RESERVOIR CHARACTERISTICS AND GEOCHEMICAL EVALUATION OF THE UPPER PERMIAN LONGTAN FORMATION SHALE IN SOUTHWESTERN GUIZHOU, CHINA

The Longtan Formation of the Upper Permian in the southwestern Guizhou Province is widely exposed in the area. From the northwest to the southeast, there are terrestrial, sea-continental and marine sediments with thicknesses ranging from 0 to 543 m. The mudstone intervals are thicker. Good shale gas reservoir conditions. Through the reservoir characteristics of the Upper Permian Longtan Formation shale in the southwestern Guizhou and the kerogen (soul group and vitrinite, chitin group, inertin group), organic carbon content (TOC) and organic maturity (Ro) and other analytical studies. The results show that the organic matter types of the shale in the Longtan Formation are mainly type II2, and II1 and III are present. The organic carbon content is 4.54% on average and the organic carbon content is very good. The maturity of organic matter averaged 2.03%, and the degree of evolution was generally higher. The Longtan Formation mud shale has low porosity and low permeability, and the water medium has a certain softening effect on rock strength. The favorable area is mainly located in the east of the ShuichengPu'an-Xingyi line.