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Hunt, David1, Steen Petersen1, Susanne Lund Jensen1 
(1) Norsk Hydro Research Centre, Bergen, Norway

ABSTRACT: Seismic Modeling of Paleokarst Heterogeneity In Carbonate Platform Strata: An Example From The Upper Permian Yates Formation of West Texas and New Mexico

Many carbonate platform reservoirs are cut by steeply dipping syndepositional fault and fracture systems that parallel the platform margin and can localise penetrative paleokarst formation. Such paleokarst systems can have vertical extent of <300 m and are typically narrow (<15 m). These features are laterally persistent and can have an enormous impact on reservoir performance depending on whether they remained open or are filled by sediments and cements. In the subsurface, the distribution, fill and impact of fault- and fracture-controlled paleokarst on reservoir performance is typically hard to predict because they are difficult to detect in seismic data due to their steep dip and narrow width. Here, we show how spectacular outcrops of fault- and fracture-controlled paleokarst features, exposed in the Guadalupe Mountains of New Mexico have been used to generate a seismic forward model that helps to better understand their seismic expression. In order to fully incorporate complexity related to the deposition, structure, diagenesis of the platform and paleokarst we have utilized the new Compound Modelling seismic forward modelling software, developed by the Hydro Research Centre. The software incorporates data from well-logs to make a realistic distribution of rock properties with either sharp boundaries or vertical and lateral transitions in depositional facies, diagenesis and between structures. The software allows the full detail of outcrop analogue studies to be incorporated into a seismic forward model, making for a better realization of subsurface complexity and further narrowing the gap between outcrop and the subsurface.


AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.