New Insight on the Depositional Environment and Facies Atlas of Aptian in a Super Giant Carbonate Field in the Middle East

Abstract

The 3D architecture of flow units is a key parameter influencing production and recovery from oil reservoirs. Depositional facies and their 3D stacking patterns are commonly fundamental building blocks of flow units. Hence, the recognition of facies, and their placement in conceptual depositional environments is the basic requirement to establish 3 dimensional architectural models of reservoirs. In order to establish facies, facies stacking patterns and the 3D architecture of a super giant field contained in the Aptian in onshore Abu Dhabi , detailed sedimentological and petrographic core description have been carried out using about 13000 ft of core from a total of 49 cored wells. In total 27 facies have been established using fabric and bio content. They have been placed into conceptual depositional models following an evolving platform to basin topography during transgressive, early highstand and late highstand phases of carbonate platform development during the Aptian. This paper presents a comprehensive facies atlas that contains for each facies a detailed description of fabric and bio content, core and thin section pictures, petrophysical summaries and an interpretation of depositional environment. The large areal distribution of core coverage over more than 800 square km paired with the location of the reservoir transgressing platform interior to basinal settings ensures a comprehensive coverage of facies typical for most of the Aptian. The study developed an updated and unified facies scheme embedded in the existing interpretation of the depositional environments and high resolution sequence stratigraphy, and completed the core facies scheme definition which is understood as a fundamental criteria for the population of 3D static and dynamic model, in order to effectively enhance future reservoir development.

Larger benthic and planktonic biostratigraphy and facies of Albian sediments in Coastal Fars Zone (Zagros area, south‐west Iran)

“…However, the textural aspect allows medium sorting of the grains, which are scattered in microsparitic to sparry calcite matrix. The presence of red algae ( Permocalculu s) and lack of calcareous mud confirm the high energy in the environment during sedimentation, which is assigned to a shallow water, above fair‐weather wave‐base, and outer Carbonate Platform setting (El Wazir et al, 2010). Furthermore, the ferrification is distinguished in some part of this microfacies with a stylolitic structure, which is marked by opaque minerals (Fe 2 O 3 ).…”