Acoustic and Microresistivity Borehole Image Logs and Core Data Integration in Well DN-22, Drago Field, Oriente Basin, Ecuador

Abstract

Abstract Studies of petroleum reservoirs are based on a multidisciplinary integration focused on developing 3D models that honor reservoir heterogeneities; the sedimentological and stratigraphic models play the most important role to honor these heterogeneities; in order to obtain good models it is important to acquire and integrate the highest volume of well data, preferably state of the art technology. This paper presents how electrical log-core data integration obtained a correlation between lithology, lithological accessories, sedimentary structures, structural features, fossils, ichnofossils and fluid impregnation, among others, from the interpretation of two hundred and twenty nine feet of a sedimentary sequence within core data and a high-resolution acoustic-resistivity image log from well DN-22 in Drago field. High-resolution borehole image logs are much more cost effective as compared to coring and subsequent analysis. From the analysis of the features associated with rock factory (grain size, sorting, roundness) and other associated features like sedimentary and post-sedimentary processes (lithological accessories, fossils traces, diagenetic features), sedimentary facies were identified, which were correlated and adapted to existing sedimentary facies catalog and used for Drago field. Likewise, based on patterns and characteristic responses seen in resistivity and acoustic image log (coloring and shading contrast, texture, clasts, clay laminations, fossils traces, fossils), electrofacies were identified and framed into the same facies catalog. The resulting analysis established eight sedimentary-electrofacies, this contributes to further extrapolate detail sedimentological analysis for coming wells in this field by using high-resolution image logs. This study is unique in the area and will help to better characterize rock properties for field development.