Seismic Attribute Utilization for FFDP Well Placement Optimization, Upper Cretaceous Fractured Complex Carbonate Reservoir, Onshore Oil Field, U.A.E.

Abstract

AbstractAn Upper Cretaceous carbonate reservoir, onshore oil field in Abu Dhabi is characterized by its vigorous surface topography and subsurface complex structural setting. The studied reservoir is a highly fractured elongated anticline trending NE-SW. Fracture occurrence and distribution have influenced the reservoir performance in terms of oil production and water cut from the field. Seismic attributes integrated with well log data and well performance have provided a good understanding of the lineament/fracture distribution within the reservoir. In addition, this integration enhanced the Full Field Development Plan (FFDP) optimization in terms of well placement and reservoir performance to avoid early water break through (EWBT) due to fractures. 3D seismic data was acquired with high fold and wide azimuth over the field in 2007. The 3D seismic data was processed in 2008 with some processing issues. In 2012, new algorithms were applied over a pilot area in order to resolve the processing issues and to preserve relative true amplitude for further reservoir characterization purposes. The pilot products have better identified short falls in the 2008 processed data. Seismic attributes were analyzed and the interpreted lineaments/fractures distribution will help better understand fracture orientation and their impact on oil production and water cut for full field development. The Seismic attributes successfully captured additional information and guided the well planning to avoid the highly lineament/fractured area. In addition, the new identified fracture system provides essential information for the ongoing and future development plans for this field. This 3D seismic input for fracture detection and well trajectories optimization resulted in better well performance and delay of water production especially in mid flank wells. The preliminary results of the attribute extraction at the reservoir targets are encouraging and new 3D seismic reprocessing data is considered a potential solution for the quantitative seismic interpretation and the reservoir characterization which achieved optimum well locations and orientation in this complicated onshore field.