RU1800012C - Method for determination of point of contact of drilling bit with coal seam - Google Patents

Abstract

The invention relates to the mining industry and allows with high accuracy to determine the moment of meeting of the bit with the coal seam during drilling. SUMMARY OF THE INVENTION: Elastic vibrations are simultaneously recorded in a coal seam and in the main roof of this seam using geophones installed in a previously drilled well located at a distance of no more than 5000 m from the boring well. Then these vibrations are measured and compared with each other, and the moment of encounter is determined by the excess of elastic vibrations in the coal seam over the vibrations in the main roof and the increase in drilling speed. The method will increase drilling productivity by 15-20%. 1 ill. Ј

Description

The invention relates to the mining industry, in particular, it is intended to determine when a bit meets a coal seam during drilling.

The purpose of the invention is to increase labor productivity by increasing the accuracy of determining when a bit meets a coal seam.

The goal is achieved by simultaneously registering elastic vibrations in the coal seam and in the surrounding surrounding rocks, installed in a previously drilled well, located at a distance of not more than 5000 m from a boring well, the first geophone in the coal seam, and the second in nearby rocks, for example, in the main roof of this formation, the converted and amplified signals are rectified separately from. of both seismic receivers, measure and compare these signals with each other, and then determine the moment the bit meets the coal seam by the event that the seismic signal from the first seismic receiver exceeds the seismic signal from the second seismic receiver due to the formation of channel waves in the coal seam and an increase in the drilling speed due to lower coal strength compared to overlying rocks.

The control of the moment, the encounter of a bit with a coal seam during drilling by simultaneously registering channel waves in the coal seam and seismic vibrations in the main roof of this seam using seismic receivers and comparing these fluctuations in magnitude give the method new properties, which are significant differences that

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Allow to determine the moment of entry of olota into the coal seam.

It is known 2 that a coal seam is a waveguide zone in which a source of elastic vibrations (a bit) forms channel waves (see 2, pp. 88-100). In this case, the bulk of the elastic energy does not extend beyond the formation, but is distributed within it. Therefore, at the moment of penetration of the bit into the coal seam and its drilling, the first seismic receiver located in the coal seam will record much larger seismic vibrations than the second seismic receiver, which is located above the coal seam in the main roof, which is the main feature for the proposed method determining when the bit meets the coal seam while drilling. The second sign is an increase in the drilling speed, starting from the moment the bit enters. Into the coal seam, is auxiliary. The drawing shows the drilling of the well, channel waves in the coal seam and a functional diagram of a device that implements the method, where 1 is a rock mass, 2 is angular formation, 3 - drilled well, 4 - drilling rig, 5 - drilling from the well, 6 - chisel, 7 - channel waves, 8 and 9 - first and second geophones, 10 and 11 - amplifiers, 12 and 13 - rectifiers, 14 is a comparator and 15 is an indicator.

The first seismic receiver 8 is connected to an amplifier 10, which is connected to a rectifier 12 connected to the first input of the comparator 14. The second seismic receiver 8 is connected to an amplifier 11 connected to a rectifier 13, which is connected to a second input of the comparator 14, the output of which is connected to an indicator fifteen.

The physical premises of the proposed method for determining the rotation speed are as follows. It is known that when a well is drilled before entering the coal seam, seismic vibrations occurring at the bottom of the well propagated in the rock mass are reflected from the boundary with the coal seam, i.e. seismic vibrations in a coal seam are small compared with seismic oscillations in a rock mass lying in the bottom of a coal seam. When a bit enters a coal seam and during the entire time it is drilled, seismic oscillations arising in this case are reflected from the boundary with the array, propagating in the coal seam, represented a waveguide zone. These seismic waves, called channel waves, have a much larger amplitude than waves in an array. Taking into account the physics of the process at the time of the transition of the drilling tool from the rock into the coal seam, the proposed method has been developed.

The method is carried out as follows.

For the studied area in the previously drilled borehole, a geophone 9 is installed in the coal seam 2, and the geophone 8 in the main roof

coal seam. When drilling the rock mass to the entrance of bit 6 into the coal seam 2, seismic vibrations coming from the bottom of the well are received by geophones 8 and 9, respectively amplified, straightened for 5 s and compared by a comparator. 14. At the same time, since the signal from the geophone 9 located in the coal seam is less than the signal from the geophone 8 located in the roof, then from the comparator

0, a signal is sent to indicator 15 that drilling is being carried out on the rock. When drilling a coal seam, there are more seismic oscillations in it than in the main roof. Therefore, the geophone 9 records the signal more than the geophone 8. These converted signals are compared by a comparator. In this case, the signal from the coal seam (from the seismic receiver 9) is greater than from the overlying rock mass (from the seismic receiver 8), therefore, a signal is sent from comparator 14 to indicator 15 that they have begun drilling the coal seam. In this case, the drilling speed increases.

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By increasing the seismic signal obtained from the coal seam and increasing the drilling speed, the moment of the meeting of the drilling tool with

0 coal seam.

When evaluating specialists, the introduction of the proposed method will increase the productivity of exploration of coal seams by 20%.

Claims (1)

5 Claims A method for determining the meeting place of a bit with a coal seam, including the registration of elastic vibrations arising in a borehole during drilling while propagating in the host rocks, with a seismic receiver located in a previously drilled well, converting them into an electrical signal and amplification, characterized in , 5 what. In order to increase the accuracy of determining the encounter of a bit with a coal seam during drilling, a drilling well is located at a distance of not more than 5000 m from the previous one. drilled well and. simultaneously with the registration of elastic vibrations in the host rocks, elastic vibrations in the coal seam are recorded by a second seismic receiver located in a previously drilled well in the coal seam, they are converted into an electrical signal and amplified, amplified signals from both the seismic receivers are straightened and compared with each other, and the moment the bit meets the coal seam is determined by the excess of the seismic signal from the second seismic receiver over the seismic signal from the first seismic receiver.