Application of Azimuthal Density while Drilling Images for Dips, Facies and Reservoir Characterization – Niger/Delta Experience

Abstract

Abstract The azimuthal density while drilling tool has been successfully utilized in high angle well drilling and evaluation. The evolution of the imaging technology from this tool has opened new avenues in horizontal well evaluation, and the resultant imaging answer product has successfully been used for detailed structural and sedimentological analysis for characterizing reservoirs beyond the resolution of surface seismic. Conventional well to well correlation techniques have often proven inconclusive in placing laterals in the optimum position within the reservoir. Resulting production from the lateral drain holes has been seen to be greatly influenced by the positioning of the well bore relative to structural and formation dip. Formation dip and structural features have historically been acquired from wire-line logging tools. However, high angle wells present operational difficulties which often result in a decreased use of wireline. Images acquired while drilling by the azimuthal density tool provide a method of resolving the correlation uncertainties, and allow quantification of the structural and sedimentological interpretation and the subsequent production contribution of each zone in the lateral. The fields where this application was utilized are analyzed. From the data analysis an extra opportunity in terms of reserves has been identified.