姬塬地区长6油层组砂岩储层中粘土矿物分布规律研究

Regularities of clay minerals distribution in sandstone reservoir of Chang 6 in Jiyuan district

为研究区寻找优质储层,指导勘探开发部署提供指导。以鄂尔多斯盆地姬塬地区延长组长6油层组砂岩储层中粘土矿物为研究对象,通过铸体薄片、扫描电镜、X衍射等方法对主要粘土矿物类型进行了研究;结合沉积环境,深入分析了粘土矿物的分布规律及控制因素;同时探讨了粘土矿物对储层物性的影响;从而研究表明,研究区储层中粘土矿物主要成份为伊利石、高岭石、绿泥石和蒙/伊混合层,且具有质点微小、比表面积大等特征。其形成与分布主要受沉积与成岩两大作用控制。其中,绿泥石含量东北体系高于西北体系;在长石溶蚀作用影响下,高岭石含量西部高于东部;沉积水体影响下,伊利石含量由北向南逐渐增大。绿泥石、高岭石对储层孔隙具有建设性影响,而伊利石主要破坏原始孔隙。粘土矿物组成及含量明显控制着储层平面上孔渗分布,使得相对高孔高渗区主要分布在研究区东北部,是下步勘探开发的主要对象。

In order to find high quality reservoir and provide guidance for oil exploration and development,the clay minerals of Chang 6 oil bearing formation（ Yanchang layer） in Jiyuan district,Ordos basin are studied. The types of clay minerals were identified by different methods,such as thin sections,SEM,X-ray scattering techniques,etc. Then,the distribution rule of different clay minerals were summarized and analyzed based on sedimentary environment. The influence of clay minerals on porosity and permeability were also discussed. Research results show that,main types of clay minerals are illite,kaolinite,chlorite and smectite / illite,with characteristics of micro particles,big specific surface area,etc. The generation and distribution of clay minerals are controlled by sedimentation and diagenesis process. The content of chlorite in northeast sedimentation system is much higher than that of northwest. While,the content of kaolinite northwest is higher than northeast because of minerals solution difference caused by feldspar. The content of illite is decreased from north to south,because of difference of water depth. Different clay minerals have various effect on porosity and permeability of reservoir,with chlorite and kaolinite have profitable effect,illite have detrimental effect on the controry. In short,the constitution and content of clay minerals have obvious effect on distribution of porosity and permeability. That northeast system in Jiyuan district with reservoir of high porosity and permeability is the main target for future oil exploration and development.