Yielded Zone Characterization While Drilling a Wellbore into Clastic Reservoirs Using Elastoplastic Modeling Approaches

Abstract

ABSTRACT Drilling a wellbore into a clastic reservoir exhibits complex rock behavior, including plastic deformation and yield zone development, which can affect wellbore stability and hydrocarbon production efficiency. Elastoplastic modeling methods have been increasingly used to simulate the drilling process and predict the location, shape, and size of yielded zones in the reservoir. This study aims to characterize the yielded zones in a sandstone reservoir during a borehole lifetime using elastoplastic modeling approaches. The methodology involves developing a finite element model of the sandstone reservoir using appropriate meshing techniques and boundary conditions definition for the problem. The constitutive model used in this study is the Drucker-Prager yielded criterion, which accounts for the non-linear behavior of the material during plastic deformation and yielding. The numerical method used is the finite element method, which discretizes the reservoir into small elements and solves for the stresses and strains in each element. The drilling process is simulated using incremental loading, miming the gradual application of drilling forces on the reservoir. The stress and strain fields in the reservoir were monitored during drilling, and areas of plastic deformation and yield were identified. The results showed that the elastoplastic modeling approaches used in this study accurately predicted the size, shape, and location of yielded zones in the clastic reservoir. The location and shape of the yielded zones agreed with the field observations. Additionally, the model predicted the formation of a narrow, highly deformed zone around the wellbore, which is consistent with field observations. The size of the yielded zone depended on the drilling parameters, rock mechanical properties, and in-situ stresses. This study concludes that elastoplastic modeling approaches can be used to predict the size, shape, and location of yielded zones in sandstone reservoirs during wellbore drilling and production operations. The methodology used in this study can be used as a valuable tool for borehole planning and reservoir management. The innovation of this study lies within the use of elastoplastic modeling approaches to optimize drilling parameters and reduce the risk of wellbore instability in sandstone reservoirs. The results of this study can aid in designing drilling strategies that minimize the impact of yielded zones and improve wellbore stability, ultimately leading to increased production efficiency.