3D Numerical Modeling of the Propagation of Hydraulic Fracture at Its Intersection with Natural (Pre-existing) Fracture

Dehghan, Ali Naghi; Goshtasbi, Kamran; Ahangari, Kaveh; Jin, Yan; Bahmani, Aram

doi:10.1007/s00603-016-1097-7

Cited by 49 publications

(29 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The initiation and propagation of main fractures were normal to the maximal principal in-situ stress. This behavior was also observed in the previous experiments [10]. The morphology of the fracture network varied with the stress ratio, which was in agreement with the simulation results of previous research [29].…”

Section: Impact Of Stress Ratiosupporting

confidence: 92%

“…This technology improves the permeability of shale reservoirs by pumping a high-pressure fracturing fluid into the borehole and fracturing the tight formation [2][3][4]. Water is the main fracturing fluid used, and the effects of water-based fluids on fracture behaviors have been well investigated [5][6][7][8][9][10][11]. However, this traditional technology requires huge quantities of water and causes serious water wastage.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Study of Fracture Network Evolution during Nitrogen Fracturing Processes in Shale Reservoirs

et al. 2018

View full text Add to dashboard Cite

This paper develops a numerical model to study fracture network evolution during the nitrogen fracturing process in shale reservoirs. This model considers the differences of incompressible and compressible fluids, shear and tensile failure modes, shale heterogeneity, and the strength and permeability of both shale matrix and bedding planes through the coupling of mechanical-seepage-damage during fracturing fluid injection. The results show that nitrogen fracturing has a lower breakdown pressure and larger seepage zone than hydraulic fracturing under the same injection pressure. Tensile failure was identified as the major reason for the initiation and propagation of fractures. Ignoring the effect of bedding planes, the fracture initiation pressure, breakdown pressure, and fracturing effectiveness reached their maxima when the stress ratio is 1. Under the same strength ratio, the propagation path of the fractures was controlled by the stronger effect that was casused by the bedding angle and stress ratio. With increasing the strength ratio, the fracture number and shearing of the bedding plane increased significantly and the failure pattern changed from tensile-only mode to tensile-shear mode. These analyses indicated that the fracture network of bedding shale was typically induced by the combined impacts of stress ratio, bedding angle and strength ratio.Energies 2018, 11, 2503 2 of 22 more effective if N 2 is applied for the hydraulic fracturing [22,23]. Different fracturing fluids lead to the different pore pressure distributions during fluid flow due to the various properties such as viscosity and compressibility. According to the principle of effective stress, the difference in pore pressure distribution induces the difference in the stress distribution in rocks, which plays an important role in fracturing behavior during the fracturing process [24][25][26][27]. Lower breakdown pressure, larger seepage zone and more complex fracture network were observed during nitrogen fracturing [24][25][26][27]. However, these studies were performed on simple rock samples and the influence of other factors during nitrogen fracturing has not been well evaluated. It is essential to investigate fracture network evolution during the nitrogen fracturing process.Several numerical models have been developed to investigate fracture behaviors during the hydraulic fracturing process. These models include the boundary element method [28], finite element method [29][30][31], and discrete element method [32,33]. Wang et al. [29] applied a new mathematical model to investigate fracture network evolution of multi-stranded fractures with pre-existing natural fractures. Shalev and Lyakhovsky [31] studied the damage evolution and seismicity phenomenon in hydraulic fracturing using an improved damage model based on the finite element method. However, there are still only a few studies on a numerical model for nitrogen fracturing and the comparison between water fracturing and nitrogen fracturing. On the other hand, shale reservoirs occur at di...

show abstract

Section: Impact Of Stress Ratiosupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Numerical Study of Fracture Network Evolution during Nitrogen Fracturing Processes in Shale Reservoirs

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Some studies (e.g., Dehghan et al, 2017, Zhang and Fan, 2016, Wang et al, 2016, Yushi et al, 2016, Hofmann et al, 2016, Tiegang et al, 2014, Chuprakov et al, 2013, Casas et al, 2006, have shown the intricate mechanisms that govern interactions between discontinuities and propagating hydraulic fractures. Analytical and numerical analyses have been employed by Chen et al (2016), Chuprakov et al (2013) and Dehghan et al (2017) to explore the crossing mechanism and the evolution of both hydraulic fracture geometry and injection pressure during interactions between hydraulic fractures and natural fractures. Several contributing factors were underscored including the interfacial shear strength of the natural fractures, in-situ stresses, intersection angles, initial conductivity and apertures of the natural fractures (or preexisting fractures), injection rate, fracturing fluid viscosity and energy release rate.…”

Section: Introductionmentioning

confidence: 99%

Numerical modelling to predict fracturing rock (Thanet chalk) due to naturally occurring faults and fluid pressure

Eshiet

Welch

Sheng

2018

Journal of Structural Geology

View full text Add to dashboard Cite

The fracturing process within the subsurface environment is often affected by pre-existing features such as naturally occurring faults. The interaction between these features and the propagating fractures together with their response to fluid pressure perturbations are multifaceted and in many instances not well understood. Faults play a major role in the containment of fractures and (depending on their size, configuration and mechanical properties) may instigate initiation of fractures. Outcrop mapping of a chalk cliff and wavecut platform in Thanet, Southeast England show a complex fracture pattern that seems to be controlled by meso-scale strike-slip faults within the chalk. The response of these faults to changes to in situ stress and fluid pressure is thought to control the nucleation and propagation of fractures in the chalk. In this study the DEM (Discrete Element Method) technique has been employed as a follow up to previous field and numerical (boundary and finite element method) investigations to ascertain the role of the faults in the initiation and nucleation of fractures, as well as their role in expediting or constraining further fracture proliferation. The role of fluid pressure, in-situ stress, and fault geometry are recognised as focal factors. Two fault geometries were studied: a strike-slip fault containing a releasing bend and a strike slip fault containing a restraining bend. The generation of localised areas of tensile stresses due to fluid pressure and stress perturbations have been shown to cause the initiation of fractures around the fault bends. Although this phenomenon occurs for both fault geometries, the location of the highest fluid pressure and initiation of fracture is different in each case. The dissimilarity in the fracturing process due to differences in the geometry of pre-existing faults demonstrates the significance of both fault geometry and fluid behaviour in controlling fracturing.

show abstract

“…Recently, the XFEM has been extensively used to simulate HF. [2][3][4][5][6][7][8][9] Liu et al 6,7 proposed a stabilized XFEM framework for simulating the fully coupled HF process. In their method, the cohesive fracture model is used to characterize the fracture propagation.…”

Section: Introductionmentioning

confidence: 99%

“…Consider a cracked triangular element in its local mesh, as shown in Figure 3A. The real node set of this cracked element is [1,2,3], and the virtual node set is [4,5,6,7]. The cracked element is divided into three subelements (Figure 3 B), namely, subjoint element with nodes [4,5,6,7], subtriangular element [7,6,3], and subquadrilateral element [1,2,5,4].…”

Section: Introductionmentioning

confidence: 99%

Fully coupled hydraulic fracture simulation using the improved element partition method

Shu

Zhang

Mou

et al. 2018

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

Summary The improved element partition method (IEPM) is a newly developed fracture simulation approach. IEPM allows a fracture to run across an element without introducing extra degrees of freedom. It can also simulate any number of fractures in a prescribed mesh without remeshing. In this study, the IEPM is extended to hydraulic fracture simulation. First, the seepage and volumetric storage matrix of a cracked element are derived using virtual nodes (the intersection points of a crack with element edges). Subsequently, the fully coupled hydromechanical equation is derived for this cracked element. To eliminate the extra degrees of freedom (virtual nodal quantities), the water pressure and displacement of the virtual nodes are associated with their adjacent nodes through least squares interpolation. Finally, the fully coupled equation in terms of nodal quantities is obtained. The verification cases validate the method. By using this method, the field‐scale hydraulic fracturing process is well simulated. The proposed approach is simple and efficient for field‐scale hydraulic fracture simulation.

show abstract

3D Numerical Modeling of the Propagation of Hydraulic Fracture at Its Intersection with Natural (Pre-existing) Fracture

Cited by 49 publications

References 74 publications

Numerical Study of Fracture Network Evolution during Nitrogen Fracturing Processes in Shale Reservoirs

Numerical Study of Fracture Network Evolution during Nitrogen Fracturing Processes in Shale Reservoirs

Numerical modelling to predict fracturing rock (Thanet chalk) due to naturally occurring faults and fluid pressure

Fully coupled hydraulic fracture simulation using the improved element partition method

Contact Info

Product

Resources

About