Geomechanical unit modeling using seismic and well log data in one of the southwestern Iranian oilfields

Abstract

Geomechanical modeling plays a substantial role in the life cycle of a hydrocarbon reservoir and is a key factor in drilling operation optimization. Formations with low mechanical stability can cause wellbore instability or failure during drilling. The main objective of this paper is to predict the elastic parameters (UCS, Young’s Modulus, and Poisson’s Ratio) at the well and the reservoir volume, using well logs and empirical relationship. The distribution of the elastic parameters in the reservoir is calculated by utilizing geomechanical units (GMUs), which characterize different aspects of the mechanical properties of reservoir and caprocks. The elastic parameters of 30 wells are classified, into five geomechanical units based on the elastic moduli and the mechanical properties of the formations. Each unit is a cluster consisting of Young’s modulus, Poisson’s ratio, bulk, shear modulus, and UCS. Unit 1 is considered suitable for drilling while maintaining stability, because of its higher values of elastic parameters. Unit 5 possesses the lowest values of predicted elastic parameters. In this study, we also obtain a three-dimensional model of geomechanical parameters for the studied reservoir, using the statistical method.