CDEM-based analysis of the 3D initiation and propagation of hydrofracturing cracks in heterogeneous glutenites

Ju, Yang; Liu, Peng; Chen, Jialiang; Yang, Yongming; Ranjith, P.G.

doi:10.1016/j.jngse.2016.09.011

Cited by 95 publications

(47 citation statements)

References 38 publications

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“…For analysing the effects of pre-existing microcracks on the supercritical CO 2 fracture network [32], the authors of this paper have established the threedimensional (3D) bonded particle models (BPMs), based on the discrete element method (DEM) [33]. For investigating the hydrofracturing cracks in heterogeneous media, the authors of this paper developed the continuum-based discrete element method (CDEM) [34]. The conventional FEM has limitations to deal with the fracture propagation; furthermore, the mesh refinements have to be adopted [35].…”

Section: Introductionmentioning

confidence: 99%

Adaptive Finite Element-Discrete Element Analysis for Microseismic Modelling of Hydraulic Fracture Propagation of Perforation in Horizontal Well considering Pre-Existing Fractures

Wang

Yang

2018

Shock and Vibration

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Hydrofracturing technology of perforated horizontal well has been widely used to stimulate the tight hydrocarbon reservoirs for gas production. To predict the hydraulic fracture propagation, the microseismicity can be used to infer hydraulic fractures state; by the effective numerical methods, microseismic events can be addressed from changes of the computed stresses. In numerical models, due to the challenges in accurately representing the complex structure of naturally fractured reservoir, the interaction between hydraulic and pre-existing fractures has not yet been considered and handled satisfactorily. To overcome these challenges, the adaptive finite element-discrete element method is used to refine mesh, effectively identify the fractures propagation, and investigate microseismic modelling. Numerical models are composed of hydraulic fractures, pre-existing fractures, and microscale pores, and the seepage analysis based on the Darcy's law is used to determine fluid flow; then moment tensors in microseismicity are computed based on the computed stresses. Unfractured and naturally fractured models are compared to assess the influences of pre-existing fractures on hydrofracturing. The damaged and contact slip events were detected by the magnitudes, -values, Hudson source type plots, and focal spheres.

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Section: Introductionmentioning

confidence: 99%

Adaptive Finite Element-Discrete Element Analysis for Microseismic Modelling of Hydraulic Fracture Propagation of Perforation in Horizontal Well considering Pre-Existing Fractures

Wang

Yang

2018

Shock and Vibration

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“…For the engineering field-scale model, we used the adaptive FE-DE method to investigate the dynamic propagation of cracks and stress evolution in multistage fracturing, flowback, and gas production stages in a naturally fractured reservoir; in this investigation, the natural fractures have important impacts on the propagation of hydraulic fractures and gas production (Ju et al, 2018). Combining the accuracy of FEM stress solutions in continuum solids with the flexibility of fracture propagation in the DEM results in a coupled approach that presents a potential technique for dealing with hydraulic fracturing problems: the continuum-based DEM (CDEM; Wang, Li, Zhang, et al, 2013;Ju et al, 2016). As we will introduce in this paper, this approach allows for the completion of unsolved HM coupling effects by the finite volume method (FVM) for fluid flow computation.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Hydrofracturing Behaviors and Mechanisms of Heterogeneous Reservoir Glutenite, Using the Continuum‐Based Discrete Element Method While Considering Hydromechanical Coupling and Leak‐Off Effects

Chen

Wang

et al. 2018

JGR Solid Earth

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Hydrofracturing technology has been widely used to stimulate the tight hydrocarbon reservoirs that usually comprise heterogeneous glutenites. Hydromechanical coupling and leak-off are essential characteristics of this process and need to be properly addressed in numerical simulation, which plays an important role in quantitatively evaluating the efficiency of this technology. Due to the challenges in accurately representing the complex structure and physical properties of heterogeneous glutenites as well as hydraulic-driven crack propagation, however, the hydromechanical coupling, leak-off, and material heterogeneity have not yet been handled satisfactorily. To overcome these challenges, we use the continuum-based discrete element method (CDEM) to simulate the hydraulic fracturing of heterogeneous glutenites, considering hydromechanical coupling and leak-off effects. The CDEM models are constructed using the geometrical and physical parameters that were extracted from natural heterogeneous glutenites using computed tomography, X-ray diffraction, and triaxial tests, based on image processing and reconstruction approaches. The CDEM models are composed of hydraulic fractures and microscale pores, and Darcy's law was integrated within the model to govern fluid leak-off; this is a nontraditional approach to leak-off effects. The coupled finite element-discrete element-finite volume approach is used to determine the fracturing behaviors of heterogeneous models. The fracturing crack propagation and distribution patterns of homogeneous and heterogeneous models under various horizontal in situ stress differences are characterized by fractal theory, and the models are compared to assess the influences of material heterogeneity and in situ stresses on the hydraulic fracturing of heterogeneous glutenites.Such natural reservoirs usually have composite or heterogeneous microstructures that can be seen with the naked eye or observed by detection methods (Fouché et al., 2004;He et al., 2015). Glutenite is a representative heterogeneous rock medium that is widely found in tight gas reservoirs (H. Liu et al., 2010; P. Zhang et al., 2014).

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“…Previous studies on this issue have been conducted through these two approaches. Laboratory experiment has always been a direct and compelling method to conduct such investigations and valuable related findings have been achieved [8,11,12,[17][18][19]. However, similarly, limited by the inner invisibility of a rock specimen and lack of suitable observation methods, in most cases fractured samples after wellbore shut-in are cut open to observe the fracture geometry, which may partly destroy the HF geometry due to the tough manual separation, leave out small HFs or branches, and lead to loss of the emerge of the fracturing process that is quite essential to illuminate problems in some cases.…”

Section: Introductionmentioning

confidence: 99%

The Fracturing Behavior of Tight Glutenites Subjected to Hydraulic Pressure

Zhang

et al. 2018

Processes

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Tight glutenites are typically composed of heterogeneous sandstone and gravel. Due to low or ultra-low permeability, it is difficult to achieve commercial production in tight glutenites without hydraulic fracturing. Efficient exploitation requires an in-depth understanding of the fracturing behavior of these reservoirs. This paper provides a numerical method that integrates the digital image processing (DIP) technique into a numerical code rock failure process analysis (RFPA). This method could consider the glutenite heterogeneities, including intrarock and interrock heterogeneities, and the practicability is verified through two numerical tests. Two-dimensional (2D) simulations show hydraulic fractures (HFs) can penetrate or deflect to propagate along the gravels, depending on the magnitude of stress anisotropy and gravel strength. Three-dimensional (3D) simulations with the consideration of gravel distribution orientation, gravel size and axial ratio show HFs could propagate past the gravel with no deflection, forming a bypass fracture that is not easy to observe in common laboratory experiments. HFs could also deflect to propagate along the gravels. The impacts of the gravel distribution orientation, gravel size and axial ratio are discussed in detail. The main propagation modes of HFs intersecting the gravels are summarized as: (1) penetrating directly; (2) deflecting to propagate along the gravels to form distorted HFs; (3) propagating to bypass the gravels; (4) a combination of (1) and (2), or (2) and (3).

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CDEM-based analysis of the 3D initiation and propagation of hydrofracturing cracks in heterogeneous glutenites

Cited by 95 publications

References 38 publications

Adaptive Finite Element-Discrete Element Analysis for Microseismic Modelling of Hydraulic Fracture Propagation of Perforation in Horizontal Well considering Pre-Existing Fractures

Adaptive Finite Element-Discrete Element Analysis for Microseismic Modelling of Hydraulic Fracture Propagation of Perforation in Horizontal Well considering Pre-Existing Fractures

Numerical Analysis of Hydrofracturing Behaviors and Mechanisms of Heterogeneous Reservoir Glutenite, Using the Continuum‐Based Discrete Element Method While Considering Hydromechanical Coupling and Leak‐Off Effects

The Fracturing Behavior of Tight Glutenites Subjected to Hydraulic Pressure

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