Oil and Gas Reservoir Characterization; A Case Study of Agbada Field

Abstract

This study on reservoir characterization was conducted using seismic data and well logs. The aim was to characterize the petrophysical properties and structural element in the field for hydrocarbon volume estimation and determination of infill well locations. Three reservoirs were identified (J100, K100, L100) at shallow, middle and deep depths and correlated across the field using gamma ray log. Petrophysical characterization revealed porosity ranges from 25 to 27% in J100 reservoir, 16% to 27% in K100 reservoir and 11 and 18% in L100 reservoir. This shows good to very good porosity values for reservoir rocks. On average, water saturation is 80%, 68% and 70% in J100, K100, and L100 reservoirs. Net to gross ranged from 24 to 77% in J100, 38 to 82% in K100 and 29 to 75% in L100 and L100 reservoir. Average net to gross revealed that the sands are cleaner with depth. Resistivity and neutron-density logs revealed the reservoirs are oil bearing. Structural characterization of seismic date revealed the presence of synthetic and antithetic faults. Depth structure maps generated revealed closures that are anticlinal and fault supported. Oil water contact super-imposed on the structural maps revealed closures that were oil bearing. Estimation of stock tank oil initially in place revealed 19.511 mmstb, 73.576 mmstb and 19.169 mmstb for J100, K100 and L100 reservoirs respectively, indicate that they can be produced at significant profits. Two infill well placement locations were identified from petrophysical and structural characterization; one at the north central part of J100 reservoir and another at the North-Western part of K100 reservoir.