Palynofacies, organic geochemical analyses and hydrocarbon potential of the takoradi 11-1 well, saltpond basin, Ghana

Abstract

Hydrocarbon potential of the rocks in Takoradi 11-1 well in the Saltpond Basin have been investigated. Palynological and organic geochemical analysis were carried out on 49 cutting samples and 18 core samples respectively. Palynofacies analysis of the Albian - Cenomanian sediments reveal three palynofacies associations: PA-1 reflects deposition in distal mud-dominated oxic shelf conditions, PA-2 and PA-3 depo-sition under distal dysoxic - anoxic outer and inner shelf respectively. Palynofloral association which is indicative of the Albian - Cenomanian elaterate province, has pteridophytic and xerophytic forms that reflect a palaeoenvironment which was moist and humid in a warm coastal plain under arid/semi-arid climatic condition. Geochemical analysis shows low to moderate total organic content (TOC). It varies between 0.53 - 2.73 (ave 0.83 wt% TOC) and S2 values 0.33 - 8.36 (ave. 1.32 mg HC/g rock) which implies a poor to fair source rock. Rock- Eval pyrolysis indicates mainly kerogen type III (gas prone) of hydrogen index (HI) values 53 - 387 (ave 135 mg HC/g TOC). The thermal maturation parameters, Tmax of values between 427 - 441 (ave 436.5 °C) and production index (PI) 0.02 - 0.15 (ave 0.06 mg HC/g rock) indi-cate that the rocks in the well are at immature to early mature stage oil window.