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It Is Rough to Be a Fracture – But How Rough?
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 82nd EAGE Annual Conference & Exhibition, Oct 2021, Volume 2021, p.1 - 5
Abstract
Summary
From its initiation to propagation, opening and closing, a fracture is under continuous pressure as a result of coupled hydromechanical and geochemical processes. The combination of these processes, including for example dissolution and precipitation, karstification and shearing, leads to complex fracture surface geometries that resemble anything but the parallel plate representation that is typically assumed in fracture network models to calculate aperture and permeability.
Using a novel workflow for characterizing fracture roughness and aperture from core plugs, we aim to gain new insights into how different mechanical and chemical processes impact fracture roughness and how the resulting fracture surface geometry influences permeability of shear fractures in shales, to assess the leakage potential of natural fractures in CO2 storage site caprocks.
We make use of a digital microscope and python-based image processing and roughness quantification. The roughness parameters are correlated to permeability data to derive empirical relations for fracture flow modelling based on a known mineralogy and bedding orientation. The results are used to populate caprock leakage risk models in a joint industry research project for CO2 storage, but the methodology can also be applied to naturally fractured reservoirs.
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