ISO 18871:2015提供了在钻井过程中通过取芯或井壁取芯获得的煤芯样品的煤层气含量测量方法。如果根据相关国家标准测定煤层气含量的设备不可用，则其也应适用于钻屑样品。选择最合适的方法应考虑试验的目的和取样的可能性。 ISO 18871:2015适用于直接测量煤层气含量的方法。 包括样品制备、实验程序和计算方法。测量煤中气体含量的间接方法（不包括在本标准中）通常基于定义/规定压力和温度条件下煤的气体吸附特性。 ISO 18871:2015包括三种直接测量方法:岩芯样品的常规解吸（缓慢解吸）、岩芯样品的快速解吸、岩屑或块状样品的快速解吸。 它们之间的区别在于最终粉碎前气体解吸的时间以及样品的大小和形状。 ISO 18871:2015适用于煤炭和煤层气勘探过程中煤炭甲烷含量的测定，包括低阶煤炭游离气含量的测定。

ISO 18871:2015 provides methodology for measuring coalbed methane content of coal core samples obtained by coring or sidewall coring during well drilling. It shall be also applied to drill cuttings samples, if the equipment for the determination of the coalbed methane content according to a respective national standard is not available. The selection of the most appropriate method shall consider the purpose of the test and the possibilities of sampling. ISO 18871:2015 is applicable for the direct method of measuring coalbed methane content. It includes sample preparation, experimental procedures and calculation methods. Indirect methods of measuring gas content of coal (not included in this standard) are generally based on either the gas sorption characteristics of coal under defined/specified pressure and temperature conditions. ISO 18871:2015 includes three types of direct measuring methods: conventional desorption (slow desorption) of core samples, fast desorption of core samples, fast desorption of cuttings or lump samples. The difference among them lies in the time allowed for gas to desorb before final crushing and in sample size and shape. ISO 18871:2015 is applicable for the determination of the methane content of coal during coal and coalbed methane exploration for the determination of free gas content of low rank coals is included.