Borehole Stability Assessment Using Elastoplastic Thermo-elastoplastic Finite Element Modeling Approaches

Abstract Wellbore stability modeling has been known in the oil and gas industry and academia for a long time. The instability-related issues significantly impact field developments, especially in complex deep reservoirs. This instability can substantially jeopardize the drilling objectives, leading to poor wellbore conditions. Most available software uses simple linear elastic modeling approaches to predict wellbore failure and determine the safe mud weight for the planned boreholes. This assumption might lead to inaccurate results. The main objective of this research is to use an elastoplastic modeling approach to predict a yielded zone around the wellbore using Finite Element Modeling (FEM). These elastoplastic models were used in conjunction with the Drucker-Prager yield criteria. The yielded zone is interpreted utilizing volumetric strain analysis. The result of this study will be used for any potential breakout development while drilling that might lead to increase wellbore stability-related problems. The damage or yielded zone results will be used for completion packer positioning to avoid pressure communications while packers expand. These novel techniques will be applied to compute wellbore stability for tight sandstone formation. The methodology can be applied to other locations using the FEM approach. Introduction Drilling geomechanics has been well established in the oil and gas industry and academia due to wellbore stability-related issues, costing around $ billion annually (Kang et al., 2009). Many researchers have studied the impact of geomechanics on drilling operations, mainly including saving mud weight window prediction and wellbore failure to perform drilling operations safely to the TD. Plumb et al. (2004) have introduced new geomechanics processes to reduce operational risks. Their study focuses mainly on the role of geomechanics in drilling operations. Satya et al. (2011) discussed the role of geomechanics in appraising a deep tight gas reservoir. This study provided a solution for drilling a well without damaging the reservoir using underbalanced drilling technology. Hamid et al. (2014) studied wellbore stability using elastoplastic models to predict induced stresses and yield zone around the wellbore. Hamid and Rahim (2015) studied the impact of rock mechanical properties on drilling operations. Hamid et al. (2016) investigated the impact of the predrilling wellbore stability modeling in improving drilling efficiencies. All these studies provided solutions for only drilling operations without considering the role of wellbore quality on completion and stimulations.