Seismic characterization of delta front sand bodies in Lower Magdalena Valley basin and their potentiality as reservoirs in Cienaga de Oro Formation, Colombia.

Abstract

Introduction The Lower Magdalena Basin is located in the northwest of Colombia where oblique subduction along the Romeral fault system has produced transpressional and transtensional deformation since late Cretaceous to present day. The Lower Magdalena Basin is limited to the northeast by the Bucaramanga Santa Marta fault system; to the south by the Central Cordillera and to the west by the Romeral fault system. This basin is subdivided by three structural elements that have controlled sedimentation since Eocene to late Miocene. These structural elements are: The Plato sub-basin to the north, the Cicuco Arch in the central part, and the San Jorge sub-basin to the south. Within the sequence, Cienaga de Oro Formation is subdivided in Upper and Lower, where the Upper corresponds to transitional delta facies and the lower to delta front sandstone deposits, the objective of this study. Delta front deposits are from transitional environment deposits and are formed by high volumes of sediments that have been transported from their original location due to hyperpycnal flow. Although the bulk of the material in delta front deposits are sand and silt blocks that could represent potential reservoir, having good reservoir quality and being surrounded by shale material of distal delta facies. The objective of this study is to highlight these sandstone blocks within the Lower Cienaga de Oro formation using seismic attributes and estimate the amount of hydrocarbon present in one of those blocks.