Abstract
The fine-grained nature of many unconventional reservoir rocks poses severe challenges for routine and special core analyses. A digital rocks approach to generate pore-and grain-network models for calculation of flow and mechanical properties is an appealing alternative, but presents its own set of imaging challenges. In this study, mini-plugs from four unconventional carbonate-rich samples were imaged by micro-CT in a sequence of states designed to selectively enhance X-ray attenuation contrast and resolution. Pressure saturation by diiodomethane enormously boosted the attenuation of pores such that even sparse micro/nano-porosity became appreciably brightened. Exposure to iodine stained the organic matter to highlight its distribution. Registration and differencing of the mini-plug tomograms acquired in these states then provided separate 3D maps of porosity and organic matter for image analysis. Segmentation yielded overall volume fractions in good agreement (within 20% relative error) with porosity and TOC measured on core plugs. Scatter histograms gave statistical measures to type the unconventional sample according to its relative populations of features locally rich or lean in porosity and/or organic matter. Higher resolution SEM images of an ion-milled section through the mini-plug and its registration into the tomograms provided a means to associate pore morphologies and sizes to these features towards construction of a 3D map of preferred flow pathways.
Original language | English |
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Pages | SCA2014-027-1-12 |
Publication status | Published - 2014 |
Event | International Symposium of the Society of Core Analysts - Avignon, France Duration: 1 Jan 2014 → … |
Conference
Conference | International Symposium of the Society of Core Analysts |
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Period | 1/01/14 → … |
Other | 8-11 September 2014 |