AAPG Annual Convention and Exhibition

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The Influence of Structure on Pore Pressure in Confined Sediments


Pore pressure in confined sediment packages is often controlled by the seal potential of the bounding elements. The interpreted structure and history of the confined region and its surrounding formations have a direct impact on pressure prediction of such units. With data which support detailed geologic models, high quality pressure predictions can often be made; even with poorer quality data it is possible to construct useful pressure bounds and scenarios to facilitate real-time interpretation during well execution and to insure that appropriate contingency plans are available. In all cases an appropriate range of geologic models and associated interpretation uncertainties are necessary to properly characterize and risk pre-drill pressure estimates and to support interpretation of sometimes ambiguous real-time data during well execution. Pressure controls for several different geometries will be discussed along with the impact of geologic uncertainties on their interpretations. Vertical and lateral sediment boundaries will be considered as well as the impact of salt. Specific well examples will be used to illustrate the application of such models in different stratigraphic and geometric settings for both pre-drill and execution phases – again, examining the impact of geologic uncertainty on the pressure estimates as well as on operational decisions.