鄂尔多斯盆地王家湾地区长2油层组储层特征及分类评价

Study on Reservoir Characteristics and Classified Evaluation of Chang-2 Oil Layer in Wangjiawan Block,Ordos Basin

为了充分认识王家湾地区长2油层组储层特征,并提出合理的分类评价方法,本文综合运用砂岩普通薄片、铸体薄片、扫描电镜和压汞资料等,对研究区长2油层组储层岩石学特征、储集空间特征及物性特征进行了研究,在分析影响储层物性主控因素的基础上对储层进行了分类评价。研究结果表明:研究区长2油层组储层以长石砂岩为主;储层孔隙以原生粒间孔隙和溶蚀孔为主,储层孔隙结构可分为3种类型;储层孔隙度平均为12.41%,渗透率平均为21.68mD,属于低孔低渗储层;成岩作用和沉积微相是储层发育的主要控制因素。依据储层物性、孔隙结构以及沉积微相等因素,将研究区长2油层组储层分为3种类型,其中Ⅰ类储层最好,Ⅱ类储层中等—好,Ⅲ类储层最差。各类储层平面上的分布明显受沉积微相控制。以上研究成果对研究区精细开发有一定的借鉴意义。

In order to fully research reservoirs＇ characteristics of Chang-2 oil-bearing formation in Wangjiawan area,and to put forward reasonable classification and reservior evaluation methods,this paper studied the characteristics of reservoir petrologic,the type of reservoir space and physical property which based on the data of common sandstone thin section,casting thin section observation,scanning electron microscope study and mercury penetration data of Chang-2 oil-bearing formation in Wangjiawan area.Furthermore,through analyzed the mainly controlling factors of reservoir physical properties,we conducted the classification and evaluation for the reservoir.The results showed that Chang-2 oil bearing formation reservoir＇s lithologic character is an arkose sandstone.Primary intergranular pore and dissolved pore are the dominant reservoir spaces,the reservoir pore structure can be classified into three types.The reservoir shows the character of low porosity and low permeability,with an average porosity of 12.41% and an average permeability of 21.68 mD.Diagenesis and sedimentary microfacies are the main controlling factors for reservoir development.Based on three main factors（permeability,pore structure types and sedimentary micro-facies）,the paper classified reservoir into three types.TypeⅠ reservoir shows the best quality of physical property and oil gas potential,typeⅡ reservoir ranks the medium-good level compared with typeⅠ,and theⅢtype reservoir is the worst one.All types of reservoir distribution is controlled by sedimentary microfacies.The research results have certain significance for the fine development of the study area.