sequence to form a drilling trajectory B; the coordinate points corresponding to the drilling trajectory A and the drilling trajectory B are connected to establish a three-dimensional trajectory model to form a trajectory surface, so that the changes in the undulation inclination of the formation can be anticipated;

[0034] Step F: When actually drilling the target thin layer of limestone, the drilling trajectory is guided in combination with the three-dimensional trajectory model; since the trajectory adjustment is limited by the full-angle change rate, it is necessary to guide the drilling construction trajectory according to the expected formation conditions, so as to ensure that the borehole is accurately drilled over a long distance in the thin layer of limestone.

[0035] Through practical verification, the present embodiment has calculated that the average limestone layer-aligning rate of directional horizontal hole drilling into thin limestone is as high as 95%.

[0036] 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 long-distance precision drilling of ground directional holes in thin limestone, characterized in that: The following steps are involved: Step A: Collect the hydrogeological parameters of the treatment area, including the thickness of the thin limestone layer in the treatment area, the interlayer distance between the thin limestone layer and the coal seam, and the properties of the top and bottom plates of the thin limestone layer; Step B: construct a large-angle exploration hole on the ground into the treatment area, record and accurately determine the vertical depth, layer thickness and spacing of each rock layer in the treatment area; Step C: After confirming the target thin limestone layer, the drill tool is lifted up, and then the drill tool is horizontally drilled into the target thin limestone layer and drilled along the target thin limestone layer; Step D: During the drilling construction in the target thin limestone, the continuity and specific location of the borehole in the target thin limestone are comprehensively confirmed by combining the returned rock cuttings, the natural gamma measurement data while drilling, and the logging data during drilling; Step E: During the horizontal drilling construction, the coordinate points of the current drilling tool are recorded at regular intervals. After the drilling is completed, the coordinate points are sequentially connected to form a drilling trajectory A; Step F: construct branch drilling holes adjacent to the drilling trajectory A in the target thin layer of limestone. When drilling the branch drilling holes, the coordinate points of the current drilling tool are recorded at regular intervals. After the construction is completed, the coordinate points are sequentially connected to form the drilling trajectory B. Step G: Connect the coordinate points corresponding to the drilling trajectory A and the drilling trajectory B to establish a three-dimensional trajectory model, so as to predict the change of the stratum undulation inclination angle; Step H: When performing actual drilling construction on the target thin layer of limestone, the drilling trajectory is guided in combination with the situation of the three-dimensional trajectory model.

2. A method for long-distance precision drilling of ground directional holes in thin limestone according to claim 1, characterized in that: In step A, after collecting the hydrogeological parameters of the treatment area, a comprehensive column chart is drawn to record in detail the thickness and vertical depth of the coal seam, the thickness and vertical depth of each layer of limestone, and calculate the interlayer distance between the coal seam and each layer of limestone.

3. The method for long-distance precision drilling of ground directional holes in thin limestone according to claim 1, characterized in that: In step B, during the construction of the exploration hole, the inclination of the exploration hole inclination section is maintained at 60-70°.

4. The method for long-distance precision drilling of ground directional holes in thin limestone according to claim 1, characterized in that: In step B, the exploration hole is drilled through each rock layer in turn, and the relevant data is recorded and calculated to obtain the specific vertical depth, layer thickness, and distance between each layer of limestone and coal seam of each stratum, and compared and analyzed with the data in step A to accurately determine the location of the target thin layer of limestone.

5. The method for long-distance precision drilling of ground directional holes in thin limestone according to claim 1, characterized in that: In step D, during the drilling of the exploration hole, the drilling fluid carries the rock cuttings back to the wellhead on the ground, and rock cutting samples are collected. The rock cutting samples are titrated and analyzed using dilute hydrochloric acid to determine the properties of the rock cutting samples.

6. The method for long-distance precision drilling of ground directional holes in thin limestone according to claim 1, characterized in that: In step E and step F, during the drilling construction process, the drill tool performs inclination measurement every 10 meters, and records the hole depth, well inclination, azimuth, and east-west displacement data of the current point to form a coordinate point.

7. The method for long-distance precision drilling of ground directional holes in thin limestone according to claim 1, characterized in that: In step D, the natural gamma measurement data while drilling is analyzed to monitor the surrounding rock properties of the drilling trajectory in real time. The continuity of the drilling in the thin limestone is determined by the different radioactive properties of different rocks.

8. The method for long-distance precision drilling of ground directional holes in thin limestone according to claim 1, characterized in that: In step D, the properties of the rock cut by the drill bit and the stratum in which the drill bit is located are determined based on the logging data during drilling.

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