CAREER: Understanding the Physiocochemical and Systems-Level Processes that Would Enable Sustainable CO2 Sequestration in Shales

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

1254839 (Clarens) This project seeks to understand the processes that would enable geologic storage of CO2 in fractured shale formations. Two objectives will be pursued to achieve this overarching goal. The first is to study the physicochemical processes, e.g., interfacial properties like wettability and bubble rheology and physical and chemical characteristics like residual trapping and sorption, in multicomponent and multiphase systems containing CO2, brine, minerals, and hydrocarbons. Experimental methods at several spatial scales will be used to test the hypothesis that CO2 can enhance CH4 extraction from low permeability shales and that these formations can be managed as repositories for geological carbon sequestration (GCS). The second objective is to model the systems-level processes driving the industrial ecology of carbon cycling by the oil and gas industry. Life cycle analysis will be used to understand how and when the technology proposed here might be implemented to achieve large-scale climate benefits. Geospatial analysis, scenario development, and multicriteria decision analysis will be used to evaluate the long-term viability of coupled shale gas and GCS deployment. In support of this research effort, the PI will carry out an integrated education project studying novel pedagogical techniques based on the boundary object literature for teaching climate change. The boundary object approach focuses students on common ideas, tools, or frameworks (e.g., schematics or models) that can be used by groups to start dialog, build consensus, and successfully collaborate. This work will make the following contributions to the academic literature: (1) measure the interfacial properties that will govern the reactive transport of CO2 through shales; (2) identify the chemical formulations that would enable the use of CO2-based "green" fracturing fluids as substitutes for water-based fluids; and (3) test approaches for "healing" shales post extraction using CO2 to minimize the risks of induced seismicity and leakage. These outcomes could help improve well production over time and lead to long term stable repositories for CO2. GCS is attractive because it is proven and could scale large enough to meaningfully reduce worldwide carbon emissions. Systems models of known shale reservoirs will estimate the total sequestration capacity of these formations. This project will build much-needed understanding of how ongoing fuel development will impact climate dynamics and will directly inform the economic and legal consequences of GCS. This understanding will reduce the uncertainties currently associated with unconventional fuel deployment and with GCS in saline aquifers. Both could have unforeseen environmental, economic, legal, and social impacts if developed improperly. Shale gas and GCS are now poised for broad deployment. Consequently, this work is timely for meeting national greenhouse gas and energy independence objectives. In support of this research effort, the PI will carry out an integrated education project studying novel pedagogical techniques based on the boundary object literature for teaching climate change. The boundary object approach focuses students on common ideas, tools, or frameworks (e.g., schematics or models) that can be used by groups to start dialog, build consensus, and successfully collaborate. The PI will identify and test these boundary objects in a variety of settings, including a new Introduction to Green Engineering course being developed for second year undergraduates.