Seismic forward model of a Natih Formation outcrop: the Adam Foothills Transect (northern Oman)

Abstract

ABSTRACT The platform carbonates of the Natih Formation (Albian-Turonian) are hydrocarbon reservoirs throughout the Middle East. This study uses a high-resolution sequence stratigraphic model built from the Natih outcrops of the Adam Foothills Transect, in northern Oman, as the basis for the construction of synthetic seismic sections along the Natih outcrops. The model covers the seaward progression from a proximal carbonate platform to a distal intrashelf basin. Three third-order depositional sequences had been identified and correlated across the outcrops, and facies were mini-core plugged for petrophysical data measurement, which were then used to construct an impedance model from the stratigraphic model. This impedance model was used to construct synthetic seismic sections with a zero phase Ricker wavelet at varying peak frequencies (80 Hz, 60 Hz and 40 Hz). The high-frequency synthetic seismic identified seismic characteristics of specific depositional environments, notably the organic-rich intrashelf basin, the platform margin and the platform interior. These seismic characteristics were very subtle on the lower frequency data, but could nonetheless be identified. A seismic line passing through a nearly analogous setting in the subsurface Natih was used to try and identify the characteristics observed on the synthetic seismic data. Many of the synthetically-produced characteristics were found on the industry seismic, which shows that this method is a good way of using the detail of the outcrop to help with predictions on the lower frequency/resolution seismic.