Method for forecasting coal and gas outburst on site

Abstract

The invention relates to a method for forecasting coal and gas outburst, which is characterized by comprising the following steps: firstly, measuring a forecasting preliminary index K1 value of coal and gas outburst by a drillings gas desorption index measuring method stipulated by AQ / T1065-2008; secondly, introducing new forecasting judgment index i value, wherein the computational formula is Q=K3T-WL; and in the formula, Q is the total amount of gas desorption of time T, cm / g, T is the time, the minWL is the gas loss of a coal sample before measurement, cm / g, and K3 is a constant; thirdly, measuring i value according to the following steps: 1) placing the coal sample in a coal sample tank; and 2) converting the pressure formed by the gas desorption amount of the coal sample into an electrical signal by a pressure sensor connected with the coal sample tank, sending the electrical signal to an amplifying circuit for signal amplification, then sending the electrical signal to a singlechip, and performing data processing by a least square method to obtain the i value; and fourthly, combining the i value and the K1 value to determine the gas outburst.

Description

technical field

[0001] The invention relates to a method for predicting coal and gas outburst, in particular to a method for on-site prediction of coal and gas outburst which can improve prediction accuracy. Background technique

[0002] The judgment parameters used before the prediction of coal and gas outburst include drilling cuttings gas desorption index method, cuttings amount (S) method, drilling gas gushing initial velocity method (q), R value method, etc. The above-mentioned methods are all legal judgment methods and indicators in my country. These methods are all based on the principle of gas desorption except the cuttings quantity method.

[0003] Taking the drilling cuttings gas desorption method as an example, Δh 2 The difference between the gas per gram of coal formed in the varactor and the atmospheric pressure within 2 minutes of the coal sample after the test is used as the judgment standard. And another indicator K 1 The value is determined by using the ...

Examples

Embodiment Construction

[0058] The first step is to measure the preliminary index of coal and gas outburst prediction K1 value;

[0059] The second step is to introduce a new prediction and judgment index i value,

[0060] Its calculation formula is as follows:

[0061] Q=K 3 T i -W L

[0062] In the formula:

[0063] Q------The total amount of gas desorption when the time is T, cm 3 / g;

[0064] T----time, min

[0065] W L --- Gas loss of coal sample before testing, cm 3 / g;

[0066] K 3 ---constant

[0067] The third step is to determine the value of i, as follows

[0068] 1) Take the coal sample and place it in the coal sample tank;

[0069] 2) Take out the coal sample from the coal seam when converting the desorption speed of the coal sample through the pressure sensor connected to the coal sample tank, put the sample into the coal sample tank after the coal sample sieve, and the sensor converts the speed of the coal sample tank into an electrical signal , sent to the amplifier cir...

technical field

[0001] The invention relates to a method for predicting coal and gas outburst, in particular to a method for on-site prediction of coal and gas outburst which can improve prediction accuracy. Background technique

[0002] The judgment parameters used before the prediction of coal and gas outburst include drilling cuttings gas desorption index method, cuttings amount (S) method, drilling gas gushing initial velocity method (q), R value method, etc. The above-mentioned methods are all legal judgment methods and indicators in my country. These methods are all based on the principle of gas desorption except the cuttings quantity method.

[0003] Taking the drilling cuttings gas desorption method as an example, Δh 2 The difference between the gas per gram of coal formed in the varactor and the atmospheric pressure within 2 minutes of the coal sample after the test is used as the judgment standard. And another indicator K 1 The value is determined by using the ...

Examples

Embodiment Construction

[0058] The first step is to measure the preliminary index of coal and gas outburst prediction K1 value;

[0059] The second step is to introduce a new prediction and judgment index i value,

[0060] Its calculation formula is as follows:

[0061] Q=K 3 T i -W L

[0062] In the formula:

[0063] Q------The total amount of gas desorption when the time is T, cm 3 / g;

[0064] T----time, min

[0065] W L --- Gas loss of coal sample before testing, cm 3 / g;

[0066] K 3 ---constant

[0067] The third step is to determine the value of i, as follows

[0068] 1) Take the coal sample and place it in the coal sample tank;

[0069] 2) Take out the coal sample from the coal seam when converting the desorption speed of the coal sample through the pressure sensor connected to the coal sample tank, put the sample into the coal sample tank after the coal sample sieve, and the sensor converts the speed of the coal sample tank into an electrical signal , sent to the amplifier cir...

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