Reservoir Characterization of Merit-T Field (South western Niger Delta) from well log petrphysical analysis and sequence stratigraphy

Abstract

In this study, reservoir petrophysical analysis, and sequence stratigraphy of the “Meri_T” field, Southwestern Niger Delta, has been carried out using well logs with a view to characterizing the reservoir. Petrophysical analysis began with lithology identification. Lithologic panels interpreted from well log data show that the study area is characterized by sand-shale interbedding. The reservoirs were interpreted for their fluid content using appropriate logs. Consequently, hydrocarbons versus water bearing zones were delineated. In all five hydrocarbon bearing sands were discovered, and porosity estimates in the reservoirs were very high varying between 0.17 and 0.39. Sequence stratigraphic interpretation was carried out to interpret the depositional environment of the area using well log motifs. Sequence stratigraphic interpretation of the area shows that the four main depositional environments that are dominant in the area include the following: channel sands and shoreface sands, reworked sandstones, coastal deposits, and the basin floor fan environment. From these depositional environments, the shoreface sand, reworked sandstones and channel sands are located within hydrocarbon bearing zones. It is predicted that the shoreface sands will be the most favorable region for hydrocarbon accumulation as reservoir petrophysical properties like porosity has shown high values recorded in this area. The interpretation that there have been slope stability, unhurried deposition of sediments and longer period of deposition in the region has been predicted to be one of the contributing factors for the hydrocarbon accumulation observed in the area. The purpose of this paper is to illustrate why petrophysics is so important to hydrocarbon exploration and to demonstrate how carefully interpreted analysis can help the geoscientist relate the petrophysical analysis to environment of deposition.