Seminar: "Geochemical Alteration of Fractures in the Subsurface Environment: A Pore- and Core-Scale Perspective"

Feb 23, 2018
11 a.m.
Brauer Hall, Room 12

Hang Deng, Postdoctoral Fellow, Lawrence Berkeley National Lab, will present.

Abstract: Fractures are the preferential flow pathways in the subsurface environment, and are subject to alteration caused by coupled geochemical-mechanical-hydrological-thermal processes triggered by mineral-fluid inter-actions. Improved understanding of fracture evolution is critical for the assessment and prediction of the performance of various geological systems associated with subsurface energy harness and storage, resources (e.g. ground-water and minerals) recovery, waste disposal and etc..

My research puts an emphasis on the coupled geochemical and hydrological processes that affect fracture evolution in heterogene-ous porous media. The objectivesare (1) to provide fundamental understanding of mechanisms that control fracture alteration at the pore-and core-scale, and (2) to develop predictive models and constitutive relations for effective integration of fine scale processes and heterogeneity into large scale analysis. In this talk, I will present core-scale simulation results from a reactive transport model that was developed and validated based on laboratory experiments. The numerical experiments were performed under a range of flow, geometric and mineralogical conditions , and used to develop a multi-reaction Damköhler number for the prediction of fracture evolution in multi-mineral systems. This framework provides important implications for caprock integrity in geologic carbon storage systems. I will also present a pore-scale investigation of the compound effects of surface roughness on reaction rates of a single rough fracture. In addition to providing mechanistic understanding of the interplay between flow, transport and reactions at extremely fine scale, the simulations were used to develop upscaling rules such that pore-scale processes arising from surface roughness can be accounted for in continuum-scale models effectively.