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Reservoir Characterisation of the Paradise and Hickory Discoveries, Offshore Ghana: Integration of Depositional and Diagenetic Concepts


The Paradise and Hickory discoveries represent two of the seven discoveries made by Hess in the Deepwater Tano Cape Three Points Licence, Offshore Ghana between 2011 and 2013. These two discoveries have reservoirs within a Cenomanian aged turbidite sandstone interval and are comprised of a rich gas condensate fluid. Both accumulations are within four way dip closures with the reservoirs occupying the same seismically defined deep water slope canyon (the Paradise Canyon), with the Paradise discovery occupying a more axial part of the canyon system and Hickory representing more of a marginal location. The Paradise Canyon is interpreted to be a high net-to-gross confined slope canyon complex, with the fill dominated by stacked, coarse grained high density turbidite channel deposits and and hetrolithic debris flow deposits. Following burial, these reservoirs have undergone multiple phases of diagenesis including the growth of carbonate cements and authigenic clays. This paper highlights some of the work to characterise the reservoir using a combination of seismic, Image logs, sidewall cores and conventional logs to further our understanding of the controls on reservoir quality and deliverability within these two fields. We present an integrated depositional and diagenetic model, where the architecture of the channel fill exerts a first order control on reservoir quality, yet also has a role in influencing the digenetic overprint. The rock types associated with the channel axis, while having overall the best porosity and permeability, are also prone to cementation by allowing the preferential passing of basinal pore waters, particularly above scoured zones at the channel base. The model and geological understanding has implications for the reservoir flow behaviour and possible development strategies.