We try to figure out the complicated process of diagenesis by studying a whole diagenetic system, which are composed of the deeply buried (3100∼3300m) lenticular sandbodies and the surrounded shales. We used 141 core samples, including sandstones and shales, and the analysis of thin section, X-Ray Diffraction, Scanning Electron Microscopy and Cathodoluminescence Micrography to analyze those samples' diagenesis heterogeneity. We found the lenticular sandstones got high porosity (20%) at the interior and low porosity (4%) at the SSC. The reason for low porosity was the present of carbonate cements. Shale supplied the source for a portion of the diagenetic cements...