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Technical Paper: Anatomy Of MPD Well Failures: Lessons Learned from a Series of Difficult Wells

Society: IADC
Paper Number: 163546
Presentation Date: 2013
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Abstract

Managed pressure drilling is a technique viewed as a means of improving the chances to drill the most challenging wells. Wellbore pressure management allows operators to address key technical risks such as narrow pore pressure and fracture gradient windows, sensitive wellbore stability environments and navigating steep and unknown pore pressure ramps. Certainly, the technology delivers added advantages while the drilling team attempts difficult wells. Successful execution, however, requires awareness of all aspects throughout the drilling process and full integration of the entire well construction team. Even best laid plans can encounter challenges that quickly become insurmountable. Despite being on alert, as is most often the case with MPD wells, misunderstanding subtle signs throughout the drilling process, poorly synchronized execution or untimely technical failures can lead to catastrophic outcomes for the operator. Additionally, it is not until execution when a full understanding of the wellbore sensitivity to pressure swings becomes apparent.

The authors will look at a series of uniquely different wells, all employing MPD but for different technical reasons. Exploration drilling through challenging pore pressure ramps, high angle and horizontal wells across formations highly sensitive to pressure cycling, PMCD wells and wells drilled through very narrow pore pressure and stability window across depleted zones. Analysis of the detailed design during the planning phase, with the information that was known at that time, will lay the foundation of how each well was executed. In each case, the desired outcome was not achieved for reasons unique to the respective project falling outside the core MPD engineering design. Analysis of the failures will identify key lessons learned and show progressive continuous improvement that has made MPD critical to success on future projects and raised confidence of the users.

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