Underground cave depot water curtain hole exploration method

Abstract

The invention provides an underground cave depot water curtain hole investigation method, and relates to the technical field of underground cave depot investigation. The water curtain hole investigation method is a novel underground water-sealed cave depot construction investigation method. The method breaks through the cognition of the underground water-sealed cave depot about the use function of the water curtain hole in decades of years in China. The water curtain holes are formed in the position about 25 m above the oil storage cavern in parallel, the arrangement distance is smaller than ten m, the water curtain holes have the advantages of being close to the oil storage cavern, comprehensive in coverage range and capable of covering the oil storage cavern in advance, the oil storage cavern is finely surveyed in advance through the water curtain holes, the engineering geology and hydrogeology conditions of the oil storage cavern are found out, and the oil storage cavern can be found out in advance. A water curtain hole investigation result is established before construction of the oil storage cavern, grouting water plugging and supporting design of the oil storage cavern can be effectively guided, water seepage control of the underground water-sealed cavern and stability of the cavern are ensured, the project quality of project construction of the underground water-sealed cavern is integrally improved, and the later operation cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of underground cavern exploration, and in particular to a method for exploring water curtain holes in underground caverns. Background Art

[0002] The underground water-sealed cavern project is a new type of project developed in recent years to store oil or liquefied gas in underground rocks. The underground water-sealed cavern has great advantages in terms of safety, environmental protection, and economy, and has become the main direction of national energy reserve construction. The storage principle of the underground water-sealed cavern is to use the pressure generated by the groundwater stored in the rock mass cracks to seal the medium in the cavern to ensure that the medium does not leak. The groundwater seepage characteristics in the construction area, especially the saturated state of the fissure water in the rock mass, need to be identified during the construction of the project, and the groundwater should be controlled during construction to ensure that a certain water level pressure is always maintained around the cavern, providing guarantees for the safe excavation of the cavern and the stable operation of the cavern after completion.

[0003] Underground water-sealed caverns are generally built in magmatic rocks or metamorphic rocks more than 100 meters underground, and their construction is greatly affected by geological factors. The two key geological factors for the success or failure of water-sealed cavern construction are groundwater control and surrounding rock stability. The oil storage cavern is a tunnel with a large span and high side walls, which is covered by a water curtain system consisting of water curtain tunnels and water curtain holes. During the excavation, support, grouting and water blocking operations of the oil storage cavern, as detailed engineering geological and hydrogeological information as possible is required to guide the implementation of the construction project, ensure effective groundwater control and guarantee the stability of the surrounding rock.

[0004] In the past, during the construction of underground water-sealed caverns, detailed site surveys, construction surveys and geological predictions were used to obtain the engineering and hydrogeological conditions of the surrounding rock of the oil storage caverns. The detailed site survey mainly uses geophysical exploration and drilling methods to identify the basic geological conditions of the oil storage caverns, including lithology, large-scale geological structures, and overall permeability characteristics. A certain number of geophysical detection lines and boreholes are arranged on the ground projection of the oil storage caverns. The spacing between boreholes is generally 150 to 250 meters. The main purpose is to verify the geological structure revealed by geophysical exploration. The construction survey mainly uses geological sketches and seepage measurement methods to obtain the geological conditions of the excavated caverns, including lithology, joints and fissures, broken zones and dense zones, alteration conditions, water outlets and water output. The detailed survey results are continuously supplemented and corrected through construction surveys. Geological prediction mainly uses advanced drilling and geological radar to predict the geological conditions of the surrounding rocks that have not been exposed, including the location and scale of the development of broken zones and dense zones, and water output conditions.

[0005] However, the engineering geophysical exploration of detailed site survey mainly detects the geological conditions of the surrounding rock 150 to 200 meters below the ground. The geophysical exploration line is arranged above the oil storage cavern, and there is only one survey line in each cavern. It mainly detects the large-scale geological structures and geological conditions of the weathering boundary of the strata developed in the oil storage cavern area. The oil storage cavern is about 20 meters wide, and the geophysical exploration cannot fully cover the entire section of the oil storage cavern. There are limitations on cavern exploration, and it is difficult to achieve detailed exploration of small-scale geological structures and water-conducting fractures. In addition, the accuracy of engineering geophysical exploration mainly depends on the reliability of geophysical data collection and analysis, and geophysical data has multiple solutions. Engineering geological drilling arranges boreholes, catalogs the boreholes geologically, and conducts relevant tests and experiments in the boreholes. The exploration boreholes are arranged at large intervals (generally more than 150 meters apart), limited in number (generally 30 to 50), and arranged vertically. The oil storage cavern is long, extends horizontally, and has a large length. The geological information revealed by drilling is limited, and it is difficult to truly reflect the specific geological conditions of the oil storage cavern area.

[0006] Construction surveys carry out geological sketches and seepage measurements on excavated caverns to obtain geological information of the caverns after excavation. The oil storage cavern is an important structure in the construction of water-sealed caverns, and its seepage control requires advanced pre-grouting measures. Through construction survey technology, it is not possible to efficiently obtain its geological information before excavation, and it is difficult to provide effective advanced pre-grouting guidance for the oil storage cavern. As a result, construction survey technology cannot form systematic advanced geological results.

[0007] The geological forecasting work makes advance predictions for unexcavated caverns and obtains geological information of a certain range in front of the unexcavated caverns. This technology mainly uses advanced drilling, geological radar and in-hole imaging methods to detect the geological conditions in front of the oil storage caverns. However, since the detection is carried out on the excavation surface of the oil storage caverns, it is impossible to form systematic geological results before the excavation of the oil storage caverns, which has great limitations in optimizing construction plans and process parameters. At the same time, there is cross-operation between geological forecasting work and cavern excavation, which is inconvenient in on-site coordination and safety management. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention provides a method for surveying water curtain holes in underground caverns, which solves the problem of poor survey results in underground caverns, especially oil storage caverns.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0010] A method for surveying water curtain holes in underground caverns, the survey method comprising: drilling measurement and description of water curtain holes;

[0011] During the water curtain hole drilling process, the drilling rate measuring instrument is used to measure the drilling rate of the water curtain hole, forming a curve of the water curtain hole drilling rate changing with depth, and analyzing and determining the rock strength and the location of the fracture zone and weak layer in the water curtain hole;

[0012] During the drilling process of the water curtain hole, a seepage meter is used to measure the water flow rate of the water curtain hole, and a water curtain hole seepage change curve with depth is formed to analyze and determine the seepage position and seepage amount in the water curtain hole;

[0013] During the water curtain hole drilling process, the drilling return water color and drill sticking conditions are described to form a water curtain hole return water color band map, and the location of alteration and lithology changes in the water curtain hole is analyzed and determined;

[0014] Based on the lithology, fractured zones, weak layers, water seepage and locations determined by each water curtain hole, the lithology, fractured zones, alteration zones, densely populated fracture zones and groundwater seepage characteristics of the oil storage cavern area were analyzed and determined, greatly improving the survey accuracy of the rock mass characteristics within this range.

[0015] Preferably, the survey method further comprises: horizontal hole intelligent television imaging;

[0016] After the water curtain hole is drilled, the water curtain hole is imaged by intelligent TV at the horizontal hole; the output plane development map, stereo column map and three-dimensional space map of the borehole are obtained, the inclination, dip angle and width of the fracture, alteration zone and fracture zone are automatically calculated and extracted, and the lithology, structure and other information are described on the development map;

[0017] According to the occurrence and position of the water-conducting fissures and broken zones determined by each water curtain hole and combined with the orientation of the water curtain hole, the geological structure of the water-conducting fissures and broken zones developed in the oil storage cavern area below can be effectively analyzed and inferred.

[0018] Preferably, the survey method further comprises: a water curtain hole water injection fall test;

[0019] After the water curtain hole is formed, a water injection facility is installed at the hole mouth of the water curtain hole to ensure that the water curtain hole forms a closed space. Then, water is injected into the water curtain hole until the hole is saturated, and then the water supply valve is closed to make the water curtain hole enter a natural static state. After the static state is completed, the natural hydrostatic pressure P0 is obtained; next, water is injected into the water curtain hole at a pressure of P. After the water injection is completed, the water supply valve is closed to enter the pressure drop stage. The pressure and flow data of the entire water curtain hole water injection and drop process are observed and recorded to form a pressure and flow change curve of each water curtain hole and a plane distribution diagram of the water curtain hole permeability coefficient; the natural hydrostatic pressure and rock permeability coefficient of each water curtain hole are determined through the water curtain hole water injection drop test, so as to analyze and evaluate the rock permeability characteristics of the oil storage cavern area, which can provide effective technical support for the selection and optimization of process parameters in its excavation and grouting construction in the later stage.

[0020] Preferably, the survey method further comprises: a water curtain hole tracer test;

[0021] During the water curtain hole injection process, when the water injection flow rate of the water curtain hole exceeds 30 cubic meters / day and it is determined to be a large-flow water curtain hole, a tracer test is carried out on the water curtain hole; a solution prepared with fluorescent powder is continuously injected into the large-flow water curtain hole. As the water injection increases, groundwater containing fluorescent powder will enter the rock mass along the fracture channel; the time and color of the appearance of groundwater containing fluorescent powder in the oil storage cavern below the water curtain hole where the tracer is placed are observed and recorded; based on the exposure time and color, the hydraulic connection between the water curtain hole and the oil storage cavern is comprehensively analyzed to determine the channel of groundwater flow and the water-conducting fractures developed in the oil storage cavern area, thereby improving the accuracy of the exploration of the hydrogeological characteristics of the oil storage cavern area.

[0022] Preferably, the survey method further comprises: water curtain tunnel floor geological radar testing;

[0023] In the water curtain tunnel, select the abnormal hole section revealed by water curtain hole drilling, TV imaging and water injection test, and conduct geological radar test on the floor of this area;

[0024] The geological radar uses a transmitting antenna to transmit high-frequency electromagnetic waves into the surrounding rock in the form of wide-band short pulses. The electromagnetic waves are reflected back when encountering a geological reflection surface and then received by a receiving antenna. The two-way travel time of the reflected wave is measured to calculate the distance of the unfavorable geology from the heading face. The nature of the unfavorable geology is determined by analyzing the amplitude, waveform, wave velocity, frequency, etc. of the reflected wave, and the causes of the abnormal results revealed by the water curtain hole drilling work are further identified. The water-richness of the rock mass and the development of water-conducting fractures in the oil storage cavern area are further identified, and the previous survey data are supplemented and corrected.

[0025] The present invention provides a method for surveying water curtain holes in underground caverns. Compared with the prior art, it has the following beneficial effects:

[0026] In the present invention, the water curtain holes are close to the oil storage caverns, have a comprehensive coverage range, are arranged parallel to the oil storage caverns, and are spaced less than ten meters apart, so as to cover the oil storage caverns in advance. The water curtain holes are used to conduct a detailed survey of the rock mass within the oil storage caverns in advance, so as to comprehensively and accurately ascertain the engineering geology and hydrogeology conditions of the area. The survey results of the water curtain holes obtained before the construction of the oil storage caverns have greatly improved the effect of guiding the grouting, water blocking and support design of the caverns in a targeted manner, and have played a positive role in increasing the benefits of the entire engineering construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a flow chart of the survey method in Example 1 of the present invention;

[0029] Figure 2 Schematic diagram of arrangement of water curtain holes in Example 1 of the present invention;

[0030] Figure 3 This is an example of a curve showing the variation of the water curtain hole drilling rate with depth in Example 1 of the present invention;

[0031] Figure 4 This is an example of a curve showing water seepage variation with depth of a water curtain hole in Example 1 of the present invention;

[0032] Figure 5 This is an example of a color strip diagram of water return from a water curtain hole in Example 1 of the present invention;

[0033] Figure 6 This is an example of a three-dimensional column diagram of a water curtain hole in Example 1 of the present invention;

[0034] Figure 7 This is an example of a planar expansion diagram of a water curtain hole in Embodiment 1 of the present invention;

[0035] Figure 8 This is a schematic diagram of the structure of the water injection and fall test facility installed at the orifice of the water curtain hole in Example 1 of the present invention;

[0036] Fig. 9 This is an example of a pressure change curve of a water curtain hole in a water injection fallback test in Example 1 of the present invention;

[0037] Fig.10 This is an example of a flow rate variation curve of a water curtain hole in a water injection fallback test in Example 1 of the present invention;

[0038] Fig.11 This is a water curtain hole survey result diagram in Example 2 of the present invention;

[0039] Fig.12 The curve of the water curtain hole drilling rate changing with depth in Example 2 of the present invention;

[0040] Fig.13 The water seepage of the water curtain hole varies with depth in Example 2 of the present invention;

[0041] Fig.14 This is a diagram describing the position of the D1 water-conducting fracture zone in Example 2 of the present invention;

[0042] Fig.15 This is a color band diagram of water return from the water curtain hole in Example 2 of the present invention;

[0043] Fig.16 This is the imaging result of the water curtain hole smart TV in Example 2 of the present invention Figure 1 ;

[0044] Fig.17 This is the imaging result of the water curtain hole smart TV in Example 2 of the present invention Figure 2 ;

[0045] Fig.18 The permeability coefficient distribution diagram of the water curtain hole in Example 2 of the present invention;

[0046] Fig.19 This is a location diagram of the D1 water-conducting fracture zone in Example 2 of the present invention;

[0047] Fig. 20 The results of the water curtain hole tracing test in Example 2 of the present invention Figure 1 ;

[0048] Fig.21 The results of the water curtain hole tracing test in Example 2 of the present invention Figure 2 ;

[0049] Fig. 22 This is the geological radar result map of the bottom plate of the water curtain tunnel in Example 2 of the present invention;

[0050] Fig.23 This is a water curtain hole survey result diagram in Example 3 of the present invention;

[0051] Fig.24 The curve of the water curtain hole drilling rate changing with depth in Example 3 of the present invention;

[0052] Fig.25 The water seepage of the water curtain hole varies with depth in Example 3 of the present invention;

[0053] Fig.26 The water curtain hole smart TV imaging result in Example 3 of the present invention Figure 1 ;

[0054] Fig. 27 The water curtain hole smart TV imaging result in Example 3 of the present invention Figure 2 ;

[0055] Fig.28 The water curtain hole smart TV imaging result in Example 3 of the present invention Figure 3 ;

[0056] Fig.29 The permeability coefficient distribution diagram of the water curtain hole in Example 3 of the present invention;

[0057] Fig.30 This is a location diagram of the J3 crack-intensive zone in Example 3 of the present invention;

[0058] Fig.31 This is a diagram showing the results of the water curtain hole tracing test in Example 3 of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] The embodiment of the present application solves the problem of poor survey results of underground caverns, especially oil storage caverns, by providing a method for surveying water curtain holes in underground caverns.

[0061] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0062] Embodiment 1:

[0063] like Figure 1 to Figure 5 As shown, the present invention provides a method for surveying water curtain holes in underground caverns, the survey method comprising: drilling measurement and description of water curtain holes;

[0064] The water curtain hole drilling measurement and description includes the following steps:

[0065] During the water curtain hole drilling process, the drilling rate and water output of all water curtain holes are measured, and the water return color and drill jamming of the water curtain hole are described;

[0066] The drilling rate measuring instrument is used to measure the drilling rate of the water curtain hole, forming a curve of the variation of the drilling rate of the water curtain hole with depth, and analyzing and determining the rock strength and the location of the fracture zone and weak layer in the water curtain hole;

[0067] Use a seepage meter to measure the water flow rate of the water curtain hole, form a water curtain hole seepage rate versus depth curve, and analyze and determine the seepage position and seepage rate in the water curtain hole;

[0068] During the water curtain hole drilling process, the drilling return water color and drill sticking conditions are described to form a water curtain hole return water color band map, and the location of alteration and lithology changes in the water curtain hole is analyzed and determined;

[0069] According to the lithology, fractured zone, weak layer, water seepage and location determined by each water curtain hole, the geological structure such as lithology, fractured zone, alteration zone, fissure development and groundwater seepage characteristics of the oil storage cavern area are analyzed and determined.

[0070] like Figure 6 , Figure 7 As shown, the survey method further includes: horizontal hole intelligent TV imaging;

[0071] Since the water curtain hole is a horizontal hole without coring, the intelligent TV imaging of the horizontal hole can not only obtain the location and state of the development of geological structures such as water-conducting fissures and broken zones, but also analyze their development occurrence, width and other information, which is crucial to obtain the specific geological characteristics of the water curtain hole and analyze the geological structures such as water-conducting fissures and broken zones developed above the oil storage caverns;

[0072] Therefore, after the water curtain hole is drilled, the water curtain hole is imaged by horizontal hole intelligent TV; the horizontal hole intelligent TV imaging analyzer is a comprehensive drilling detection equipment that can integrate drilling imaging, drilling video (peeping), and drilling trajectory detection. The supporting analysis software can display the output plane development map, stereo column map and three-dimensional space graphics of the borehole, and automatically calculate and extract the inclination, dip and width of the crack, alteration zone and broken zone. The width accuracy can reach 0.1mm, the azimuth angle accuracy can reach 0.1°, and the lithology, structure and other information can be described on the development map;

[0073] According to the occurrence and position of water-conducting fissures and broken zones determined by each water curtain hole, the geological structures such as water-conducting fissures and broken zones developed in the oil storage cavern area can be analyzed and determined.

[0074] like Figure 8 to Figure 10 As shown, the survey method further includes: a water curtain hole water injection fall test;

[0075] After the water curtain hole is formed, a water injection facility is installed at the hole mouth of the water curtain hole to ensure that the water curtain hole forms a closed space. Then, water is injected into the water curtain hole until the hole is saturated, and then the water supply valve is closed to make the water curtain hole enter a natural static state. After the static state is completed, the natural static water pressure P0 is obtained; next, water is injected into the water curtain hole at a pressure P, P = P0 + ΔP, ΔP is the additional pressure, and the value is taken according to the on-site conditions; after the water injection is completed, the water supply valve is closed and the pressure falls back. The pressure and flow data of the entire water curtain hole water injection and fall back process are observed and recorded to form a pressure and flow change curve diagram of each water curtain hole and a plane distribution diagram of the water curtain hole permeability coefficient; the natural static water pressure and rock permeability coefficient of each water curtain hole are determined through the water curtain hole water injection fall back test, so as to analyze and evaluate the rock permeability characteristics of the oil storage cavern area, which can provide effective technical support for the selection and optimization of process parameters in its excavation and grouting construction in the later stage.

[0076] The survey method also includes: a water curtain hole tracer test;

[0077] During the water curtain hole injection process, when the water curtain hole injection flow rate exceeds 30 cubic meters / day and is determined to be a large-flow water curtain hole, a tracer test is conducted on the water curtain hole. Through the water curtain hole tracer test, the flow direction of the large-flow water curtain hole injection can be identified, the water conduction channel between the water curtain hole and the oil storage cavern area can be analyzed, and then the water conduction fractures in the oil storage cavern area can be determined;

[0078] The water curtain hole tracer test uses sodium fluorescein as a groundwater tracer. Sodium fluorescein is an organic compound, orange-red powder, odorless, hygroscopic, easily soluble in water, and has a very strong yellow-green fluorescence. The solution prepared by the fluorescent powder is continuously injected into the large-flow water curtain hole. As the water injection increases, the groundwater containing the fluorescent powder will enter the rock mass through the fracture channel. The time and color of the appearance of the groundwater containing the fluorescent powder are observed and recorded in the oil storage cavern below the water curtain hole where the tracer is placed. According to the exposure time, color, etc., the hydraulic connection between the water curtain hole and the oil storage cavern is comprehensively analyzed to determine the channel of the groundwater flow and the water-conducting fractures developed in the oil storage cavern area, thereby improving the accuracy of the exploration of the hydrogeological characteristics of the oil storage cavern area.

[0079] The survey method also includes: water curtain tunnel floor geological radar testing;

[0080] In order to verify and supplement the observation, test and experimental results in the water curtain hole mentioned above, analyze the scale, water richness and rock fragmentation of the geological structure, and correct the geological structure of the previous survey; select the bottom plate of the abnormal hole section (rock fragmentation and large water output) drilled in the water curtain hole in the water curtain tunnel for geological radar testing.

[0081] Geological radar is a geophysical exploration method for underground exploration and engineering inspection that uses the properties of electromagnetic waves that change as their path, electromagnetic field strength and waveform change with the electrical properties and geometric shape of the medium they pass through when propagating in the medium.

[0082] The geological radar uses a transmitting antenna to transmit high-frequency electromagnetic waves into the surrounding rock in the form of wide-band short pulses. When the electromagnetic waves encounter a geological reflection surface, they are reflected back and then received by the receiving antenna. The distance of the unfavorable geology from the tunnel face is calculated by measuring the two-way travel time of the reflected wave, and the nature of the unfavorable geology is judged by analyzing the amplitude, waveform, wave velocity, frequency, etc. of the reflected wave. Within a length of 15 meters on both sides of the water curtain hole area detected by the geological radar, a measuring line (length 30m) is arranged on the bottom plate of the water curtain tunnel (close to the side wall where the water curtain hole is located), and the test is repeated once. Data collection adopts point measurement with a point measurement interval of 20cm.

[0083] Through the geological radar test on the bottom plate of the water curtain tunnel, we can further find out the reasons for the abnormal results revealed by the water curtain hole drilling work, further find out the water-richness of the rock mass and the development of water-conducting fractures in the oil storage cavern area, and supplement and correct the previous survey data.

[0084] After comprehensive analysis of the above-mentioned water curtain hole test and test methods, the water curtain hole survey results of the water seal cavern are formed. Before the construction of the oil storage cavern, the water curtain hole survey results are used to optimize the layout of the main cavern advance exploration holes, accurately guide the design and construction of pre-grouting, and improve the efficiency of advance pre-grouting water blocking. After the main cavern is excavated, the key seepage control areas are divided according to the water curtain hole water injection flow monitoring situation, the associated water-conducting fissures are analyzed, the post-grouting design and construction are guided, and the post-grouting water blocking is carried out in a targeted manner to improve the efficiency of post-grouting water blocking.

[0085] From the perspective of water-sealed cavern construction in recent years, the control of seepage in the surrounding rock of underground water-sealed caverns is an important issue that needs to be solved at present, and the seepage control in the oil storage cavern area directly determines the success or failure of the construction of underground water-sealed caverns. As a new and important technology for the construction of water-sealed caverns, the results of water curtain hole exploration technology can fully provide important technical guidance for the seepage control in the oil storage cavern area. In terms of seepage control, the results of water curtain hole exploration technology are mainly used in the design and construction of advance water exploration and pre-grouting in the oil storage cavern area. The introduction of this technical method not only supplements and improves the water-sealed cavern exploration technology, but also identifies the engineering geological and hydrogeological conditions of the oil storage cavern, supplements, corrects and improves the exploration results, and provides effective technical support for the seepage control work in the oil storage cavern area.

[0086] Embodiment 2:

[0087] The design storage capacity of an underground water-sealed cavern is 500×10 4 m 3 It mainly includes 4 groups of oil storage caverns, 9 water curtain tunnels, 660 water curtain holes, and 4 construction tunnels. The design section of the oil storage cavern is a straight wall round arch, with a design section size of 20.0m wide and 30.0m high. The design section size of the water curtain tunnel is 7.0m wide and 6.0m high. The diameter of the water curtain hole is 115mm, the spacing is 10m, and the hole length is generally 90-106m.

[0088] like Fig.11 As shown in the figure, water curtain hole exploration technology was applied during the construction period of this project. Through water curtain hole exploration, three water-conducting fracture zones (D1-D3), three joint-intensive zones (L1-L3), and three alteration zones (S3-S5) were newly discovered in the oil storage cavern area, and the fault fracture zones (F1, F5) discovered in the previous exploration were corrected and improved.

[0089] Before the construction of the oil storage cavern, the main water-conducting fissures and water outlet locations in the oil storage cavern area were determined in advance based on the results of the water curtain hole survey, and the water blocking treatment was carried out in advance by means of advanced pre-grouting. The larger water seepage points and main water-conducting fissures in the water seal cavern were successfully blocked, thus avoiding the large loss of groundwater during the construction of the oil storage cavern. After the construction, according to the results of the water curtain hole survey, the correlation between the local water-conducting fissures and the water curtain hole was analyzed, and the post-grouting water blocking scheme was optimized to improve the post-grouting water blocking efficiency. After the water curtain hole survey technology was used in this project, the water seepage volume of the cavern was controlled from the previously estimated 7,000 cubic meters / day to less than 1,000 cubic meters / day, and the water seepage control effect was obvious.

[0090] The following takes the determination of the D1 water-conducting fracture zone as an example to illustrate the technical method of water curtain hole exploration.

[0091] The D1 water-conducting fracture zone was newly discovered by adopting the water curtain hole exploration technology method. The characteristics of the D1 water-conducting fracture zone such as the occurrence and location were analyzed and determined, and the location of the D1 water-conducting fracture zone crossing the oil storage cavern, water output and surrounding rock quality were predicted in advance. The D1 water-conducting fracture zone is mainly characterized by high water-rich surrounding rock, large water output, developed joints and fissures, and severe rock alteration. Its affected width is about 30 to 50m. The surrounding rock grades are mainly Ⅲ2 and Ⅵ. The water curtain hole exploration technology method used in this project to determine the D1 water-conducting fracture zone is as follows:

[0092] like Figure 12 to Figure 14 The red marked area and Fig.15 In the yellow marked area shown, the location of the D1 water-conducting fracture zone in the water curtain hole, the water discharge conditions, and the area with severe rock alteration were determined through water curtain hole drilling measurement and description.

[0093] like Fig.16 , Fig.17 As shown, the development characteristics of the D1 water-conducting fracture zone in the water curtain hole were determined by horizontal hole intelligent TV imaging. The strike was 143°∠87°, the joints were densely developed, the rock mass was broken, and the rock was altered.

[0094] like Fig.18 As shown in the figure, the permeability characteristics of the D1 water-conducting fracture zone were determined by the water curtain hole water injection fallback test, and its permeability coefficient is generally greater than 1*10 -2 m / d, high permeability.

[0095] like Fig.19 As shown, the location of the D1 water-conducting fracture zone in the oil storage cavern area was comprehensively determined by combining the location of the D1 water-conducting fracture zone revealed in each water curtain hole and the information such as the occurrence determined by imaging.

[0096] like Fig. 20 , Fig.21 As shown, the results of the D1 water-conducting fracture zone were verified through a water curtain hole tracer test.

[0097] like Fig. 22 As shown, the results of the D1 water-conducting fracture zone were verified by the geological radar test on the bottom plate of the water curtain tunnel. The area marked by the blue line is the development area of ​​the D1 water-conducting fracture zone (pile numbers 160-210), and the surrounding rock is rich in water.

[0098] The seepage characteristics of the D1 water-conducting fracture zone were verified by advanced water exploration before construction, and the D1 water-conducting fracture zone was treated with advanced water exploration and advanced pre-grouting. After the cavern was excavated, there was only moisture or dripping in the cavern, and the water seepage control effect was excellent.

[0099] Before the main cavern was excavated, advance water exploration was conducted in advance for the D1 water-conducting fracture zone through the tunnel section, and three advance exploration holes were arranged. All three advance exploration holes had water output, and the maximum water output of a single advance exploration was more than 100L / min, and the return water color of the exploration hole was yellow, reflecting the development of rock alteration. Based on the technical results of the water curtain hole survey, advance pre-grouting and advance support treatment were carried out on this tunnel section.

[0100] Embodiment 3:

[0101] The design storage capacity of an underground water-sealed cavern is 300×10 4 m 3 It mainly includes 3 groups (9 in total) of oil storage caverns, 6 water curtain tunnels, 529 water curtain holes, and 2 construction tunnels. The design cross-section of the oil storage cavern is oval (five-center circle type), and the design cross-section dimensions are: maximum side wall span 24m (cavern floor span 19m), height 29m, and the design cross-section dimensions of the water curtain tunnel are: width 7.0m, height 6.0m, water curtain hole diameter 110mm, spacing is generally 10m, and hole length is generally 80-116m.

[0102] like Fig.23 As shown in the figure, water curtain hole exploration technology was applied during the construction period of this project. Through the water curtain hole exploration, 6 new water-conducting fracture zones (D1-D6) and 2 fracture-intensive zones (JX1-JX3) were discovered in the oil storage cavern area. The fracture-intensive zones (J3 and J5) discovered in the previous exploration were corrected and improved, and it was found that the rock mass in the area affected by the J3 and J5 fracture-intensive zones was broken and had strong water conductivity.

[0103] Before the construction of the oil storage cavern, the main water-conducting structure and water outlet position of the oil storage cavern area were determined in advance according to the results of the water curtain hole survey. Before the excavation construction, the advanced pre-grouting method was used to carry out water blocking treatment in advance, successfully blocking the main water-conducting cracks and avoiding the large-scale loss of groundwater during the construction of the oil storage cavern. After the excavation and support construction was completed, according to the results of the water curtain hole survey, the correlation between the water-conducting structure and the water curtain hole was analyzed, the post-grouting water blocking scheme was optimized, and the post-grouting water blocking efficiency was improved. After the water curtain hole survey technology was used in this project, the water seepage of the cavern was controlled from the previous estimated 4,000 cubic meters / day to less than 500 cubic meters / day, and the water seepage control effect was obvious.

[0104] The following takes the determination of the J3 fissure zone as an example to illustrate the technical method of water curtain hole exploration.

[0105] The J3 fissure-intensive zone was corrected by adopting the water curtain hole exploration technology method, and the characteristics of the J3 fissure-intensive zone such as the occurrence, location and influence range were analyzed and determined. The J3 fissure-intensive zone's crossing of the oil storage cavern location, water discharge and surrounding rock quality were predicted in advance. The impact of the J3 fissure-intensive zone on the project is mainly manifested in the impact width of about 15.0 to 45.0 m, a wide extension range, and a large impact depth. The rock mass has developed fissures, which are generally filled with clay minerals such as kaolin, with poor bonding, and some rock masses are strongly altered. The rock mass has a fissure-block structure, and the engineering rock mass level is generally level IV, with strong water richness and water conductivity.

[0106] The water curtain hole exploration technology method used in the J3 fracture-intensive zone determined in this project is as follows:

[0107] like Fig.24 , Fig.25 As shown in the red marked area, the position of the J3 fracture-intensive zone in the water curtain hole and the water output were determined through water curtain hole drilling measurement and description. The drilling speed in the J3 affected area became faster and the water output was large.

[0108] like Figure 26 to Figure 28 As shown, the development characteristics of the J3 fracture-intensive zone in the water curtain hole were determined by horizontal hole intelligent TV imaging. The occurrence is 300-320°, the dip angle is 60°, the joints are well developed, the rock mass is broken, the local rock mass is severely altered, some joint surfaces are filled with chlorite or kaolin, and water-conducting fractures are developed.

[0109] like Fig.29 As shown in the figure, the permeability characteristics of the J3 fracture-intensive zone were determined by the water curtain hole injection fallback test, and its permeability coefficient is generally greater than 1*10 -3 m / d, high permeability.

[0110] like Fig.30 As shown in the figure, the position of the J3 fracture-intensive zone in the oil storage cavern area was comprehensively determined by combining the position of the J3 fracture-intensive zone revealed in each water curtain hole and the information such as the occurrence determined by imaging.

[0111] like Fig.31 As shown in the figure, the J3 joint intensive zone was verified by the water curtain hole tracer test. Fluorescent tracer was put into the water curtain hole C015 in the water curtain tunnel 2, and finally it was exposed in the main cavern 3 associated with it.

[0112] The seepage characteristics of the J3 fracture-dense zone were verified by advanced water exploration before construction, and advanced water exploration and advanced pre-grouting treatment were carried out on the J3 fracture-dense zone.

[0113] Before the main cavern was excavated, advance water exploration was carried out in advance for the J3 fissure-intensive zone through the cavern according to the results of the water curtain hole survey. Three advance exploration holes were arranged, and all three advance exploration holes had water output. The maximum single advance water output was more than 127L / min, and the return water color of the exploration hole was yellow. According to the technical results of the water curtain hole survey, the tunnel section was treated with advance pre-grouting and advance support. After the cavern was excavated, there was only moisture or dripping in the cavern, and the water seepage control effect was excellent.

[0114] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0115] 1. In the embodiment of the present invention, the water curtain hole survey technical method is proposed for the first time, which breaks the domestic cognition about the use function of water curtain holes in underground water-sealed caverns for decades; the water curtain holes are close to the oil storage caverns and have a comprehensive coverage range. The water curtain holes are arranged parallel to the oil storage caverns with an arrangement spacing of less than ten meters, and the oil storage caverns are covered in advance. The water curtain holes are used to conduct a detailed survey of the oil storage caverns in advance, which can comprehensively identify the engineering geological and hydrogeological conditions of the oil storage caverns, establish the water curtain hole survey results before the construction of the oil storage caverns, and can provide targeted guidance for the cavern grouting, water blocking and support design.

[0116] 2. In the embodiment of the present invention, the conventional concept of water curtain holes is broken, the use function of water curtain holes is expanded, a water curtain hole survey system is established, and a new water curtain hole survey technology method is proposed, which not only supplements and improves the survey technology method during the construction period of water seal caverns, but also can effectively guide the water seepage control and surrounding rock stability of oil storage caverns, which is of great significance to ensuring the successful seepage control of water seal caverns and construction safety.

[0117] 3. In the embodiment of the present invention, the water-sealed cavern project using the water curtain hole survey technology method has a significant decrease in water seepage after construction and excavation. The water-sealed cavern project using the water curtain hole survey technology method has a decrease of 80% to 85% compared with the previous estimated water seepage, and the water-sealed cavern project without the water curtain hole survey technology has a decrease of 40% to 50% compared with the previous estimated water seepage.

[0118] 4. In the embodiment of the present invention, the water curtain hole survey technology is used to improve the cavern construction survey results, optimize the advance exploration hole arrangement and grouting water blocking design, improve the grouting water blocking effect, and save the cost of advance exploration hole construction and grouting water blocking engineering. At least about 20% of the cost of advance exploration hole construction and water blocking grouting engineering can be saved.

[0119] 5. In the embodiment of the present invention, the present invention is adopted during the construction period of the underground water-sealed cavern, and the application of technology is integrated with construction management. The water seepage volume can be timely and effectively controlled from the construction links such as excavation and grouting, thereby avoiding repeated cavern water blocking grouting work, reducing the drainage volume of the cavern, and improving the efficiency of water blocking design and construction work. Overall, it can save about 5% of the total construction period.

[0120] 6. In the embodiment of the present invention, based on the technical results of water curtain hole survey, the unfavorable geological sections of the oil storage cavern development are predicted in advance. During the cavern construction process, relevant advanced support and weak blasting excavation measures are taken in advance to prevent the occurrence of landslides and block slides in the underground cavern, thereby ensuring the safety and stability of the cavern construction.

[0121] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0122] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for surveying water curtain holes in underground caverns, characterized in that: The survey method includes: water curtain hole drilling measurement and description; The water curtain hole drilling measurement and description includes the following steps: During the water curtain hole drilling process, the drilling rate measuring instrument is used to measure the drilling rate of the water curtain hole, forming a curve of the water curtain hole drilling rate changing with depth, and analyzing and determining the rock strength and the location of the fracture zone and weak layer in the water curtain hole; During the drilling process of the water curtain hole, a seepage meter is used to measure the water flow rate of the water curtain hole, and a water curtain hole seepage change curve with depth is formed to analyze and determine the seepage position and seepage amount in the water curtain hole; During the water curtain hole drilling process, the drilling return water color and drill sticking conditions are described to form a water curtain hole return water color strip map, and the location of alteration and lithology changes in the water curtain hole is analyzed and determined; According to the lithology, fracture zone, weak layer, water seepage and location determined by each water curtain hole, the lithology, fracture zone, alteration zone, fissure-intensive zone and groundwater seepage characteristics of the oil storage cavern area are analyzed and determined.

2. The underground cavern water curtain hole survey method according to claim 1, characterized in that: The survey method further comprises: horizontal hole intelligent TV imaging; After the water curtain hole is drilled, the water curtain hole is imaged by intelligent TV at the horizontal hole; the output plane development map, stereo column map and three-dimensional space map of the borehole are obtained, the inclination, dip angle and width of the fracture, alteration zone and fracture zone are automatically calculated and extracted, and the lithology, structure and other information are described on the development map; According to the occurrence and position of water-conducting fissures and broken zones determined by each water curtain hole, the geological structure of the water-conducting fissures and broken zones developed in the oil storage cavern area is analyzed and determined.

3. The underground cavern water curtain hole survey method according to claim 1, characterized in that: The survey method also includes: a water curtain hole water injection fall test; After the water curtain hole is formed, a water injection facility is installed at the hole mouth of the water curtain hole to ensure that the water curtain hole forms a closed space. Then, water is injected into the water curtain hole until the hole is saturated. Then, the water supply valve is closed to make the water curtain hole enter a natural static state. After the static state is completed, the natural hydrostatic pressure P0 is obtained. Next, water is injected into the water curtain hole at a pressure of P. After the water injection is completed, the water supply valve is closed to enter the pressure drop stage. The pressure and flow data of the entire water curtain hole water injection and drop process are observed and recorded to form a pressure and flow change curve of each water curtain hole and a plane distribution diagram of the water curtain hole permeability coefficient. The natural hydrostatic pressure and rock permeability coefficient of each water curtain hole are determined through the water curtain hole water injection drop test, so as to analyze and evaluate the rock permeability characteristics of the oil storage cavern area.

4. The underground cavern water curtain hole survey method according to claim 1, characterized in that: The survey method also includes: a water curtain hole tracer test; During the water curtain hole injection process, when the water injection flow rate of the water curtain hole exceeds 30 cubic meters / day and it is judged to be a large-flow water curtain hole, a tracer test is carried out on the water curtain hole; a solution prepared by fluorescent powder is continuously injected into the large-flow water curtain hole. As the water injection increases, groundwater containing fluorescent powder will enter the rock mass along the fracture channel; the time and color of the appearance of groundwater containing fluorescent powder in the oil storage cavern below the water curtain hole where the tracer is placed are observed and recorded; based on the exposure time and color, the hydraulic connection between the water curtain hole and the oil storage cavern is comprehensively analyzed to determine the channel of groundwater flow and determine the water-conducting fractures developed in the oil storage cavern area.

5. The underground cavern water curtain hole survey method according to claim 1, characterized in that: The survey method also includes: water curtain tunnel floor geological radar testing; In the water curtain tunnel, select the abnormal hole section revealed by water curtain hole drilling, TV imaging and water injection test, and conduct geological radar test on the floor of this area; The geological radar uses a transmitting antenna to transmit high-frequency electromagnetic waves into the surrounding rock in the form of wide-band short pulses. The electromagnetic waves are reflected back when encountering a geological reflection surface and then received by a receiving antenna. The two-way travel time of the reflected wave is measured to calculate the distance of the unfavorable geology from the heading face. The nature of the unfavorable geology is determined by analyzing the amplitude, waveform, wave velocity, frequency, etc. of the reflected wave, and the causes of the abnormal results revealed by the water curtain hole drilling work are further identified. The water-richness of the rock mass and the development of water-conducting fractures in the oil storage cavern area are further identified, and the previous survey data are supplemented and corrected.

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