华北石炭、二叠系煤化变质程度与煤层气储集性的关系  

RELATIONS BETWEEN METAMORPHISM AND COAL-BED GAS RESERVOIRING OF CARBONIC-PERMIAN IN NORTH CHINA

作　　者：宁正伟[1] 陈霞[1] 

机构地区：[1]地质矿产部华北石油地质局地质研究大队

出　　处：《石油与天然气地质》1996年第2期156-160,共5页Oil & Gas Geology

基　　金："八五"国家重点科技攻关项目

摘　　要：煤化变质程度与煤层气储集性关系密切。华北石炭、二叠系煤化变质程度分为低、中、高三级。低演化变质程度的煤，微孔隙发育而大中孔隙及裂隙不发育，渗透率和解吸率虽然较高，但吸附性和甲烷含量较低，对煤层气的扩散、运移不利。高演化变质程度的煤因受高温高压的影响，亦是微孔隙较发育而大中孔隙及裂隙不发育，虽然吸附性和甲烷含量高，但渗透率和解吸率都低，是储层评价中不利的煤级。中演化变质程度的煤，因温度和压力适中，产生大量的内裂隙，大中孔隙十分发育，增加了渗透性和孔隙连通性，大量的气体生成后得以吸附保存，在勘探开发中易降压、解吸、扩散和运移，是煤层气勘探中最有利的煤级。太原－长治－郑州弧形高演化变质带的内外翼及弧形内侧太行山东麓含煤区是寻找煤层气的有利地区。Reservoiring property bears close relation to metamorphic grade. According to the metamorphic grade, the Carboniferous and Permian Systems in North China could be divided into three kinds. In lower metamorphic coal beds, micropores developed well, but middle to big pores and fractures are not so well; though permeability and desorption are high enough, sorption capacity and methane content are both low. This kind of coal formations are not favourable for the diffusion and migration of coal-bed gas. High metamorphic coal suffered high pressure and high temperatiure, contains rich micropores, less fractures and less big to mid size pores. This kind of coal is not good in reservoiring property even if its sorption capacity and methane content are high. Mid metamorphic grade coal contains large amounts of internal fractures, big and mid pores developed well due to proper temperature and pressure. Most of the gas could be sorbed and preserved after generation, and the gas could be degraded, desorbed and migrated easily. This kind of coal is most favourable for coal-bed gas exploration. So it is proposed that the coal-bearing areas of the outer and inner flanks, the arc inside Taiyuan-Changzhi-Zhengzhou high metamorphic zone and the esat foot of Taihang Mountains should be taken as target areas for coal-bed gas explortion.

关 键 词：煤层气 石炭 二叠系 煤化变质程度 储层 

分 类 号：P618.130.2[天文地球—矿床学]