宜川—旬邑地区长 6 ∼ 长 8 油层组成岩作用特征

通过岩芯观察, 铸体薄片、 扫描电镜、 阴极发光、 碳氧同位素、 粘土矿物 X 衍射及流体包裹体等测试分析指出, 宜川—旬邑地区延长组长 6 ∼ 长 8 油层组主要为灰色、 灰褐色、 灰白色长石砂岩和岩屑长石砂岩,储集层砂岩经历了机械压实、 胶结、 溶蚀和交代等一系列成岩作用。X 衍射分析显示该区常见的粘土矿物主要是伊利石、 伊利石／蒙皂石混层、 绿泥石等, 镜质体反射率测试 Ro为 1.03∼1.31, 结合包裹体测温及成岩现象等综合研究表明： 该区油层组砂岩主要进入了晚成岩 A2亚期, 部分已经达到了晚成岩 B 早期, 且厘定了该区的成岩作用序列, 指出压实作用和胶结作用是导致该区储层物性变差的主要因素, 长 6 长 8 油层组因压实作用与胶结作用损失的孔隙分别达 23.82%, 25.65%, 3.99% 和 3.31%, 溶蚀作用新增孔隙度分别仅为 0.84% 和 0.83%, 储集层砂岩绿泥石环边的生长与早期石英弱次生加大对原生孔隙的保存起到了极大的积极作用, 旺 9 井—旺 16 井区、 旺 6 井区及庙 38 井区为该区有利成岩相展布区域, 在平面上开展有利成岩相研究可以有效地指导该区优质储层的识别与预测, 为该区油气勘探服务。

CONTROLLING EFFECT OF METEJAN PALEOSTRUCTURE ON THE FORMATION OF GAS RESERVOIR

In order to obtain the controlling factors of reservoirs and gas productive concentration rules,the formation and evolution of Metejan fracture are studied by layer flattening technique.From the study,the forming period and scale of Palaeostructure and Neotectonics are clarified.Through the study of the timespace relationship between gas generation,migration and formation,the main controlling factors of reservoirs are found.The research result shows that Neotectonics have little effection on the formation of gas reservoir,while Paleostructure have more effects on the formation of gas reservoir.The size of Paleostructure determines the reservoir scales and gas distribution.The research on controlling factors of reservoirs has clarified the gas reservoir type and highyield & enrichment rules.Wells located in super or upslope of Paleostructure have high level of production and better physical property.On the contrary,wells located in the bottom or downslope have a low level of production and poor physical property.