Numerical Simulation of Hydraulic Fracturing in Heterogeneous Rock: The Effect of Perforation Angles and Bedding Plane on Hydraulic Fractures Evolutions

Abstract

Considering the heterogeneity of rock, the hydraulic fracturing process of rock specimen due to internal hydraulic pressure was numerically simulated in a meso-scale by RFPA2D2.0 (Realistic Failure Process Analysis). The differences of perforation angle, bedding angle and bedding material of rock specimens are considered. The numerical results showed that the initiation and propagation of hydraulic fractures were controlled by both global pore pressure's distribution gradient and local pore pressure around the crack tip. Both the lateral compressive pressure ratio and the bedding angle could affect the evolution of the hydraulic fractures. The numerically simulated results were in agreement with the experimental results.

Hydraulic Fracture Propagation in Layered Heterogeneous Rocks with Spatially Non-Gaussian Random Hydromechanical Features

“…18a, b. This behaviour is compatible with the results of Men et al (2013), who modelled the layered rock using parallel weak and highly permeable interfaces embedded in the rock matrix. The PDFs of the deviation angle for different cases of perforation angle and in situ stresses are shown in Fig.…”

“…The second approach, on which the current study concentrates, models the heterogeneities by spatially distributing material properties as random fields over the computational mesh, resulting in smooth spatial distributions of material properties. Numerical studies have previously modelled material heterogeneities by distributing randomly generated properties over the elements in three general patterns depending on the nature of the rock: (i) totally random with no auto-correlation, for example (Chen et al 2018;He et al 2021;Li et al 2016a;Li et al 2021;Sarmadi and Mousavi Nezhad 2021;Lu and He 2020;Men et al 2013;Pakzad et al 2018;Santillán et al 2017;Wang et al 2009); (ii) spatially correlated (auto-correlated) as stiff bulk inclusions (Li et al 2020(Li et al , 2021Tang et al 2018;Xia et al 2017); (iii) layered lithologic settings through use of anisotropic autocorrelation (Mousavi Nezhad et al 2018a, b;Li et al 2020Li et al , 2021.…”

“…Continuum-based fracture models can be recognised as the most widely used approaches in heterogeneous materials due to their inherent versatility in numerical implementation (Li et al 2016a;Li et al 2020;Li et al 2021;Lu and He 2020;Men et al 2013;Pakzad et al 2018;Santillán et al 2017;Xia et al 2017). Consideration of rock heterogeneity has been mainly of interest in studying the vertical fracture growth height in unconventional reservoirs (Li et al 2016a(Li et al , 2020Tang et al 2018) to look for possible arrests and possible fracture containment as well as in identifying its random effects on the HF trajectory (Chen et al 2018;He et al 2021;Men et al 2013;Pakzad et al 2018;Santillán et al 2017). Increasing the degree of heterogeneity in rocks usually results in lowering the breakdown pressure to initiate the HF propagation from the point of fluid injection (Li et al 2016a(Li et al , 2020Pakzad et al 2018).…”

A procedure to detect, construct, quantify, numerically simulate and validate fracture networks in coal blocks

“…The hydraulic fracturing is one of the critical techniques used in the production of shale gas, coalbed methane and extraction of geothermal energy. Men et al (2013) numerically simulated the hydraulic fracturing process in heterogeneous rock specimens using Realistic Failure Process Analysis (RFPA2D). The numerical results show that the initiation pressure, the breakdown pressure and the fracture evolution vary with the different bedding plane angles.…”