Triterpenes in a Nigerian oil

A series of monounsaturated triterpenes have been identified in an oil from Utue Field of the Niger delta. The triterpenes are the angiosperm-derived olean-13(18)-ene, olean-12-ene, olean-18-ene, baur-7-ene, and urs-12-ene. The presence of these compounds in oils is attributed to the extraction of thermally immature Agbada shales by the migrating fluid and in the reservoir. The terpane biomarker signature of the oil does not appear to have been altered by this phenomenon.