永进地区西山窑组成岩作用及储层影响因素

SANDSTONE DIAGENESIS AND THE INFLUENCE FACTORS ON RESERVOIR OF XISHANYAO FORMATION IN YONGJIN AREA

通过砂岩薄片、铸体薄片、扫描电镜、X-衍射分析,认为永进地区西山窑组砂岩储层主要经历过压实、胶结和溶蚀等成岩作用。由于岩石类型主要为岩屑砂岩,含较多的塑性岩屑,因此强烈的压实作用极大地降低了储层的孔隙度,是储层物性的主要破坏因素。溶蚀作用对储集层性质有一定的改善,产生的次生孔隙可达7%。分析表明,沉积相一方面控制了储层的分布;同时控制了压实以及溶蚀作用。另外,生烃导致的异常高压及早期油气充注对成岩作用具有抑制作用,在一定程度上改善了储层物性,为油气聚集提供了有利空间。

Based on the data analysis of casting lamella,scanning electron microscope and X-diffraction,the authors hold that Yongjin area Xishanyao Formation sandstone reservoir diagenesis includes compaction,cementation and dissolution.Because the plasticity lithic sandstone is the main component,the compaction lowers the reservoir porosity,which is the main damaging factor of the reservoir physical property.The dissolution improves the reservoirs physical property to some extent and could higher the porosity up to 7%.On the basis of the study above,the conclusion is reached that the facies control the distribution of the reservoir and have some influences on the compaction and dissolution,so beneficial facies belt is the base of good reservoir.On the other hand,high abnormal pressure of oil/gas generation and hydrocarbon emplacement occurred at early stage could prevent the lithologenesis,to some extent improve the reservoir porosity,and provide interspace for hydrocarbon accumulation.