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

Abstract

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.

Unstable propagation of hydraulic fractures under varying well spacing and initiation sequence of multiple horizontal wells considering shear stress shadows

“…The numerical discretization of the coupled governing equations and the fracture criterion based on the form of fracture energy can be used from the literature of previous relevant researches (Wang et al. , 2019; Wang, 2023).…”

“…The main mechanism of the coupling process is shown in Figure 2 (Wang et al, 2019). Through the transfer between the solid stress, fluid pressure, heat and fracture network, the thermal-hydro-mechanical coupling and fracture network mechanisms are introduced (Wang et al, 2019;Wang, 2023).…”

“…The total fracture length of alternate fracturing is longer than that in simultaneous and sequential fracturing; it is, however, the best method for volume fracturing (Liu et al, 2020). By building a three-dimensional numerical model based on actual reservoir data, the continuous and simultaneous fracturing of multiple vertical wells in tight reservoirs can be analyzed in three dimensions (Wang, 2023).…”

“…, 2020). By building a three-dimensional numerical model based on actual reservoir data, the continuous and simultaneous fracturing of multiple vertical wells in tight reservoirs can be analyzed in three dimensions (Wang, 2023).…”

The Influence of the Thermal Treatment of Copper Slag on the Microstructure and Performance of Phosphate Cements

“…Three different metakaolins, along with waste-fired brick, were utilized in the production of the geopolymers. As the availability of raw material resources [ 13 , 14 ] becomes more and more limited, the need to find alternative precursors based on waste or industrial by-products intensifies. For ecological reasons, the valorization of these by-products can reduce the huge amount of produced slag, which remains unutilized.…”