海陆过渡相泥页岩储层特征研究——以沁水盆地为例

通过扫描电镜、X射线衍射、压汞实验及等温吸附实验等对沁水盆地太原组泥页岩进行了实验分析,从地球化学特征、岩石学特征、物性与储集空间特征等方面对泥页岩储层特征进行了研究。结果表明,研究区太原组页岩气储层泥页岩厚50~70 m,储层有利层段为太原组上段,最大连续厚度为10.7~25.13 m;有机碳质量分数为0.12%~22.78%,平均为2.5%以上;成熟度为1.72%~3.6%,总体偏高,处于高-过成熟阶段;矿物成分以黏土矿物和石英为主,脆性矿物平均为32.12%~45.25%;微孔裂隙发育,类型多样。孔隙结构以微孔、小孔和超大孔为主,孔隙间连通性比较好。沁水盆地太原组泥页岩具有储层埋藏深度适中,泥页岩累计厚度大,有机碳含量高,脆性矿物含量高,微孔裂隙发育,孔隙间连通性好等特征,是页岩气的有利储集层。其不利条件主要表现在单层厚度小,黏土矿物含量高,成熟度较高等。

Characteristics of the mud shale reservoirs of transitional facies: with Qinshui basin as an example

From geochemistry, petrology-physical properties and characteristics of the reservoir space, the shale reservoir characteristics are studied by scanning electron microscope, X ray diffraction, mercury experiment and isothermal adsorption experiment analysis of mud shales from Taiyuan Formation in Qinshui basin. The results show that the shale reservoir of Taiyuan Formation is 50~70 m thick, the favorable reservoir layers are mainly upper Taiyuan Formation, the maximum continuous thickness is 10.7~25.13 m in the study area. Organic matter content is high, ranges from 0.12% to 22.78%, above 2.5% on average. The maturity is high, between 1.72% to 3.6%, belonging to a high-over mature stage. Mineral composition mainly includes quartz, clay minerals and its average content of brittle mineral is between 32.12%~45.25%.The micropores are well developed. The pore structure is mainly microporous, holes and large pore, pore connectivity is good. The shale of Taiyuan Formation in Qinshui basin has the characteristics of moderate buried depth of reservoir, large accumulated shale thickness, high organic carbon content, high brittle mineral, well developed micro fracture, good pore connectivity. The adverse conditions are small monolayer thickness, high clay mineral content and higher maturity.