A novel approach to quantify reservoir pressure along the horizontal section and to optimize multistage treatments and spacing between hydraulic fractures

2023

PurposeThe purpose of this study is to investigate the unstable propagation of parallel hydraulic fractures induced by interferences of adjacent perforation clusters and thermal diffusion. Fracture propagation in the process of multistage fracturing of a rock mass is deflected owing to various factors. Hydrofracturing of rock masses in deep tight reservoirs involves thermal diffusion, fluid flow and deformation of rock between the rock matrix and fluid in pores and fractures.Design/methodology/approachTo study the unstable propagation behaviours of three-dimensional (3D) parallel hydraulic fractures induced by the interferences of adjacent perforation clusters and thermal diffusion, a 3D engineering-scale numerical model is established under different fracturing scenarios (sequential, simultaneous and alternate fracturing) and different perforation cluster spacings while considering the thermal-hydro-mechanical coupling effect. Stress disturbance region caused by fracture propagation in a deep tight rock mass is superimposed and overlaid with multiple fractures, resulting in a stress shadow effect and fracture deflection.FindingsThe results show that the size of the stress shadow areas and the interaction between fractures increase with decreasing multiple perforation cluster spacing in horizontal wells. Alternate fracturing can produce more fracture areas and improve the fracturing effect compared with those of sequential and simultaneous fracturing. The larger the temperature gradient between the fracturing fluid and rock matrix, the stronger the thermal diffusion effect, and the effect of thermal diffusion on the fracture propagation is significant.Originality/valueThis study focuses on the behaviours of the unstable dynamic propagation of 3D parallel hydraulic fractures induced by the interferences of adjacent perforation clusters and thermal diffusion. Further, the temperature field affects the fracture deflection requires could be investigated from the mechanisms; this paper is to study the unstable propagation of fractures in single horizontal well, which can provide a basis for fracture propagation and stress field disturbance in multiple horizontal wells.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical analysis of unstable propagation of three-dimensional parallel hydraulic fractures induced by interferences of adjacent perforation clusters and thermal diffusion

2023

“…In the process of hydraulic fracture propagation, 3D fractures are accompanied by spatial deflection and compression between fractures, resulting in unstable fracture propagation [7,8]. The perforation cluster spacing of multistage fracturing causes deflection of Energies 2022, 15, 4888 2 of 15 hydraulic fractures to varying degrees, and the unstable propagation of fractures affects the control and design of the final fracture network [9,10].…”

Section: Introductionmentioning

confidence: 99%

Deflection of Hydraulic Fractures and Shear Stress Disturbance Considering Thermal Effects: A Numerical Case Study

Liu

2022

Energies

Quantitative characterization of propagation behaviors and morphology of hydraulic fractures is crucial for controlling and optimizing hydrofracturing effects. To study the disturbance deflection behaviors of multiple hydraulic fractures, a three-dimensional field-scale numerical model for multistage fracturing is established to study the shear stress disturbance and unstable propagation behavior of hydraulic fractures under different perforation cluster spacing. In the model, the thermal diffusion, fluid flow and deformation in reservoirs are considered to describe the thermal-hydro-mechanical coupling. In the numerical case study, the derived results show that the thermal effect between fracturing fluid and rock matrix is an important factor affecting fracture propagation, and thermal effects may increase the extent of fracture propagation. The size of stress shadow areas and the deflection of hydraulic fractures will increase with a decrease in multiple perforation cluster spacing in horizontal wells. The shear stress disturbance caused by fracture propagation is superimposed in multiple fractures, resulting in the stress shadow effect and deflection of fractures.

“…In addition to the coupling of multiple physical fields, which is an internal factor affecting the internal properties of rock mass, the interaction of multiple fractures in fracture propagation also affects fracture propagation. In the process of hydraulic fracture propagation, 3D fractures are accompanied by spatial deflection and compression between fractures, resulting in unstable fracture propagation (Wong et al, 2013;Manriquez et al, 2017). The different perforation cluster spacing of multistage fracturing will cause different degrees of of hydraulic fractures spatial deflection, and the unstable propagation of fractures will affect control and design of final fracture network (Zhang and Jeffrey, 2012;Bažant et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Spatial Deflection of Parallel Hydraulic Fractures and Induced Shear Stress Disturbance Under Different Perforation Cluster Spacing Considering Thermal Effects

Liu

Cui

et al. 2022

Front. Built Environ.

Reliable estimation of fracture network length and morphology in hydrofracturing is crucial for controlling and optimizing fracturing effects. Hydraulic fracture propagation will be affected by a variety of factors to produce deflection, resulting in different fracture network morphology. To study the spatial deflection behaviours of multiple parallel hydraulic fractures, three-dimensional engineering-scale numerical model for multistage fracturing is established to study the induced shear stress disturbance and unstable spatial propagation behavior of hydraulic fractures under different perforation cluster spacing. In the model, the thermal diffusion, fluid flow and deformation of rock between the rock matrix and fluid in pores and fractures are considered to describe the thermal-hydro-mechanical coupling. In this study, the results show that the thermal effect between fracturing fluid and rock matrix is an important factor affecting fracture propagation, and thermal effects can increase induced shear stress area and promote fracture propagation. The induced shear stress disturbance caused by fracture propagation is superimposed in multiple fractures, resulting in stress shadow effect and spatial deflection of parallel fractures. The stress shadow areas and the spatial deflection of parallel hydraulic fractures will increase with the decrease of multiple perforation cluster spacing.