Subseabed disposal of radioactive waste: effects of consolidational fluid flow

Faults commonly trap fluids such as hydrocarbons and water and therefore are of economic significance. During hydrocarbon field development, smaller faults can provide baffles and/or conduits to flow. There are relatively simple, well established workflows to carry out a fault seal analysis for siliciclastic rocks based primarily on clay content. There are, however, outstanding challenges related to other rock types, to calibrating fault seal models (with static and dynamic data) and to handling uncertainty.The variety of studies presented here demonstrate the types of data required and workflows followed in today's environment in order to understand the uncertainties, risks and upsides associated with fault-related fluid flow. These studies span all parts of the hydrocarbon value chain from exploration to production but are also of relevance for other industries such as radioactive waste and CO2 containment.

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Recent Advances in Repository Seal Materials

MRS Proceedings ◽

10.1557/proc-11-631 ◽

1981 ◽

Vol 11 ◽

Cited By ~ 1

Author(s):

D.M. Roy ◽

F.L. Burns

Keyword(s):

Fluid Flow ◽

Radioactive Waste ◽

Host Rock ◽

Recent Advances

One long-term solution proposed for isolating radioactive waste from the biosphere is containment in underground geologic repositories. A requirement for this procedure is that most penetrations into the repository region be sealed following emplacement of the waste. The general requirements of repository seal materials and the seal system are that these potential pathways to the biosphere be sealed adequately to prevent a) excess fluid flow into the repository and b) radionuclides in the waste from reaching the biosphere in quantities in excess of acceptable levels. For boreholes, shafts and tunnels it is generally recommended that in the post-closure phase, the permeability of sealed boreholes and shafts be approximately the same as the host rock or the aquitards in the zones where aquitards are intersected.

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Numerical Model of Fluid Flow through Heterogeneous Rock for High Level Radioactive Waste Disposal

10.1063/1.2721249 ◽

2007 ◽

Author(s):

M. Shirai ◽

R. Chiba ◽

S. Fomin ◽

V. Chugunov ◽

T. Takahashi ◽

...

Keyword(s):

Fluid Flow ◽

Numerical Model ◽

Radioactive Waste ◽

Waste Disposal ◽

Radioactive Waste Disposal ◽

High Level Radioactive Waste ◽

Heterogeneous Rock ◽

Flow Through ◽

High Level

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Numerical simulation of coupled processes in a single fracture employing a continuum approach

10.5194/egusphere-egu21-5064 ◽

2021 ◽

Author(s):

Iman Vaezi ◽

Víctor Vilarrasa ◽

Francesco Parisio ◽

Keita Yoshioka

Keyword(s):

Fluid Flow ◽

Radioactive Waste ◽

Pore Pressure ◽

Coupled Processes ◽

Simple Problem ◽

Fluid Injection ◽

Single Fracture ◽

Rock Masses ◽

Continuum Approach ◽

The Real

Fractures control fluid flow and the coupled geomechanical response of geological media in many geo-engineering applications. For instance, fractures dominate fluid flow and deformation in enhanced geothermal systems, underground radioactive waste repositories, and CO2 storage. Coupled thermo-hydro-mechanical processes in rock masses are a result of perturbations in the pore pressure, as in fluid injection and/or production, and/or temperature, as in cold fluid injection and disposal of radioactive waste. For example, fractures open as a result of pore pressure increase, which simultaneously increases permeability and reduces overpressure.Geo-engineering and geo-energy applications involve a large portion of rock masses that include several fractures. Numerical computations of coupled processes occurring in rock masses while considering a large number of fractures pose several challenges. In this study, we firstly focus on a simple problem to fully understand the hydro-mechanical behavior of a single fracture subjected to a constant injection flow rate. We use the FEM software CODE_BRIGHT, which solves the thermo-hydro-mechanical governing equations in a fully coupled way. Since standard FEM can solve equations in continuum media, we investigate the behavior of a single fracture by analyzing the hydro-mechanical parameters that control the fracture response in a continuum fashion. However, simulating fractures with the real aperture is not simply feasible, hence, we search the equivalent properties of thicker fractures that are more feasible to be discretized in large-scale models with several fractures.As the pore pressure increases inside a fracture, the fracture aperture increases and enhances its transmissivity. The embedded model uses variable permeability as a function of the cubic law. The simulation results show that a continuum approach can represent a fracture with a relatively large thickness (in the cm order) instead of the real aperture dimension (in the order of the micron).

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