Precise exploration method for complex geology of tunnel plateau based on ultra-deep horizontal drilling

Abstract

The invention discloses a tunnel plateau complex geology accurate exploration method based on ultra-deep horizontal drilling, which comprises the following steps: step (1) horizontal drilling layout: selecting a construction site on the ground of a to-be-tunneled tunnel, and planning a horizontal drilling track along a tunnel line; (2) horizontal drilling and multi-dimensional geological exploration are constructed, specifically, according to the planned horizontal drilling track, a petroleum drilling machine is used for constructing horizontal drilling; logging operation is carried out in the horizontal drilling construction process, and comprehensive logging and transient electromagnetic detection are carried out after horizontal drilling construction is completed; and step (3), integration and analysis of geological exploration data information: integrating and analyzing the data information collected by multi-dimensional geological exploration, determining geological conditions along the tunnel line, and identifying geological abnormal sections. According to the invention, the problems of discontinuous exploration and poor accuracy of traditional vertical drilling and geophysical prospecting means can be solved, and high-precision and continuous exploration of geological conditions near the tunnel line is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geological exploration. Specifically, it is a tunnel plateau complex geological precision exploration method based on ultra-deep horizontal drilling. BACKGROUND

[0002] At present, the EH4 electromagnetic imaging system, V8 magnetotelluric system and other geophysical prospecting methods are used for geological exploration of tunnels in the early stage of tunnel survey, and the geological conditions of the tunnel are analyzed in combination with surface surveying, regional geological investigation and surface exploration (trenching). However, geophysical interpretation has obvious multiple solutions, often leading to large uncertainty in the judgment of deep-buried tunnel geological conditions.

[0003] At the same time, limited by technical equipment, the maximum drilling depth of the early-stage survey drilling is relatively shallow, and all are vertical drilling operation modes. This operation mode can only reveal the geological conditions of a local "point", and cannot fully reflect the actual geological conditions along the tunnel line, especially in the plateau deep complex environment, which is more likely to lead to insufficient risk prediction due to insufficient geological information.

[0004] Therefore, a new drilling and exploration method that can break through the limitations of vertical shafts, has greater drilling depth and can "reveal the tunnel line" is urgently needed to solve the problem of large uncertainty in deep-buried tunnel plateau complex geological exploration. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to provide a tunnel plateau complex geological precision exploration method based on ultra-deep horizontal drilling, to solve the problem of discontinuity and poor accuracy of traditional vertical drilling and geophysical prospecting methods, and to realize high-precision and continuous exploration of the geological conditions near the tunnel line.

[0006] To solve the above technical problems, the present application provides the following technical solutions:

[0007] A tunnel plateau complex geological precision exploration method based on ultra-deep horizontal drilling, comprising the following steps:

[0008] Step (1), horizontal drilling layout: selecting a construction site on the ground of the tunnel to be excavated, and planning a horizontal drilling trajectory along the tunnel line;

[0009] Step (2), construction of horizontal drilling and multi-dimensional geological exploration: constructing horizontal drilling using an oil drilling rig according to the planned horizontal drilling trajectory; performing logging operations during horizontal drilling construction, and performing comprehensive logging and transient electromagnetic detection after horizontal drilling construction is completed;

[0010] Step (3), integration and analysis of geological exploration data: the data collected by multi-dimensional geological exploration are integrated and analyzed to determine the geological conditions along the tunnel line and identify the geological anomaly section, so as to predict the water-bearing layer and water-rich section in advance and provide the basis for advanced prediction and treatment for tunnel construction.

[0011] In step (1) of the above-mentioned tunnel plateau complex geological precise exploration method based on ultra-deep horizontal drilling, the horizontal drilling includes a first open casing vertical section, a second open casing deviation section and a third open horizontal bare hole section; the drilling diameter of the first open casing vertical section is 300-320 mm, the casing diameter is 240-250 mm, and the drilling depth is 50-200 m (the first open casing vertical section needs to pass through the bedrock horizon, and the drilling depth of the first open casing vertical section is generally determined according to the actual stratum condition); the drilling diameter of the second open casing deviation section is 210-220 mm, the casing diameter is 170-180 mm, and the drilling length is 1700-1780 m (the second open casing deviation section needs to be lowered into the casing to the exploration horizon, so the specific length of the drilling of the second open casing deviation section is determined according to the position of the exploration horizon); the drilling diameter of the third open horizontal bare hole section is 150-160 mm, and the length is 600-900 m (determined according to the length of the tunnel).

[0012] In step (1) of the above-mentioned tunnel plateau complex geological precise exploration method based on ultra-deep horizontal drilling, the number of horizontal drilling is 1-4, and the three open horizontal bare hole sections of the horizontal drilling are distributed around the tunnel section to be excavated. In the actual construction process, the number of horizontal drilling can be determined according to the comprehensive factors such as exploration accuracy and fund investment.

[0013] In step (1) of the tunnel plateau complex geological precision exploration method based on the ultra-deep horizontal drilling, the number of horizontal drilling holes is 4, and the number of three-opening horizontal bare hole sections of each horizontal drilling hole is 1 (a total of 4 three-opening horizontal bare hole sections); or the number of horizontal drilling holes is 1, a branch drilling hole is constructed by window sidetracking at the two-opening casing build-up section, and 4 three-opening horizontal bare hole sections (a total of 4 three-opening horizontal bare hole sections) are arranged; or the number of horizontal drilling holes is 2, a branch drilling hole is constructed by window sidetracking at the two-opening casing build-up section of each horizontal drilling hole, and 2 three-opening horizontal bare hole sections (a total of 4 three-opening horizontal bare hole sections) are arranged respectively; the three-opening horizontal bare hole sections of all horizontal drilling holes are uniformly distributed around the tunnel section to be excavated, and all the three-opening horizontal bare hole sections extend along the tunnel line and are controlled within a range of 8-10m outside the tunnel axis; the tunnel diameter is generally 6-12m, and the arrangement of 4 three-opening horizontal bare hole sections in the 4 directions of up, down, left and right of the tunnel can make the exploration result most accurate; if the three-opening horizontal bare hole section is too close to the tunnel axis, the instrument error of the drilling directional instrument itself may cause the drilling hole to penetrate into the tunnel excavation contour line, which may affect the tunnel excavated by TBM. If the three-opening horizontal bare hole section is too far from the tunnel axis, the diffusion range is limited after the exploration process is completed, and the treatment effect is affected; considering the drilling directional trajectory accuracy and the treatment effect in the later period, the distance of the three-opening horizontal bare hole section to the outside of the tunnel axis is controlled within 8-10m, which is the most appropriate.

[0014] In the tunnel plateau complex geological precision exploration method based on the ultra-deep horizontal drilling, the drilling diameter of the one-opening casing vertical section is 311mm, the drilling depth is 150m, and the Φ244.5mm*8.94mm J55 casing is lowered; the drilling diameter of the two-opening casing build-up section is 216mm, the length is 1750m, and the Φ177.8mm*8.05mm J55 casing is lowered; and the drilling diameter of the three-opening horizontal bare hole section is 152mm, and the length is 700m.

[0015] In step (2) of the tunnel plateau complex geological precision exploration method based on the ultra-deep horizontal drilling, the oil drilling rig is a 2000m level oil drilling rig, the surface oil drilling rig with a drilling depth of more than 2000m is used to construct the horizontal drilling hole, so that the drilling trajectory can be as close as possible to the tunnel line to reveal the geological conditions along the tunnel.

[0016] In step (2) of the tunnel plateau complex geological precision exploration method based on the ultra-deep horizontal drilling, the mud logging operation includes engineering parameter logging, cutting logging, coring logging and gamma logging while drilling; the engineering parameter logging includes drilling time, drilling pressure, rotation speed and drilling speed and other data in the horizontal drilling construction process; the comprehensive logging includes natural potential, natural gamma, X-Y caliper, dipole sonic wave, deep lateral resistivity, shallow lateral resistivity, continuous well temperature, inclination azimuth and microspherical focusing.

[0017] The tunnel plateau complex geological precision exploration method based on the ultra-deep horizontal drilling, the coring logging is carried out in the key paragraph; the selection method of the key paragraph is: selecting the paragraph with abnormal fluctuation of logging parameters in the drilling process as the key paragraph, for example, the layer change of the returned cuttings, the obvious change of the drilling time, the speed and other parameters can be cored; and the position with abnormal fluctuation of the resistivity (lower) and gamma value in the well logging as the key paragraph.

[0018] In step (3) of the tunnel plateau complex geological precision exploration method based on the ultra-deep horizontal drilling, the stratum interface along the tunnel line is divided, and the geological abnormal section including faults, fracture zones, aquifers and water-rich sections is identified through the integration and analysis of geological exploration data information.

[0019] In step (3) of the tunnel plateau complex geological precision exploration method based on the ultra-deep horizontal drilling, the drilling time, drilling pressure, speed, drilling speed and other data recorded by the engineering parameter logging are used to preliminarily judge the hardness and integrity of the stratum; the lithology characteristics are identified by analyzing the cuttings carried in the drilling process according to the cuttings logging; the physical and mechanical properties and water-richness of the core samples are analyzed according to the coring logging; the real-time stratum checking, horizon comparison and geological interface identification are carried out according to the stratum gamma response monitored by the while-drilling gamma logging; the nine logging curves including resistivity, acoustic time difference, natural potential, density and the like are drawn according to the comprehensive well logging, so as to realize the fine division of the stratum interface; the faults, fracture zones, aquifers and water-rich sections are identified with the aid of transient electromagnetic detection. Through the comprehensive interpretation of multidimensional exploration data, the geological conditions along the tunnel line are determined, and the positions of the identified fracture zones and water-rich sections and other geological abnormal sections are fed back to the design and construction.

[0020] The technical scheme of the present application has the following beneficial technical effects:

[0021] 1、The tunnel plateau complex geological precision exploration method based on the ultra-deep horizontal drilling, uses the surface oil drilling rig with drilling depth of more than 2000m to construct the horizontal drilling, realizes the continuous exposure of the geological conditions near the tunnel line. In the process of horizontal drilling construction, the engineering parameter logging (drilling time, drilling pressure, speed, drilling speed), cuttings logging, coring logging, while-drilling gamma logging, comprehensive well logging (nine curves) and transient electromagnetic and other methods are comprehensively applied to realize the accurate division of the stratum and the identification of the geological abnormal section, and improve the accuracy and reliability of the tunnel deep geological exploration. The present application can be widely applied to the geological prediction and advanced exploration of complex tunnel engineering in plateau areas.

[0022] 2. This invention is based on a method for precise exploration of complex geological conditions in tunnels on plateaus using ultra-deep horizontal boreholes. By implementing ultra-deep horizontal borehole exploration, it transforms the exploration from "point" to "line," significantly improving the accuracy and reliability of geological exploration along the tunnel. Compared with traditional methods, this invention has the following significant advantages: (1) Wide exposure range: it expands from single-point exposure to continuous tunnel line exposure; (2) Large exploration depth: the drilling depth can exceed 2000m; (3) Multiple information dimensions: engineering, logging, well logging, and electrical logging are comprehensively applied to form multi-dimensional data support; (4) Strong anomaly identification capability: it can detect fracture zones and aquifers in advance, reducing construction risks.

[0023] 3. This invention, based on an ultra-deep horizontal borehole method for precise geological exploration of tunnels in complex plateau regions, overcomes the limitations of traditional vertical borehole depth and range, enabling continuous exposure of geological conditions along the tunnel route. Through the integrated application of various logging, well logging, and transient electromagnetic detection methods, it significantly improves the accuracy and reliability of geological prediction for complex plateau tunnels, possessing broad engineering application value and promising prospects for wider application. Attached Figure Description

[0024] Figure 1 A schematic diagram of the structure of the ultra-deep horizontal borehole in an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the arrangement of ultra-deep horizontal boreholes in an embodiment of the present invention;

[0026] Figure 3 A side view of the drilling arrangement in an embodiment of the present invention;

[0027] Figure 4 Flowchart of precise exploration of complex geology in plateau tunnels based on ultra-deep horizontal boreholes in this invention;

[0028] Figure 5 A schematic diagram of typical stratigraphic division and anomaly segment identification results in an embodiment of the present invention;

[0029] Figure 6 A comprehensive analysis diagram of the exploration results in this embodiment of the invention (in the diagram, holes J1, J2, J3, and J4 represent respectively) Figure 3 The horizontal bare hole section of the four horizontal boreholes, i.e., the exploratory boreholes. Detailed Implementation

[0030] This embodiment uses the exploration of a plateau tunnel as an example to conduct engineering tests on the method of accurate exploration of complex geological conditions in plateau tunnels based on ultra-deep horizontal boreholes, as described above. Figure 4 As shown, the specific steps include the following:

[0031] Step (1), horizontal drilling layout: select a drilling site on the ground where the tunnel to be excavated, plan the trajectory of the horizontal drilling along the tunnel line, and avoid the tunnel excavation line in advance. The structure of the horizontal drilling is shown in Figure 1 , including a first open casing vertical section, a second open casing build-up section, and a third open horizontal bare hole section. The drilling diameter of the first open casing vertical section is 311.1 mm, the depth is 150 m, and the casing specification is Φ244.5 mm x 8.94 mm J55 casing. The drilling diameter of the second open casing build-up section is 215.9 mm, the length is 1750 m, and the casing specification is Φ177.8 mm x 8.05 mm J55 casing. The drilling diameter of the third open horizontal bare hole section (i.e. the exploration drilling section) is 152.4 mm, and the length is 700 m. The third open horizontal bare hole section extends along the tunnel line and is controlled within a range of 8-10 m outside the tunnel axis (as shown in Figure 2 ).

[0032] As shown in Figure 3 , four horizontal drillings (each with only one third open horizontal bare hole section) are laid out in this embodiment, and the third open horizontal bare hole sections (i.e. the exploration drilling sections) of the four horizontal drillings are evenly distributed around the upper, lower, left and right directions of the tunnel section to be excavated.

[0033] Step (2), construction of horizontal drilling and multi-dimensional geological exploration: according to the planned horizontal drilling trajectory, a 2000m-level oil drilling rig with a drilling depth of more than 2000m is used to construct the horizontal drilling; logging operations are carried out during the construction of the horizontal drilling, and comprehensive logging and transient electromagnetic detection are carried out after the construction of the horizontal drilling is completed; specifically:

[0034] Logging operations include engineering parameter logging, cuttings logging, coring logging, and gamma logging while drilling; among them, engineering parameter logging includes real-time monitoring and collection of parameters such as drilling time, drilling pressure, rotation speed and drilling speed during the construction of the horizontal drilling, which is used to preliminarily judge the hardness and integrity of the stratum in combination with cuttings; coring logging is carried out at key sections, and in this embodiment, Figure 5 , the six black parts are the key section positions for coring. As can be seen from the figure, there is an average of one coring position every 100m, and the places where the drilling time, rotation speed, low resistance, gamma value, etc. change or fluctuate are densely cored, and the coring section is about 3m long.

[0035] Comprehensive logging includes spontaneous potential, natural gamma, X-Y caliper, dipole sonic, deep lateral resistivity, shallow lateral resistivity, continuous well temperature, inclination azimuth, and microspherical focusing to achieve fine division of the stratum.

[0036] Step (3) Integration and analysis of geological exploration data: Integrate and analyze the data collected from multi-dimensional geological exploration, clarify the geological conditions along the tunnel line, finely divide the geological strata along the tunnel line, and identify geological anomalies including faults, fracture zones, aquifers and water-rich sections, and predict geological anomalies such as aquifers and water-rich sections in advance, so as to provide advance forecasting and treatment basis for tunnel construction.

[0037] Specifically, the hardness and integrity of the formation are initially determined based on data such as drilling time, drilling pressure, rotation speed, and drilling rate recorded in the well logging data. Different rocks require different drilling time, drilling pressure, rotation speed, and drilling rate; specific criteria are shown in Table 1.

[0038] Table 1

[0039]

[0040] Based on cuttings logging, lithological characteristics are identified by analyzing the cuttings carried during drilling: mudstone cuttings are dark gray, flaky and scaly, with a soft and brittle muddy structure that softens significantly upon contact with water and can be kneaded into a muddy state; sandstone cuttings are light yellow to grayish-white, granular and angular, with visible quartz sand grains, moderate cementation, moderate hardness, and break into sand grains; granite cuttings are grayish-white to light red, angular and hard, with a granular structure, containing transparent quartz grains, white feldspar, and a small amount of biotite, and the cuttings are hard and dense.

[0041] Based on the core logging, the physical and mechanical properties and water-bearing capacity of the core samples were analyzed; based on the formation gamma response monitored by the gamma logging during drilling, real-time formation verification, stratigraphic correlation, and geological interface identification were performed. The geological interface identification criteria are shown in Table 2.

[0042] Table 2

[0043]

[0044] Based on comprehensive well logging, nine logging curves are generated, including spontaneous potential, natural gamma, XY diameter, dipole acoustic wave, deep lateral resistivity, shallow lateral resistivity, continuous well temperature, well inclination azimuth, and microspherical focusing, to achieve fine division of formation interfaces.

[0045] Transient electromagnetic detection is used to assist in the identification of faults, fracture zones, aquifers, and water-rich sections; this embodiment mainly relies on resistivity, such as... Figure 5 As shown, the blue area between the two blue boxes has a lower resistance, indicating that it may be water-rich, while the red area indicates a higher resistance and that the formation does not contain water.

[0046] Through the comprehensive interpretation of the multi-dimensional exploration data described above, the geological conditions along the tunnel route were clarified, and the locations of identified geological anomalies such as fracture zones and water-rich sections were fed back to the design and construction. The data integration and analysis results of this embodiment for plateau tunnel exploration are shown below. Figure 6 .from Figure 6 As can be seen, the exploration method in this embodiment ultimately determined the depth range of faults and water-rich fracture zones along the construction route of the plateau tunnel. The exploration results can provide geological basis for "fault avoidance and water inrush prevention" in tunnel construction.

[0047] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for precise exploration of complex geological conditions in high-altitude tunnels based on ultra-deep horizontal drilling, characterized in that, Includes the following steps: Step (1) Horizontal borehole layout: Select a construction site on the ground of the tunnel to be excavated, and plan the horizontal borehole trajectory along the tunnel line; Step (2), Construction of horizontal boreholes and multidimensional geological exploration: Horizontal boreholes are constructed using oil drilling rigs according to the planned horizontal borehole trajectory; logging operations are carried out during the horizontal borehole construction process, and comprehensive logging and transient electromagnetic detection are carried out after the horizontal borehole construction is completed; Step (3) Integration and analysis of geological exploration data: Integrate and analyze the data collected from multi-dimensional geological exploration, clarify the geological conditions along the tunnel line, and identify geologically abnormal sections.

2. The method for precise exploration of complex geological conditions in high-altitude tunnels based on ultra-deep horizontal boreholes according to claim 1, characterized in that, In step (1), the horizontal drilling includes a vertical section with one casing, a directional section with two casings, and a horizontal bare hole section with three casings. The vertical section with one casing has a drilling diameter of 300-320mm, a casing diameter of 240-250mm, and a drilling depth of 50-200m. The directional section with two casings has a drilling diameter of 210-220mm, a casing diameter of 170-180mm, and a drilling length of 1700-1780m. The horizontal bare hole section with three casings has a drilling diameter of 150-160mm and a length of 600-900m.

3. The method for precise exploration of complex geological conditions in high-altitude tunnels based on ultra-deep horizontal boreholes according to claim 2, characterized in that, In step (1), the number of horizontal boreholes is 1-4; the three horizontal bare borehole sections of the horizontal boreholes are distributed around the cross section of the tunnel to be excavated.

4. The method for precise exploration of complex geological conditions in high-altitude tunnels based on ultra-deep horizontal boreholes according to claim 3, characterized in that, In step (1), there are 4 horizontal boreholes, and each horizontal borehole has 1 three-section horizontal bare hole; or there is 1 horizontal borehole, and a construction branch borehole is drilled on the side of the opening of the two-section casing inclined section, and 4 three-section horizontal bare hole sections are arranged; or there are 2 horizontal boreholes, and a construction branch borehole is drilled on the side of the opening of the opening of the two-section casing inclined section of each horizontal borehole, and 2 three-section horizontal bare hole sections are arranged respectively; the three-section horizontal bare hole sections of all horizontal boreholes are evenly distributed around the cross section of the tunnel to be excavated, and all three-section horizontal bare hole sections extend along the tunnel line and are controlled within 8-10m outside the tunnel axis.

5. The method for precise exploration of complex geological conditions in plateau tunnels based on ultra-deep horizontal boreholes according to any one of claims 2-4, characterized in that, The vertical section of the first casing has a drilling diameter of 311mm and a drilling depth of 150m, with a Φ244.5mm×8.94mm J55 casing installed. The inclined section of the second casing has a drilling diameter of 216mm and a length of 1750m, with a Φ177.8mm×8.05mm J55 casing installed. The horizontal bare hole section of the third casing has a drilling diameter of 152mm and a length of 700m.

6. The method for precise exploration of complex geological conditions in high-altitude tunnels based on ultra-deep horizontal boreholes according to claim 1, characterized in that, In step (2), the oil drilling rig is a 2000m-class oil drilling rig.

7. The method for precise exploration of complex geological conditions in high-altitude tunnels based on ultra-deep horizontal boreholes according to claim 1, characterized in that, In step (2), logging operations include engineering parameter logging, cuttings logging, core logging and gamma logging while drilling; engineering parameter logging includes drilling time, drilling pressure, rotation speed and drilling speed during horizontal borehole construction; comprehensive logging includes spontaneous potential, spontaneous gamma, XY caliper, dipole acoustic wave, deep lateral resistivity, shallow lateral resistivity, continuous well temperature, well inclination azimuth and microsphere focusing.

8. The method for precise exploration of complex geological conditions in plateau tunnels based on ultra-deep horizontal boreholes according to claim 7, characterized in that, Core logging involves taking core samples at specific points in critical sections. The selection of critical sections is as follows: sections where logging parameters fluctuate abnormally during drilling are selected as critical sections, as are locations where resistivity and gamma values ​​fluctuate abnormally during logging.

9. The method for precise exploration of complex geological conditions in high-altitude tunnels based on ultra-deep horizontal boreholes according to claim 8, characterized in that, In step (3), through the integration and analysis of geological exploration data, the geological strata along the tunnel line are divided into interfaces, and geological anomalies including faults, fracture zones, aquifers and water-rich sections are identified.

10. The method for precise exploration of complex geological conditions in plateau tunnels based on ultra-deep horizontal boreholes according to claim 9, characterized in that, In step (3), the hardness and integrity of the formation are initially determined based on the engineering parameters logging; the lithological characteristics are identified based on the cuttings logging; the physical and mechanical properties and water-bearing properties of the core are analyzed based on the core logging; the formation gamma response monitored by the drilling gamma logging is used for real-time formation verification, stratigraphic comparison and geological interface identification; logging curves are drawn based on the comprehensive logging and the formation interface is divided; and faults, fracture zones, aquifers and water-bearing sections are identified with the help of transient electromagnetic detection.

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