煤系粗粒低渗储层自生粘土矿物特征及其对储层特性的影响——以焉耆盆地侏罗系三工河组油层为例

CHARACTERISTICS OF AUTHIGENIC CLAY MINERALS IN COARSE-GRAINED AND LOW PERMEABILITY RESERVOIRS IN COAL MEASURES AND ITS EFFECT ON RESERVIOR PROPERTY—AN EXAMPLE OF OIL RESERVOIR IN JURASSIC SANGONGHE FORMATION IN YANQI BASIN

姚光庆 孙尚如

Yao Guangqing Sun Shangru

中国中西部侏罗系煤系粗粒低渗储层中自生粘土矿物含量高,尤其是高岭石矿物的相对含量较高。焉耆盆地下侏罗统三工河组储层研究表明,粘土总量和高岭石含量在不整合面下随深度加大而减少,而伊利石和绿泥石的含量却随深度增加而加大。相同深度下,长石成分含量较高、厚度较大的主河道砂体中高岭石含量普遍较高。煤系地层中酸性流体介质环境下的水岩相互作用对粘土矿物的产生起关键作用。焉耆盆地粘土矿物的大量存在加剧了此类储层的低渗透性;增加了储层潜在敏感性;严重影响了油田增产效果。

The coarse-grained and low permeability sandstone reservoirs in Jurassic coal measures in west-central China is characterized by high content of authigenic clay minerals. Especially, the content of kaolinite is very high relative to other clay minerals. The study made in Yanqi basin shows that the total content of clay minerals and kaolinite content decreases with depth below the unconformity, but the content of illite and chlorite increases with depth. At same burial depth, the sandbodies with higher feldspar content and larger thickness in the main channel have more abundant kaolinite. The acidic fluid medium environment was the key factor controlling the formation of clay minerals in coal measure strata. The existence of abundant clay minerals has reduced the permeability and enhanced the sensibility of reservoir, and strongly affected the EOR efficiency in the oilfield.

10.11743/ogg20030116