ABSTRACT

This research work was carried out to evaluate the hydrocarbon potential of Kazi field, located in the central part of the Western Niger Delta. The field was discovered in 1990, through the kaz-1 wildcat well and till date, 3 other wells have been drilled in the field to further appraise and develop the field. These wells traversed about five (5) hydrocarbon bearing sands (levels), out of which 2 were approved for this study. Geological, Engineering and production data were made available for the study. These datasets include Seismic data, well log data, Production data, PVT data, Deviation data and checkshot data which were quality checked and then utilized for seismic interpretation, Petrophysical evaluation, Static reservoir modeling and STOIIP estimation. Checkshot data acquired in Kaz-01, was distributed across the other Kazi well based on spatial relationship, from which the velocity data was generated to create a synthetic seismogram from the well logs. The Seismic survey was tied to the well logs, which showed a fair to moderate tie before very minimal squeeze and drag. The field consists of several reservoirs of the Agbada formation, a succession of alternating deltaic or near-shore sands and marine shales of Oligocene-Miocene age. Structurally, Kazi field is controlled by a NW-SE trending major growth fault, which formed a rollover anticline on the reservoirs considered, with crestal faults resulting in a collapsed crest structure that constitutes the main hydrocarbon trapping system in the field. There are several synthetic and antithetic intra-reservoir faults within the field.

The petrophysical evaluation revealed excellent reservoir properties, which favour storage and flow of hydrocarbon through the reservoirs of interest. Porosity in the field ranges between 17% to 30%, while the water saturation ranged between 11% and 33%. The irreducible water saturation calculated for the wells were below 11% which indicated more hydrocarbons in the reservoirs. The permeability of the reservoirs indicates good to excellent permeability, with values ranging between 28mD and 3959mD. The petrophysical parameters generally reflect the prolific nature of the reservoirs under review. The stock tank oil in place (STOIIP), based on the analysis of the data made available for this study, are estimated at about 15.28MMSTB and 14.65MMSTB for reservoirs KA5 and KA6 respectively.The evaluated and derived reservoir parameters reflect the profile of prolific fields. It is therefore recommended that Kazi field is fully appraised and developed to exploit the resources in the field in a sustainable manner.