Ismail Mostfa1, Mohamed R. Ayoub2, M.G. Salah AbouSayed3
(1) Abu Dhabi Company for Onshore Oil Operation, Abu Dhabi, P.O. Box 270, United Arab Emirates
(2) Abu Dhabi Company For Onshore Oil Operation, Abu Dhabi, P.O. Box 270, United Arab Emirates
(3) Reservoir Charcterization Research & Consulting, Abu Dhabi, P.O. Box 270, United Arab Emirates
ABSTRACT: Integrated reservoir modeling, A structure, United Arab Emirates
A multidisciplinary approach including geology, petrophysics, geophysics and reservoir engineering has been used to assess the Lower Cretaceous reservoir in the A Structure, United Arab Emirates. The A structure, defined as a 600 square kilometers undulated anticline with a structural relief of 200 feet, was formed by the movement of the Precambrian salt during the Cretaceous. The main producing horizon, Thamama Zone B (TZB) consists of a carbonate section that was deposited over an extensive carbonate ramp platform. A rock type scheme for the TZB resulted in generating six main lithofacies, which were developed as a basis for detailed reservoir fine layering, constructing a 3D static model and simulation studies. The main pore types within this reservoir are interparticle porosity. Reservoir quality depends mainly on the effect of diagenetic processes such as leaching, stylolitization and secondary pore filling. A faulted framework for this heavily faulted field has been constructed and populated geostatistically with the porosity, using the sequential Gaussian simulation and permeability using the cloud transforms technique. The reservoir facies has been modeled stochastically using the sequential indicator simulation. The main faults that bound the B Structure were analyzed to investigate their flow properties, both with regard to a static model (pre-production conditions) and with regard to a dynamic model (production history).The analysis of GOR, API, bubble point, formation volume factor, water saturation and H2S content within TZB shows lateral variation in its fluids properties. Variations in reservoir pressure equilibrium is interpreted to be due to southwest gas feeding and/or vertical gas migration across the faults to shallower reservoirs.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado