Integrated Seismic Interpretation and Petrophysical Evaluation for Hydrocarbon Volumetric Estimation in the BUKS Offshore Field, Niger Delta, Nigeria

Abstract

Hydrocarbon reserve estimation and reservoir characterization remain critical aspects of field development planning, particularly in mature offshore basins such as the Niger Delta. This study integrates 3D seismic interpretation with petrophysical analysis to evaluate reservoir quality and estimate hydrocarbon volumes within the BUKS offshore field, Niger Delta, Nigeria. Structural interpretation of the seismic data identified a NNW-trending rollover anticline associated with four major listric growth faults (F1–F4), forming the principal trapping system in the field. Petrophysical evaluation of four wells revealed favourable reservoir properties, with average porosity values ranging from 25% to 31%, permeability between 83 and 1452 mD, and shale volume varying from 20.5% to 38.6%. Water saturation values range from 15% to 41%, corresponding to hydrocarbon saturation values of 59%–85%, indicating good hydrocarbon potential across the mapped reservoirs. Volumetric calculations based on the interpreted reservoir parameters yielded a combined Stock Tank Oil Initially in Place (STOIIP) estimate of approximately 45.37 MMSTB, while a conservative recovery factor of 10% suggests recoverable reserves of about 4.54 MMSTB. The results indicate that the BUKS field possesses good reservoir quality, and the recoverable volume, while modest, may warrant further appraisal to assess development options, including potential tie-back to existing regional infrastructure. The study further demonstrates that integrating seismic interpretation with conventional petrophysical evaluation provides a practical and reliable approach for preliminary reserve estimation and field appraisal in offshore Niger Delta reservoirs.