鄂尔多斯盆地陇东地区长8段储层特征及成岩相定量研究

Reservoir Characteristics of Chang 8 Oil-bearing Formation and Quantitative Analysis of Diagenetic Facies in Longdong Area of Ordos Basin

综合铸体薄片、物性特征、岩心相等资料,系统分析了鄂尔多斯盆地陇东地区长8段油层组的储层特征,并以此为指导进行成岩相类型的划分;在此基础上优选出有利成岩相,以优势成岩相为主要依据,对区内有利储层成岩相带分布规律进行预测。结果表明,受成岩作用影响,研究区长8段储层可划分出4类成岩相,分别为杂基充填相(致密非储层)、碳酸盐胶结相(致密非储层)、绿泥石膜相(优质储层)和溶蚀相(相对优质储层)。孔隙演化规律的定量分析结果进一步优选出绿泥石膜相为研究区最有利成岩相。此外,平面成岩相分布规律研究表明,研究区有利成岩相带在平面上连续性好,分布区域较广,整体呈条带状分布于西北部环县地区和东南部合水地区,是优质储层发育的主要区域。

Based on the casting films,physical properties,core facies and other data,the reservoir characteristics of the Chang 8 oil-bearing formation in the Longdong area of Ordos Basin were systematically analyzed,and the classification of diagenetic facies was guided by reservoir characteristics.On this basis,the favorable diagenetic facies were selected and used as the main basis for predicting the distribution law of diagenetic facies in high quality reservoirs.The results have shown that affected by diagenesis,the diagenetic facies of the Chang 8 oil-bearing formation in the study area can be divided into four types,which are heterogeneous filling facies(tight non-reservoir),carbonate cemented facies(tight non-reservoir),chlorite membrane facies(high-quality reservoirs)and dissolution facies(relatively high-quality reservoirs).The quantitative analysis results of the pore evolution law further selected the chlorite membrane facies as the most favorable diagenetic facies in the study area.In addition,the distribution law of planar diagenetic facies shows that the favorable diagenetic facies belts in the study area are in a strip shape with good continuity and wide distribution,mainly in the northwestern Huanxian area and the southeastern Heshui area,which is the main area for high-quality reservoir development.