SEISMIC RESERVOIR CHARACTERIZATION AND MODELLING OF “JEL” FIELD, ONSHORE NIGER DELTA, NIGERIA

Abstract

Seismic and well log data was utilized to carried out seismic reservoir characterization and modelling of “JEL” Onshore oil field Niger Delta. Lithology and hydrocarbon reservoirs were identified from gamma ray and resistivity logs. Well log correlation was done using the principle of similarity in log signatures across the studied wells. Computation of reservoir parameters such as porosity, hydrocarbon saturation, water saturation and permeability was done using standard equations. Seismic structural interpretation involved the identification and mapping of faults and horizons from seismic sections using attributes such as amplitude and reflection geometry. Geological modelling was carried out by integrating information from seismic and petrophysics using geostatistical methods of Sequential Gaussian Simulation and Kriging. Volumetric estimation of hydrocarbon was performed using probabilistic approach. The general stratigraphy is typical of Agbada formation comprising alternation of sands and shales. Two reservoirs located at a depth interval of 1896-2027 m were identified and mapped. Reservoir 1 has average total porosity of 31%, effective porosity 29%, hydrocarbon saturation 85% and permeability 734 mD. Reservoir 2 has average total porosity of 28%, effective porosity 27%, hydrocarbon saturation 75% and permeability 712 mD. A network of growth faults and two horizons were also mapped. Seismic structural maps gave insight into rock disposition and hydrocarbon potential. The probable structures harbouring oil and gas are a combination of faulted and fault assisted anticlinal structures. Modelling of critical reservoir properties into maps of porosity, facies and water saturation aided in the study of areal distribution of the parameters and influence on oil and gas production. Finally, reservoirs 1 and 2 have 75× 106 and 46× 106 STB of oil. Both reservoirs have oil in commercial quantities.