Lucapa-1 Discovery, Offshore Cabinda — Petroleum Characteristics and Comparison with Surrounding Oils and Gases
Joseph A. Curiale1 and Kevin M. Doyle2
1ETC, Chevron, Sugar Land, TX
2CIEP, Chevron, Houston, TX
Chevron flow-tested oil and gas in Miocene channel sands of the Lucapa-1 discovery well, offshore Cabinda, in 2006. The tested gas is thermogenic and generated from a source interval at significantly higher thermal maturity than its current reservoir location. Molecular and isotopic analysis of the tested oil indicates that it is derived from a source rock containing a mixture of marine algal organic matter and land-plant derived angiosperm-rich organic matter; clear indications of lacustrine input are absent. The tested oil and gas appear to be co-sourced, based on maturity considerations; both oil and gas are bacterially degraded. The Lucapa oil and gas correlate well with surrounding petroleums in this area of Block 14, particularly with the fluids of the nearby Gabela-1 well. Based upon detailed molecular marker analysis and compound-specific carbon isotope ratio analysis, these co-sourced petroleums appear to be derived from the Late Cretaceous and Tertiary oil-prone source units responsible for much of the deep water oils of offshore West Africa. Regional evaluation suggests that the proportion of Tertiary input, as determined by biomarkers specific to this time period, decreases from east to west throughout Block 14.
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