GB/T 23249-2009 English PDF (GBT23249-2009)

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GB/T 23249-2009: Coalbed gas content measurement methods in geological exploration period
GB/T 23249-2009
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 13.100
D 09
Coalbed Gas Content Measurement Methods in
Geological Exploration Period
ISSUED ON: MARCH 11, 2009
IMPLEMENTED ON: NOVEMBER 1, 2009
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative References ... 4 
3 Terms and Definitions ... 4 
4 Determination Method of Coalbed Gas Content in Geological Exploration
Period ... 5 
5 Record and Sample Delivery ... 11 
6 Coal Sample Degassing and Gas Analysis ... 11 
7 Calculation and Evaluation of Determination Result ... 16 
Appendix A (normative) Format of Gas Content Determination Record Table 23 
Appendix B (informative) Saturated Water Vapor Pressure at Different
Temperatures ... 30 
Appendix C (informative) Saturated Vapor Pressure of Saturated Saline at
Different Temperatures ... 31 
Coalbed Gas Content Measurement Methods in
Geological Exploration Period
1 Scope
This Standard stipulates the terms and definitions, measurement methods, records
and sample delivery, coal sample degassing and gas analysis, determination result
calculation and evaluation of coalbed gas content in geological exploration period.
This Standard is applicable to the determination of coalbed gas content and gas
composition through coal core during the geological exploration period.
2 Normative References
Through the reference in this Standard, clauses of the following documents become
clauses of this Standard. In terms of references with a specific date, all the subsequent
modification sheets (excluding the corrected content) or the revised editions are not
applicable to this Standard. However, all parties that reach an agreement in
accordance with this Standard are encouraged to explore the possibility of adopting
the latest version of these documents. In terms of references without a specific date,
the latest version is applicable to this Standard.
GB/T 212 Proximate Analysis of Coal (GB/T 212-2008, ISO 11722:1999, NEQ)
GB 474 Method for Preparation of Coal Sample (GB 474-2008, ISO 18283:2006, MOD)
GB/T 3715 Terms Relating to Properties and Analysis of Coal (GB/T 3715-2007, ISO
1213-2:1992, NEQ)
GB/T 13610 Analysis of Natural Gas Composition - Gas Chromatography
GB/T 15663.8 Terms Relating to Coal Mining - Part 8: Mine Safety
3 Terms and Definitions
What is defined in GB/T 15663.8 and GB/T 3715, and the following terms and
definitions are applicable to this Standard.
3.1 Coalbed Gas Content
Coalbed gas content refers to methane and heavy hydrocarbon gas content that unit
mass or unit volume of coal body contains under the original state.
b) Before using the desorption instrument, use suction balloon to raise the liquid
level in the measuring tube to the zero point; close the screw clamp (see Figure
2). Then, place it still for 10 min, if the liquid level in the measuring tube remains
still, then, it shall be qualified.
4.1.3 Sampling of coal sample
Sampling and requirements are as follows:
a) Use common coal core tube to drill-take coal core. The length of coal core
taken in one time shall be not less than 0.4 m;
b) After the coal-drilling is completed, during the process of elevating the drilling
tool, back-fill flushing fluid into the drill hole; maintain the drill hole often filled
with flushing fluid (if this requirement cannot be satisfied because the drill hole
severely leaks water, this shall be indicated in the sampling record). The
elevating process shall be as continuous as possible. If due to mechanical
failure, this process is suspended in the midway, in area where the hole depth
is less than 200 m, the suspension time shall not exceed 5 min; in area where
the hole depth is 200 m ~ 500 m, the suspension time shall not exceed 10 min;
in area where the hole depth is 500 m ~ 1,000 m, the suspension time shall
not exceed 20 min; in area where the hole depth is more than 1,000 m, the
suspension time shall not exceed 30 min (conditions of suspension time: under
1/2 hole depth; the medium of well drilling is water or mud);
c) In terms of sampling time, relevant items shall be filled out in details in
accordance with the format of Table A.1 in Appendix A. The stipulations of the
timing (accurate to min) of several operations are as follows:
T1---drill-elevating time, expressed in (min);
T2---time of elevating drilling tool to the well head (calculated by the finished
elevation of the last drilling tool), expressed in (min);
T3---time of starting desorption and determination (calculated by the time of
opening the spring clip after the desorption instrument’s exhaust tube is
connected with the puncture needle), expressed in (min);
d) After coal core is pulled out of the drill hole, disassemble the coal core tube as
soon as possible. Fill the adopted coal sample into the sealing tank. The time
that the coal core is exposed in the air shall not exceed 8 min;
e) After taking out the coal core, in terms of columnar coal core, adopt an intact
part from the middle which contains little gangue; in terms of powdered and
blocky coal core, the gangue, mudstone and grinding burnt parts shall be
eliminated. Do not use water to clean the coal sample; maintain its natural
state, load it into the sealing tank. Do not compact it. The tank mouth shall
retain around 10 mm of space;
f) Firstly, insert the puncture needle into the sealing rubber pad, which is above
the tank cover, then, use a wrench to screw on the tank cover. Then, connect
the desorption instrument’s exhaust tube with the puncture needle;
immediately open the spring clip 8 (see Figure 2); record this time as T3.
4.2 Determination of Gas Desorption Speed
4.2.1 Gas desorption speed determination device is shown in Figure 2. After the
sealing tank connects with the desorption instrument through exhaust tube 9, open the
spring clip 8. Soon after that, gas, which leaks out from coal sample, enters the
measuring tube. Open the sink’s water discharge tube 7; use water drainage and gas
collection method to collect gas in the measuring tube.
4.2.2 Within a certain interval, record the reading of the measuring tube and the
determination time; maintain consecutive observation for 120 min. The stipulations of
the reading interval time are as follows: within 60 min before starting the observation,
1 min ~ 2 min of interval from the 1st point to the 3rd point; after that, at each interval of
2 min ~ 5 min, read once; within the second hour, at each interval of 10 min ~ 20 min,
read once.
4.2.3 If the volume of the measuring tube is not sufficient to contain all the gas, which
leaks out from coal sample within 120 min, use spring clip 8 to firmly clamp the exhaust
tube in the midway, re-elevate the liquid level to the measuring tube’s zero point,
meanwhile, supply sufficient clean water into the sink. Then, open the spring clip,
continue the observation.
4.2.4 The above-mentioned observation shall be conducted in places with relatively
stable temperature. The sealing tank shall receive thermal insulation and anti-freezing
treatment.
4.2.5 If under the observation with the desorption instrument, no gas is discharged,
examine whether the puncture needle, the exhaust tube and the upper gas vent of the
sealing tank are blocked. If they are not blocked, then, it is caused b...