Abstract: Prediction of elastic properties using crossplot analyses and seismic inversion quantitative interpretation in Zeta field was carried out to improve quantitative interpretation in the field. The dataset used comprises of well logs and full stack seismic data. Rock attribute properties modelled from well logs and analysed in the cross-plot space show strong sensitivity to reservoir lithology and fluids. The cross-plot of lambda-rho (λρ) versus mu-rho (μρ) distinguishes the reservoirs into shale, brine sands, oil sands and gas sands. The cross-plots show that hydrocarbon sands have low λρ and high μρ values. λρ is sensitive to fluid and μρ sensitive to rock matrix only. This makes μρ versus λρ a good fluid discriminator. This suggests that the inversion result could be useful to distinguish sands from shale and brine from oil. Simultaneous seismic inversion method was applied to transform seismic reflection data into quantifiable rock properties. Results reveal low lambda-rho values which are indicative of hydrocarbon saturated-sands. These values confirm the availability of hydrocarbons around Wells 3, 4 & 5 locations and to the North-west of the horizon’s slices. However, shale zones and brine are observed to the western part of the field and surrounding the hydrocarbon zones, indicating probable depleted zones and/or source rock. Moderately compacted clean hydrocarbon filled reservoir sands exhibits relatively high values of mu-rho due to their high opposition to shearing, while unconsolidated clean hydrocarbon saturated reservoir formations exhibit low mu-rho values. The inversion indicates that lambda-Rho attribute is more diagnostic of fluid characterization. This study can be applied in identification of new prospects as an effective economic and decision-making tool.

Keywords: Lambda-Rho, Mu-Rho, Simultaneous Inversion, Elastic Properties.

| DOI: 10.17148/IARJSET.2022.9126