Sweet success in sour Arab reservoirs: How successful coring improved data integration. 9th Middle East Geosciences Conference, GEO 2010.

The South Rub’ al-Khali Company Ltd. (SRAK) is an Incorporated Joint Venture between Shell and Saudi Aramco and is engaged in exploring for non-associated gas and liquids in parts of the South Rub’ al-Khali Basin. The licence area contains significant quantities of ultra-sour gas in the Jurassic Arab Formation reservoir. Acquiring accurate subsurface data forms a key objective for SRAK in its currently ongoing exploration drilling campaign in the remote and challenging environment of the South Rub’ al-Khali desert. SRAK’s fourth exploration well targeted the Palaeozoic Khuff Formation but also gathered new data from the Mesozoic ultra-sour Arab Formation, where Saudi Aramco previously discovered hydrocarbon-bearing reservoirs in the late 1960s. Over 350 ft of continuous core over the Arab Formation was cut to address the reservoir characteristics and determine the rock types, whilst downhole fluid samples and well-test data confirmed the fluid compositions. This presentation will focus on the extensive technical and operational planning and strategy that eventually led to a safe and successful coring job. It will also demonstrate how the results of the detailed and extensively planned and executed routine and special core analysis programme resulted in better interpretation of well-test data. We will also demonstrate how the detailed rock typing was used to construct new field models to update SRAK’s view of the Arab Formation hydrocarbon resource.