THE DISTRIBUTION CHARACTERISTICS OF CLAY MINERALS AND RESERVOIR SENSITIVITY IN THE LOWER SECTION OF XINGOUJU FORMATION

The combination and distribution of clay minerals in lower section of Xingouju Formation of Jiangling sag are obviously controlled by the sedimentary environment,kaolinite exists only in delta plain facies,the minerals are characterized by illite,kaolinite,ordered to disordered illite/montmorillonite mixing layer and small amount of chlorite.The clay minerals combination in delta front facies include illite,chlorite and ordered illite/montmorillonite mixing layer.The two main clay minerals in prodelta and lacustrine mudstone are illite and chlorite.The sensitivity test result shows that the reservoir has medium velocity sensitivity,strong-superstrong water sensitivity,strong salt sensitivity and strong acid sensitivity in the study area.