酒东坳陷深部下沟组下段储层特征及控制因素

根据大量钻井及岩心资料，结合薄片鉴定、扫描电镜、X-射线衍射和压汞实验等测试手段，对酒东坳陷深部下白垩统下沟组下段储层特征及其控制因素进行研究。研究表明，下沟组下段砂岩以长石质岩屑砂岩和岩屑质长石砂岩为主，成分成熟度和结构成熟度均较低，储集空间主要为次生溶蚀孔隙，同时也发育有原生粒间孔隙和裂缝，储层整体表现为特低孔特低渗的特征。该套砂岩储层储集性能主要控制因素为沉积相和成岩作用。沉积相带控制着砂体平面展布，成岩作用主要影响储层的孔隙结构特征和物性，其中压实作用和胶结作用导致储层的原生储集空间大量损失，储层物性被严重破坏，而溶蚀作用是孔隙得以改善的主要因素。

Reservoir Characteristics and Controlling Factors of Lower Member of Xiagou Formation in Jiudong Depression

According to massive drilling data,core samples as well as identification of casting thin sections,electron scanning microscope,X-ray diffraction,and capillary pressure experiments,we discuss the reservoir characteristics in lower member of Xiagou Formation in the Jiudong depression and their controlling factors.The feldspar lithic sandstones and lithic arkose are dominated in the lower member of Xiagou Formation,indicating the low maturity of rock composition and structure.The secondary dissolution pores are the dominant reservoir spaces,and the primary intergranular pores and fratures are secondary.The reservoir is characterized by extra-low porosity and extra-low permeability.The main controlling factors of reservoir development are sedimentary facies and diagenesis.Sedimentary facies determine the distribution of sandbody while diagenesis affects the pore structure and reservoir properties.Compaction and cementation caused great loss of primary pores space and destroyed physical property of reservoir,but dissolution led to development of secondary pores,and increase porosity and permeability of reservoir.