Development characteristics and exploration significance of basement reservoirs in block-6 of the Muglad Basin, Sudan

doi:10.3969/j.issn.1672-7703.2020.04.014

Abstract

Abstract: Basement exploration in the Muglad Basin in Sudan has attracted a lot of attention following recent breakthroughs in the exploration of basement buried hill in several adjacent basins. This study analyzes the basement lithology and reservoir development characteristics in the basin and considers its significance as an exploration target. Analysis is based on exploration practice, using drilling, well logging, testing, and 3D seismic data from block-6 of the basin. The basement rock is composed of feldspar, quartz, hornblende, and mica. The protolith is felsic granite or granodiorite, which experienced varying degrees of regional metamorphism or dynamic metamorphism, so that the basement rocks are metamorphic rocks of low to intermediate metamorphism. Basement reservoirs in the study area have double-layer structures: shallow layers of weathering crust and middle- deep layers primarily composed of fracture zones. The weathering crusts are usually of small thickness (less than 50 m) and are mostly developed on the surfaces of uplifts (bulges). Weathering and leaching have resulted in widespread broken rocks and dissolved minerals, with vugs developed. The fracture zones are generally thick, but distribution is uneven. It is evident in the basin margin and in the transition zone between depression and uplift that fracture zones form the principal reservoir type in the basin basement. Fracture development areas such as the steep-slope zones at the edge of petroleum-rich depressions (or sags) and depression-uplift transition zones should be priority targets for basement exploration in the future.

CLC Number:

Zhao Jian, Zhang Guangya, Liu Aixiang, Ke Weili, Shi Yanli, Zou Quan, Cheng Dingsheng, Zheng Yonglin, Yu Yongjun. Development characteristics and exploration significance of basement reservoirs in block-6 of the Muglad Basin, Sudan[J]. China Petroleum Exploration, 2020, 25(4): 133-142.

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