The interpretation of 3D seismic and well logs data from ‘SUYI’ Field reveal that the reservoir sand is in the parallic sequence of the Agbada Formation and also typical structural features of the Niger Delta, namely: The roll over anticline and growth fault with a promising good hydrocarbon accumulation. In this paper, 3D seismic data and well logs data were interpreted and analyse to delineate potential reservoirs and map structures favourable to hydrocarbon accumulation, this will aid further exploration activities within the field of study. Two reservoir sands were delineated from the well logs using gamma ray logs for the lithology identification and resistivity logs for the fluid content identification. Seven faults (F1, F2, F3, F4, F5, F6, and F7) were delineated while three horizons (Horizon 1, 2 and 3) were picked across the seismic section. Most of the major faults delineated in the area trends east-west, cutting across the low structure area. The generated time and depth structure maps shows the area is characterized by low structural features but some high anticlinal structures were observed at different flanks on the maps generated, these areas are likely to be good prospect for the accumulation of hydrocarbon.

Capillary pressure is an important characteristic that indicates the zones of interaction between two-phase fluids or fluid and rock occurring in the subsurface. The analysis of transition zones (TZs) using Goda (Sam) et al.'s empirical capillary pressure from well logs and 3D seismic data in 'Stephs' field, Niger Delta, was carried out to remove the effect of mobile water above the oil-water contact in reservoirs in the absence of core data/information. Two reservoirs (RES B and C) were utilized for this study with net thicknesses (NTG) ranging from 194.14 to 209.08 m. Petrophysical parameters computed from well logs indicate that the reservoirs' effective porosity ranges from 10 to 30% and the permeability ranges from 100 to > 1000 mD, which are important characteristics of good hydrocarbon bearing zone. Checkshot data were used to tie the well to the seismic section. Faults and horizons were mapped on the seismic section. Time structure maps were generated, and a velocity model was used to convert the time structure maps to its depth equivalent. A total of six faults were mapped, three of which are major growth faults (F1, F4 and F5) and cut across the study area. Reservoir properties were modelled using SIS and SGS. The capillary pressure log, curves and models generated were useful in identifying the impact of mobile water in the reservoir as they show the trend of saturating and interacting fluids. The volume of oil estimated from reservoirs B and C without taking TZ into consideration was 273 × 10 6 and 406 × 10 6 mmbbls, respectively, and was found to be higher than the volume of oil estimated from the two reservoirs while taking TZ into consideration which was 242 × 10 6 and 256 × 10 6 mmbbls, respectively. The results have indicated the presence of mobile water, which have further established that conventionally recoverable hydrocarbon (RHC) is usually overestimated; hence, TZ analysis has to be performed for enhancing RHC for cost-effective extraction and profit maximization.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

No abstract