Seismic Characteristics and Distribution Patterns of Maokou Formation Dolomite Reservoirs in The Hechuan Area of Central Sichuan

Abstract

Abstract In recent years, the exploration of dolomite reservoirs of the Permian Maokou Formation in the Hechuan area has made a breakthrough, making the Maokou Formation the main exploration layer in the central part of the Sichuan area. The reservoir lithology of the Maokou Formation in central Sichuan is mainly composed of fine to medium crystalline dolomite and residual granular dolomite. The dolomite reservoir is relatively thin, located in the middle of the second member of Maokou Formation vertically and distributed stably laterally. Based on rock physics, this study analyzes the factors influencing the seismic response characteristics of the dolomite reservoir of Maokou Formation, and makes it clear that the dolomite reservoir shows the characteristics of continuous strong peak reflection in the seismic profile. By analyzing the positive correlation between reservoir quality and amplitude intensity, the amplitude attribute can be used to determine the favorable area of dolomite reservoir development, and the reservoir distribution can be quantitatively described by seismic inversion. According to the seismic attributes, the dolomite reservoirs are distributed in contiguous regions, mainly along the TS3 ~TS4~TS11~MX39, which are distributed in a NW - SE direction. Seismic inversion results further clarify the stable distribution of dolomite reservoirs, with regional contiguous features. Through the study, it is clear that the favorable area of the dolomite reservoir in the second member of Maokou Formation is distributed in the central part of the Hechuan area, and the area of the reservoir is more than 1200km2. Multiple Wells have been deployed to obtain more than one million square meters of industrial air flow, and billions of square meters of proved reserves have been submitted.