a Surrogate Hybrid Three Dimensional Model for Fluid-Induced Fracture Propagation Under Conditions of Uncertainty
Abstract
Numerical simulations become increasingly widespread to support decision-making and policy-making processes in energy-related emerging technologies such as enhanced geothermal systems, extraction of tight-gas to name a few. However, numerical models typically have uncertainty associated with their inputs (parametric, conceptual and structural), leading to uncertainty in model outputs. Effective abstraction of model results to decision-making requires proper characterization, propagation, and analysis of that uncertainty. Propagation of uncertainty often relies on complex multiphysics models. For instance, fluid-induced fracturing calls for hydro-mechanical, or hydro-thermal-mechanical or hydro-thermal-mechanical-chemical coupling. For the past decade several complex coupled deterministic models have been proposed to address the hydro-fracking problem with moderate successes. Despite that these models can be used as drivers for the uncertainty quantification, they are numerically and computationally cumbersome. In this paper, we present a surrogate model that can handle, for instance, 1) the hydromechanical coupling with minimum computational costs, 2) the tracking of simultaneous propagation of hundreds of fracture tips, with propagation velocities proportional to the stress intensity factor at each crack tip, 3) and the propagation of uncertainty from inputs to outputs, for example via Monte Carlo simulation. We also present a novel hybrid modeling scheme designed for propagating uncertainty and performing a global sensitivity analysis, while maintaining the quantitative rigor of the analysis by providing confidence intervals on predictions. (Prepared by LLNL under Contract DE-AC52-07NA27344).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.H31L..05E
- Keywords:
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- 1800 HYDROLOGY;
- 1847 HYDROLOGY / Modeling;
- 1873 HYDROLOGY / Uncertainty assessment