| Abstract [eng] |
ABSTRACT This study presents shale volume result and porosity result from geophysical well logs in OTI field Niger delta basin, Nigeria. The study aims to identify the lithology, fluid type, estimate the shale volume, porosity, and identify through correlation analysis the more reliable logging tool between density, neutron-density, and sonic estimated porosity and core derived porosity. Three reservoirs (D, E, and F) in OTI-X01, 02, and 03 were selected since core information were provided. Well logs shows that the study area was characterized by sand-shale interbeds. Hydrocarbon fluid identified were oil and water for OTI-02, and 03 well while OTI-X01 was identified to be gas saturated. The shale volume ranges from 0.061 to 0.115, 0.052 to 0.152, 0.057 to 0.15 in OTI-02, X01, and 03 respectively indicative of very good reservoir and minimal shale presence. Log derived porosity estimated from density, neutron-density, and sonic revealed porosity within the study area to range between good to excellent. Correlation analysis between core porosity versus PHIT_ND, PHIT_S, and PHIT_D log derived porosities in sand E of OTI-02 well were 0.9465, 0.1533, 0.5991, in sand D of OTI-X01 well were 0.08306, 0.0002, and 0.05259, and in sand F of OTI-03 well were 0.8554, 0.082, and 0.6811 respectively. Hence the neutron-density log derived porosities were considered to be a more reliable measure of porosity in the reservoirs of the field as it had high correlation with core derived porosity across the field. |
