Matrix Compressibility and Its Controlling Factors of the Marine Shale Gas Reservoir: A Case Study of the Ning228 Well in the Southwest Sichuan Basin, China

Exploring the compressibility of deeply buried marine shale matrix and its controlling factors can help achieve efficient petroleum production. Taking ten sets core samples from Ning228 wells in Yanjin area as an example, pore characteristics reservoirs were investigated by applying mercury intrusion porosimetry (MIP) nitrogen adsorption/desorption isotherms at a low temperature 77 K. Mathematical models (based on MIP isotherms) established to analyze effects TOC, mineral components, structure compressibility. The relationship between coefficient brittleness index was also established. results show that is significant when injection pressure ranges 8.66 37 MPa. For shale, range 0.23 × 10−4–22.03 10−4 MPa−1. influence TOC minerals mainly reflected control effect structure. High content decreases overall elastic modulus, high clay enhances stress sensitivity, resulting effect. compressibility, has positive In addition, pore-specific surface critical effective variation indicating complexity key factor affecting