Accurate prediction method of coal and gas outburst based on gas geology research and judgment

Abstract

The present invention belongs to the technical field of coal mine coal and gas outburst disaster prevention and control, and is specifically an accurate coal and gas outburst prediction method based on gas geological research and judgment. It includes S100 to predict coal and gas according to different situations, specifically including: 1) prediction of gas outburst before design, well construction, and mine extension; 2) prediction of gas outburst before uncovering rock reservoirs and coal; 3) prediction of gas outburst in surrounding rocks; 4) prediction of gas outburst in adjacent coal seams; 5) prediction of gas outburst in geological anomalies of the coal seam; 6) prediction of coal and gas outburst in two or more gas geological high potential areas of coal seam groups; S200 outburst prediction verification and measures; S300 cancellation of outburst prediction. The present invention solves the problem of coal and gas outburst prediction based on gas geological research and judgment.

Description

Technical Field

[0001] The present invention belongs to the technical field of prevention and control of coal and gas outburst disasters in coal mines, and specifically relates to an accurate method for predicting coal and gas outburst based on gas geology research and judgment. Background Technique

[0002] Coal and gas outburst is a mine gas dynamic phenomenon caused by the excavation disturbance of the gas geological body enclosed in the coal series strata, and it is one of the major disasters in underground coal mine production. A large number of physical simulation tests have been carried out by experts and scholars at home and abroad, but so far the mechanism of coal and gas outburst is still in the stage of four hypotheses. The current technical basis for preventing and controlling coal and gas outburst in China is still the comprehensive action hypothesis.

[0003] The engineering and technical personnel of the applicant recognized from the practice of excavation engineering and extended it from the coal seam to the coal series strata, and put forward the theory of gas geology zoning, and expounded the mechanism of coal and gas outburst as follows: in the excavation activities of the coal series strata, the gas in the coal body near the driving roadway and the mining face diffuses and seeps into the excavation area, making the coal body in the excavation area a low gas potential area; the excavation disturbance destroys the enclosure of the geological body with gas elastic energy accumulation, and the gas in the high gas potential area spontaneously enters the coal body in the low gas potential area, squeezing, splitting, destroying, and pulverizing the coal body in the low gas potential area, causing coal and gas to outburst into the excavation space.

[0004] On this basis, the engineering and technical personnel of the applicant put forward the classification of coal and gas outburst types and the distribution of outburst areas, that is, the types of coal and gas outburst are divided into surrounding rock gas outburst, adjacent coal seam gas outburst, and gas outburst in the geological abnormal area of the coal seam. The sedimentation of the coal series strata can be divided into source-caprock sedimentation and source-reservoir-caprock sedimentation, and the source-reservoir-caprock sedimentation is mainly adopted. The coal seam generates gas and stores gas, belonging to self-generation and self-storage; under the condition of source-reservoir-caprock sedimentation, the coal seam generates gas and migrates upward to the rock reservoir nearby, belonging to lower-generation and upper-storage. The gas in the coal seam and the gas in the rock reservoir will both cause coal and gas outburst. This breaks the traditional concept that only the gas in the coal seam causes coal and gas outburst in the four hypotheses, and makes a technical innovation in theory.

[0005] Under the guidance of the new theory of "gas geology zoning theory", on the basis of the classification of coal and gas outburst mines, regional distribution, determination of high gas potential areas of gas geology, prediction of surrounding rock gas outburst, etc., it is very necessary to conduct coal and gas outburst prediction through gas geology research and judgment. Summary of the Invention

[0006] The present invention aims to solve the problem of predicting coal and gas outburst based on gas geology research and judgment, and provides an accurate method for predicting coal and gas outburst based on gas geology research and judgment.

[0007] The present invention adopts the following technical solutions: A precise coal and gas outburst prediction method based on gas geology research and judgment, including:

[0008] S100: Conduct coal and gas prediction according to different situations, specifically including:

[0009] 1) Gas outburst prediction before design, shaft sinking, and mine extension;

[0010] 2) Gas outburst prediction before uncovering rock reservoirs and coal seams;

[0011] 3) Gas outburst prediction of surrounding rocks;

[0012] 4) Gas outburst prediction of adjacent coal seams;

[0013] 5) Gas outburst prediction in geological abnormal areas of the coal seam itself;

[0014] 6) Coal and gas outburst prediction in two or more gas geology high-pressure areas of coal seam groups;

[0015] S200: Verify outburst prediction and take measures;

[0016] S300: Lift the outburst prediction.

[0017] In some embodiments, in step S100, when the following situations occur, conduct gas outburst prediction before design, shaft sinking, and mine extension:

[0018] 1) When abnormal conditions occur in the gas geology map of the mine itself, conduct gas outburst prediction, where the abnormal conditions in the gas geology map of the mine itself include:

[0019] ① The coal seam has no outcrop, that is, the coal seam does not outcrop to the surface, there is no escape channel for coal seam gas, and the gas content per ton of coal is less than 10 m 3 / t;

[0020] ② In the same mine, the gas isopleth per ton of coal in the deep coal seam is lower than that in the shallow coal seam;

[0021] ③ In the same coal seam, the gas isopleth per ton of coal is abnormal, and the gas isopleth per ton of coal in the deep coal seam is lower than that in the shallow coal seam; or in the same coal seam, the gas isopleth map is chaotic and disordered, contrary to the influence law of burial depth, structure, and hydrogeology on coal seam gas;

[0022] 2) When gas dynamic phenomena or coal and gas outbursts occur in adjacent construction and production mines, conduct gas outburst prediction, including the following situations:

[0023] ① Gas dynamic phenomena or outbursts continuously occur in the roadway of the same coal seam;

[0024] ② At the location where gas dynamic phenomena or outbursts occur in the coal seam roadway, gas dynamic phenomena or outbursts occur again during the repair of the roadway.

[0025] ③ During an outburst, the gas emission volume is equal to or more than twice the gas volume contained in the outburst coal.

[0026] In some embodiments, in step S100, when the following situations occur, gas outburst prediction is carried out before uncovering the rock reservoir and uncovering the coal:

[0027] 1) When there is no outcrop of the coal-bearing strata to uncover the rock reservoir:

[0028] When the upper part of the coal seam to be uncovered is a rock reservoir and the water pressure in the rock reservoir ≥ 0.5 MPa, gas outburst prediction is carried out 10 m before the minimum normal distance from the coal and rock reservoir.

[0029] 2) When uncovering the coal seam with an outcrop:

[0030] The gas pressure at the coal uncovering point is calculated by the following formula:

[0031] P = g p (H - H0) + P0

[0032] Where: P: The gas pressure at a depth H in the predicted methane zone, MPa;

[0033] g p : Gas pressure gradient;

[0034] H: The elevation of the coal-seeing point, the depth value in the predicted methane zone;

[0035] H0: The depth of the upper boundary of the methane zone;

[0036] P0: The gas pressure at the upper boundary of the methane zone, generally taken as 0.2 MPa;

[0037] When P ≥ 0.5 MPa after calculation, gas outburst prediction is carried out 10 m before the minimum normal distance from the coal and rock reservoir.

[0038] 3) When uncovering the coal seam without an outcrop:

[0039] When the water pressure in the rock reservoir ≥ 0.5 MPa, gas outburst prediction is carried out at the minimum normal distance of 10 m from the coal and rock reservoir.

[0040] 4) When there is a gas outburst in the underlying coal seam:

[0041] The underlying coal seam is the overlying strata, and the coal seam gas pressure P = g p (H - H0) + P0;

[0042] When P ≥ 0.5 MPa and there is a risk of outburst after uncovering the coal, gas outburst prediction is carried out 10 m before the minimum normal distance from the coal and rock reservoir.

[0043] The underlying coal seam is the source rock-reservoir-caprock formation, and the gas pressure in the rock reservoir is equal to the water pressure;

[0044] When the water pressure ≥ 0.5 MPa, there is a risk of gas outburst after uncovering the coal seam. Gas outburst prediction is carried out 10 m before the minimum normal distance from the coal and rock reservoirs.

[0045] In some embodiments, in step S100, the gas outburst prediction of the surrounding rock includes:

[0046] 1) Gas outburst prediction of the roof surrounding rock of the coal seam. The gas outburst prediction of the roof surrounding rock of the coal seam includes:

[0047] ① Gas outburst prediction of the heading face:

[0048] When the distance between the rock reservoir and the coal seam < 10 m, the distance from the floor of the rock reservoir to the roof of the coal seam < 10 m, the gas pressure in the rock reservoir ≥ 0.5 MPa or the outburst risk index ≥ 0.05 MPa / m, the gas in the surrounding rock will protrude along the fault and the weak surface fissures of the rock layer. Gas outburst prediction is carried out before tunneling;

[0049] When the rock reservoir is located in the caving zone, the distance between the rock reservoir and the coal seam ≥ 10 m, but in the caving zone, the gas pressure in the rock reservoir ≥ 0.5 MPa or the outburst risk index ≥ 0.05 MPa / m, the gas in the surrounding rock will protrude along the fault zone. Gas outburst prediction is carried out before tunneling;

[0050] ② Gas outburst prediction of the roof surrounding rock of the longwall face:

[0051] When the thickness of the surrounding rock < 10 m, gas outburst prediction is carried out, and gas overrun in the upper corner is predicted;

[0052] When the thickness of the surrounding rock ≥ 10 m, gas outburst prediction is carried out, and gas outburst in the upper corner, serious gas overrun in the return air of the mining face, and long overrun time are predicted;

[0053] 2) Gas outburst prediction of the floor surrounding rock of the coal seam. The gas outburst prediction of the floor surrounding rock of the coal seam includes:

[0054] ① Gas outburst prediction of the heading face:

[0055] When the distance from the roof of the rock reservoir to the floor of the coal seam is less than 10 m, the gas pressure in the rock reservoir ≥ 0.5 MPa or the outburst risk index ≥ 0.05 MPa / m, the gas in the floor surrounding rock will protrude along the fault and the weak surface fissures of the rock layer. Gas outburst prediction is carried out before tunneling;

[0056] When the distance from the roof of the rock reservoir to the floor of the coal seam ≥ 10 m, the gas pressure in the rock reservoir ≥ 0.5 MPa or the outburst risk index ≥ 0.05 MPa / m, gas outburst prediction is made before tunneling;

[0057] ②Gas outburst prediction for the surrounding rock of the floor in the coal mining face:

[0058] During the coal mining in the coal mining face, determine the depth of the floor failure zone;

[0059] If the floor rock reservoir is within the floor failure zone, all the gas in the rock reservoir will enter the gob; if it is within the affected zone, part of the gas will enter the gob;

[0060] When the gas pressure in the floor rock reservoir ≥ 0.5 MPa or the outburst risk index ≥ 0.05, a coal and gas outburst will occur in the coal mining face, and a gas outburst prediction is carried out;

[0061] The prediction content is:

[0062] The overlying surrounding rock is relatively thin, and the gas in the surrounding rock enters the gob of the coal mining face, and the gas concentration in the upper corner exceeds the limit;

[0063] The underlying floor rock reservoir is relatively thick and is within the floor failure zone, and a gas outburst will occur in the upper corner, and the gas in the return airway seriously exceeds the limit and lasts for a long time.

[0064] In some embodiments, in step S100, the gas outburst prediction for the adjacent coal seams includes:

[0065] 1) Gas outburst prediction for the adjacent coal seam above the roof:

[0066] When the adjacent coal seam above the roof has a layer spacing < 10 m, a gas pressure ≥ 0.5 MPa or an outburst risk index ≥ 0.05 MPa / m, a gas outburst prediction is carried out;

[0067] 2) Gas outburst prediction for the adjacent coal seam below the coal seam floor. The gas outburst prediction for the adjacent coal seam below the coal seam floor includes:

[0068] ①Gas outburst prediction for the heading face:

[0069] For the adjacent coal seam below the floor with a layer spacing < 10 m, a gas pressure ≥ 0.5 MPa or an outburst risk index ≥ 0.05 MPa / m, a gas outburst prediction is carried out at small faults and weak rock layer fissures;

[0070] For the adjacent coal seam below the floor with a layer spacing ≥ 10 m, a gas pressure ≥ 0.5 MPa or an outburst risk index ≥ 0.05 MPa / m, a gas outburst prediction is carried out at faults;

[0071] ②Gas outburst prediction for the coal mining face:

[0072] During the coal mining in the coal mining face, determine the depth of the floor failure zone;

[0073] When the underlying coal seam is within the floor failure zone, a gas outburst prediction for the coal mining face is made;

[0074] The predicted content is as follows:

[0075] The underlying coal seam is relatively thin, and the gas from the adjacent coal seam enters the goaf, resulting in over-limit at the upper corner;

[0076] Or the underlying coal seam is thick and located within the floor failure zone, with serious over-limit of gas at the upper corner, which may cause gas outburst and over-limit of gas in the return air current.

[0077] In some embodiments, the outburst danger index O b :

[0078] O b =P0 / He

[0079] Where O b : outburst danger index;

[0080] P0: gas pressure of the surrounding rock;

[0081] He: effective barrier thickness.

[0082] In some embodiments, in step S100, when the following situation occurs, gas outburst prediction for the geological abnormal area of the coal seam is carried out:

[0083] Combined with the geological body positions of faults, collapse columns, and dikes in the geological report, when drilling to detect the geological body position of the coal seam and finding that the drill bit is jammed or stuck and then measuring the gas pressure, the location where the gas pressure is greater than 0.5 MPa is determined as the geological abnormal area of the coal seam gas, the isobar of 0.5 MPa of the gas pressure in the geological abnormal area is circled, and gas outburst prediction is carried out 20 m in advance.

[0084] In some embodiments, in step S100, when the following situation occurs, coal and gas outburst prediction for two or more high-gas-potential areas of the coal seam group is carried out:

[0085] Outside the coal mining and excavation working face of the coal seam, in the coal seam group, when there are two or more high-gas-potential areas of the gas geology, that is, two or more gas outburst sources, gas outburst prediction is carried out.

[0086] In some embodiments, step S200 includes:

[0087] 1) Verification of outburst prediction;

[0088] 2) Pressure relief after gas extraction.

[0089] In some embodiments, step S300 includes: the gas pressure drops below the allowable value of 0.5 MPa, and the gas outburst danger index drops below 0.05 MPa / m, and continue tunneling; during tunneling, gas extraction cannot be stopped to prevent gas accumulation and pressure rise again after stopping extraction, which may cause outburst.

[0090] Compared with the prior art, based on the type classification, regional distribution, determination of high-gas-potential areas in gas geology, prediction of surrounding-rock gas outbursts, etc. of coal and gas outburst mines, the method of making coal and gas outburst forecasts through gas geology research and judgment is a key link in preventing and controlling coal and gas outbursts. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 This is a flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0092] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0093] As Figure 1 shown, a precise method for forecasting coal and gas outbursts based on gas geology research and judgment includes:

[0094] S100: Conduct coal and gas outburst forecasts according to different situations, specifically including:

[0095] 1) Gas outburst forecasts before design, shaft construction, and mine extension;

[0096] 2) Gas outburst forecasts before uncovering rock reservoirs and coal seams;

[0097] 3) Gas outburst forecasts for surrounding rocks;

[0098] 4) Gas outburst forecasts for adjacent coal seams;

[0099] 5) Gas outburst forecasts for geological anomaly areas in the coal seam;

[0100] 6) Coal and gas outburst forecasts for two or more high-gas-potential areas in coal seam groups.

[0101] S200: Verify the outburst forecast and take measures;

[0102] Step S200 includes:

[0103] 1) Verify the outburst forecast;

[0104] Verifying the outburst forecast lies in accurately testing parameters such as gas pressure;

[0105] When testing gas pressure, good sealing and pressure resistance tests should be carried out; when testing gas pressure, concentration, flow rate, etc., scientific and reasonable positions should be selected for design; the maximum value of gas pressure should be taken.

[0106] 2) Pressure relief after gas drainage.

[0107] S300: Release of outburst prediction;

[0108] Step S300 includes: The gas pressure drops below the allowable value of 0.5 MPa, and the gas outburst risk index drops below 0.05 MPa / m, and then continue tunneling; during tunneling, gas drainage cannot stop to prevent gas accumulation and pressure rise again after stopping drainage, which may cause outbursts.

[0109] In step S100, when the following situations occur, gas outburst prediction is carried out before design, shaft construction, and mine extension:

[0110] 1) When the gas geology map of the mine shows anomalies, gas outburst prediction is carried out. The anomalies in the gas geology map of the mine include:

[0111] ① The coal seam has no outcrop, that is, the coal seam does not outcrop to the surface, there is no external escape channel for coal seam gas, and the gas content per ton of coal is less than 10 m 3 / t;

[0112] ② In the same mine, the gas isopleth per ton of coal in the deep coal seam is lower than that in the shallow coal seam;

[0113] ③ In the same coal seam, the gas isopleth per ton of coal is abnormal, and the gas isopleth per ton of coal in the deep coal seam is lower than that in the shallow coal seam; or in the same coal seam, the gas isopleth map is chaotic and disordered, contrary to the influence law of burial depth, structure, and hydrogeology on coal seam gas;

[0114] The above anomalies are the manifestations of coal and gas outbursts on the gas geology map of the mine.

[0115] 2) When gas dynamic phenomena or coal and gas outbursts occur in adjacent construction or production mines, gas outburst prediction is carried out, including the following situations:

[0116] ① Gas dynamic phenomena or outbursts continuously occur in the same coal seam roadway;

[0117] ② At the location where gas dynamic phenomena or outbursts occur in the coal seam roadway, gas dynamic phenomena or outbursts occur again during roadway maintenance;

[0118] ③ When outburst occurs, the gas ejection volume is equal to or exceeds twice the gas content contained in the outburst coal volume.

[0119] Such outbursts in adjacent mines are the manifestations of gas outbursts in rock reservoirs. In newly built mines without being separated by large and medium-sized structures, such outbursts will also occur near the same coal seam floor contour line.

[0120] In step S100, when the following situations occur, gas outburst prediction is carried out before uncovering rock reservoirs and coal seams:

[0121] 1) When uncovering the rock reservoir without outcropping of coal-bearing strata:

[0122] The upper part of the uncovered coal seam is the rock reservoir. When the water pressure in the rock reservoir ≥ 0.5 MPa, gas outburst prediction is carried out 10 m before the minimum normal distance between the coal and rock reservoirs.

[0123] 2) When uncovering coal seams with outcrops:

[0124] The gas pressure at the coal uncovering point is calculated by the following formula:

[0125] P = g p (H - H0) + P0

[0126] Where: P: The gas pressure at depth H in the predicted methane zone, MPa;

[0127] g p : Gas pressure gradient;

[0128] H: The elevation of the coal-seeing point, the depth value in the predicted methane zone;

[0129] H0: The depth of the upper boundary of the methane zone;

[0130] P0: The gas pressure at the upper boundary of the methane zone, generally taking 0.2 MPa;

[0131] When P ≥ 0.5 MPa after calculation, gas outburst prediction is carried out 10 m before the minimum normal distance between the coal and rock reservoirs.

[0132] 3) When uncovering coal seams without outcrops:

[0133] When the water pressure in the rock reservoir ≥ 0.5 MPa, gas outburst prediction is carried out at the minimum normal distance of 10 m between the coal and rock reservoirs.

[0134] 4) When there is a gas outburst in the underlying coal seam:

[0135] The underlying coal seam is the source rock and caprock. The gas pressure of the coal seam P = g p (H - H0) + P0;

[0136] When P ≥ 0.5 MPa and there is a risk of outburst after uncovering the coal, gas outburst prediction is carried out 10 m before the minimum normal distance between the coal and rock reservoirs.

[0137] The underlying coal seam is the source rock, reservoir rock and caprock. The gas pressure of the rock reservoir is equal to the water pressure;

[0138] When the water pressure ≥ 0.5 MPa and there is a risk of gas outburst after uncovering the coal, gas outburst prediction is carried out 10 m before the minimum normal distance between the coal and rock reservoirs.

[0139] In step S100, the gas outburst prediction of the surrounding rock includes:

[0140] 1) Gas outburst prediction for the surrounding rock of the coal seam roof. The gas outburst prediction for the surrounding rock of the coal seam roof includes:

[0141] ① Gas outburst prediction for the heading face:

[0142] When the distance between the rock reservoir layer and the coal seam is < 10m, the distance from the bottom plate of the rock reservoir layer to the roof of the coal seam is < 10m, the gas pressure of the rock reservoir layer ≥ 0.5MPa or the outburst risk index ≥ 0.05MPa / m, the gas in the surrounding rock will protrude along the fault and the weak surface fissures of the rock layer. Gas outburst prediction should be carried out before tunneling;

[0143] When the rock reservoir layer is within the caving zone, the distance between the rock reservoir layer and the coal seam is ≥ 10m, but within the caving zone, the gas pressure of the rock reservoir layer ≥ 0.5MPa or the outburst risk index ≥ 0.05MPa / m, the gas in the surrounding rock will protrude along the fault zone. Gas outburst prediction should be carried out before tunneling;

[0144] ② Gas outburst prediction for the surrounding rock of the roof in the longwall face:

[0145] When the thickness of the surrounding rock < 10m, gas outburst prediction should be carried out to predict gas overrun in the upper corner;

[0146] When the thickness of the surrounding rock ≥ 10m, gas outburst prediction should be carried out to predict gas outburst in the upper corner and serious gas overrun in the return air of the mining face for a long time;

[0147] 2) Gas outburst prediction for the surrounding rock of the coal seam floor. The gas outburst prediction for the surrounding rock of the coal seam floor includes:

[0148] ① Gas outburst prediction for the heading face:

[0149] When the distance from the roof of the rock reservoir layer to the bottom plate of the coal seam is less than 10m, the gas pressure of the rock reservoir layer ≥ 0.5MPa or the outburst risk index ≥ 0.05MPa / m, the gas in the bottom plate surrounding rock will protrude along the fault and the weak surface fissures of the rock layer. Gas outburst prediction should be carried out before tunneling;

[0150] When the distance from the roof of the rock reservoir layer to the bottom plate of the coal seam ≥ 10m, the gas pressure of the rock reservoir layer ≥ 0.5MPa or the outburst risk index ≥ 0.05MPa / m, gas outburst prediction should be made before tunneling;

[0151] ② Gas outburst prediction for the surrounding rock of the bottom plate in the longwall face:

[0152] During the mining of the longwall face, determine the depth of the floor failure zone;

[0153] If the rock reservoir layer at the bottom plate is within the floor failure zone, all the gas in the rock reservoir layer will enter the goaf; if it is within the affected zone, part of the gas will enter the goaf;

[0154] When the underlying floor rock reservoir of the coal seam is relatively thick, that is, the gas pressure of the floor rock reservoir ≥ 0.5 MPa or the outburst danger index ≥ 0.05, coal and gas outburst will occur in the mining face, and gas outburst prediction is carried out;

[0155] The prediction content is:

[0156] The overlying surrounding rock is relatively thin, and the gas in the surrounding rock enters the goaf of the mining face, causing the upper corner to exceed the limit;

[0157] The underlying floor rock reservoir is relatively thick and is located within the floor failure zone. Gas outburst will occur at the upper corner, and the gas in the return air current will seriously exceed the limit and last for a long time.

[0158] In step S100, the gas outburst prediction of adjacent coal seams includes:

[0159] 1) Gas outburst prediction of adjacent coal seams above the roof:

[0160] When the adjacent coal seam above the roof has a seam spacing < 10 m, gas pressure ≥ 0.5 MPa or outburst danger index ≥ 0.05 MPa / m, gas outburst prediction is carried out;

[0161] 2) Gas outburst prediction of adjacent coal seams below the coal seam floor. The gas outburst prediction of adjacent coal seams below the coal seam floor includes:

[0162] ① Gas outburst prediction of the heading face:

[0163] For adjacent coal seams below the floor, with a seam spacing < 10 m, gas pressure ≥ 0.5 MPa or outburst danger index ≥ 0.05 MPa / m, gas outburst prediction is carried out at small faults and weak rock layer fissures;

[0164] For adjacent coal seams below the floor, with a seam spacing ≥ 10 m, gas pressure ≥ 0.5 MPa or outburst danger index ≥ 0.05 MPa / m, gas outburst prediction is carried out at faults;

[0165] ② Gas outburst prediction of the mining face:

[0166] During the mining of the mining face, determine the depth of the floor failure zone;

[0167] When the underlying coal seam is located within the floor failure zone, make a gas outburst prediction for the mining face;

[0168] The prediction content is:

[0169] The underlying coal seam is relatively thin, and the gas in the adjacent coal seam enters the goaf, causing the upper corner to exceed the limit;

[0170] Or the underlying coal seam is thick and is located within the floor failure zone. The gas at the upper corner seriously exceeds the limit, which will cause gas outburst and the gas in the return air current to exceed the limit.

[0171] Among them, the prominent danger index O b :

[0172] O b = P0 / He

[0173] Among them, O b : Prominent danger index;

[0174] P0: Gas pressure of surrounding rock;

[0175] He: Effective barrier thickness.

[0176] In step S100, when the following situations occur, gas outburst prediction for the geological abnormal area of the coal seam is carried out:

[0177] Combined with the geological body positions of faults, collapse columns, and dikes in the geological report, when drilling to detect the geological body position of the coal seam and top drilling or sticking of the drill occurs, measure the gas pressure. The location where the gas pressure is greater than 0.5 MPa is determined as the gas geological abnormal area of the coal seam, and the isobar of 0.5 MPa of the gas pressure in the geological abnormal area is circled, and gas outburst prediction is carried out 20 m in advance.

[0178] In step S100, when the following situations occur, coal and gas outburst prediction for two or more gas geological high-potential areas of coal seam groups is carried out:

[0179] Outside the coal mining and excavation working faces of the coal seam, in the coal seam group, when there are two or more gas geological high-potential areas, that is, two or more gas outburst sources, gas outburst prediction is carried out.

[0180] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: They can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A precise coal and gas outburst prediction method based on gas geology research and judgment, characterized in that Including: S100: Conduct coal and gas prediction according to different situations, specifically including: 1) Gas outburst prediction before design, shaft construction, and mine extension; 2) Gas outburst prediction before uncovering rock reservoirs and coal seams; When the following situations occur, conduct gas outburst prediction before uncovering rock reservoirs and coal seams: 1) When uncovering rock reservoirs without coal series geological outcrops: When the upper part of the coal seam to be uncovered is a rock reservoir and the water pressure in the rock reservoir ≥ 0.5 MPa, conduct gas outburst prediction 10 m before the minimum normal distance from the coal and rock reservoirs; 2) When uncovering coal seams with outcrops: The gas pressure at the coal uncovering point is calculated by the following formula: P = g p (H - H0)+P0 Where: P: Gas pressure at depth H in the predicted methane zone, MPa; g p : gas pressure gradient; H: Elevation of the coal-seeing point, depth value in the predicted methane zone; H0: Depth of the upper boundary of the methane zone; P0: Gas pressure at the upper boundary of the methane zone, generally taking 0.2 MPa; When P ≥ 0.5 MPa after calculation, conduct gas outburst prediction 10 m before the minimum normal distance from the coal and rock reservoirs; 3) When uncovering coal seams without outcrops: When the water pressure in the rock reservoir ≥ 0.5 MPa, conduct gas outburst prediction at the minimum normal distance of 10 m from the coal and rock reservoirs; 4) When there is a gas outburst in the underlying coal seam: The underlying coal seam is the generating and capping stratum, and the coal seam gas pressure P = g p (H - H0) + P0; When P ≥ 0.5 MPa and there is a risk of outburst after uncovering the coal seam, conduct gas outburst prediction 10 m before the minimum normal distance from the coal and rock reservoirs; The underlying coal seam is a source rock-seal rock formation, and the gas pressure in the rock reservoir is equal to the water pressure; When the water pressure ≥ 0.5 MPa and there is a risk of gas outburst after uncovering the coal seam, conduct gas outburst prediction 10 m before the minimum normal distance from the coal and rock reservoirs; 3) Gas outburst prediction of surrounding rocks; 4) Gas outburst prediction of adjacent coal seams; The gas outburst prediction of adjacent coal seams includes: 1) Gas outburst prediction of adjacent coal seams above the roof: When the adjacent coal seam above the roof has a layer spacing < 10 m, a gas pressure ≥ 0.5 MPa, or a outburst risk index ≥ 0.05 MPa / m, conduct gas outburst prediction; 2) Gas outburst prediction of adjacent coal seams below the coal seam floor. The gas outburst prediction of adjacent coal seams below the coal seam floor includes: ① Gas outburst prediction in the heading face: For adjacent coal seams below the floor with a layer spacing < 10 m, a gas pressure ≥ 0.5 MPa, or a outburst risk index ≥ 0.05 MPa / m, conduct gas outburst prediction at small faults and weak rock surface fissures; For adjacent coal seams below the floor with a layer spacing ≥ 10 m, a gas pressure ≥ 0.5 MPa, or a outburst risk index ≥ 0.05 MPa / m, conduct gas outburst prediction at faults; ② Gas outburst prediction in the longwall face: During the longwall face mining, determine the depth of the floor failure zone; When the underlying coal seam is within the floor failure zone, make a gas outburst prediction for the longwall face; The prediction content is: The underlying coal seam is thin, and the gas in the adjacent coal seam enters the goaf, causing the upper corner to exceed the limit; Or the underlying coal seam is thick and is within the floor failure zone, and the gas in the upper corner seriously exceeds the limit, which may cause a gas outburst and the gas in the return air to exceed the limit; 5) Gas outburst prediction in the geological abnormal area of the coal seam; 6) Coal and gas outburst prediction in two or more gas geological high-pressure areas of coal seam groups; When the following situations occur, conduct the coal and gas outburst prediction for two or more high-gas-potential areas in coal seam groups: Outside the coal mining and excavation working faces of the coal seam itself, in the coal seam group, when there are two or more high-gas-potential areas, that is, two or more gas outburst sources, conduct the gas outburst prediction; S200: Verification of outburst prediction and taking measures; S300: Lift of outburst prediction.

2. The accurate coal and gas outburst prediction method based on gas geology research as claimed in claim 1, wherein In the step S100, when the following situations occur, conduct the gas outburst prediction before design, shaft sinking, and mine extension: 1) When the gas geology map of the mine shows anomalies, conduct the gas outburst prediction. The anomalies in the gas geology map of the mine include: ①The coal seam has no outcrop, that is, the coal seam does not outcrop to the surface, there is no escape channel for coal seam gas, and the gas content per ton of coal is less than 10 m 3 / t; ② In the same mine, the tonnage coal gas isopleth of the deep coal seam is lower than that of the shallow coal seam; ③ In the same coal seam, the tonnage coal gas isopleth is abnormal, and the tonnage coal gas isopleth of the deep coal seam is lower than that of the shallow coal seam; or in the same coal seam, the tonnage coal gas isopleth map is chaotic and disordered, contrary to the influence law of burial depth, structure, and hydrogeology on coal seam gas; 2) When gas dynamic phenomena or coal and gas outbursts occur in adjacent construction and production mines, conduct the gas outburst prediction, including the following situations: ① Gas dynamic phenomena or outbursts continuously occur in the roadway of the same coal seam; ② At the location where gas dynamic phenomena or outbursts occur in the coal seam roadway, gas dynamic phenomena or outbursts occur again during roadway maintenance; ③ When outburst occurs, the gas ejection volume is equal to or exceeds twice the gas volume contained in the outburst coal.

3. The accurate coal and gas outburst prediction method based on gas geology research and judgment according to claim 1, characterized in that In the step S100, the gas outburst prediction of surrounding rock includes: 1) Gas outburst prediction of the surrounding rock of the coal seam roof. The gas outburst prediction of the surrounding rock of the coal seam roof includes: ① Gas outburst prediction of the driving face: When the distance between the rock reservoir layer and the coal seam is < 10m, the distance from the bottom plate of the rock reservoir layer to the top plate of the coal seam is < 10m, and the gas pressure of the rock reservoir layer ≥ 0.5MPa or the outburst risk index ≥ 0.05MPa / m, the gas in the surrounding rock will protrude along the fault and weak surface fissures of the rock layer. Conduct the gas outburst prediction before driving; When the rock reservoir layer is located in the caving zone, the distance between the rock reservoir layer and the coal seam is ≥ 10m, but in the caving zone, the gas pressure of the rock reservoir layer ≥ 0.5MPa or the outburst risk index ≥ 0.05MPa / m, the gas in the surrounding rock will protrude along the fault zone. Conduct the gas outburst prediction before driving; ② Gas outburst prediction of the surrounding rock of the roof in the longwall face: When the thickness of the surrounding rock < 10m, conduct the gas outburst prediction and predict the overlimit of gas in the upper corner; When the thickness of the surrounding rock ≥ 10m, conduct the gas outburst prediction and predict the gas outburst in the upper corner, serious overlimit of the return air gas in the mining face, and a long overlimit time; 2) Gas outburst prediction of the surrounding rock of the coal seam floor. The gas outburst prediction of the surrounding rock of the coal seam floor includes: ① Gas outburst prediction of the driving face: When the distance from the top plate of the rock reservoir layer to the bottom plate of the coal seam is less than 10m, the gas pressure of the rock reservoir layer ≥ 0.5MPa or the outburst risk index ≥ 0.05MPa / m, the gas in the floor surrounding rock will protrude along the fault and weak surface fissures of the rock layer. Conduct the gas outburst prediction before driving; When the distance from the top plate of the rock reservoir layer to the bottom plate of the coal seam is ≥ 10m, the gas pressure of the rock reservoir layer ≥ 0.5MPa or the outburst risk index ≥ 0.05MPa / m, make the gas outburst prediction before driving; ②Gas outburst prediction for the surrounding rock of the floor in the coal mining face: During the coal mining in the coal mining face, determine the depth of the floor failure zone; If the floor rock reservoir is located within the floor failure zone, all the gas in the rock reservoir will enter the goaf; if it is located within the affected zone, part of the gas will enter the goaf; When the gas pressure in the floor rock reservoir ≥ 0.5 MPa or the outburst risk index ≥ 0.05, a coal and gas outburst will occur in the coal mining face, and a gas outburst prediction will be carried out; The prediction content is: The overlying surrounding rock is relatively thin, the gas in the surrounding rock enters the goaf of the coal mining face, and the gas concentration in the upper corner exceeds the limit; The underlying floor rock reservoir is relatively thick and located within the floor failure zone, and gas outburst will occur in the upper corner, the gas in the return air seriously exceeds the limit, and it lasts for a long time.

4. The accurate coal and gas outburst prediction method based on gas geology research as claimed in claim 3, wherein The outburst danger index O b : O b =P0 / He Among which O b : prominent danger index; P0: Gas pressure in the surrounding rock; He: Effective barrier thickness.

5. The accurate coal and gas outburst prediction method based on gas geology research and judgment according to claim 1, characterized in that In the step S100, when the following situations occur, a gas outburst prediction for the gas geological abnormal area of the coal seam will be carried out: Combined with the geological body positions of faults, collapse columns, and dikes in the geological report, when drilling to detect the geological body position of the coal seam and finding a location where the drill bit is jammed or stuck and then measuring the gas pressure, and the gas pressure is greater than 0.5 MPa, it is determined as the gas geological abnormal area of the coal seam, the isobar of 0.5 MPa of the gas pressure in the geological abnormal area is circled, and a gas outburst prediction is carried out 20 m in advance.

6. The accurate coal and gas outburst prediction method based on gas geology research as claimed in claim 1, wherein The step S200 includes: 1) Verification of outburst prediction; 2) Pressure relief after drainage.

7. The accurate coal and gas outburst prediction method based on gas geology research and judgment according to claim 1, characterized in that The step S300 includes: the gas pressure drops below the allowable value of 0.5 MPa, and the gas outburst risk index drops below 0.05 MPa / m, and then continue tunneling; during tunneling, gas drainage cannot be stopped to prevent gas accumulation and pressure increase after stopping drainage, which may cause outburst.

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