A new computational model for flow in karst-carbonates containing solution-collapse breccias
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We develop a new three-scale (micro/meso/macro) computational model based on a reiterated homogenization procedure to describe flow in carbonate rocks containing complex geological structures, such as fractures and solution-collapse breccias in the sense of Loucks (AAPG Bull. 83(11), 1795–1834, 1999). In this setting, we construct a hierarchical karst-fracture model wherein the larger geological objects are incorporated explicitly whereas the higher density microscopic structures are homogenized and replaced by equivalent continua with properties computed from self-consistent homogenization schemes. In the upscaling method, we subdivide the different clastic arrangements in the breccia into crackle, mosaic, and chaotic substructures where equivalent permeability and elastic constants are assigned to each layer within the breccia. After reconstructing the mesoscopic coefficients, we adopt a flow-based upscaling to the macroscale, where the characteristic length is associated with a typical coarse grid cell of a reservoir simulator. The mesoscopic flow equations are constructed based on the discrete fracture model (DFM) and discretized by a robust computationally scheme with the ability to handle strong heterogeneity induced by the collapse breccia and pressure jumps across flow barriers. In addition to the scenario wherein the collapse breccia network is composed of disconnected objects (isolated chambers), we also develop a reduced model for the case of connected karst facies playing the role of a network of enlarged fractures. Numerical results, with input data extracted from outcrops drone images, are presented illustrating the influence of different settings on flow patterns and their effect upon the magnitude of macroscopic properties.
KeywordsCarbonate reservoir Collapsed paleocaves Damage zone Discrete fracture model Self-consistent homogenization Finite element Outcrop images Flow-based upscaling
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The authors would like to express their gratitude for the financial support provided by Petrobras under the agreement number 0050.0079860.12.9, FAPERJ under the agreement number E-26/202.867/2017 and CNPQ under the agreement number 304054/2014-3.
- 10.Coussy, O.: Poromechanics. Wiley, New York (2004)Google Scholar
- 18.Hashin, Z.: Theory of Fiber Reinforced Materials. National Aeronautics and Space Administration, Washington (1972)Google Scholar
- 19.Hill, C.A.: Sulfuric acid speleogenesis of Carlsbad Cavern and its relationship to hydrocarbons, Delaware basin, New Mexico. AAPG Bull. 74, 1685–1694 (1990)Google Scholar
- 22.Hornung, U.: Homogenization and Porous Media, volume 6 of Interdisciplinary Applied Mathematics. Springer, Berlin (1997)Google Scholar
- 25.Klimchouk, A.: Hypogene speleogenesis: hydrogeological and morphogenetic perspective. NCKRI Special Paper 1, 1 (2007)Google Scholar
- 26.Klimchouk, A., Tymokhina, E., Amelichev, G.: Speleogenetic effects of interaction between deeply derived fracture-conduit and intrastratal matrix flow in hypogene karst settings 41, 35–55 (2012)Google Scholar
- 28.List, F., Kumar, K.: Rigorous upscaling of unsaturated flow in fractured porous media (2018)Google Scholar
- 29.List, F., Kumar, K.: Upscaling of unsaturated flow in fractured porous media (2018)Google Scholar
- 30.Loucks, R.G.: Paleocave carbonate reservoirs; origins, burial-depth modifications, spatial complexity, and reservoir implications. AAPG Bull. 83(11), 1795–1834 (1999)Google Scholar
- 31.Loucks, R.G.: A review of coalesced, collapsed-paleocave systems and associated suprastratal deformation. Time in KARST, pp. 121–132 (2007)Google Scholar
- 39.Sutera, P.S., Skalak, R.: The history of Poiseuille’s law 25, 1–20, 11 (2003)Google Scholar