Effect of carbonate platform controls on large scale platform heterogeneity and seismically imaged geometries.

Hydrocarbon exploration is based on identification of reservoir location, geometry and size from the interpretation of seismic images. The inherited uncertainty of the estimations about reservoir volume and properties is improved by accurate prediction of facies distribution imaged on seismic sections.
Carbonate platform’s heterogeneity at all scales, large scale, whole platform geometry and sub-seismic facies distribution is achieved with a modified version of the CarboCAT. The modifications developed for this project include wave energy calculation, cross-platform sediment transportation and deposition of siliciclastic sediments.
The seismic behaviour of the produced stratigraphic models is studied with generation of synthetic seismic images using a new model. The new model uses grain texture and porosity to calculate the pseudo-acoustic impedance of Carbo-CAT generated carbonate strata. The new model is validated using sensitivity analysis based on a real seismic image of a carbonate platform.
The modified version of CarboCAT is used to reproduce the platform geometry of Upper Cretaceous (Santonian) outcrops in South-Central Pyrenees, Spain and the Cenomanian-Turonian Mishrif formation, South Iraq. Modelling of the Santonian outcrops reveals the controls on platform development and the non-uniqueness of the platform strata. Modelling of the Cenomanian-Turonian Mishrif formation shows the platform’s internal structure and calculates the connectivity and volume of specific strata of interest.
Sensitivity analysis demonstrates the effect of cross-platform sediment transportation and grain size on large scale platform geometry. Furthermore, the interaction of sediment transportation and production on the formation of autocycles, compartmentalisation of platform interior and specific facies distribution is studied.