Integration of Seismic Attributes and Borehole Images for Exploring the Prospectivity of Late Jurassic and Early Cretaceous Carbonates in North Western Desert, Egypt

Abstract

Abstract Seismic attributes play an important role in hydrocarbon exploration and production because they bring additional information about the lithological and petrophysical changes in the subsurface along the main seismic reflectors. Borehole images are commonly used to evaluate carbonates, particularly for qualitative and quantitative study of fractured and vuggy carbonate. The main goal of this study is to combine seismic attributes with borehole images to improve the confidence in mapping the fractured carbonate prospect. The workflow started with an integrated formation evaluation that aims to identify possible promising zones based on wireline and mud logs. It then moved on to integrating borehole images with available core data and thin sections to analyze and interpret the reservoir lithofacies, as well as decoding possible diagenesis effects, with a focus on fracture identification and analysis. As a result, wells with the best reservoir quality were identified. Finally, structural mapping was completed using a combination of seismic features, including edge detection, coherence, and minimum curvature to find fracture areas. The occurrence of fractured dolomite or vuggy dolomite was discovered in wells with prospective pays connected with oil and gas shows. It was also observed that borehole analysis for some wells shows that they have low porosity (3%). Seismic attribute maps around these wells, on the other hand, show a high fractured density, emphasizing that combining borehole images with seismic attributes is critical for evaluating these carbonates. Most of the fractures are oriented Northwest-Southeast and are linked to deformation zones. We also identified that several varieties of features and fractures collected from borehole images exhibit a strong link with discontinuities on the seismic amplitude, evident from the variance seismic cube, allowing us to pinpoint areas with high fractured density. Several carbonate prospects have been identified, with a high density of fractures expected. Several carbonate prospects have been identified, with high fractures expected. Additional exploration for new carbonate reservoirs in the Western Desert will be enhanced by the workflow provided in this paper. This workflow also helped us in better-identifying carbonate prospects with high fractured density.