"Conventional wellbore trajectory planning is commonly based on an Andersonian state of stress [SoS] and the optimum well azimuth and inclination for a specific depth can be determined using stereographic projections of the safe mud weight window. In this thesis a new methodology using the complete stress tensor is developed to determine optimal well trajectories for complex in-situ stress scenarios. This study uses a 3D finite element analysis to simulate the SoS based on an integrated 3D MEM. The model yields the complete stress tensor at every location for a planned future well path. Using standard equations to determine the wellbore SoS for inclined wellbores the safe operational pressure window can be determined.
Included is a wellbore integrity study on the cement sheath of a well proposed for CO₂ sequestration. This includes both the mechanical interactions of the casing, cement, and formation as well as the effects of temperature change which would be caused by CO₂ injection. The use of a staged finite element model to accurately predict the pre-cementing wellbore SoS is proposed. The SoS results are then implemented into a wellbore model with a perfectly bonded cement sheath in order to investigate the effects of cement curing and degradation.
In this study the evolution of Young's Modulus during cement curing, and de-evolution during cement degradation is accounted for. Traditional cement integrity studies use only a constant value for Young's Modulus. The finite element models show that inclusion of cement hardening may increase the risk of shear failure in the cement, while inclusion of cement degradation may lead to tensile failure during cold CO₂ injection."--Abstract, page iii.
Flori, Ralph E.
Geosciences and Geological and Petroleum Engineering
M.S. in Petroleum Engineering
United States. Department of Energy
Missouri University of Science and Technology
xiv, 156 pages
© 2014 Nevan Christopher Himmelberg, All rights reserved.
Thesis - Open Access
Library of Congress Subject Headings
Stress concentration -- Mathematical models
Concrete -- Elastic properties -- Testing
Geological carbon sequestration
Finite element method
Electronic OCLC #
Himmelberg, Nevan Christopher, "Numerical simulations for wellbore stability and integrity for drilling and completions" (2014). Masters Theses. 7250.