Title

Numerical Simulation of Micro-Annuli Generation by Thermal Cycling

Abstract

During the life span of a well, the cement sheath may fail to provide zonal isolation and micro-annuli may develop between the cement-casing and cement-rock interfaces. Multiple factors during well construction and injection processes may have individual or combined influence on the micro-annuli formation. This paper presents a staged finite element modeling approach to simulate the well construction processes and injection cycle. Loads from the in-situ stress field, mud/slurry pressure, and periodic temperature changes are incorporated in the model. A “realistic” bottom-hole state of stress is generated in the model and micro-annuli generation is simulated by the tensile debonding of the cement-formation interface. The simulation results indicate the generation of micro-annuli is highly affected by the temperature difference between injection fluid and formation and the time span of the fluid injection cycle. Resulting debonding apertures in the models are in the order of 10-5m which corresponds with previous studies. The modeling results of this study indictates once debonding occurs, the debonding aperture increases quickly and may exceed the ranges considered hazardeous.

Meeting Name

51st U.S. Rock Mechanics/Geomechanics Symposium (2017: Jun. 25-28, San Francisco, CA)

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Cements; Oil field equipment; Wellbore cement

International Standard Book Number (ISBN)

978-151085758-2

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2017 American Rock Mechanics Association (ARMA), All rights reserved.

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