APPROACHES TO THE DIAGENESIS OF SANDSTONES AND THE RELATIONSHIP BETWEEN ORGANIC MATTER AND CLAY MINERAL——An Example of Diagenetic Changes in Oligocene Reservoir of Dongpu Depression

Based on the researches on the diagenesis of Oligocene sands tone-mudstone sequences in Dongpu Depression,the authors of this paper analyse the diagenesis and the relationship between organic matter and clay mineral.It reveals that the transformation of the clay minerals is closely related to the thermal evolution of organic matter.Simultaneously,the diagenesis of the sandstones would,somehow,depend on the evolution of organic matter and through their influence on the property of porous water.The understanding of such a relationship would be favourable for the prediction of secondary porosity and the evolution of organic matter in other basin.Meanwhile,the possible diagenesis reaction and changes are also discussed theoretically.