Developing a geomechanical model to mitigate the risks of wellbore instability in an Iraqi oilfield
By: Issa, Mustafa Adil
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Contributor(s): Issa, Muntadher Adil.
Publisher: USA Springer 2023Edition: Vol.53(5), Oct.Description: 1064-1077p.Subject(s): Construction Engineering and Management (CEM)Online resources: Click here
In:
Indian geotechnical journalSummary: Wellbore instability is one of the significant challenges in the southern Iraqi oilfields. Numerous wellbore instability issues, such as shale caving, tight holes, pipe sticking, sidetracking, and fishing, were experienced throughout the drilling operations. These issues are a critical contributor to increasing non-productive time. In this study, a field case in the south of Iraq was conducted, and a one-dimensional mechanical earth model was constructed of the problematic zones that extended from the Sadi to the Zubair Formations using well log data and core analysis from the offset wells. Then, the Mogi–Coulomb failure criterion was utilized to determine the optimum mud weight and wellbore trajectory for planned wells within this oilfield. The results indicated that the major cause of the wellbore instability issues was improper mud weight, i.e., 10 pound per gallon (ppg) employed to drill the area of interest. Wells with inclination angles ranging from 0° to 30° are more stable, and the recommended mud weight is 11.4 to 12 ppg. While the strongly deviated and horizontal wells are less secure, the recommended mud weight is 12.1 to 12.6 ppg. The findings of this study may be used as cost-effective tools when planning for future nearby directional wells, improving drilling efficiency.
| Item type | Current location | Call number | Status | Date due | Barcode | Item holds |
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Articles Abstract Database
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School of Engineering & Technology (PG) Archieval Section | Not for loan | 2024-0049 |
Wellbore instability is one of the significant challenges in the southern Iraqi oilfields. Numerous wellbore instability issues, such as shale caving, tight holes, pipe sticking, sidetracking, and fishing, were experienced throughout the drilling operations. These issues are a critical contributor to increasing non-productive time. In this study, a field case in the south of Iraq was conducted, and a one-dimensional mechanical earth model was constructed of the problematic zones that extended from the Sadi to the Zubair Formations using well log data and core analysis from the offset wells. Then, the Mogi–Coulomb failure criterion was utilized to determine the optimum mud weight and wellbore trajectory for planned wells within this oilfield. The results indicated that the major cause of the wellbore instability issues was improper mud weight, i.e., 10 pound per gallon (ppg) employed to drill the area of interest. Wells with inclination angles ranging from 0° to 30° are more stable, and the recommended mud weight is 11.4 to 12 ppg. While the strongly deviated and horizontal wells are less secure, the recommended mud weight is 12.1 to 12.6 ppg. The findings of this study may be used as cost-effective tools when planning for future nearby directional wells, improving drilling efficiency.
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