Seismic inversion as a predictive tool for porosity and facies delineation in Paleocene fluvial/lacustrine reservoirs,Melut Basin,Sudan |
| |
| Institution: | 1. Universiti Teknologi PETRONAS, Malaysia;2. King Fahd University of Petroleum and Minerals, Saudi Arabia;1. Department of Arctic Geology, University Centre in Svalbard (UNIS), PO Box 156, 9171 Longyearbyen, Svalbard, Norway;2. Eni Norge AS, PO Box 101 Forus, 4064 Stavanger, Norway;3. Department of Geosciences, University of Oslo (UiO), PO Box 1047, Blindern 0316, Oslo, Norway;1. Departamento de Geología, Universidad de Buenos Aires, IGEBA-CONICET, Pabellón II Ciudad Universitaria, 1428 Ciudad Autónoma de Buenos Aires, Argentina;2. Sinopec Argentina Exploration and Production Inc, Manuela Saenz 323, Puerto Madero, Ciudad Autónoma de Buenos Aires, Argentina;1. School of Geosciences, China University of Petroleum East China, Qingdao, 266580, China;2. Pilot National Laboratory for Marine Science and Technology Qingdao, Qingdao, 266580, China;3. Shandong Provincial Key Laboratory of Deep Oil and Gas, Qingdao, 266580, China;1. Department of Geology, University of Malaya, Kuala Lumpur, 50603, Malaysia;2. Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen, AB24 3UE, Scotland, UK;3. Geology Department, Faculty of Applied Science, Taiz University, Taiz, 6803, Yemen;4. Department of Geology, Federal University, Lokoja, P.M.B 1154, Nigeria |
| |
| Abstract: | The Melut Basin is a rift basin in the interior Sudan linked to the Mesozoic-Cenozoic Central and Western African Rift System. The Paleocene Yabus Formation is the main reservoir deposited in heterogeneous fluvial/lacustrine environment. Delineation of channel sandstone from shale is a challenge in reservoir exploration and development. We demonstrate a detailed 3D quantitative seismic interpretation approach that integrates petrophysical properties derived from well logs analysis. A porosity transform of acoustic impedance inversion provided a link between elastic and rock properties. Thus, we used seismic porosity to discriminate between different facies with appropriate validation by well logs. At the basin scale, the results revealed lateral and vertical facies heterogeneity in the Melut Basin. Good reservoir quality is observed in the Paleocene Yabus Formation. The sand facies indicated high porosity (20%) corresponding to low acoustic impedance (20000–24000 g ft/(cm3.s)). However, lower quality reservoir is observed in the Cretaceous Melut Formation. The porosity of sand/shale facies is low (5%), corresponding to high acoustic impedance (29000–34000 g ft/(cm3.s)). This suggests that the Yabus Sandstone is potentially forming a better reservoir quality than Melut Formation. At the reservoir scale, we evaluated the facies quality of Yabus Formation subsequences using petrophysical analysis. The subsequences YB1 to YB3, YB4 to YB7 and YB8 to YB10 showed relatively similar linear regressions, respectively. The subsequence of YB4 to YB7 is considered the best reservoir with higher porosity (25%). However, subsequence YB1 to YB3 showed lower reservoir quality with higher shale volume (30%). This attributed to floodplain shale deposits in this subsequence. Similarly, the high porosity (20%) recognized in deeper subsequences YB6 to YB9 is due to clean sand facies. We learnt a lesson that appropriate seismic preconditioning, exhaustive petrophysical analysis and well log validation are important keys for improved reservoir quality prediction results in fluvial/lacustrine basins. |
| |
| Keywords: | Fluvial/lacustrine rift basins Melut Basin Yabus Sandstone Reservoir characterization Seismic inversion |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
