Petrophysical Evaluation of Reservoir Properties Using Well Logs and 3D Seismic Data: A Case Study of the ‘Northern' Field, Niger Delta

An integrated 3-D seismic data, check shot data and a suite of four well logs within the Northern field, Niger Delta were analyzed with Petrel software for reservoir characterization and petrophysical analysis of the field. The method adopted involves petrophysical analysis, structural analysis and reservoir classification. Detailed petrophysical analysis revealed two reservoirs. Average reservoir parameters such as porosity, gross thickness, hydrocarbon saturation, net-gross were derived from the petrophysical analysis. Structural analysis of the data showed fault assisted anticlinal structures which serve as structural traps that prevent the leakage of hydrocarbon from the reservoirs. The analysis of the all the well sections revealed that each of the sand units extends through the field and varies in thickness with some unit occurring at greater depth than their adjacent unit that is possibly evidence of faulting. The shale layers were observed to increase with depth along with a corresponding decrease in sand layers. From the analysis of the resistivity log, the two delineated reservoirs were identified as hydrocarbon bearing units across the four wells (North 10, North 5, North 7, and North 11). The area extent of the reservoir from the depth maps and the summary of the average results of the significant petrophysical parameters used as variables that determine reservoir quality in the Northern field and based on this, RES 1 was classified as the most prolific reservoir in the Northern field while RES 2 is less prolific.