INFLUENCE OF THE DIAGENESIS OF CLAY MINERALS ON RESERVOIRS AND PRODUCTIVITY-A CASE STUDY ON THE FU-3 RESERVOIRS OF TAIXIN oil field, THE NORTH JIANGSU BASIN

On basis of X ray diffraction of clay minerals,analysis of resin cast thin sections of cores and SEM observation of samples in twelve wells,the clay mineral types and their distribution in four oil groups of the third member of Fuling Group in Taixin oil field,the northern Jiangsu Basin were described.The relationship between clay mineral types and porosity or pore structure of reservoirs was discussed.The inf luence of transform of clay minerals with geological evolution on reservoir character was analyzed.The results showed that kaolinite was positive correlation with porosity,but chlorite and illite were negative correlation with that.The chlorite showed obvious negative influence on preservation of porosity.Occurrence of secondary pores was accordance with the first rapid transform zonation of clay minerals in burial depth of 2 350-2 750m.The most favourable position for development of secondary pores was forecasted.