The exploration direction of the Cretaceous pre-salt lacustrine carbonate rocks in the Kwanza Basin, Western Africa

LIU Jingjing, GUO Rongtao, HUO Hong, GONG Yue, JI Shengzhen

Marine Origin Petroleum Geology ›› 2025, Vol. 30 ›› Issue (5) : 425-434.

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ISSN 1672-9854
CN 33-1328/P
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Marine Origin Petroleum Geology ›› 2025, Vol. 30 ›› Issue (5) : 425-434. DOI: 10.3969/j.issn.1672-9854.2025.05.004

The exploration direction of the Cretaceous pre-salt lacustrine carbonate rocks in the Kwanza Basin, Western Africa

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Abstract

Kwanza Basin, located in Angola and its adjacent offshore area along the West African coast, is a typical passive continental margin salt-bearing basin. It comprises three major structural layers: pre-salt structural layer, salt structural layer, and suprasalt structural layer. The pre-salt Cretaceous lacustrine carbonate rocks represent the primary target for hydrocarbon exploration in the basin. The pre-salt structural layer exhibits a tectonic pattern of alternating depressions and uplifts, which can be divided into the Inner Rift Zone, Central Uplift Zone, and Outer Rift Zone from east to west. The hydrocarbon accumulation mechanism in pre-salt lacustrine carbonate rocks is characterized by "rift-controlled source rocks, uplift-controlled reservoirs, salt-controlled seals, and high-quality reservoirs controlling accumulation". The Central Uplift Zone, with well-developed basement uplifts, not only facilitates trap formation and carbonate reservoir development but also serves as the migration pathway for hydrocarbons, making it the most favorable area for pre-salt Cretaceous carbonate reservoir accumulation. The presence of high-quality reservoirs is critical for successful exploration. Based on newly acquired seismic and drilling data, this study investigates the factors influencing the differential distribution of pre-salt lacustrine carbonate reservoirs. The analysis further narrows down the prospective exploration areas for subsalt hydrocarbon plays in the Kwanza Basin to the northern part of the Central Uplift Zone, providing guidance for regional evaluation and exploration target selection.

Key words

lacustrine carbonate rocks / pre-salt / hydrocarbon accumulation model / Central Uplift Zone / Kwanza Basin

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LIU Jingjing , GUO Rongtao , HUO Hong , et al . The exploration direction of the Cretaceous pre-salt lacustrine carbonate rocks in the Kwanza Basin, Western Africa[J]. Marine Origin Petroleum Geology. 2025, 30(5): 425-434 https://doi.org/10.3969/j.issn.1672-9854.2025.05.004

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