oa Quantification of Holocene and Pleistocene heterogeneity of a carbonate depositional system, Bar Al Hikman, Oman

Spatial heterogeneity is a basic characteristic of carbonate depositional systems. Poor seismic resolution and the limited density of well data are not always adequate to extract sufficient information on the geometric characteristics of depositional facies and their horizontal extent at the reservoir scale. Examining and quantifying spatial depositional patterns, in modern analogs, may elucidate depositional dynamics, assist in facies interpretation in the subsurface, and predict the distribution patterns that are required as inputs for geologic models. Various quantitative modern analog studies, mainly in the Bahamas, have assisted in predicting carbonate reservoir attributes; however, in other regional settings, quantitative analog data on a reservoir scale remains very limited. This study investigated the Bar Al Hikman region in Oman, which represents a ramp-type, progradational system, which underwent a forced regression involving significant structural influence. The co-existence of Holocene and Pleistocene deposits is ideal for a comparative study of several geomorphic features (e.g. barrier bars, beach ridges, sand waves, lagoons, reefs), and addresses the fundamental issue of the preservation potential of modern sediments. Satellite and airborne remote-sensing tools, in particular, provided an efficient way to quantify the regional spatial complexity of the depositional system in plan view. The main objective was to explore trends of facies attributes (e.g. abundance, size, shape, facies interrelationships) of the various depositional features. The results will help to predict the heterogeneity at the field or interwell scale and thus establish the likelihood of communication between geological bodies within producing fields. This is particularly relevant in many mature Cretaceous fields, where prediction of interwell heterogeneity is increasingly critical in the drive to enhance hydrocarbon recovery.