煤岩气相渗透率变化类型及判别模式

摘要

煤岩气相渗透率变化类型具有多样性。针对我国32个煤矿的不同变质程度煤岩样品（制备54个岩心柱），开展气相（ CO2）渗透率动态变化规律研究，基于气体反弹压力和渗透率伤害率2项指标，划分了煤岩气相渗透率变化类型；结合煤岩煤质数据，建立了渗透率变化类型判别模式。我国煤岩气相（ CO2）渗透率变化主要表现为下降型、反弹型和上升型3大类，包括8个小类；通过最大镜质组反射率—初始渗透率、惰镜比（惰质组含量与镜质组含量之比）—初始渗透率、固灰比（固定碳含量与灰分产率之比）—初始渗透率和惰镜比—固灰比交会图法，可有效识别煤岩气相渗透率变化类型，为优选有利的煤层气开发储层提供依据。%Coal shows a variety of permeabilities to gas flow. Coal samples of different ranks were collected from 32 mines in China, and were prepared into 54 cylindrical cores to investigate coal permeability to gas ( CO2 ) flow. The results were classified based on rebound pressure and permeability damage rate. Furthermore, apattern of change types was established. These included “declining type”, “rebounding type” and “increasing type”, which could be further sub⁃divided into 8 types. The permeability change types can be identified from cross⁃plots of “maximum vitrinite reflectance-initial permeability”, “ratio of inertinite content to vitrinite content-initial permeability”,“ratio of fixed carbon content to ash yield-initial permeability” and“ratio of inertinite content to vitrinite content-ratio of fixed carbon content to ash yield”.