Recognization and characterization of sources rocks in well BX in the sedimentary basin of Cote d’Ivoire

Abstract

In order to recognize and characterize the sources rocks in the BX well, samples of this well have been selected and analysed using Rock-Eval pyrolysis method and another set samples were prepared and observed through microscope for visual kerogen characterisation. The total organic carbon of BX well sediments varies between 0.41 and 3.41 wt%, with 1.29 wt% on average. These high values indicate good organic matter content in this well. The hydrogen index (HI) of the studied samples ranges from 49 to 292 mgHC/gTOC, with an average of 109 mgHC/gTOC, indicating mainly a type III kerogen. This kerogen is composed of humic material (vitrinite and inertinite) and amorphous organic matter with marine microfossils (dinoflagellate cysts and micro-foraminiferal linings). Thermal maturity parameters show that, Maastrichtian, Campanian, Early Senonian and Turonian are immature with Tmax values below 435 °C. However, according to Tmax values, samples reach oil window in Albian at 9840 ft while spore colour index indicate that this limit can be put at 9210 ft into Cenomanian age. The section from 7260 to 7590 ft in Campanian interval displays the best qualities of source rock. This section is composed of good quantity of type III and type II/III kerogen with moderate hydrocarbon potential, but this source rock is immature to generate hydrocarbons.

Keywords

• offshore
• geochemical
• stratigraphy
• rock-eval analyze
• petroleum potential