乌石凹陷流沙港组高岭石的分布特征、影响因素及演化

Distribution and evolution of kaolinite and its influencing factors in the reservoir of Liushagang formation of Wushi sag

高岭石广泛发育于乌石凹陷流沙港组,对储层物性具有重要的影响。以乌石凹陷流沙港组砂岩中的高岭石作为研究对象,通过岩石薄片、扫描电镜、阴极发光和X衍射等测试方法分析高岭石的分布特征、影响因素及演化规律。研究结果表明,垂向上,流一段高岭石含量最高,流二段其次,流三段最低;平面上,WSA区高岭石含量最高,WSC区其次,WSB区最低。高岭石与优质储层关系密切,影响高岭石分布的因素主要有温度及压力、构造运动、岩性差异和物源性质。通过分析长石溶蚀与高岭石差异沉淀,建立高岭石发育型储层的甜点发育模式。

Kaolinite is widely developed in Liushagang formation of Wushi sag,which has an important influence on reservoir physical properties.By taking the kaolinite in Liushagang formation sandstone of Wushi sag as the research object,the distribution characteristics,influencing factors and evolution rules of kaolinite were analyzed by means of thin section,SEM,cathodoluminescence and X-ray diffraction.The results show that in vertical direction the content of kaolinite is the highest in the first member of Liushaguang formation,the second in the second member,and the lowest in the third member.In the plane,the content of kaolinite is the highest in WSA area,the second in WSC area and the lowest in WSB area.There is a close relationship between kaolinite and high-quality reservoir.The main factors affecting the distribution of kaolinite are temperature and pressure,structural movement,lithologic differences and source properties.Based on the analysis of feldspar dissolution and kaolinite differential precipitation,the sweet spot development model of kaolinite developed reservoir was established.