SP Koah Na Lebogo, Bisso D, Mbida Y, Eyong TJ and Etoundi PRA
Previous studies indicates that the Paleocene-Eocene represented by the N’kapa Formation in Douala onshore basin, has been a target for water supply. However, the hydrogeological research work highlights in this formation important heterogeneity linked to the nature and the geometry of the sedimentary bodies constituted the aquifer system. Taking into account the state of alteration of existing outcrops, this study aims to reconstruct a sedimentological model during the Paleocene-Eocene, using on integration of Gamma Ray (GR) well logs with outcrops data. The research methodology involved sedimentary facies described in outcrops, delineation of lithologies and identification of electrofacies corresponding to depositional environments, from GR reponses. The results obtained from this study show that the lithofacies is dominated by clays, silts and sands/sandstones. The GR log facies gave an altenating cylindrcal to funnel shaped log curve with few units of bell shapes. Also, the recognise facies associations combine by GR log pattern help to define three depositional environments that correspond to : (1) fluviatil, (2) deltaic plain, and (3) delta front. The Gamma Ray log correlations between well to well, make it possible to determine the high-resolution geometry of the sedimentary bodies. The sedimentation reflects a fluvial to shallow marine environment dominated by fluvial processes and sometimes tidal processes. From the above results and their analysis, it is established that the sedimentary bodies which are potential aquifer, are associated with fluvial channel sands, tidal channel sands and delta front sands bars. The results obtained will be useful for rationalization of future hydrogeological research in the Douala onshore basin.
Published Date: 2020-02-26; Received Date: 2020-02-05