Measurement-while-drilling method and device for obtaining coal seam gas parameter

Patent metadata

Field	Value
Publication number	US-11268377-B2
Application number	US-201716618171-A
Country	US
Kind code	B2
Filing date	Nov 27, 2017
Priority date	Oct 12, 2017
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

Disclosed are a measurement-while-drilling method and device for obtaining a coal seam gas parameter applicable to measurement of a coal seam gas/coal seam methane parameter while drilling and evaluation of gas drainage performance. The invention performs a measurement-while-drilling operation to obtain information about downhole gas and a coal seam, thereby realizing on-site measurement of a coal seam gas parameter while drilling. The measurement-while-drilling device for obtaining a coal seam gas parameter comprises a compartment (17), a pressure sensor (15), a temperature sensor (14), a flow sensor (4), an acoustic emission sensor (16), a monitoring and control module (11), a power module and a communication module. The device is installed between a drill bit (1) and a first drill pipe (20). The method comprises: in a drilling process, using the temperature sensor (14) to monitor, in real time, a temperature at a spot under measurement; when drilling stops, sealing a borehole to form a pressure measurement cavity, and using the pressure sensor (15) to monitor a gas pressure in real time; after completion of the pressure measurement, using the flow sensor (4) to monitor, in real time, an amount of gas emitted from the borehole; and performing comprehensive calculation to obtain a gas pressure, a gas content, and an amount of initially desorbed gas at the spot of the coal seam. The invention can perform on-site measurement while drilling and calculate to obtain a coal seam gas/coal seam methane parameter, can perform on-site measurement while drilling without sampling, and can use multiple parameters to perform synchronous measurement.

First claim

The invention claimed is:

1. A measuring method of a measurement-while-drilling device for obtaining coal seam gas parameter, comprising:
providing a measurement-while-drilling device for obtaining coal seam gas parameter, said measurement-while-drilling device comprising:
a compartment ( 17 ), a pressure sensor ( 15 ), a temperature sensor ( 14 ), an acoustic emission sensor ( 16 ), a borehole sealing module, a flow measuring module, a communication interface ( 8 ), a monitoring and control module ( 11 ), and a power supply compartment ( 10 ) that has an electric charging interface ( 9 ) and can be removed and mounted quickly, wherein, the measurement-while-drilling device is installed between a drill bit ( 1 ) and a drilling inclinometer ( 21 ) or a first drill pipe ( 20 ); the compartment ( 17 ) is a pipe body that is configured to fix various sensors and modules, is hollow so that water can flow through it, and has a threading hole ( 12 ); the flow sensor ( 4 ), the temperature sensor ( 14 ), the pressure sensor ( 15 ), the acoustic emission sensor ( 16 ), the power supply compartment ( 10 ), and the communication interface ( 8 ) are connected to corresponding interfaces of the monitoring and control module ( 11 ) respectively, the power supply compartment ( 10 ) supplies power to the monitoring and control module ( 11 ) and the power utilization modules or sensors connected to the monitoring and control module ( 11 );
the borehole sealing module comprises a borehole sealing capsule ( 2 ) wrapped on an external rim of the compartment, a main water circuit switch ( 13 ) and a borehole sealing capsule water circuit switch ( 7 ) that are mounted on the front end of a hollow water pipe and attain a cut-off effect during borehole sealing; an arc-shaped wear plate ( 6 ) is wrapped on the outer side of the borehole sealing capsule ( 2 );
the monitoring and control module comprises a variety of sensors and module interfaces, a data storage unit, a timer, a monitoring and control CPU, and a monitoring and control circuit;
wherein, the sensors comprise a flow sensor, a temperature sensor, a pressure sensor, and an acoustic emission sensor, the sensors are connected in shunt and operate separately from each other without any interference, and they are connected via their interfaces to corresponding interfaces of the monitoring and control module, and have functions including monitoring signal conversion, triggering data acquisition, timing data acquisition, data analysis and control; the flow measuring module comprises a gas flow hole ( 5 ) and a gas circuit switch ( 3 ) and a flow sensor ( 4 ) that are installed in the gas flow hole ( 5 );
measuring and calculating coal seam gas parameters automatically while drilling, and monitoring and logging the temperature at a measuring point in real time with the measurement-while-drilling device for obtaining coal seam gas parameter in the process of drilling in a coal seam; sealing the borehole to form a pressure measurement chamber ( 18 ), and monitoring and logging the gas pressure in the pressure measurement chamber ( 18 ) in real time during the time when the drilling is stopped or the first drill pipe ( 20 ) is replaced;
monitoring the gas discharge flow in the pressure measurement chamber ( 18 ) and the gas gushing flow from the borehole in real time after the pressure measurement is finished;
calculating the coal seam gas pressure, gas content, and initial amount of desorption gas at the measuring point comprehensively; the specific steps are as follows:
a. installing a drill bit ( 1 ) and a drilling inclinometer ( 21 ) that can measure and log the position of the drill bit on the front end of the first drill pipe ( 20 ) before the drilling in the coal seam is commenced, switching on the power switch of the measurement-while-drilling device and driving the drill bit ( 1 ) into the borehole ( 19 ) after the drill bit ( 1 ) is installed in place; logging water flow Q si , pressure P i , temperature T i , and acoustic emission signal A i in real time after the acoustic emission signal identifying that the first drill pipe ( 20 ) starts drilling is detected;
b. keeping the main water circuit switch ( 13 ) on the compartment ( 17 ) in the ON state so that water flows out from the drill bit ( 1 ) to carry out drilling and cuttings discharging normally during normal drilling; controlling the action of the borehole sealing module with the monitoring and control CPU; switching off the main water circuit switch ( 13 ) and switching on the borehole sealing capsule water circuit switch ( 7 ) so that the high pressure water enters into the borehole sealing capsule ( 2 ) after an acoustic emission signal identifying drilling stop is detected and the withdrawal of the drill bit is completed, wherein, when the water pressure becomes stable and there is no flow, it indicates that the borehole has been sealed by the capsule ( 2 ); stopping the water supply, switching off the borehole sealing capsule water circuit switch ( 7 ), and sealing the pressure measurement chamber ( 18 ) at the bottom of the borehole, so that gas gushes from the borehole wall and thereby the pressure P i in the pressure measurement chamber ( 18 ) at the bottom of the borehole is increased continuously; adding a drill pipe at the drilling machine during this time; completing the pressure measurement within specified time, switching on the gas circuit switch ( 3 ), and measuring and logging the gas flow Q wi in real time; stopping logging Q wi and switching off the gas circuit switch ( 3 ) at the end of the flow measurement or when the flow is lower than a preset value; switching on the borehole sealing capsule water circuit switch ( 7 ), so that the borehole sealing capsule ( 2 ) contracts and discharges water automatically; feeding water and continuing the drilling after the borehole sealing capsule contracts in place;
c. stopping the drilling when a design position is reached; stopping the acquisition and monitoring of the signals after the measurement of gas flow parameter is finished and the acoustic emission sensor ( 16 ) receives no drilling signal for a long time;
obtaining the parameters or waveform data of various indicators including temperature, pressure, water flow, gas flow, and acoustic emission at different times with measurement-while-drilling device; calculating and ascertaining the coal seam gas content, gas pressure, and initial amount of desorption gas in the coal seam at different times and different positions with the monitoring and control device according to the gas pressure and its change, gas flow, temperature and its change rule in the pressure measurement chamber ( 18 ) during the time when the drilling is stopped;

d. withdrawing the drill pipe, removing the measurement-while-drilling device, and performing data communication; ascertaining the coal seam gas content, gas pressure, and initial amount of desorption gas in the coal seam at different measuring points in the borehole in a computer with reference to the position data of the drilling inclinometer ( 21 ) after the communication;
e. repeating steps a-d, and performing the measurement for an additional borehole.

2. The measuring method of the measurement-while-drilling device for obtaining coal seam gas parameter according to claim 1 , wherein: the drill pipe is rotated for 1-2 cycles at a low speed in order to achieve a better sealing elect during the time when the high pressure water enters into the borehole sealing capsule ( 2 ).

3. The measuring method according to claim 1 , wherein: the power supply is recharged or the power supply module is replaced before the measurement for the additional borehole is commenced.

Assignees

• Univ China Mining

Inventors

• Wang Enyuan
• Li Zhonghui
• Ou Jianchun
• Qiu Liming

Classifications

• E21B47/12

  Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling · CPC title

• E21B47/14 Primary

  using acoustic waves · CPC title

• E21B47/07

  Temperature · CPC title

• E21F17/00 Primary

  Methods or devices for use in mines or tunnels, not covered elsewhere (mine lighting F21, H05B) · CPC title

• E21B47/06

  Measuring temperature or pressure · CPC title