Identification of Diagenetic Facies Based on Diagenetic Process: An Example from Paleogene Lake Sediment Sandstone in Bozhong X Oilfield

Based on diagenetic evolution, reservoir diagenetic facies evolution was restored in burial history through quantitatively calculating the original porosity reconstructed by compaction, cementation and dissolution using core measurement data. The essence of this method was illustrated and its effectiveness was demonstrated using Paleogene lake sediment sandstone in Bozhong X oilfield, Bohai Bay Basin, China. Because diagenetic field changes as the structure depth increases or decreases and acts on deposition, diagenetic facies can be significantly different in different geological period. The Ed1 reservoir has experienced such an evolutionary process of W-Com_W-Cla-C_M-Car-C to M-Com_M-Clay-C_W-Qua-C_W-Fel-D_W-Car-D to M-Com_M-Cla-C_W-Qua-C_W-Fel-D_W-Car-D, while the Ed 2 , the Ed3 and the Es 1 are W-Com_W-Cla-C to M-Com_M-Cla-C-S-Com_S-Clay-C_W-Qua-C_W-Fel-D to S-Com_S-Cla-C_W-Qua-C_M-Fel-D, M-Com_W-Cla-C_W-Qua-C_W-Fel-D to M-Com_M-Cla-C_W-Qua-C_W-Fel-D to S-Com_M-Clay-C_W-Qua-C_S-Fel-D to S-Com_S-Clay-C_M-Qua-C_S-Fel-D and M-Com_W-Cla-C_W-Car-C to M-Com_M-Cla-C_W-Car-C_M-Fel-D_W-Car-D to M-Com_M-Clay-C_S-Fel-D_M-Car-D to S-Com_M-Cla-C _S-Fel-D_ M-Car-D respectively. Through this study, the reason for the dynamic change of sand body in the diagenetic field and the anisotropy of the reservoir are revealed.