Abstract
During drilling operations for the E oilfield in the Mishrif formation in southern Iraq, stuck pipe has been identified as a significant geomechanical problem for several wells. In this study, a 1-D mechanical earth model (MEM) of the Mishrif formation is compiled based on its state of stress and rock strength parameters and is utilized to assess the contribution of borehole collapse leading to the stuck pipe problems. The MEM model is based on the principal in situ stresses and their orientation obtained from wireline logs measurements, measuring while drilling (MWD), and leak off test (LOT). Rock strength properties are obtained from empirical equations and extended leak off tests. The in-situ stresses are transformed to calculate and analyze mud pressure conditions for all wellbore azimuths and inclinations. Two different failure criteria (the Mohr-Coulomb and Mogi-Coulomb rock failure criteria) are used in order to determine feasible drilling trajectories (with respect to the σH orientation) and mud pressure conditions for several wells. This work was conducted to study the behavior of the collapse pressure for Mishrif formation under a normal faulting (NF) in situ stress regime. The results of this study show that wells characterized by stuck pipe are drilled along azimuths which promote wellbore collapse. Based on the MEM results, the mud pressure window is calculated, and stable azimuths and inclinations for each well are suggested. If a specific azimuth for a well cannot be altered, an optimum inclination is recommended to reduce the severity of the borehole collapse. This study based on a 1-D MEM model for directional drilling can improve the well drilling efficiency by reducing non-productive time due to the wellbore instability.
Recommended Citation
E. H. Alkamil et al., "Wellbore Stability Evaluation for Mishrif Formation," SPE Middle East Oil and Gas Show and Conference, MEOS, Proceedings, pp. 3004 - 3018, Society of Petroleum Engineers, Jan 2017.
The definitive version is available at https://doi.org/10.2118/183668-ms
Department(s)
Geosciences and Geological and Petroleum Engineering
Publication Status
Available Access
International Standard Book Number (ISBN)
978-151083887-1
Document Type
Article - Conference proceedings
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 Society of Petroleum Engineers, All rights reserved.
Publication Date
01 Jan 2017
Included in
Geological Engineering Commons, Geology Commons, Mining Engineering Commons, Petroleum Engineering Commons
