山东东营牛庄洼陷沙三中亚段浊积砂体储层特征及影响因素

山东东营牛庄洼陷沙三中亚段浊积砂体储层以长石细砂岩、岩屑细砂岩及粉砂岩为主 ,结构成熟度及成分成熟度均较低。储层微观特征研究表明 ,砂体中发育了剩余原生粒间孔、粘土矿物杂基内的微孔隙、粒间溶孔、粒内溶孔及微裂缝等储集空间类型 ,孔隙结构以低渗细喉型为主 ,为物性较差的中低孔、低渗型储层。通过对储层物性影响因素的研究得出 ,岩石组构、沉积微相、成岩作用和异常超压的形成与分布是影响本区浊积砂体储层物性的主要因素。其中 ,碳酸盐胶结物、硅质胶结物及自生粘土矿物是致使储层物性变差的主要原因 ,沉积物中有机质的大量生烃以及粘土矿物在转化过程中所释放出的酸性水的溶解作用是产生次生孔隙的重要因素 ,而异常超压的存在、高的地温场及烃类的早期进入是部分原生孔隙和次生孔隙得以保存的重要条件。

RESERVOIR CHARACTERISTICS AND INFLUENCE FACTORS OF THE TURBIDITE SANDBODY SHASAN INTERMEDIATE MEMBER IN THE NIUZHUANG SAG,DONGYING DEPRESSION,SHANDONG PROVINCE

Turbidite sandbody reservoir of the Shasan intermediate member at the Niuzhuang sag of Dongying in Shandong Province,mainly consists of feldspathic packsand, litharenite and siltstone with low compositional maturity and textural maturity. An investigation for microscopic reservoir characteristics shows that the type of the reservoir pore space include primary pore, micro-pore of clay mineral matrix, intergranular dissolution pore, intragranular dissolution pore and micro-fissure, and the pore structure is mainly characterized by low permeability-fine throat, and that the reservoir have medium-low porosity and low permeability and poor physical properties. Through the study on the factors which affect the reservoir physical properties, the authors of this paper think that rock composition and texture, sedimentary micro-facies, diagenesis and the generation and distribution of the abnormal high pressure systems are the main factors to control the reservoir physical properties. The carbonate cement, siliceous cement and authigenic clay mineral are the main causes of the poor physical properties. The dissolution of organic acid produced in wide hydrocarbon generation and transformation of clay minerals may produce substantial secondary porosity in reservoir, and the existence of the abnormal high pressure, high geothermal field and early hydrocarbon invasion are a crucial requirement for partial original porosity and secondary porosity to be preserved.