Prediction of tectonic fractures in low permeability sandstone reservoirs: A case study of the Es3m reservoir in the Block Shishen 100 and adjacent regions, Dongying Depression

An improved geomechanical model for the prediction of fracture generation and distribution in brittle reservoirs

“…Commonly, tectonic fractures are divided into tensile and shear fractures based on the formation mechanism, and they can be discriminated with the Griffith Criterion and Coulomb-Navier Criterion (also called the Mohr-Coulomb Criterion), respectively [ 52 ], [ 33 ], [ 53 ], [ 13 ]. For the fractures under confining pressure conditions, if there existed only compressive stresses ( σ 3 ≥ 0), the Mohr-Coulomb criterion would be selected, which was …”

“…In general, tight sandstone reservoirs distinctively differ from conventional reservoirs because of their great burial depth, strong diagenesis, strong heterogeneity, abnormal overpressure, low porosity and low permeability, and developed fractures [ 4 ], [ 5 ], [ 6 ], [ 7 ]. In these tight low-permeability sandstones, the majority of reservoir spaces and seepage channels for hydrocarbon are primarily provided by widely distributed natural fractures, especially tectonic fractures, which can significantly and effectively improve the permeability of a reservoir and enhance hydrocarbon delivery to wellbores [ 8 ], [ 9 ], [ 10 ], [ 11 ], [ 12 ], [ 13 ]. Therefore, understanding and interpreting where and when tectonic fractures develop within a geological structure, along with their orientation, intensity and porosity, are important in both exploration and production of tight sandstone reservoirs.…”

Development Characteristics and Quantitative Prediction of Multiperiod Fractures in Superdeep Thrust-Fold Belt

“…Stress field simulation is usually influenced and restricted by many factors such as buried depth, structure (e.g., folds and faults), strata thickness, rock mechanical properties, and 10 Lithosphere boundary conditions [15,56,[64][65][66]. In this simulation, based on log interpretation and rock mechanics experiments, the mechanical parameters of different elements in K 1 bs formation were calculated by dynamic-static corrections.…”

“…Geomechanical Models of Fracture Density and Aperture. Generally, the formation of shear fracture and tension fracture are, respectively, described by the Coulomb-Navier criterion (i.e., Mohr-Coulomb Criterion) and Griffith criterion [15,64,71,72], which is called as elastic-plastic composite criterion relating normal stress and shear stress. For subsurface structural fractures, if there were only compressive stresses (σ 3 ≥ 0), the Mohr-Coulomb criterion would be preferred as follows:…”

“…In particular, for deep/superdeep tight sandstones, structural fractures are widely developed due to their distinct characteristics from other conventional reservoirs, such as large burial depth, large pressure coefficient, high compaction, high reservoir heterogeneity, super-low permeability, and developed structural fractures [8][9][10][11][12]. This extensively developed structural fracture system is not only an important seepage channel and space of the tight sandstone reservoir but also seriously affects the productivity of a single well [13][14][15][16][17]. Therefore, understanding where the subsurface structural fractures develop and when they were formed, including their development degree, physical properties, and seepage characteristics, is very important for the effective exploration and development of fractured tight reservoirs.…”