CS244489B1 - Method of desorption's initial speed "in situ",desorable gas carrying capacity,initial gas production and gas pressure measuring - Google Patents

Abstract

The solution relates to the method of initial measurement desorption rate, desorbable gas production, initial gas production and gas pressure in the underground coal mine finding out the possibility of coal and gas bursts. In this way, the mining work drilling a diameter bore in the coal seam 30 to 50 mm, 5 to 12 m long, from which a drill pulp sample is always taken at an interval of 0.2 m before reaching the whole the depth of the borehole, starting at 2.0 m the initial desorption rate is determined in situ and desorbable gas resistance. Doing so drilling is interrupted only when it is reached the whole one meter of the borehole depth it first measures the initial gas and then the last 0.5 to 1.0 meter borehole and the gas pressure is measured. This the gas pressure is measured to 3 m in wells 1 min after interruption of drilling and in each other the length of the borehole is extended max. 0.5 minutes

Description

(54) Method of measuring the initial rate of desorption in situ, desorbable gas capacity, initial gas production and gas pressure

The present invention relates to a method for measuring the initial rate of in situ desorption, desorbable gas capacity, initial gas production and gas pressure in a deep coal mine to determine the possibility of coal and gas bursts. In this method, a borehole with a diameter of 30 to 50 mm, a length of 5 to 12 m, is drilled from the mine work towards the coal seam, from which a sample of the borehole is sampled, at intervals of 0.2 m before reaching the whole meter depth. starting from 2.0 m. The initial in-situ desorption rate and desorbable plyphonicity are determined from the sample. In this case, the drilling is interrupted only when one meter of the borehole depth is reached, where the initial gas production is measured first and then the last 0.5 to 1.0 meter borehole is sealed and the gas pressure is measured. This gas pressure shall be measured for boreholes of 3 m in length within 1 min of the interruption of the drilling and shall be extended by a maximum of 0,5 minutes for each additional meter of the well length.

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The present invention provides a method of measuring the initial rate of desorption of the In sieve, the desorbable gas capacity, the initial gas production and the gas pressure to determine the possibility of coal and gas bursts in a coal mine.

Methods are known to measure the initial in-situ desorption rate, desorbable gas capacity, initial gas production, and gas pressure to determine the possibility of coal and gas bursts. These methods are characterized in that said values are measured from boreholes with a maximum depth of 3 meters, with only one location being measured in each borehole.

There are also known methods for measuring desorbable gas capacity in wells of 42 to 65 mm in diameter 3 meters or more in which the gas desorption is measured continuously, whereby after drilling each meter well bore, the drilling speed is zero until the initial rate of gas desorption in situ reaches 1. 5 cm @ 2 per 10 g of coal pulp for 35 s.

A disadvantage of the known methods so far is that the measured values are obtained from only one borehole location. It is therefore not possible to monitor the course of these values at individual wells. Another disadvantage is obtaining these values only from a depth of max. 3 meters, ie from a place that is still strongly influenced by the foot pressures of the mine work.

Therefore, the values obtained are often an indefinable combination of the effects of natural conditions and the effects of mining and technical activities. In other prior art methods, although the initial rate of desorption of gases in situ, even in wells longer than 3 meters, is continuously measured, the desorbable gas capacity, initial gas production and gas pressure are not simultaneously measured.

Therefore, it is difficult to interpret from the values thus obtained assessing the possibility of coal and gas bursts. ₍

These shortcomings of the prior art are eliminated by measuring the initial in situ desorption rate, desorbable gas capacity, initial gas production and gas pressure, ascertained for assessing the possibility of coal and gas bursts by drilling from a mine work into a 30-mm borehole. up to 50 mm, length 5 to 12 m according to the invention, and from the borehole, a sample of the borehole is taken from which the initial in-situ desorption rate and desorbable gas capacity are determined and in which the gas pressure values and the initial gas production are measured.

The essence of the invention is that the sampling of the borehole is carried out starting at 2.0 meters each at 0.2 meter intervals before reaching the limit of each full one meter of borehole length. , 'l

The bore is interrupted only when this limit is reached, where the initial gas production is measured and the last 0.5 to 1.0 meter borehole is first measured and the gas pressure is measured in the chamber thus formed.

This gas pressure is measured at 3-meter boreholes within 1 minute of interrupting the drilling, and is extended by a maximum of 0.5 minutes for each additional meter of length.

The advantage of the method of measuring the initial in-situ desorption rate, desorbable gas capacity, initial gas production and gas pressure according to the invention is that it is possible to obtain standard parameters for assessing the possibility of coal bursts and gases from the individual depth horizons of the coal pillar.

At the same time, due to the selected borehole distance, it is possible to obtain the parameters also from areas intact by foot pressures.

In order to determine the possibility of a burst of coal and gases in the mine workings of the deep coal mine, a borehole with a diameter of 42 mm was carried out in the side of the long mine workings towards the coal seam. Drilling without interruption to a depth of 3.0 meters. In the course of drilling in the interval from 2.8 m to 3.0 m, a sample of the drill bit was taken from which one worker determined the initial rate of in-situ desorption and desorbable gas capacity.

Meanwhile, the second worker drilled the 3.0 m limit, immediately measured the gas production value and quickly sealed the borehole at a depth of 2.5 m using a sealing probe. This created a chamber of 0.5 m length in which the worker measured the gas pressure.

This measurement was made 40 seconds after the drilling break. The sealing probe was then removed from the borehole and drilling continued for about 5 minutes without interruption to a depth of 4.0 m.

Again, in the interval of 3.8 to 4.0 m, a sample of the drill bit was taken from which the initial rate of in-situ desorption and desorptible gas capacity were determined. In depth <

The gas production was measured at 4.0 meters, when the borehole was interrupted, and the borehole at a depth of 3.5 meters was sealed with the aid of an emergency probe.

The gas pressure was measured in the resulting chamber. This measurement was made 80 seconds after the drilling break. The sealing probe was pulled out of the borehole and drilling continued without interruption until the final borehole length - 5.0 meters.

In the interval 4.8 to 5.0 m, a sample of the well was also taken, from which the initial in-situ desorption rate and desorbable gas capacity were determined. Gas production was measured at a depth of 5.0 meters, when the bore was interrupted, the borehole was sealed at a depth of 4.5 meters, and gas pressure was measured 50 seconds after the bore was interrupted.

In this way the measured values of the in situ desorption rate, desorbable gas capacity, gas pressure and initial gas production were used to determine the possibility of coal and gas bursts in the area of the mine from which the well was drilled.

Claims (1)

SUBJECT OF THE INVENTION Method of measuring the initial rate of desorption in situ, desorbable gas capacity, initial gas production and gas pressure to determine the possibility of coal and gas bursts, in which a borehole with a diameter of 30 to 50 mm, 5 to 12 meters, from which a sample of the borehole is sampled from which the initial in-situ desorption rate and desorptible gas capacity are determined and the initial gas production and gas pressure values are measured, characterized in that the borehole sample is taken from a depth of 2; 0 meters at intervals of 0.2 meters before reaching the limit of each full meter of borehole length, but drilling is only interrupted when this limit is reached, where the initial gas production is measured first and then the last 0.5 to 1.0 meters sealed borehole, and in the chamber thus created, the gas pressure is measured for borehole boreholes 3 meters within a period of 1 minute from the interruption of drilling and in each additional meter of the borehole length, this time is extended by a maximum of 0.5 minutes.