Reservoir characteristics of fault-controlled hydrothermal dolomite bodies: Ramales Platform case study
J. Dewit, M. Huysmans, Ph. Muchez, D. W. Hunt, J. B. Thurmond, J. Verges, E. Saura, N. Fernandez, I. Romaire, P. Esestime, R. Swennen, 2012. "Reservoir characteristics of fault-controlled hydrothermal dolomite bodies: Ramales Platform case study", Advances in Carbonate Exploration and Reservoir Analysis, J. Garland, J. E. Neilson, S. E. Laubach, K. J. Whidden
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Hydrothermal dolomite (HTD) bodies are known as high-quality hydrocarbon reservoirs; however few studies focus on the geometry and distribution of reservoir characteristics. Across the platform-to-basin transition of the Ramales Platform, fault-controlled HTD bodies are present. Three kinds of bodies can be distinguished based on their morphology, that is, elongated HTD corridors, a massive HTD body (Pozalagua body) and an HTD-cemented breccia body. The differences in size and shape of the HTD bodies can be attributed to differences in local structural setting. For the Pozalagua body, an additional sedimentological control is invoked to explain the difference in HTD geometry.
A (geo)-statistical investigation of the reservoir characteristics in the Pozalagua body revealed that the HTD types (defined based on their texture) show spatial clustering controlled by the orientation of faults, joints and the platform edge. Porosity and permeability values are distributed in clusters of high and low values; however, they are not significantly different for the three HTD types. Two dolomitization phases (i.e. ferroan and non-ferroan) can be observed in all HTD bodies. In general, the HTDs resulting from the second non-ferroan dolomitization phase have lower porosity values. No difference in permeability is found for the ferroan and non-ferroan dolomites.
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Carbonate reservoirs contain an increasingly important percentage of the world's hydrocarbon reserves. This volume presents key recent advances in carbonate exploration and reservoir analysis. As well as a comprehensive overview of the trends in carbonate over the years, the volume focuses on four key areas:
emerging plays and techniques – with special reference to lacustrine plays in syn-rift basins and development of super-giant heavy oil plays
improved reservoir characterization – with examples from the Middle East and Europe and case studies of how outcrop analogues can provide key data for input to geological models
impact of fractures and faults in carbonates –contributors highlight the need for integrated structural and diagenetic approaches in order to understand how fractures evolve as fluid-flow conduits
advances in geomodelling of carbonate reservoirs –several papers discuss the application of new and innovative geomodelling and geostatistical techniques to carbonate reservoirs.