Reservoir rocks of early Cretaceous Denglouku and Quantou Formation in the Yaoyingtai area of southern Songliao Basin are mainly composed of feldspathic litharenite and litharenite arkoses,with low compositional and textural maturity,belonging to ultra low porosity and permeability reservoir,The Denglouku Formation with high porosity and permeability distributes in the Y81 well field.With the line crossing YB4,Y8102 and Y8101 well as boundary,the western reservoir is of better porosity and permeability than the western part.The porosity and permeability of Quantou Formation decrease from south to north,and permeability falls more rapidly comparing to porosity.Diagenesis of the reservoir includes compaction,cementation,dissolution,replacement and secondary overgrowth.The study shows that the reservoir rocks is in the A period and B period of late diagenesis.Diagenesis mainly affects the porosity and permeability of reservoir.Compaction,cementation,replacement and secondary overgrowth of the reservoir rocks contribute to the rapid reduction of primary porosity and permeability,which are the main reasons resulting in the poor physical properties;but dissolution is the main factor for formation of secondary porosity,which improves the physical properties of the reservoir sandstones.%松辽盆地南部腰英台地区早白垩世登娄库—泉头组储层岩石类型以长石岩屑质石英砂岩、长石质岩屑砂岩和岩屑砂岩为主,岩石结构成熟度和成分成熟度均不高,为超低孔超低渗和特低孔特低渗储层。登娄库组储层孔隙度和渗透率的高值区主要分布在Y81井区。以YB4—Y8102—Y8101井一线为界,西部孔渗值较高、物性较好,东部孔渗值较低、物性变差。泉头组储层孔渗值总体上由南向北递减,其中渗透率值递减速率较快。研究区目的层段成岩作用类型主要有压实、胶结、溶蚀、交代以及次生加大五种作用;成岩演化处于晚成岩A期和B期,成岩作用对储集物性的影响主要表现为对孔隙度和渗透率的影响,其中压实、胶结、交代和次生加大作用使储层原生孔隙迅速减少、渗透率降低,是导致研究区储层物性变差的主要原因,溶蚀作用则是次生孔隙发育的主要因素,从而在一定程度上改善研究区砂岩的储层物性。
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