Great Palogue Field in Melut Basin, Sudan

Xiaoguang Tong¹, Kunye Xiao¹, Lirong Dou¹, and Buqing Shi^2
1 CNODC,No.6-1, Fucheng Beidajie, Xicheng District, Beijing, China
² CNODC Research Center, Beijing, China

Melut Basin is one of the Mesozoic-Cenozoic rift basin, onshore Sudan, southeast of CASZ, trending NW-SE. There are 5 sub-basins in the Basin, in which Northern sub basin (NMSB) is the biggest. All the sub basins are half-grabens initiated from earlier Cretaceous. The dominant dip and trend of master faults is NE/NEE and NW/NWW. Vertical sequences of fluvial lacustrine shale and sand were deposited in Cretaceous and Teritary. Sandstones in Yabus and Samma Formations (Paleocene to Oilgocene) act as main reservoirs. Meandering rivers and braided rivers are the main sedimentary facies. Massive claystone of Adar Formation (Miocene) is considered to be the regionally stable seals. Meanwhile, the shales of Galhak Formation (Cenomanian-Santonian) and Al Renk Formation (Albian) display good source potential. Similar to other grabens in CASZ, Melut basin has a low thermal gradient as 29.4oC/km. It kept late for oil generation, expulsion and migration, which was estimated in late Miocene. Upper Cretaceous Melut formation is mainly massive sandstones. It should be the regional pathway of hydrocarbon lateral migration from the source kitchen to plays. In the half graben, source rocks were generally deposited in the deep-side and uplifted gradually towards the other side. Therefore, a large scale of hydrocarbon migration occurred laterally along mass sandstones from south to north and vertically along faults. After regional geologic study, Great Palogue oil field in NMSB was discovered in 2003 with OOIP about 2.9 Billion barrels and URR of 850 MMstb. It is a fault-complicated anticline. It is the largest field in the Central rift belt. The main pay zones are Paleogene sandstones, with high porosity.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005