Regional variation of permeability in Thamama-B reservoirs of Abu Dhabi

Abstract

Abstract To better understand reservoir quality in a major oil-producing limestone unit, the Thamama-B zone of the Lower Cretaceous (Barremian) Kharaib Formation, this study compiles and analyzes average values of porosity and permeability measured on 330 well cores in both onshore and offshore areas of the Abu Dhabi Emirate. Most average and individual values plot along a single porosity-permeability trend, which is unaffected by porosity-preserving early oil emplacement and only moderately influenced by texture and clay content. The main trend corresponds with the established field for mud-dominated, microporous limestones, but a subordinate proportion, termed “hi-K” plug samples, have significantly higher permeability-for-given-porosity. The hi-K samples are more abundant in the southwestern part of the study area and also show spatial clustering within individual oilfields. The present macro-scale view of Thamama-B reservoir quality is a new resource that can be useful for both exploration and production planning.