荥巩煤田谷山井田构造演化与煤层气含量的关系  

Relations between tectonic evolution and coalbed methane content in Gushan coal mine of Xinggong coalfield

作　　者：林晓英[1] 苏现波[1] 颜少权[2] 

机构地区：[1]河南省生物遗迹与成矿过程重点实验室 [2]河南省地矿局第十一地质队,河南商丘476000

出　　处：《河南理工大学学报（自然科学版）》2008年第2期168-172,共5页Journal of Henan Polytechnic University（Natural Science）

基　　金：国家自然科学基金重点项目(50534070-104);国家自然科学基金资助项目(40602017);河南省生物遗迹与成矿过程重点实验室开放课题(otmp0803)

摘　　要：煤层气含量及其控制因素的研究是煤矿瓦斯灾害预测和煤层气的可开发性评价的基础.根据勘探和建井阶段的资料,荥巩煤田谷山井田东部山西组二1煤埋深200 m以下的区域,煤层气含量与井田构造演化有着密切的关系.印支期(T末)在正常地温梯度下发生第一次生烃和燕山期(J3-K1)在异常热事件作用下发生了第二次生烃,奠定了高含气量的基础.但由于燕山期煤体所受温度极高(300℃),煤的理论吸附量不超过15 m3/t.K2到喜山早期,随南部嵩山不断隆起,浅部煤层中的煤层气在地下水作用下向深部运移,在滞留区煤层内聚集.这一时期构造决定的地下水动力条件控制着煤层气的运移富集.第三纪晚期形成的滑动构造使煤体破坏严重,储层渗透性降低,沿滑动构造面形成的糜棱岩带增加了煤的吸附能力,阻止了煤层气的扩散,并可能存在动力变质引起的生烃,对含气量进行补充.The study of coalbed methane content and its controlling factors is the foundation of gas hazards forecasting and coalbed methane exploitability assessment. Based on data obtained from coal and coal mine exploration, and measured data, there is osculating relation between coalbed methane content and tectonic evolution in the area, where the burial depth of No. Ⅱ1 coal seam is more than 200 m in the east of Gushan coal mine. The first hydrocarbon generation occurred with a normal paleogeothermal gradient during the end of Triassic. From the late Jurassic to the end of Cretaceous, the hydrocarbon generation reached its peak during Yanshanian orogeny caused an abnormal thermal event, which established the foundation of high gas content. The theoretic adsorption capacity is less than 15 m^3/t. From the late Cretaceous to the forepart of Himalayan orogeny, the groundwater migrated from the south to the deep part because the Songshan mountain was continually uplifted in the south. The coalbed methane in the shallow coal seam migrated to the deep part, and accu- mulated in the deep stagnant zone. In this period, The hydrodynamic was decided by techtonic setting,whieh eontrolled the migration and aeeumulation of eoalbed methane. The eoal body was seriously destroyed beeause of sliding strueture whieh formed in the late Tertiary. The permeability of eoal reservoir redueed whieh inereased the adsorption eapability of eoal. The mylonitie eoal zone formed along with sliding strueture surfaee, whieh prevented eoalbed methane diffusing. There probably existed hydroearbon generation that eaused by dynamometamorphism, to eomplement eoalbed methane eontent.

关 键 词：谷山井田 构造演化 煤层气 含气量 

分 类 号：P618.11[天文地球—矿床学]