oa Charge evaluation of the South Rub’ Al-Khali Basin, Saudi Arabia (Part II; see Bell et al. for Part I)

The South Rub Al Khali Company (SRAK) is exploring for gas condensate in two contract areas, which together encompass an area of about 200,000 square km. For the evaluation of SRAK’s first exploration well in the Rub‘ Al-Khali basin, a comprehensive geochemical analysis program was implemented. The latest mud-gas technology (Geoservices’ Flex-Flair Technology) was deployed to accurately measure gas compositions and isotube sampling was performed for mud-gas isotope logging. Cores were taken in the Silurian Qusaiba Formation for source-rock evaluation, as it was recognised that source-rock quality and characteristics could be markedly different from the nearest calibration point, which is several 100 km away. Finally, fluid inclusion screening<br>and crusher-CSIA (compound specific isotope analysis) were performed to provide an integrated analysis of the petroleum systems. Crusher-CSIA is a Shell proprietary analysis that measures the composition and carbon-isotope ratios of gas trapped in fluid inclusions or adsorbed to cuttings. Based on these carbon-isotope ratios, gas-tosource rock correlations were made, and it was shown that at the well location, at least two different Paleozoic gases were present. Finally, these results from the geochemical well evaluation were added to the model to produce an updated view on the Paleozoic petroleum systems in the Rub‘ Al-Khali Basin.