Integration of 3D-seismic and petrophysical analysis with rock physics analysis in the characterization of SOKAB field, Niger delta, Nigeria

Abstract

Compartmentalization of reservoirs and technical failures experienced in data acquisition, processing and interpretation, without doubt, hinder the effective characterization of reservoirs. In this research, to ensure accuracy, three methods were integrated to characterize reservoirs in SOKAB field. Petrophysical analysis, seismic interpretation, and modeling, and rock physics analysis were utilized. Its objectives were: to develop a template to facilitate improvements in future reservoir characterization research works and producibility determination; to utilize rock physics models to quality check the seismic results and to properly define the pore connectivity of the reservoirs, and to locate the best productive zones for future wells in the field. Forty-three faults were mapped and this included five major faults. Two hydrocarbon bearing sand units (A & B) were correlated across five wells. Structural maps were generated for both reservoirs from which majorly fault assisted and dependent closures were observed. The petrophysical analysis indicated that the reservoirs have good pore interconnectivity (Average Фeffective = 23% & 22% and Kaverage = 1754md & 2295md). The seismic interpretation and modeling alongside the petrophysical analysis were then quality checked via qualitative rock physics analysis. From the Kdry/Porosity plot, the sands were generally observed to lie within the lower Reuss and upper Voigt bound which indicates a low level of compaction. From the velocity–porosity cross plot, it was revealed that the lower portions of the reservoirs were poorly cemented and this could hinder their producibility.