Analysis of sedimentary facies and depositional environments of Paleogene sequence of Cambay basin, India

Abstract

A study on the sedimentary facies characterization and depositional environment interpretations for the K#Field (K-Oil Field) in Cambay petroleum basin of western onshore, India was conducted based on the sub-surface data from drilled wells, including well logs, borehole images, cores and the regional knowledge of the basin. In this work, an effort is made to integrate the current data from seismics and well logging, to study and analyze its depositional environments and establish the petroleum systems. The study regions for the present work are K45 and K48 blocks. The target strata includes 2 oil-bearing formations of Paleogene, which is about 3600 ft; they are M#Fm (M-Formation) of the Eocene and N#Fm (N-Formation) of Oligocene, subdivided into 11 zones. The sediment fill is mostly of Tertiary. The research attempts to decipher the oil - depositional source correlation problems of the basin. Sedimentary models were established referring to the core analysis, core photographs and well logs. Reservoir and heterogeneity study included reservoir lithology features, physical properties and pore structure features.Well facies analysis of oil well WELL-0297 and WELL-0129 was done and the results were analyzed for further drilling of new wells for oil and gas exploration. The study found that the Eocene, Oligocene, Miocene and Paleogene are fluviatile facies sand and mud interbed sediment with the thickness 2000-4000 ft, which are main oil-bearing formations in these areas. Studies concluded that the fluvial reservoirs of the K#Field are characterized by large variations from laterally extensive bodies with good interconnectedness and high net-to-gross ratios, multi-storey ribbon bodies with poor interconnections and low net-to-gross ratios.