云南老厂矿区煤层气地质条件

Geological conditions of coalbed methane in Laochang mining area in Yunnan Province

在分析矿区地质条件、煤岩及煤储层特征的基础上,探讨研究区煤层气地质条件。结果表明：老厂矿区龙潭组和长兴组含煤性好,煤层厚度大并且分布稳定,煤质以无烟煤为主,生烃量大,生烃能力强;煤岩组分稳定,镜质组含量高,对甲烷吸附性强;煤层孔隙度较低,渗透率中等;解吸率和储层压力偏高,中等含气性,含气量在6.02~18.95 m3/t。研究区构造类型和水文地质条件相对简单,围岩封盖及地下水封堵作用强,利于煤层气的富集成藏。综合分析认为,老厂矿区属中型富甲烷煤层气目标区,煤层气成藏地质条件优越,煤层气资源丰富,开采条件优越。

This paper is motivated by the need to explore the geological conditions of coal bed gas found in the Laochang mining area, an important coalbed methane （CBM） production target area in Yun- nan Province. The exploration is best obtained by comprehensively analyzing the geological characteristics as well as the property of coal and coalbed reservoir. The results show that Longtan and Changxin forma- tions in the Laochang mining area are blesses with better-developed conditions for CBM： such as a better coal bearing property, a coal higher thickness and more stable distribution, coal quality dominated by an- thracite, greater hydrocarbon generation, stronger hydrocarbon generation ability; more stable coal mac- erals, higher vitrinite content, stronger adsorption of methane ; lower coal seam porosity, medium perme- ability; higher desorption rate and reservoir pressure, medium gas-bearing properties ranging between 6.02 and 18.95 m3/to The target area has relatively simple tectonic background and hydrology geological condition, along with a better-developed sealing capability of surrounding rock and hydraulic trapping, thus facilitating coalbed methane reservoir. The comprehensive analysis finds that Laochang mining area occurs as a medium-sized CBM target area with superior geological conditions for coalbed methane reser- voir, abundant combed gas resources, and favorable exploitation conditions.