Poor quality 3-D seismic surveys are often reprocessed into modern 3-D seismic data of better quality to improve seismic imaging and resolve structural uncertainties during seismic data interpretation. This study presents an integration of a modern 3-D seismic and composite well log data, together with petrophysical analysis to re-evaluate hydrocarbon prospectivity of a historically produced Fega field, located in the onshore part of the Niger Delta Basin. Two reservoirs, S-600, and S-700 composed essentially of shoreface deposits stacked by channel sandstones with heteroliths were evaluated. The structural interpretation shows that the study interval is characterized by antithetic and synthetic-growth faults that compartmentalized the reservoirs into blocks. Besides, the reservoir structural surface maps document fault-dependent structural closures that show possible hydrocarbon prospects and leads in some yet penetrated reservoir blocks. However, reservoir S-600 shows a better hydrocarbon prospect potential, ascribed to its relatively strong amplitude structural conformity. Petrophysical analysis indicates that the sandstones generally have very good to excellent reservoir quality. Nevertheless, most of the reservoir blocks show heterogeneity in bulk volume water distribution and they may possibly not produce water-free hydrocarbon. The volumetrics analysis shows that the identified prospects are prolific and commercially viable for an increase in oil production opportunities within the study area. However, the estimated volume suggests that the current commercial status of field is fairly viable for multinational field operators, and the field may be given out to marginal field operators. The study approach could also be applied to marginal fields in the Niger Delta and other similar petroleum provinces, where contract terms are similar to those in Nigeria, to revitalize and optimize production. The study demonstrates the usefulness of reprocessing 3-D reflection seismic data and updating reservoir information as soon as new geological and geophysical data are available, together with the revaluation of hydrocarbon fields from time to time. This may increase the chances of finding new opportunities in structurally complex settings.

质量较差的 3-D 地震勘测通常被重新处理为质量更好的现代 3-D地震数据，以改善地震成像并解决地震数据解释过程中的结构不确定性。本研究将现代 3-D 地震和复合测井数据与岩石物理分析相结合，以重新评估位于尼日尔三角洲盆地陆上部分历史上生产的 Fega 油田的油气勘探前景。两个水库，S-600 和 S-700，主要由河道砂岩堆积的滨面沉积物组成与heteroliths 进行了评估。构造解释表明，研究层段的特征是对立断层和合成生长断层，将储层划分为区块。此外，储层结构表面图记录了断层相关的结构闭合，显示了一些尚未渗透的储层块中可能的油气前景和线索。然而，S-600 储层显示出更好的油气勘探潜力，这归因于其相对较强的振幅结构整合。岩石物理分析表明，砂岩的储层质量一般非常好。尽管如此，大多数储层区块在体积水分布方面表现出非均质性，并且它们可能不会产生无水烃。体积分析表明，已确定的前景对于增加研究区域内的石油生产机会而言是多产且具有商业可行性的。但是，估算的数量表明，目前油田的商业状态对于跨国油田运营商来说是相当可行的，并且该油田可能会分配给边缘油田运营商。该研究方法还可以应用于尼日尔三角洲和其他类似石油省份的边缘油田，这些地区的合同条款与尼日利亚的合同条款相似，以振兴和优化生产。该研究证明了重新处理 3-D 反射地震数据和更新储层信息的有用性，只要有新的地质和地球物理数据可用，以及不时对油气田进行重估。