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Anisotropic Rock Poroelasticity Evolution in Ultra‐low Permeability Sandstones under Pore Pressure, Confining Pressure, and Temperature: Experiments with Biot's Coefficient
Author(s) -
DU Shuheng
Publication year - 2021
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.13886
Subject(s) - biot number , poromechanics , permeability (electromagnetism) , pore water pressure , porosity , mineralogy , feldspar , materials science , overburden pressure , bulk modulus , anisotropy , saturation (graph theory) , geology , geotechnical engineering , quartz , thermodynamics , composite material , porous medium , chemistry , optics , physics , biochemistry , mathematics , combinatorics , membrane
This study aimed to show anisotropic poroelasticity evolution in ultra‐low permeability reservoirs under pore pressure, confining pressure, and temperature. Several groups of experiments examining Biot's coefficient under different conditions were carried out. Results showed that Biot's coefficient decreased with increased pore pressure, and the variation trend is linear, but the decreasing rate is variable between materials. Biot's coefficient increased with increased confining pressure; the variation trend is linear, but the increasing rate varies by material as well. Generally, Biot's coefficient remains stable with increased temperature. Lithology, clay mineral content, particle arrangement, and pore arrangement showed impacts on Biot's coefficient. For strong hydrophilic clay minerals, expansion in water could result in a strong surface adsorption reaction, which could result in an increased fluid bulk modulus and higher Biot's coefficient. For skeleton minerals with strong lipophilicity, such as quartz and feldspar, increased oil saturation will also result in an adsorption reaction, leading to increased fluid bulk modulus and a higher Biot's coefficient. The study's conclusions provide evidence of poroelasticity evolution of ultra‐low permeability and help the enhancing oil recovery (EOR) process.