Periodic Reporting for period 1 - MaPSI (Mathematical and Numerical Modelling of Process-Structure Interaction in Fractured Geothermal Systems)
Periodo di rendicontazione: 2021-08-01 al 2023-01-31
Complex dynamics such as boiling of geothermal fluids and deformation of fractured rock, resulting from the development and production of high-temperature geothermal resources, are not well understood. The EU-funded MaPSI project will provide the necessary mathematical models and simulation technology to assess subsurface process-structure interaction in the context of hydraulic and thermal stimulation during the development and production of high-temperature geothermal resources. The project will develop pioneering mathematical and numerical models to simulate multiphase flow and phase-change thermo-poroelastic media with deforming and propagating fractures. MaPSI will advance expertise and improve understanding of coupled processes in high-temperature geothermal systems development and production aiming at sustainable resource exploitation.
Objectives
In the development and production of high-temperature geothermal resources, large induced gradients in pressure and temperature during injection operations results in complex dynamics. This includes boiling of geothermal fluids and deformation of the fractured rock, dynamics that are currently not well understood. This provides a core motivation as well as challenging test cases for the mathematical and numerical developments in the MaPSI project. MaPSI has as its main objective to provide mathematical models and simulation technology required to assess subsurface process-structure interaction in the context of hydraulic and thermal stimulation in development and production of high-temperature geothermal resources.
This will be achieved by a highly novel and timely research programme which will:
- Combine new techniques with recently developed methodology to develop unprecedented mathematical and numerical approaches to enable modelling of multiphase flow and phase-change in thermo-poroelastic media with fractures that may slip, deform and propagate;
- Advance competences in the main scientific fields involved; and
- Improve understanding of coupled processes in development and production of high-temperature geothermal systems towards sustainable exploitation of the resource.
The project will provide new mathematical and numerical models along with open-source software that have capabilities in modelling of coupled process-structure interaction in fractured porous media that greatly exceed those of existing platforms. Specific case-studies will assess process-structure interactions for development and production operations in high-temperature geothermal systems, providing timely contributions to further developments of these resources.
Objectives
In the development and production of high-temperature geothermal resources, large induced gradients in pressure and temperature during injection operations results in complex dynamics. This includes boiling of geothermal fluids and deformation of the fractured rock, dynamics that are currently not well understood. This provides a core motivation as well as challenging test cases for the mathematical and numerical developments in the MaPSI project. MaPSI has as its main objective to provide mathematical models and simulation technology required to assess subsurface process-structure interaction in the context of hydraulic and thermal stimulation in development and production of high-temperature geothermal resources.
This will be achieved by a highly novel and timely research programme which will:
- Combine new techniques with recently developed methodology to develop unprecedented mathematical and numerical approaches to enable modelling of multiphase flow and phase-change in thermo-poroelastic media with fractures that may slip, deform and propagate;
- Advance competences in the main scientific fields involved; and
- Improve understanding of coupled processes in development and production of high-temperature geothermal systems towards sustainable exploitation of the resource.
The project will provide new mathematical and numerical models along with open-source software that have capabilities in modelling of coupled process-structure interaction in fractured porous media that greatly exceed those of existing platforms. Specific case-studies will assess process-structure interactions for development and production operations in high-temperature geothermal systems, providing timely contributions to further developments of these resources.
In geothermal systems, networks of fractures provide main fluid pathways. Hydraulic stimulation of fractured geothermal reservoirs can increase the possibility of geothermal fluid to flow through the formation by causing sliding and dilation of preexisting fractures as well as fracture propagation. This represent a complex coupled process-structure interaction, where the fractured structure of the formation both dominate coupled fluid flow and rock deformation and conversely is altered as a consequence of these processes. A main result achieved in the project so far is a novel hydro-mechanical simulation model for hydraulic stimulation of fractured porous rock, where slip, dilation and propagation of fractures result as a consequence of fluid injection.
Progress has also been made in the simulation of thermal multi-phase flow in high-temperature geothermal systems. The work is based on a unified formulation with persistent variables, extending the partial composition fractions of each phase. This avoids the switch of variables with the appearance and disappearance of vapor or liquid according to the laws of thermodynamic equilibrium.
Substantial work has also been performed on novel mathematical models for deformable fractured media, numerical solution strategies, and necessary software improvements, much of which is central to prepare for the next phase of the project.
Progress has also been made in the simulation of thermal multi-phase flow in high-temperature geothermal systems. The work is based on a unified formulation with persistent variables, extending the partial composition fractions of each phase. This avoids the switch of variables with the appearance and disappearance of vapor or liquid according to the laws of thermodynamic equilibrium.
Substantial work has also been performed on novel mathematical models for deformable fractured media, numerical solution strategies, and necessary software improvements, much of which is central to prepare for the next phase of the project.
Progress is achieved along two main research directions in the project, models for multiphase flow in high-temperature geothermal systems and models for fracture deformation and propagation coupled with single-phase fluid flow. This represents substantial inroads into the ambitious goal of combining the two. The combination will enable new understanding of coupled processes in high temperature geothermal systems in line with the project objectives.