Relation of diagenesis and pores in conglomerate reservoir of deep Sha 3 formation of Langgu sag

Conglomerate reservoir in deep Sha 3 formation of Langgu sag was buried below 3 500 m. The conglomerate is mainly Proterozoic limestone showing striking diagenesis of late genetic stage. The diagenesis was mainly compaction , cementation and dissolution. It was dissolution that resulted in developed secondary pores and improving of permeability of conglomerate reservoir, and was a necessary condition of forming deep conglomerate reservoir. At high temperature, the solubility of limestone is lower than that of dolomite, therefore the porosity of dolomite conglomerate reservoir is more developed than that of limestone, and reservoir forming conditions were also better than that of limestone conglomerate reservoir.