Forward Sediment Modeling of Carbonate Platform Growth and Demise, East Java Basin: Example North Madura

Hughes, Tina M.¹, Toni Simo², John Bova³, Amy Ruf⁴, Fiona Whitaker⁵ (1) ExxonMobil, Houston, TX (2) University of Wisconsin, Madison, WI (3) ExxonMobil, Houston (4) ExxonMobil, Houston, (5) University of Bristol, Bristol, United Kingdom

Interactions between tectonism, eustasy, carbonate accumulation rate, and environmental stresses impact the nucleation, growth and demise of carbonate platforms. A Miocene carbonate platform from the East Java Basin imaged by the MC3D PGS seismic dataset was selected to quantitatively investigate the interaction between these parameters in controlling carbonate platform evolution using the forward sediment modeling program CARD3D+. Analysis of a series of 3D seismic discontinuity time slices flattened on the platform base reveals that the platform originated from seven nucleation mounds, each 400-1200m in diameter. The mounds grew concentrically and amalgamated sequentially to form a single isolated platform 7km in diameter and 300m thick. The platform top is a high amplitude seismic reflector, marking the influx of siliciclastics and the demise of the platform.

We simulated accumulation of sediment on an initial surface with seven mounds which match the size, geometry, and distribution observed in the discontinuity seismic data. Relative sea level, controlled by subsidence and eustacy, and carbonate accumulation rates, controlled by production, restriction, currents and winds were varied to provide a match to seismic data. Reduction of the rates of platform top sediment production (simulating increased environmental stress) leads to platform drowning. This suggests the demise of the platform results from the interaction between increased accommodation, generated by tectonic subsidence and eustasy, and environmental stresses (influx of siliciclastics). This work has important implications for carbonate exploration where only 2D seismic data are available for imaging carbonate platforms and for predicting whether a platform has drowned or backstepped.