The Quality of Oil from Abeokuta's Tar Sands in South Western Nigeria's Dahomey Basin

Abstract

Studying the oils recovered from the Dahomey Basin's oils sand helped to determine their quantity and quality. The acquired results indicated that the oils under study are concentrated in the polar portion, which is in line with the characteristics of biodegraded oils. It is thought that these oils were initially produced as light oil, which then transformed into heavy oil. In order to reach the reservoir rocks, which are located at shallower levels, oil generation has to travel considerable distances along the planes of unconformity from deeper-buried source rocks. Degradation of the oil may have happened in the reservoir rocks or during migration. According to 
the trisnorhopane thermal maturity indicator, the investigated oils exhibit thermal maturity levels between 0.66 and 1.32% Ro, which is in line with the bitumen that has transitioned from early to late formation.