Print this pageA Salt Tectonic Model For Subsalt Exploration in Gulf of Mexico Basin
WU, S., C. CRAMEZ, and G. BITOUN
Subsalt exploration efforts are greatly challenged by understanding (1) the tectonic a history of each prospective area, (2) sedimentary fairways and (3) hydrocarbon migration pathways and timing, and by (4) mappability of the traps and reservoirs under salt (5) costly 3D pre-stack depth migration processing and (6) high drilling and development costs.
The following salt tectonic hypothesis and understanding help our exploration:
1. Mid-Jurassic Louann salt after several stages of deformations has formed various autochthonous and allochthonous salt structures. The allochthonous salt structures were first observed in the deep-water Gulf of Mexico where several allochthonous salt models were proposed and partially corroborated by modern seismic data.
2. These models have been applied to continental shelf and onshore Louisiana and Texas to explore hydrocarbons beneath allochthonous salt.
3. We have recognized allochthonous salt structures from near mid-Cretaceous shelf margin across onshore Gulf coast and continental shelf to deep Gulf.
4. The age and stage of development of allochthonous salt vary mainly due to different age, strength, amount and morphology of the sedimentary loads.
5. Mid-Cretaceous allochthonous salt is observed basinward of the carbonate platform margin. Paleo-Eocene allochthonous salt is found onshore Texas and Louisiana. Eocene to present allochthonous salt is well seen from shelf to slope of the Gulf.
6. Several levels of allochthonous salt structures exist particularly on the continental shelf offshore Louisiana due to continued massive sediment influx since Miocene.
7. The present tectonic styles and sediment distribution pattern are mainly caused by interactions between Louann salt and sediments.