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Comprehensive Finite Element Modeling Study On the Effects of Fatigue On Wellbore Cement to Enhance Environmental Assurance for Oil and Gas Wells
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
In this study, we created various finite element models to simulate the effects of evolving mechanical loads on cement sheath integrity. The changing cement mechanical properties were taken into consideration for these models. The von Mises stress were calculated and the various failure modes were detected.
We used Abaqus and Comsol fatigue finite element package for 3D modeling. Wellbore is modeled using a hole inside a cube. Abaqus mesh is refined close to the wellbore where internal pressure is applied. An 8-node brick, trilinear displacement, trilinear pore pressure (C3D8P) is used as element type. Two yield criteria are used for predicting the failure: Drucker-Prager and Mohr-Coulomb. Plastic strains and Mises stresses are plotted for three different values of applied internal pressure: 50 MPa, 80 MPa and 120 MPa. The Drucker–Prager yield criterion is a pressure-dependent model. This criterion determines whether a material has failed or undergone plastic yielding or not. The Drucker–Prager yield criterion have been applied to rock, concrete, polymers, foams, and other pressure-dependent materials.