石油および環境バイオテクノロジージャーナル

概要

Evaluation and Prospect Identification in the Olive Field, Niger Delta Basin, Nigeria

Emina R, Obiadi II* and Obiadi CM

The study area lies in the Greater Ughelli Depobelt of Niger Delta. Recently, a major focus within the Niger Delta is the rejuvenation of older fields (also called brown fields) and the identification of new prospects from these old fields. This study is focused on the evaluation of the Olive Field and the identification of new prospects within the field. Data used were; 3D seismic cube, four composite well logs and check shot. 3 dimension seismic, well log and structural interpretation were done to evaluate the petroleum potentials of the reservoirs using the petrel 2010 and the interactive petrophysic v.36 softwares. Well data were used in the identification of reservoirs and determination of petrophysical parameters and hydrocarbon presence. Four horizons that corresponded to selected well tops were mapped after well to seismic tie. Time and depth structural maps were created from the mapped horizons. Four Hydrocarbon bearing reservoirs within the depth range of 6743 ft – 9045 ft, having volume of shale (Vsh) ranging from 15.32% - 29.06% were interpreted. The total porosity of the reservoirs ranges from 24.63% - 34.01%, while the effective porosity ranges from 17.26% - 31.71%, indicating the reservoirs have very good porosities. The ratio of the Net to Gross Thickness of the reservoirs ranges from 0.720 – 0.980 while the water saturation values ranges from 19.87% - 29.07%. From the water saturation deductions, the hydrocarbon saturation ranges from 70.93% - 78.86% of gas in the given reservoirs. Amplitude attribute extraction and analysis of the horizon maps was used in the identification of areas with hydrocarbon accumulations which are conformable with structures. The use of structural and attribute maps has aided the identification of prospects in the Olive Field. Therefore, it is recommended that wells be drilled to target the new prospects which will improve the hydrocarbon recovery in Olive Field.