Multiscale imaging characterization of fracture fluid migration and reactive transport in shales
Abstract
The interaction between unconventional shale matrices and fracture fluid chemicals is poorly understood. Clarification of reactive transport mechanisms is needed to reduce environmental impacts, enhance long-term hydrocarbon recovery, and improve resource sustainability. We have built a coupled core-flood and dynamic computed tomography (CT) imaging setup for flow-through tests that provides spatial and temporal information on the evolution of the porosity distribution within shale. By using large X-ray contrast krypton before and after reaction, it is possible to image porosity changes in-situ using CT imaging. Two samples were cored (Marcellus and Bone Spring) parallel to bedding planes (1-inch diameter and 3-inch length). Besides CT imaging, additional analyses include effluent chemical composition, scanning electron microscopy analysis with energy dispersive spectroscopy of shale fabric before and after reaction, porosimetry, X-ray diffraction, and X-ray fluorescence. Our experiments indicate that optimization of fracture fluid recipes with a focus on fluid interactions with shale mineralogy is necessary, improves permeability outcomes of stimulated shale zones, and enhances matrix accessibility. Favorable physical and chemical conditions are identified for porosity generation necessary to increase matrix producibility. Representative reactive transport modeling of coupled flow and chemical reactions provides better understanding of our experimental results. The reactive transport regimes are characterized ultimately by the ratios of typical rates of reaction versus advection and diffusion - Damkohler and Peclet-Damkohler numbers to enable scaling of conditions from laboratory to field. The insights gained in our study aid in developing strategies to manipulate and maximize flow through shale matrices.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMMR13B0076G
- Keywords:
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- 1832 Groundwater transport;
- HYDROLOGY;
- 5104 Fracture and flow;
- PHYSICAL PROPERTIES OF ROCKS;
- 5139 Transport properties;
- PHYSICAL PROPERTIES OF ROCKS;
- 5199 General or miscellaneous;
- PHYSICAL PROPERTIES OF ROCKS