CN114611552A - Method for identifying large-dip-angle outcrop coal mining new-kingdom loose aquifer - Google Patents
Method for identifying large-dip-angle outcrop coal mining new-kingdom loose aquifer Download PDFInfo
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- 239000003245 coal Substances 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims abstract description 35
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 59
- 238000005553 drilling Methods 0.000 claims abstract description 24
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- 239000004576 sand Substances 0.000 description 24
- 238000005755 formation reaction Methods 0.000 description 15
- 239000004927 clay Substances 0.000 description 10
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- 239000005442 atmospheric precipitation Substances 0.000 description 1
- 230000033558 biomineral tissue development Effects 0.000 description 1
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- 239000000463 material Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
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Abstract
The invention belongs to the technical field of water prevention and control in outcrop coal mining, and relates to a method for identifying a loose aquifer in a new boundary in outcrop coal mining with a large dip angle, wherein a comprehensive histogram of a drill hole near outcrop coal and mine aquifer data are collected firstly, and the position of the loose aquifer is approximately determined; extracting logging data of the aquifer position, processing logging curves by adopting a newly-built threshold wavelet function, comparing the logging curves of different types, and identifying the specific position of the loose aquifer according to the abnormal response characteristics of the logging curves of different types; and finally, determining the water-rich property of the loose aquifer according to the resistivity abnormal response characteristics, overcoming the defects of the traditional drilling coring, greatly reducing the cost, improving the working efficiency, providing a new method for the safe exploitation of the large-dip-angle outcrop coal, and having obvious social and economic benefits.
Description
The technical field is as follows:
the invention belongs to the technical field of water prevention and control in outcrop coal mining, and relates to a method for identifying a newly-born loose aquifer in large-dip-angle outcrop coal mining, in particular to a method for identifying a newly-born loose aquifer in a huge-thickness recent large-dip-angle coal seam.
Background art:
in recent years, with the increase of mining depth, north China type coal fields have entered deep mining. The mining difficulty of the deep coal seam is increased day by day due to the influence of rock burst and an Ordovician limestone aquifer, in order to reduce the influence of the rock burst on the safe mining of the mine, the mining of the coal seam below 1000m is reduced in part of the mines, and the key point is shifted to the mining of the shallow coal seam, especially the mining of outcrop coal.
A huge thick fresh system loose layer is deposited above outcrop coal in a plurality of mining areas in the southwest Luxi, and a plurality of aquifers are locally distributed in the loose layer. As the occurrence position of the aquifer of the loose layer fluctuates irregularly and the water-rich property is not uniform, the development height of the coal seam roof fissure zone is possibly related to the position of the aquifer of the loose layer, and the roof water inrush accident is easily caused. For mining outcrop coal of a coal bed with a small inclination angle, the mining of the outcrop coal can be realized by researching the development height of a crack zone at the top of the coal bed and exploring hydrogeological conditions of the top plate and improving the mining upper limit of the coal bed. For the mining of the coal seam with a large inclination angle, if research is carried out according to a method for improving the mining upper limit of the coal seam, under the condition of spending a large amount of manpower and material resources, the coal resources capable of being mined are very limited and are not paid for from the economic point of view.
In order to realize the safe exploitation of the large-dip-angle outcrop coal, the position and the water-rich property of a newly-grown boundary loose layer above the outcrop coal need to be accurately identified. At present, the method for identifying the loose aquifer mainly comprises a geophysical prospecting method and a drilling method, wherein the position of the aquifer cannot be accurately identified due to the influence of volume effect on ground geophysical prospecting because the loose aquifer has the characteristics of sporadic distribution and nonuniform water-rich property; the drilling method can explore the position and the water-rich property of a loose aquifer through a method of exploring a hole underground, but the underground drilling hole is far away from the position of the loose layer, the engineering quantity is large, the loose layer is not easy to be directly revealed, and the hole is easy to collapse in the drilling process. Although the water-rich property of the unconsolidated formation can be detected by drilling holes on the ground to detect the position of a new boundary aquifer and the water-rich property, the extremely thick new series stratum is deposited above outcrop coal, the thickness of the stratum reaches more than 500m, a plurality of drilling holes need to be constructed, and the engineering cost is high, so that the method for constructing the ground drilling holes is not suitable.
In the case of loose aquifers, coring is difficult during drilling construction, and therefore, the level and water-rich nature of the loose aquifer cannot be directly identified. Therefore, a method for identifying a new boundary loose aquifer for large-dip-angle outcrop coal mining is needed to be designed. The method utilizes the existing exploration hole histogram near outcrop coal, combines with mine hydrogeological data, and adopts a newly-built wavelet threshold function to process the existing logging data to obtain logging curve graphs of different methods, and quickly and accurately identifies the loose water-containing position and the water-rich property by means of the abnormal response characteristics of different logging curves.
The invention content is as follows:
the invention aims to overcome the defects in the prior art, and designs and provides a method for identifying a loose aquifer in a new boundary for mining outcrop coal with a large dip angle, which comprises the steps of firstly collecting a comprehensive histogram of drill holes near the outcrop coal and mine aquifer data, and approximately determining the position of the loose aquifer; extracting logging data of the aquifer position, processing logging curves by adopting a newly-built threshold wavelet function, comparing the logging curves of different types, and identifying the specific position of the loose aquifer according to the abnormal response characteristics of the logging curves of different types; and finally, determining the water-rich property of the loose aquifer according to the resistivity abnormal response characteristics.
In order to achieve the purpose, the specific process of identifying the loose aquifer in the new kingdom is as follows:
(1) collecting data of main aquifers (rock formations with pores or cracks capable of penetrating water) and water-resisting layers (rock formations with pores or cracks incapable of penetrating water) of a mine, researching the general positions of the aquifers and the water-resisting layers of the mine, and obtaining the aquifers possibly reached in the outcrop coal mining process;
(2) on the basis of collecting drilling data of main and auxiliary wells for well construction, mainly analyzing a new boundary loose aquifer in the aquifer obtained in the step (1), and obtaining a general horizon of the new boundary loose aquifer above outcrop coal by using the existing drilling data;
(3) and analyzing whether the core exists in the drilling hole comprehensive histogram by utilizing the existing ground drilling hole comprehensive histogram data near outcrop coal. If loose aquifer cores exist in the drilled holes, directly determining the position of a newly-grown boundary loose aquifer, and if the loose aquifer cores do not exist, performing the step (4) to determine the position of the loose aquifer by means of a logging curve;
(4) collecting logging curve data and data of ground drilling, carrying out denoising processing on the logging curve by adopting an improved wavelet threshold function, and removing local oscillation interference on the logging curve, wherein the logging curve comprises a resistivity logging curve, a density logging curve and a gamma logging curve;
(5) drawing the processed logging curves under the same coordinate, independently analyzing abnormal response characteristics of different logging curves, comprehensively analyzing abnormal response characteristics of different layers of the unconsolidated formation, and finally identifying the position of the unconsolidated water-containing formation and the water-rich property.
The improved wavelet threshold function in step (4) of the present invention is:
ωm,nin order to process the pre-log signals,
the logging curve signals after denoising processing are obtained, and m and n are values of the logging curve and values of wavelet decomposition;
is a denoising threshold value;
is the variance of the noise; n discrete number of logging data signals; d1nIs the decomposition coefficient in the first layer decomposed wave.
Compared with the prior art, the method has the advantages that the position and the water-rich property of a loose aquifer are analyzed and identified after the logging curve is processed by adopting the wavelet threshold function according to the existing mine data, the defects of the traditional drilling coring are overcome, the cost is greatly reduced, the working efficiency is improved, a new method is provided for the safe mining of the large-dip-angle outcrop coal, and the social benefit and the economic benefit are obvious.
Description of the drawings:
FIG. 1 is a composite histogram of a portion of a CZ-9 borehole Q + N borehole according to an embodiment of the present invention.
FIG. 2 is a graphical representation of a CZ-9 borehole 575m-592m log according to an embodiment of the present invention.
Fig. 3 is a soft-hard threshold wavelet denoising map according to an embodiment of the present invention.
FIG. 4 is a comparison graph of the soft and hard thresholds and the improved threshold wavelet denoising effect according to the embodiment of the present invention.
FIG. 5 is a log after improved threshold resistivity processing according to an embodiment of the present invention.
FIG. 6 is a graph of an improved threshold density log after processing according to an embodiment of the present invention.
FIG. 7 is a log after improved threshold gamma processing according to an embodiment of the present invention.
FIG. 8 is a fine view of a loose aquifer horizon identified by an embodiment of the present invention.
The specific implementation mode is as follows:
the invention is further illustrated by the following examples in conjunction with the accompanying drawings.
Example (b):
the embodiment identifies the position and the water-rich property of the fourth loose aquifer of the new boundary of the outcrop coal 3602 working face of a certain coal mine, and the specific process is as follows:
(1) collecting data of main aquifers (rock formations with pores or cracks capable of penetrating water) and water-resisting layers (rock formations with pores or cracks incapable of penetrating water) of a mine, researching the general positions of the aquifers and the water-resisting layers of the mine, and obtaining the aquifers possibly reached in the outcrop coal mining process;
(1-1) the coal mine top-down aquifer mainly comprises a new boundary unconsolidated formation pore aquifer (group), a two-stacked system Shanxi group 3 coal seam top and bottom plate sandstone fracture aquifer, a Taiyuan group three-ash, a ten-lower ash, an eleven limestone karst fracture aquifer and an Ordovician limestone karst fracture aquifer;
(1-2) the mine inner water-insulation layer mainly comprises a new boundary loose layer water-insulation layer (group), a second-stacking stone box subgroup water-insulation layer (group), a 3-third-ash interval water layer (group) and a 17-seam floor-second-third-ash interval water layer (group);
(1-3) the mine water filling water source mainly comprises atmospheric precipitation, aquifer water and old empty water;
(1-4) the main water filling channel of the mine is divided into a top plate crack zone, a bottom plate damage depth, a water guide fault, a hole with poor sealing and the like;
according to the distribution of the aquifers, the newly-born unconsolidated formation pore water, the 3 coal top-bottom plate sandstone water and the bottom plate tri-ash water are mainly used in the process of mining the outcrop coal bed, wherein the top-bottom plate sandstone water and the bottom plate tri-ash water can directly detect the horizon and the water-rich property of the aquifer through geophysical prospecting and underground drilling, but the horizon and the water-rich property of the newly-born unconsolidated formation pore water are not well determined;
(2) according to hydrogeological conditions revealed during coal mine well construction, a pore aquifer of a new boundary unconsolidated formation of a mine can be divided into four aquifers (groups) from top to bottom:
(2-1) first aqueous layer (group): the thickness is 14.20-45.75 m, the average thickness is 29.03m, the layer is buried 3-5 m deep, the water level changes greatly with seasons, the layer is composed of 1-2 layers of clay or sandy clay sandwiched by clay, brown yellow fine sand, medium sand and clay sand, the group has good water permeability and strong water-rich property, and the water chemistry type is HCO according to the water quality test result of the layer by a main well inspection hole3.SO4K + Na, the degree of mineralization is 1.422g/L, and the pH value is 7.62;
(2-2) second aqueous layer (group): the thickness is 36.50-89.50 m, the average is 62.65m, the buried depth is 80-260 m, the sand layer is composed of brown yellow, clay yellow, light gray medium sand, coarse sand, multiple layers of sandy clay and clay which are sandwiched between clay sand, the thickness of the sand layer is large, the granularity is coarse, and the water-rich property is strong;
(2-3) third aqueous layer (group): the thickness is 65.30-l18.50m, the average thickness is 90.17m, the burial depth is 360 m-520 m, the sand-clay-sand-. The water quality of the layer is good, the water-rich property is moderate, the clay quality at the upper part of the aquifer is more, so the replenishment performance of the first aquifer and the second aquifer is poor, 10 water source wells are constructed in total since the mine is built, and the water supply is insufficient due to the long-term pumping nearby;
(4) fourth aqueous layer (group): a thin sand layer is developed at the bottom of a new boundary in a local zone in the well field to form a fourth water-bearing layer which is distributed in a lens shape and has the thickness of 0-5m, and the thin sand layer is scattered in distribution, so that the thin sand layer has little threat to coal mining;
based on the distribution of the loose aquifers of the mines, the first and second loose aquifers are far away from the coal seam, so that coal mining cannot be influenced, and the main loose aquifers influencing outcrop coal mining are the third aquifer and the fourth aquifer. However, the specific positions and water-richness of the third aquifer and the fourth aquifer above the outcrop coal are not clear;
(3) in order to search the position of the third four layers of loose aquifers above the outcrop, the CZK9-1 drilling comprehensive column (fig. 1) is collected in the embodiment, and the lithology of the stratum above the bottom of Q + N is as follows according to the drilling histogram: the method comprises the following steps of coreless, calcareous layer, coreless, clay and coreless, and the stratum of the aquifer can be judged only through the change characteristics of a borehole log because no rock core exists in the borehole;
(4) the third unconsolidated formation pore aquifer appears at the position 0-5m above Q + N through the step 1, and the resistivity logging curve shows that the resistivity curve obviously changes at the position with the depth of 575m-592m, so that the logging curve change in the interval is mainly analyzed;
in fig. 2, the resistivity log curve, the density log curve and the gamma log curve locally generate curve oscillation, in order to further divide the oscillation curve, in this embodiment, a wavelet threshold processing curve in the prior art is adopted first, wherein the commonly used wavelet threshold functions respectively include a hard threshold function and a soft threshold, and the processing result is as shown in fig. 3, the processing effect of the hard threshold function is obvious, the effect is good for obviously highlighting the characteristics of the curve, but the curve after processing is not smooth enough, the curve after soft threshold water-containing processing is smooth, but the curve processing effect for the water inrush position is not good;
in order to improve the processing effect of the wavelet threshold function, according to the shape of the soft and hard threshold values, an improved wavelet threshold function is constructed on the basis of the existing wavelet threshold function, and the function is as follows:
ωm,nin order to process the pre-log signals,
in order to remove the noise of the logging curve signal, the distribution of m and n is the value of the logging curve and the value of wavelet decomposition,
is a denoising threshold value;
after the improved wavelet threshold denoising, as can be seen from fig. 4, the improved wavelet threshold denoising effect is obviously better than the soft and hard threshold denoising effect, so the embodiment selects the improved wavelet threshold function to process the logging curve;
(5) the logging curves after the threshold improvement processing are shown in fig. 5-7, and processed resistivity logging curves, density logging curves and gamma logging curves are respectively obtained, compared with fig. 2, the processed three different logging curves are obviously improved, and the threshold wavelet denoising effect is more practical and obvious;
(6) drawing the processed three different logging curves to the same depth coordinate, explaining the processed three different logging curves, and finding a sand layer in a valley region according to response characteristics of the logging curves, wherein the high value is shown when the stratum contains more mud and the low value is shown when the stratum contains more sand; the density of a sand layer in a density logging curve is greater than that of a mud layer, and when the sand layer has a high density value, a high peak value is required in density logging; in the natural resistivity log, when the water content in the unconsolidated formation is high, the resistance is low, when the water content is low, the resistance is high, the water-rich property of the sand layer can be drawn by utilizing the characteristic, as shown in fig. 8, the comprehensive utilization of the properties is shown, the position of the fourth unconsolidated formation is mainly concentrated between 578m and 590m, and the fourth unconsolidated formation can be divided into three small sand layers:
the first sand layer is located near 578.2m to 580.1m, a natural gamma logging curve of the layer presents a low valley value, a density logging curve presents a high peak value, and resistivity presents a high peak value, which indicates that the water content of the first sand layer is low;
the second sand layer is positioned between 583 and 5584.3m, the resistivity natural gamma logging curve in the range presents a low valley value, the density logging curve presents a high peak value, and the resistivity logging curve presents a high resistance value, which indicates that the water content of the layer is less;
the third sand layer is located at a position from 588m to 589.8m, a resistivity natural gamma well logging curve of the layer presents a low valley value, a density well logging curve presents a high peak value, and a resistivity well logging curve presents a low resistance value, which shows that the water content of the sand layer is more, so that the fourth loose aquifer is located in a range from 578m to 590m, and the water-rich property of the lower part of the sand layer is higher than that of the upper sand layer.
Claims (2)
1. A method for identifying a large dip angle outcrop coal mining new-kingdom loose aquifer is characterized by comprising the following specific processes:
(1) collecting main aquifer and water-resisting layer data of a mine, researching the general positions of the aquifer and the water-resisting layer of the mine, and obtaining an aquifer which is possibly spread in the mining process of outcrop coal;
(2) on the basis of collecting drilling data of main and auxiliary wells, mainly analyzing a new boundary loose aquifer in the aquifer obtained in the step (1), and obtaining a general horizon of the new boundary loose aquifer above outcrop coal by using the existing drilling data;
(3) analyzing whether a core exists in the drilling comprehensive histogram by utilizing existing ground drilling comprehensive histogram data near outcrop coal, if loose aquifer cores exist in the drilling, directly determining the position of a new boundary loose aquifer, and if no loose aquifer cores exist, performing the step (4), and determining the position of the loose aquifer by means of a logging curve;
(4) collecting logging curve data and data of ground drilling, denoising the logging curve by adopting an improved wavelet threshold function, and removing local oscillation interference on the logging curve, wherein the logging curve comprises a resistivity logging curve, a density logging curve and a gamma logging curve;
(5) drawing the processed logging curves under the same coordinate, analyzing abnormal response characteristics of different logging curves independently, analyzing abnormal response characteristics of different layers of the unconsolidated formation comprehensively, and identifying the position of the unconsolidated formation and the water-rich property.
2. The method for identifying a new boundary loose aquifer for mining high-dip outcut coal according to claim 1, wherein the improved wavelet threshold function in the step (4) is as follows:
ωm,nin order to process the pre-log signals,
for the denoised logging curve signal, m and n are logging curvesThe values of the lines and the values of the wavelet decomposition;
is a denoising threshold value;
is the variance of the noise; n discrete number of logging data signals; d1nIs the decomposition coefficient in the first layer decomposed wave.
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Non-Patent Citations (4)
| Title |
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| 吴雅娟，等.: "改进的小波阈值法在测井曲线去噪中的应用", 《计算机系统应用》 * |
| 李宇刚,等.,: "测井曲线在地层划分中的应用", 《陕西煤炭》 * |
| 汤加轩主编: "《2013煤炭科技与装备发展论坛优秀论文集》" * |
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