Pore fluid evolution in sedimentary basins: integrated sedimentology and geochemistry of carbonate reservoirs

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Despite considerable research over the last two decades on the origin of diagenetic fluids involved limestone diagenesis and dolomitization, the debate about timing and chemistry of these fluids and the extent to which massive dolomites formed in near surface environments as opposed to formation of dolomite bodies at variable burial depths by hydrothermal and burial processes. These dolostones and associated limestone sequences host significant accumulations of oil and gas as well as extensive lead and zinc deposits. The present proposal is part of an ongoing research program, both conceptually and experimentally, on the chemistry, source(s) of diagenetic fluids and timing of fluid flow events in sedimentary basins. It is aimed to put special emphasis on fracture diagenesis, because fractures are often the primary conduits for diagenetic fluids. These fluids do not only result in fracture mineralization but may also induce important diagenetic modifications to the host carbonate rocks. Quantification of the fluid flow using field, structural, petrographic and geochemical tools can be also used to develop conceptual models for the spatial and temporal distribution and connectivity of reservoir porosity and permeability on a regional basinal scale. The proposed research program for the next 5 years will have the following objectives: (1) a better quantification of the main diagenetic events and their responsible originating fluids in sedimentary basins; (2) determination of the relationship between the fractures and deformational or tectonic events (i.e. fracture diagenesis); (3) numerical simulation of fluid/rock interaction (e.g. using reactive transport modeling); (4) determination of patterns of paleo-fluid flow (e.g. numerical modeling); and, (5) unravel the impact of diagenetic events porosity evolution. These objectives can be achieved through careful examination of textural parameters, mapping of regional and local distribution of diagenetic and structural components, geochemistry (stable and radiogenic isotope measurements, fluid inclusions), burial and thermal history curves and quantitative basin modeling techniques.