Calcite dissolution rates in texturally diverse calcareous rocks
Yael Levenson, May Schiller, Yevgeny Kreisserman, Simon Emmanuel, 2015. "Calcite dissolution rates in texturally diverse calcareous rocks", Fundamental Controls on Fluid Flow in Carbonates: Current Workflows to Emerging Technologies, S. M. Agar, S. Geiger
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The injection of reactive fluids into carbonate reservoirs during enhanced recovery operations can induce important changes in rock permeability. However, reliably predicting these changes requires accurate knowledge of calcite reaction rates. While numerous studies have examined calcium carbonate dissolution rates, most have focused on pure calcite crystals rather than actual rocks. In this study, two types of flow-through experiments were carried out to determine the calcite dissolution rates in texturally diverse calcareous rocks: the first type of experiment had a duration of 3 days, while the second type ran for 3 months. Our experiments show that rocks with differing textures and roughness (samples included coarse-grained oolitic limestone, fine-grained Solnhofen limestone, marble and calcite spar) do in fact dissolve by different mechanisms. However, despite these differences, bulk reaction rates were found to be remarkably similar (with a relative standard deviation of <20%) and consistent with previously reported reaction rates for calcite. Thus, our results suggest that textural differences between rock types are unlikely to have an important impact on overall reaction rates in fractured carbonate reservoirs.
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Fundamental Controls on Fluid Flow in Carbonates: Current Workflows to Emerging Technologies
This volume highlights key challenges for fluid-flow prediction in carbonate reservoirs, the approaches currently employed to address these challenges and developments in fundamental science and technology. The papers span methods and case studies that highlight workflows and emerging technologies in the fields of geology, geophysics, petrophysics, reservoir modelling and computer science. Topics include: detailed pore-scale studies that explore fundamental processes and applications of imaging and flow modelling at the pore scale; case studies of diagenetic processes with complementary perspectives from reactive transport modelling; novel methods for rock typing; petrophysical studies that investigate the impact of diagenesis and fault-rock properties on acoustic signatures; mechanical modelling and seismic imaging of faults in carbonate rocks; modelling geological influences on seismic anisotropy; novel approaches to geological modelling; methods to represent key geological details in reservoir simulations and advances in computer visualization, analytics and interactions for geoscience and engineering.