Reservoir characteristics of the first member of Middle Permian Maokou Formation in Sichuan Basin and its periphery and inspirations to petroleum exploration, SW China

SU Chengpeng,LI Rong,SHI Guoshan,JIA Huofu,SONG Xiaobo

Fig. 11. Genetic features of the reservoir with LMAs in shallow water exposed area. (a) The marl layer is loose and porous because of the dissolution of aragonite and high-magnesium calcite during early seawater burial diagenesis; (b)The limestone layer is cementing and compact due to CaCO3 precipitation during early seawater burial diagenesis; (c) The transformation of relatively dense limestone layer by meteoric freshwater is limited during the stage of eogenetic karstification; (d) The petrophysical properties of marl layer is further improved by meteoric freshwater during the stage of eogenetic karstification; (e) Continuously/discontinuously beaded limestone layer along beds occurred because of differential compaction during deep burial; (f) Disorderly limestone layer occurred because of differential compaction during deep burial.