Integrated petrophysical characterization of Late Cretaceous fluvial-deltaic channel systems in Penobscot Field, Nova Scotia: Implications for reservoir facies prediction

Abstract

Globally, deltaic channels offer promising exploration prospects as potential hydrocarbon reservoirs. Sea-level changes in deltaic systems cause facies heterogeneity in and around channels, making precise reservoir characterization essential to reduce exploration risk. This study focuses on the petrophysical characterization of the deltaic channel system within the Logan Canyon Formation in the Penobscot Field. The workflow integrates structural mapping, reservoir feasibility assessment, spectral decomposition, model-based inversion (MBI), and multi-layer perceptron (MLP) modeling. Litho-facies, acoustic impedance, and petrophysical property relationships were quantified through well-log cross plots. Subsequently, impedance and petrophysical volumes were accurately predicted using MBI and MLP techniques. The results show an 84.7 % correlation with a synthetic error of ∼0.12 and impedance error of 414 m/s*g/cm³ for P-imp, and an 89.6 % correlation with an error of ∼0.026 for the Vsh, 95.5 % correlation with an error of ∼0.013 for Nphi, and 86.1 % correlation with an error of ∼0.017 for Phie estimations. Sand reservoir facies show moderate to higher P-imp (8000–10,500 m/s*g/cm³), lower Vsh (<0.40 v/v), and lower Nphi (0.25–0.35 v/v), with higher Phie (0.12 to 0.30 v/v) signatures, whereas shale facies exhibit moderate to lower P-imp (6500–9000 m/s*g/cm³), higher Vsh (>0.40 v/v), higher Nphi (>0.30 v/v), and lower Phie (0.0 to 0.05 v/v) signatures. This facies differentiation highlights the spatial heterogeneity within the deltaic system and delineates the reservoir zones within complex channel architectures. Integration of P-imp, Nphi, Vsh, and Phie provides a robust geological model that enhances the understanding of facies dispersal pattern and reservoir potential, and identifies sweet spots for future hydrocarbon exploration within the Late Cretaceous channel system of the Penobscot Field, Nova Scotia.