Unleashing Potential: Maximizing Fracking Performance with an Innovative Mechanical Stratigraphy Framework in the Complex Reservoir: Rock Physics Approach
Authors: Al Hilali L. M. , Al-Aamri M. H. , AL Hooti K. J. 
Published: February 2024

Abstract
The petroleum industry plays a pivotal role in the economy, and A studied Field in southern Oman contributes significantly with its hydrocarbon reserves. The main reservoir, salicylate, lies at a depth of 4 kilometers and consists predominantly of 90% silica. Characterized as a tight reservoir with a porosity of 20% and permeability of range of 0.02 millidarcies, Hydraulic Fracturing has been adopted to optimize field production. This paper aims to construct a robust mechanical stratigraphy of the Athel formation by utilizing existing logs, as well as employing a rock physics model to identify pore aspect ratios, generating facies logs from core data, and characterizing the reservoir based on geomechanical properties such as Poisson's ratio and Young's modulus. The study capitalizes on a comprehensive dataset comprising wireline logs, drilling parameters, natural fracture interpretation, radioactive tracer data, and perforation interval information. The study encompasses three distinct workflows, with the first involving the construction of a rock physics model and generating plots using the Xu-Payne 2009 methodology, which is further categorized into three divisions. Subsequently, a rock physics log is created, followed by adjustments to the pore aspect ratio model. In the subsequent workflow, three core samples are meticulously analyzed to identify distinct facies, contributing to the creation of log facies that enable a comprehensive understanding of the reservoir's composition. Furthermore, employing specific equations, the Poisson's ratio and Young's modulus of the formation are calculated, facilitating the development of new logs.
The collaboration of various models culminates in the creation of a new mechanical stratigraphy model for the reservoir. This holistic approach synthesizes available data to enhance our understanding of the Athel reservoir's geomechanical properties, providing invaluable insights for future operations. The rock physics model of the eight drilling wells reveals a porosity range of 0.05% to 0.30% and velocity values ranging from 3 km/s to 5 km/s. The model also indicates the presence of crack-shaped pore spaces within the formation. Conversely, the rock physics model derived from tracer data portrays a narrower porosity range of 0.15% to 0.25%. Additionally, the pore aspect ratio log subdivides the Athel formation into five distinctive units. By integrating the facies log and geomechanics log, encompassing Poisson's ratio and Young's modulus, eight facies are identified, characterizing the lithological variations and properties observed within the Athel reservoir. By employing this novel mechanical stratigraphy approach, the project aims to enhance our understanding of the reservoir quality, ultimately increasing the probability of fracking success within the main target zone. This improved understanding enables more targeted and efficient utilization of hydraulic fracturing techniques, leading to heightened reservoir productivity and overall project success.