Exploration Insights May 2020 | Page 8

8 | Halliburton Landmark Exploration Insights | 9 ASSESSING RESERVOIR QUALITY Through regional correlations and seismic data (Figure 3), the locations of deep-water, coarse-grained siliciclastic lowstand fans have been identified. By combining this with the insights deduced from the PDEM, paleoclimate simulations, and sediment flux predictions, assessments of reservoir quality were made. To assess the potential reservoir quality of the deep-water, coarse-grained siliciclastics deposited during lowstands in the northern Arabian Gulf, it was essential that we understood the mineralogy of the surrounding hinterland. The composition of hinterland acts as a proxy for the quartz content of the derived reservoirs. Hinterland compositional data for the late Valanginian highlights the areas that were quartz- rich and the areas that comprised more mafic and intermediate rocks, from which unstable mineral assemblages are derived. By determining the relationship between hinterland mineralogy and the sediments deposited in basins, the reservoir quality of the siliciclastic lowstand fans in the northern Arabian Gulf can be high-graded. The quartz-rich nature of the sediments shed into the northern Arabian Gulf is verified by the dominance of quartz (over 80 %) found in the Zubair Formation at the Rumaila Field (Wells et al., 2017). This dominance of quartz is the result of erosion from the quartz- rich Precambrian basement and Paleozoic sediments at the Arabian Shield. By integrating the Neftex Source to Sink data from ESM with geological data in a source- to-sink regional context, it was found that the siliciclastic lowstand fans in the southern portion of the northern Arabian Gulf are likely to have better reservoir quality than those in the north. The siliciclastic lowstand fans in the north are supplied by sediment that originates from a mixed mineralogy hinterland (Figure 5). Therefore, reservoir quality in the far north of the northern Arabian Gulf is a risk that requires further consideration. Hinterland Compositional Data (Mean basin color based upon hinterland data ~quartz content proxy) Medium High High Medium Low Medium Low Figure 5> The late Valanginian Neftex® Palinspastic Gross Depositional Environment map, superimposed on the age-equivalent drainage catchment basins, and hinterland mineralogy for the Arabian Plate. The location of the Rumaila Field (star) is shown, and pie charts at the river mouths indicate the mineralogy of siliciclastic lowstand fans. The orange arrows highlight the main transport directions of sediments deposited in the northern Arabian Gulf. Quartz-rich sediments were derived from the Precambrian basement and Paleozoic sediments of the Arabian Shield, while the hinterland signature of the northern Arabian Plate was mixed. The authors would like to thank Mike Simmons, Roger Davies, Thomas Jewell and Jo Collins for sharing insight into their work on Mesozoic siliciclastic systems of the Middle East. Thanks also to Graeme Nicoll and Rachel Hopper for assistance in drafting figures for this article. AUTHORS Chris Gravestock — Senior Geoscientist, Regional Petroleum Geoscience, Halliburton Landmark Chris joined the company in 2012, and began his career working on North Africa. Since then, he has held a number of roles within a variety of teams, including Earth System Science. In 2017, Chris began working on the Late Jurassic–Cretaceous stratigraphy of the Middle East, delivering regional, exploration-focused insights into southern Arabia. Chris holds an M.Sci degree in Geology from the University of Southampton. Benjamin Gréselle — Product Owner of Earth Systems Science, Halliburton Landmark Benjamin is responsible for the development and strategy of Neftex ® global-scale products. These provide a global context for the prediction of primary petroleum system elements, built on Earth system modeling, including topography, drainage, source-to-sink, and paleoclimate. Benjamin joined Neftex as a regional geologist. Previously, he carried out research for Statoil on carbonate field analogues in Mexico. Benjamin holds a PhD and post-doctorate in carbonate sedimentology and sequence stratigraphy from the Université de Lyon in France. DISCLAIMER This article is a synthesis based upon published data and information, and derived knowledge created within Halliburton. Unless explicitly stated otherwise, no proprietary client data has been used in its preparation. If client data has been used, permission will have been obtained and is acknowledged. Reproduction of any copyrighted image is with the permission of the copyright holder and is acknowledged. The opinions found in the articles may not necessarily reflect the views and/or opinions of Halliburton Energy Services, Inc. and its affiliates including but not limited to Landmark Graphics Corporation. CONCLUSION Regional datasets that are integrated with ESM have confirmed the potential for deep-water, coarse-grained siliciclastic lowstands in the northern Arabian Gulf. These lowstands are located close to major siliciclastic input points that followed pre-existing, long-lived basement lineaments, such as Wadi al Buteen. REFERENCES Azzam, I.N. 1995. Sequence stratigraphy of Middle Cretaceous siliciclastic sandstone (Tuwayil Formation) in west Abu Dhabi: a model approach to oil exploration. In M.I. Al-Husseini (Eds.), Geo’94. The Middle East Petroleum Geosciences. Volume 1. Selected Middle East Papers from the Middle East Geoscience Conference, April 25-27, 1994, Bahrain, p. 155-165. (MEBIB13758). 300 km ACKNOWLEDGMENTS Davies, R.B., M.D. Simmons, T.O. Jewell and J. Collins 2019. Regional Controls on Siliciclastic Input into Mesozoic Depositional Systems of the Arabian Plate. In H. R. AlAnzi, R. A. Rahmani, R. J. Steel, and O. M. Soliman (Eds.), Siliciclastic reservoirs of the Arabian plate. AAPG Special Publication no. 116, p. 103-109. (XURBB_630127). We’re here to help! Our dedicated team are here to answer your questions, so get in touch if you would like a meeting with our regional experts and data enthusiasts, or if you simply want to learn more about Neftex ® Insights. Ray, D.C., F.S.P. van Buchem, G. Baines, A. Davies, B. Greselle, M.D. Simmons and C. Robson 2019. The magnitude and cause of short-term eustatic Cretaceous sea-level change: A synthesis. Earth-Science Reviews, v. 197, p. 1-20. (XURBB_641687). Stefanie Clayton Global Client Support Contact Stefanie Amy Taylor Global Client Support Contact Amy Kathleen Gould Regional: North America Contact Kathleen David Weeks Middle East Client Support Contact David Sharland, P.R., R. Archer, D.M. Casey, R.B. Davies, S. Hall, A. Heward, A. Horbury and M.D. Simmons 2001. Arabian Plate Sequence Stratigraphy. GeoArabia Special Publication no. 2, Gulf PetroLink, 1-387 p. (MEBIB20358). Wells, M., Morton A. and Frei D. 2017. Provenance of Lower Cretaceous clastic reservoirs in the Middle East. Journal of the Geological Society (Formerly Quarterly Journal of the Geological Society), v. 174, no. 3, p. 1-14. (XURBB_627869). Thomas Jewell Business Development Contact Thomas Gareth Williams Regional: Asia Pacific Contact Gareth