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We carried out time-lapse analysis in a producing Niger Delta X-field, by first investigating the response and sensitivity of rock properties/attributes to lithology and pore fill in 3-D cross plot domain and by Gassmann's fluid substitution modeling. Furthermore, 4-D seismic data were inverted into acoustic impedance volumes through model based inversion scheme. This served as input into a multi-attribute neural network algorithm for the extraction of rock attribute volumes based on the results of the petrophysical log analysis. Subsequently, horizon slices of rock properties/ attributes were extracted from the inverted seismic data and analyzed. In this way, we mapped hydrocarbon depleted wells in the field, and identified probable by-passed hydrocarbon zones. Thus, the integration of well and time lapse seismic (4-D) data in reservoir studies has remarkably improved information on the reservoir economic potential, and enhanced hydrocarbon recovery factor.

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The use of DC electrical method in baryte mineral exploration has been investigated in Buruku northeast of Markurdi, Nigeria. The objective of the study was to investigate the suitability and potential of electrical resistivity tomography (ERT) combined with vertical electrical sounding (VES) surveys in baryte mineral exploration over known deposits. Results show that the interpreted layer resistivities correlate with the 2-D observations. The study delineated averagely 28 m deep symmetrically moundshaped resistive anomalies (1500 to 5500 Ωm) encased within low resistive sandstone formation along prospective traverses. These responses are characteristics of probable vein structures associated with baryte mineralization. Two dominant E-W and NW-SE resistivity anomaly trends were delineated. The E-W trends were more prominent and persistent than the NW-SE. They are 25 to 50 m wide and stretches to over 300 m in length. The association of mineralized veins with these trends suggests that the veins must be of early Cretaceous age. These mineralized veins correlate with locations of known baryte deposits in the prospect area which hitherto, have been exploited by artisan miners. This is an obvious indication of the utility and resolution of dc electrical method in baryte mineral exploration in the area.