Structural development of the southern basin, onshore Trinidad: Implications for hydrocarbon entrapment
- Exxon Exploration Company, Houston, TX (United States)
Episodic compressional deformation across onshore southern Trinidad formed a complex spectrum of fold timing and fold types. Successful oil traps are not related to a specific time interval of structural formation, a specific oil expulsion event or a specific fold morphology. Traps that retained hydrocarbons may be related to seal facies. The tectono-stratigraphic section of onshore southern Trinidad, south of the Central Ranges, is comprised of three generalized depositional packages. Firstly, a southerly sourced Cretaceous to late Oligocene passive margin sequence of deepwater sands, shales and marls; secondly, a northerly sourced late Oligocene through middle Miocene syntectonic sequence of shallow to deep-water sands and shales; and thirdly, a west-southwesterly sourced late Miocene through Pleistocene shelfal sequence. Observations of compressional structures that folded these sediments during an early period of compressional deformation 25-10 million years before present suggest that all mudrock lithofacies could act as effective seals and trap hydrocarbons. Subsequent structural modification that occurred during a late period of compressional deformation between 5 million years and present day caused refolding and refaulting of these traps. Restructured traps that were sealed by brittle, Mesozoic deep-water facies failed and hydrocarbons migrated to shallower structural levels. Restructured folds that were sealed by ductile, Tertiary shallow-water facies retained trap fill.
- OSTI ID:
- 421027
- Report Number(s):
- CONF-9609255-; ISSN 0149-1423; TRN: 96:005770-0007
- Journal Information:
- AAPG Bulletin, Vol. 80, Issue 8; Conference: American Association of Petroleum Geologists (AAPG) international conferences and exhibition, Caracas (Venezuela), 8-11 Sep 1996; Other Information: PBD: Aug 1996
- Country of Publication:
- United States
- Language:
- English
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