国外煤层气成因与储层物性研究进展与分析

从煤层气生成机制及其地质控制、煤储层孔隙结构与吸附/解吸行为、煤储层裂隙系统及其对渗透率的影响三个方面,有重点地总结了国外有关煤层气成因和煤储层物性研究的新进展。笔者认为:国外在煤层气次生生物成因、煤层气生成矿物金属元素催化作用、煤层气固溶态赋存形式、含气量测定不确定性、煤层气近临界和超临界吸附、吸附能及其非均质性、裂隙矿物成因及其对成藏过程的指示作用、煤储层渗透率随煤层气解吸的变化规律及其控制因素等方面的研究,极大地深化了对煤层气成因和煤储层物性的理解与认识;煤岩学、煤地球化学、岩石力学等的结合是国际上煤层气地质研究手段的重要发展趋势,而煤层气成因与特殊赋存形式、含气量精确测定与评价、超临界吸附与吸附能分布、解吸过程中煤储层渗透率变化特征及其地质控制等的研究,显示出国外煤层气成因和煤储层物性研究的重要前缘方向。

Advances in overseas geological research on coalbed gas: Origin and reservoir characteristics of coalbed gas

In this paper, the advances in overseas research on the origin and reservoir characteristics of coalbed gas (CBG) are selectively summarized in the light of three aspects: the CBG-generating mechanism and its geological controls; the porous structure and adsorption/desorption of coal; fissure systems and their effect on the permeability of coal reservoirs. The understanding of the origin and reservoir characteristics of coalbed gas has been greatly deepened through some overseas research, such as the re-biogenetic action and mineral/metal catalysis of CBG formation; the occurrence of solid-solution CBG in coal; the indeterminacy of gas content measurements; the near- or super-critical adsorption of CBG; the adsorptive energy and its heterogeneity; the origin of cleat-filled minerals and its implication to CBG pool formation; and the change and controls of coal reservoir permeability with CBG desorption. The integration of coal petrology, coal geochemistry and rock mechanics is the international trend in the development of technology of coalbed gas research. The origin and idiosyncratic occurrence of CBG, the accurate measurement and evaluation of gas content, the super-critical adsorption and adsorptive energy distribution, and the change and its geological controls of coal reservoir permeability during desorbing are key frontiers of overseas research on coalbed gas origin and the characteristics of coalbed gas reservoirs.