Reservoir pore structure features and evolutionary pattern under saline sedimentary environment - taking Mawangmiao oilfield as an example

Through careful reservoirs study in Mawangmiao area, this paper reveals the microscopic feature and macro-feature of pore textures. The sedimentary environment and reservoir features under saline sedimentary conditions are different from those in fresh water sedimentary conditions. In this area, pore types of sandstone reservoir in lower member of Xingouzui formation are mainly interpar-ticle dissolved porosities; the throat shapes are mainly sheet, forniciform sheet and punctuate; the reservoir properties in Ⅱ,Ⅲ oil sets are better than Ⅰ oil sets; the pore distribution has a characteristic of zoning; the pore and throat collocations are mainly big medium throat, big pore coarse throat and medium pore medium throat are secondary. Pore textures are influenced by sedimentary environment and diagenesis. Taking Ⅱ oil sets of Ma36 well as an example, quantitative model of pore evolution has been established.