A Phase-Field Based Approach for Modeling the Cementation and Shear Slip of Fracture Networks

2021 ◽  
Author(s):  
Mohamad Jammoul ◽  
Mary Wheeler
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Phase Field ◽  
Natural Fracture ◽  
Strong Impact ◽  
Fracture Networks ◽  
Stress Changes ◽  
Shear Slip ◽  
The Impact ◽  
Element Method

Abstract Modeling the geomechanical deformations of fracture networks has become an integral part of designing enhanced geothermal systems and recovery mechanisms for unconventional reservoirs. Stress changes in the reservoir can cause large variations in the apertures of fractures resulting in drastic changes in their transmissivities. At the same time, sustained high injection pressures can induce shear slipping along existing fractures and faults and trigger seismic activity. In this work, a novel approach is introduced for the simulation of cementation and shear slip of fractures on very general semi-structured grids. Natural fracture networks are represented in large scale reservoirs using the phase-field approach. The fluid flow through fractures is simulated on spatially non-conforming grids using the enhanced velocity mixed finite element method. The geomechanics equations are discretized using the continuous Galerkin finite element method. The single-phase flow and mechanics equations are decoupled using the fixed stress iterative scheme. The model can predict shear slipping and opening/closure of fractures due to induced stresses and poromechanical effects. Two synthetic examples are presented to model the effects of injection/production processes on the cementation and shear slip of fractures. The impact of the fractures' orientation and their connectivity on the hydromechanical response of the reservoir is also considered. The examples illustrate the strong impact of the dynamic behavior of fractures and the accompanying poroelastic deformations on the safety and productivity of subsurface projects.

A Phase-Field-Based Approach for Modeling Flow and Geomechanics in Fractured Reservoirs

SPE Journal ◽  
2021 ◽  
pp. 1-14
Author(s):  
M. Jammoul ◽  
M. F. Wheeler
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Phase Field ◽  
Mixed Finite Element ◽  
Fractured Reservoirs ◽  
Phase Field Method ◽  
Enhanced Geothermal Systems ◽  
Stress Changes ◽  
The Impact ◽  
Element Method

Summary Modeling the geomechanical deformations of fracture networks has become an integral part of designing enhanced geothermal systems and recovery mechanisms for unconventional reservoirs. Stress changes in the reservoir can cause variations in the apertures of fractures resulting in large changes in their transmissivities. At the same time, sustained high-injection pressures can induce shear slipping along existing fractures and faults and trigger seismic activity. In this work, we extend the phase-field method to solve for flow and geomechanical deformations in naturally fractured reservoirs. The framework can predict the opening/closure of fractures as well as their shear slipping because of induced stresses and poromechanical effects. The flow through fractures is modeled on spatially nonconforming grids using the enhanced velocity mixed finite element method. The geomechanics equations are discretized using the continuous Galerkin (CG) finite element method. The flow and mechanics equations are decoupled using the fixed stress iterative scheme. The implementation is validated against the analytical solutions of Mandel’s problem and Sneddon’s benchmark test. Two synthetic examples are presented to illustrate the impact of poroelastic deformations and the accompanying dynamic behavior of fractures on the safety and productivity of subsurface projects. NOTE: This paper is published as part of the 2021 Reservoir Simulation Conference Special Issue.

A Fracture Mechanics Based Parametric Study of the Copper-to-Copper Direct Thermo-Compression Bonded Interface Using Finite Element Method

2013 ◽  
Author(s):  
Ah-Young Park ◽  
Satish Chaparala ◽  
Seungbae Park
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Parametric Study ◽  
Initial Crack ◽  
Bonding Interface ◽  
Interface Condition ◽  
Large Temperature ◽  
Bonded Interface ◽  
The Impact ◽  
Element Method

Through-silicon via (TSV) technology is expected to overcome the limitations of I/O density and helps in enhancing system performance of conventional flip chip packages. One of the challenges for producing reliable TSV packages is the stacking and joining of thin wafers or dies. In the case of the conventional solder interconnections, many reliability issues arise at the interface between solder and copper bump. As an alternative solution, Cu-Cu direct thermo-compression bonding (CuDB) is a possible option to enable three-dimension (3D) package integration. CuDB has several advantages over the solder based micro bump joining, such as reduction in soldering process steps, enabling higher interconnect density, enhanced thermal conductivity and decreased concerns about intermetallic compounds (IMC) formation. Critical issue of CuDB is bonding interface condition. After the bonding process, Cu-Cu direct bonding interface is obtained. However, several researchers have reported small voids at the bonded interface. These defects can act as an initial crack which may lead to eventual fracture of the interface. The fracture could happen due to the thermal expansion coefficient (CTE) mismatch between the substrate and the chip during the postbonding process, board level reflow or thermal cycling with large temperature changes. In this study, a quantitative assessment of the energy release rate has been made at the CuDB interface during temperature change finite element method (FEM). A parametric study is conducted to analyze the impact of the initial crack location and the material properties of surrounding materials. Finally, design recommendations are provided to minimize the probability of interfacial delamination in CuDB.

Influence of material parameters on 2D-martensitic transformation based on the phase-field finite-element method

2019 ◽  
Vol 116 (6) ◽  
pp. 614
Author(s):  
Li Chang ◽  
Gao Jingxiang ◽  
Zhang Dacheng ◽  
Chen Zhengwei ◽  
Han Xing
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Phase Transformation ◽  
Martensitic Transformation ◽  
Phase Field ◽  
Martensite Transformation ◽  
Transformation Process ◽  
Martensite Phase ◽  
Phase Field Method ◽  
Element Method

Obtaining an accurate microscopic representation of the martensitic transformation process is key to realizing the best performance of materials and is of great significance in the field of material design. Due to the martensite phase transformation is rapidly, the current experimental is hard to capture all the information in the Martensite phase transformation process. Combining the phase-field method with the finite-element method, a model of martensitic transformation from a metastable state to a steady state is established. The law of a single martensite nucleus during martensitic transformation is accurately described. By changing the key materials that affect martensite transformation and the phase-field parameters, the effects of the parameters on the single martensitic nucleation process are obtained. This study provides an important theoretical basis for effectively revealing the essence of martensite transformation and can determine effective ways to influence martensite transformation, obtain the optimal parameters and improve the mechanical properties of such materials.

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