鄂尔多斯盆地杭锦旗地区上古生界砂岩中储层粘土矿物特征分析

ANALYSIS OF CHARACTERITICS OF THE CLAY MINERALS IN THE UPPER PALAEOZOIC SANDSTONE RESERVOIR OF HANGJINQI AREA IN NORTH ORDOS BASIN

鄂尔多斯盆地杭锦旗地区上古生界砂岩储层中普遍发育粘土矿物，根据岩心薄片观察，自然γ能谱测井交会图识别出的粘土矿物类型有高岭石、伊利石、蒙脱石、绿泥石。薄片分析按粘土矿物形成方式划出沉积粘土和成岩粘土（蚀变、转变厦化学成因粘土），以及按其产出状态尚划出构造（骨架）粘土和结构（填隙）粘土，并定量分析出构造粘土和结构粘土含量在多数层段分别为20％以上与10％～18％。依据自然γ能谱测井分析采用多元线性逐步回归分析法，查明各粘土矿物含量同Th，U，K质量分数之间的相关系数都大于0．85，建立了粘土矿物定量计算模型X=a-b×Th＋c×U＋d×Th／K还对储层中粘土矿物进行预测及粘土矿物的纵向分布特征分析。

The clay minerals is well-developted in Upper Palaeozoic sandstone reservoir of Hangjinqi area in Ordos basin. The studies of thin sections of rocks and the natural gramma-ray spectrum logging cross plots reveal that the main clay minerals consist of kaolinite,illite ,montmorillonite ,chlorite. Thin-section analysis of rocks also subdivide the clays into sedimentary clay and diagenesis clay by formation manner as well as tectonic clay and structure clay by yielding state. The content of the tectonic clay is over 20% and structure clay is about 10%-18% for the main farmation. By the analysis of the natural gramma-ray spectrum logging,using the stepwise mhiple regression way ,the relationships between clays and the content of Th,U,K is acertained ,with the correlation coefficient of over 0.85. A quantitative models for caculating the clay minerals is established to predict the content of the clay minerals in the sandstone reservoir as well as analy size the vertical distribution characteristics of the clay minerals.