Modeling of Interaction of Hydraulic Fractures in Complex Fracture Networks

Kresse, Olga; Wu, R.; Weng, Xiaowei; Gu, Hongren; Cohen, C.

doi:10.2118/152052-ms

Cited by 148 publications

(47 citation statements)

References 17 publications

(20 reference statements)

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“…The first new insight is that using pressure plots as a proxy for reservoir depletion zones can be misleading. Pressure plots traditionally used to show the depletion of hydrocarbon reservoirs generally suggest that large areas are drained by hydraulically fractured wells [10][11][12]. Our present study shows that velocity plots and drained area plots reveal much more detail about the hydrocarbon migration in shale reservoirs than pressure plots alone.…”

Section: Prior Workmentioning

confidence: 59%

Shale Reservoir Drainage Visualized for a Wolfcamp Well (Midland Basin, West Texas, USA)

Weijermars¹,

Harmelen²

2018

Energies

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Closed-form solution-methods were applied to visualize the flow near hydraulic fractures at high resolution. The results reveal that most fluid moves into the tips of the fractures. Stranded oil may occur between the fractures in stagnant flow zones (dead zones), which remain outside the drainage reach of the hydraulic main fractures, over the economic life of the typical well (30-40 years). Highly conductive micro-cracks would further improve recovery factors. The visualization of flow near hypothetical micro-cracks normal to the main fractures in a Wolfcamp well shows such micro-cracks support the recovery of hydrocarbons from deeper in the matrix, but still leave matrix portions un-drained with the concurrent fracture spacing of 60 ft (~18 m). Our study also suggests that the traditional way of studying reservoir depletion by mainly looking at pressure plots should, for hydraulically fractured shale reservoirs, be complemented with high resolution plots of the drainage pattern based on time integration of the velocity field.

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Section: Prior Workmentioning

confidence: 59%

Shale Reservoir Drainage Visualized for a Wolfcamp Well (Midland Basin, West Texas, USA)

Weijermars¹,

Harmelen²

2018

Energies

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“…The method used collocation points at the centers of the source elements and its two adjacent neighbors, so it could maintain the same degrees of freedom as the constant elements method by sharing the DD of the two adjacent neighbors. Other methods have been suggested by in the literature [15,25] to overcome issues with kinked or intersecting cracks when utilizing neighboring elements in calculations.…”

Section: Displacement Discontinuity Methodsmentioning

confidence: 99%

“…For numerical simulations, several researchers have considered a number of issues: the coupling between fracture mechanics and fluid dynamics in the fracture [2], fracture interaction [3][4][5], proppant transport [6], and others [7][8][9]. Further, there have been specific codes developed to model complex fracture network development [14][15][16]. Nevertheless, the available literature within the oil and gas industry often ignores the significance of the crack tip in modeling applications developed for hydraulic fracture design.…”

Section: Introductionmentioning

confidence: 99%

Testing and Review of Various Displacement Discontinuity Elements for LEFM Crack Problems

Jo¹,

Hurt²

2013

Effective and Sustainable Hydraulic Fracturing

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The numerical modeling of hydraulic fractures in unconventional reservoirs presents significant challenges for field applications. There remains a need for accurate models that field personnel can use, yet remains consistent to the underlying physics of the problem [1]. For numerical simulations, several authors have considered a number of issues: the coupling between fracture mechanics and fluid dynamics in the fracture [2], fracture interaction [3][4][5], proppant transport [6], and others [7][8][9]. However, the available literature within the oil and gas industry often ignores the importance of the crack tip in modeling applications developed for engineering design. The importance of accurate modeling of the stress induced near the crack tip is likely critical in complex geological reservoirs where multiple propagating crack tips are interacting with natural fractures. This study investigates the influence of various boundary element numerical techniques on the accuracy of the calculated stress intensity factor near the crack tip and on the fracture profile, in general. The work described here is a part of a long-term project in the development of more accurate and efficient numerical simulations for field engineering applications.For this investigation, the authors used the displacement discontinuity method (DDM). The numerical technique is applied using constant and higher-order elements. Further, the authors also applied special crack tip elements, derived elsewhere [10], to capture the square root displacement variation at the crack tip, expected from Linear Elastic Fracture Mechanics (LEFM). The authors expect that special crack tip elements will provide the necessary flexibility to choose other tip profiles. The crack tip elements may prove instrumental for efficient modeling of the different near-tip displacement profiles exhibited by Viscosity-Dominated or Toughness-Dominated regimes in hydraulic fracture propagation. As others have shown [1,4,7], the accuracy of tip asymptote is critical in characterizing the stresses in the near-tip region of a propagating fracture.The authors examined the numerically derived stress intensity factor for several crack geometries with and without higher-order elements and with and without special tip elements, to analytical solutions. As expected, they found that the cases with higher-order elements and special tip elements provide more accurate results than the cases with constant displacement discontinuity and/or no tip elements. However, the numerical technique developed still proved efficient.These results show that numerical simulators can incorporate proper crack-tip treatments effectively. In addition, higher-order elements increase computational efficiency by reducing the number of elements instead of simply increasing the discretization of constant displacement elements. The accurate modeling of stress intensity factors is necessary to better simulate curved fractures, kinked cracks and interaction between fractures.

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“…In this section, a single horizontal wellbore with two parallel initial fractures is simulated and compared to the results of Wu et al [10]. As shown in Figure 20, two preset fractures are orthogonal to the wellbore axes, with the offset between the two parallel preset fractures being 10 m. A constant injection rate = 0.106 m 3 /s is applied at the middle of the horizontal wellbore.…”

Section: Simultaneous Multifracture Propagation From a Horizontalmentioning

confidence: 99%

Modeling Simultaneous Multiple Fracturing Using the Combined Finite-Discrete Element Method

et al. 2018

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Simultaneous multiple fracturing is a key technology to facilitate the production of shale oil/gas. When multiple hydraulic fractures propagate simultaneously, there is an interaction effect among these propagating hydraulic fractures, known as the stress-shadow effect, which has a significant impact on the fracture geometry. Understanding and controlling the propagation of simultaneous multiple hydraulic fractures and the interaction effects between multiple fractures are critical to optimizing oil/gas production. In this paper, the FDEM simulator and a fluid simulator are linked, named FDEM-Fluid, to handle hydromechanical-fracture coupling problems and investigate the simultaneous multiple hydraulic fracturing mechanism. The fractures propagation and the deformation of solid phase are solved by FDEM; meanwhile the fluid flow in the fractures is modeled using the principle of parallel-plate flow model. Several tests are carried out to validate the application of FDEM-Fluid in hydraulic fracturing simulation. Then, this FDEM-Fluid is used to investigate simultaneous multiple fractures treatment. Fractures repel each other when multiple fractures propagate from a single horizontal well, while the nearby fractures in different horizontal wells attract each other when multiple fractures propagate from multiple parallel horizontal wells. The in situ stress also has a significant impact on the fracture geometry.

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Modeling of Interaction of Hydraulic Fractures in Complex Fracture Networks

Cited by 148 publications

References 17 publications

Shale Reservoir Drainage Visualized for a Wolfcamp Well (Midland Basin, West Texas, USA)

Shale Reservoir Drainage Visualized for a Wolfcamp Well (Midland Basin, West Texas, USA)

Testing and Review of Various Displacement Discontinuity Elements for LEFM Crack Problems

Modeling Simultaneous Multiple Fracturing Using the Combined Finite-Discrete Element Method

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