Formulation and sequential numerical algorithms of coupled fluid/heat flow and geomechanics for multiple porosity materials

Kim, Jihoon; Sonnenthal, Eric; Rutqvist, Jonny

doi:10.1002/nme.4340

Cited by 100 publications

(82 citation statements)

References 56 publications

(193 reference statements)

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“…The high deformability of fractures also affects coupling in pore volume, which cannot be neglected; this coupling can be modeled by poromechanics (Coussy, 2004). Specifically, according to Berryman (2002) and Kim et al (2012), porosity coupling using a multiple continuum approach, which can represent a fracture-rock matrix system (or a system of the main fracture and small local fractures), can be modeled as 3 , ,…”

Section: Coupled Flow and Geomechanicsmentioning

confidence: 99%

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Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic Fracturing in Shale Gas Systems and Electromagnetic Geophysical Monitoring of Fluid Migration

Kim

Moridis

2014

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We investigate fracture propagation induced by hydraulic fracturing with water injection, using numerical simulation. For rigorous, full 3D modeling, we employ a numerical method that can model failure resulting from tensile and shear stresses, dynamic nonlinear permeability, leak-off in all directions, and thermo-poro-mechanical effects with the double porosity approach. Our numerical results indicate that fracture propagation is not the same as propagation of the water front, because fracturing is governed by geomechanics, whereas water saturation is determined by fluid flow. At early times, the water saturation front is almost identical to the fracture tip, suggesting that the fracture is mostly filled with injected water. However, at late times, advance of the water front is retarded compared to fracture propagation, yielding a significant gap between the water front and the fracture top, which is filled with reservoir gas. We also find considerable leak-off of water to the reservoir. The inconsistency between the fracture volume and the volume of injected water cannot properly calcuate the fracture length, when it is estimated based on the simple assumption that the fracture is fully saturated with injected water. As an example of flow-geomechanical responses, we identify pressure fluctuation under constant water injection, because hydraulic fracturing is itself a set of many failure processes, in which pressure consistently drops when failure occurs, but fluctuation decreases as the fracture length grows.We also study application of electromagnetic (EM) geophysical methods, because these methods are highly sensitive to changes in porosity and pore-fluid properties due to water injection into gas reservoirs. Employing a 3D finite-element EM geophysical simulator, we evaluate the sensitivity of the crosswell EM method for monitoring fluid movements in shaly reservoirs. For this sensitivity evaluation, reservoir models are generated through the coupled flow-geomechanical simulator and are transformed via a rock-physics model into electrical conductivity models. It is shown that anomalous conductivity distribution in the resulting models is closely related to injected water saturation, but not closely related to newly created unsaturated fractures. Our numerical modeling experiments demonstrate that the crosswell EM method can be highly sensitive to conductivity changes that directly indicate the migration pathways of the injected fluid. Accordingly, the EM method can serve as an effective monitoring tool for distribution of injected fluids (i.e., migration pathways) during hydraulic fracturing operations.

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Section: Coupled Flow and Geomechanicsmentioning

confidence: 99%

“…Specifically, we use the fixed-stress sequential method in solving two-way coupling in pore-volume, written as (Kim et al, 2012) …”

Section: Coupled Flow and Geomechanicsmentioning

confidence: 99%

Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic Fracturing in Shale Gas Systems and Electromagnetic Geophysical Monitoring of Fluid Migration

Kim

Moridis

2014

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“…In this sense, the double porosity model can be well suited for flow for fractured reservoirs. We modify the constitutive relations for the multiple porosity model in thermoporomechanics proposed by Kim et al (2012b), extended from the relations by Berryman (2002). We do not use the Einstein notation in this section for clarity.…”

Section: Dynamic Double Porosity Modelmentioning

confidence: 99%

“…Note that the geomechanics still accounts for both geomechanical moduli of the fracture and intact rock. Then, in the case of the double porosity model in flow and geomechanics, we modify the constitutive relations proposed by Kim et al (2012b), which generalized the constitutive model by Berryman (2002) to non-isothermal multiple porosity coupled flow and geomechanics systems.…”

Section: Introductionmentioning

confidence: 99%

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Gas Flow Tightly Coupled to Elastoplastic Geomechanics for Tight and Shale Gas Reservoirs: Material Failure and Enhanced Permeability

Kim

Moridis

2012

SPE Americas Unconventional Resources Conference

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We investigate coupled flow and geomechanics in gas production from extremely low permeability reservoirs such as tight and shale gas reservoirs, using dynamic porosity and permeability during numerical simulation. In particular, we take the intrinsic permeability as a step function of the status of material failure, and the permeability is updated every time step. We consider gas reservoirs with the vertical and horizontal primary fractures, employing the single and dynamic double porosity (dual continuum) models. We modify the multiple porosity constitutive relations for modeling the double porous continua for flow and geomechanics. The numerical results indicate that production of gas causes redistribution of the effective stress fields, increasing the effective shear stress and resulting in plasticity. Shear failure occurs not only near the fracture tips but also away from the primary fractures, which indicates generation of secondary fractures. These secondary fractures increase the permeability significantly, and change the flow pattern, which in turn causes a change in distribution of geomechanical variables. From various numerical tests, we find that shear failure is enhanced by a large pressure drop at the production well, high Biot's coefficient, low frictional and dilation angles. Smaller spacing between the horizontal wells also contributes to faster secondary fracturing. When the dynamic double porosity model is used, we observe a faster evolution of the enhanced permeability areas than that obtained from the single porosity model, mainly due to a higher permeability of the fractures in the double porosity model. These complicated physics for stress sensitive reservoirs cannot properly be captured by the uncoupled or flow-only simulation, and thus tightly coupled flow and geomechanical models are highly recommended to accurately describe the reservoir behavior during gas production in tight and shale gas reservoirs and to smartly design production scenarios. IntroductionUnconventional natural gas such as tight and shale gas has become an increasingly important source of natural gas in the United States over the past decade and the estimates of the natural gas resource potential for shale gas range from 14.16×10

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Tough3-Flac3d: A Modeling Approach for Parallel Computing of Fluid Flow and Geomechanics

Rinaldi

Rutqvist

Luu

et al. 2021

Preprint

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The recent development of the TOUGH3 code allows for a faster and more reliable fluid flow simulator. At the same time, new versions of FLAC3D are released periodically, allowing for new features and faster execution. In this paper, we present the first implementation of the coupling between TOUGH3 and FLAC3Dv6/7, maintaining parallel computing capabilities for the coupled fluid flow and geomechanical codes. We compare the newly developed version with analytical solutions and with the previous approach, and provide some performance analysis on different meshes and varying the number of running processors. Finally, we present two case studies related to fault reactivation during CO 2 sequestration and nuclear waste disposal. The use of parallel computing allows for meshes with a larger number of elements, and hence more detailed understanding of thermo-hydromechanical processes occurring at depth.

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Formulation and sequential numerical algorithms of coupled fluid/heat flow and geomechanics for multiple porosity materials

Cited by 100 publications

References 56 publications

Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic Fracturing in Shale Gas Systems and Electromagnetic Geophysical Monitoring of Fluid Migration

Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic Fracturing in Shale Gas Systems and Electromagnetic Geophysical Monitoring of Fluid Migration

Gas Flow Tightly Coupled to Elastoplastic Geomechanics for Tight and Shale Gas Reservoirs: Material Failure and Enhanced Permeability

Tough3-Flac3d: A Modeling Approach for Parallel Computing of Fluid Flow and Geomechanics

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