A New Driver for Managed Pressure Drilling: Reducing Stuck Pipe Occurence

Abstract

Differences between mud pressure in a wellbore and pore pressure in high permeability rocks can lead to differential sticking, particularly when drilling deviated wells and encountering mud losses. Several solutions, all challenging, can be used to address this problem. The conventional mitigation has been to manage mud weight (MW) accordingly. However, managed pressure drilling (MPD) offers a promising solution with positive risk-adjusted cost and other benefits. Wells in the E oilfield in southern Iraq are typically drilled overbalanced and therefore often experience a high percentage of non-productive time (NPT) due to differential sticking. This study evaluates the feasibility of using MPD to optimize the drilling process by decreasing mud weight while applying required surface pressure to achieve the target bottom hole pressure (BHP). A software simulation model uses different mud weights to determine required choke surface backp ressure (SBP) to achieve the initial target equivalent circulation density (ECD). Historically, differential sticking has not been a primary driver to justify MPD. However, MPD offers more dynamic and rapid wellbore pressure control by adjusting SBP applied to the annulus for a given MW, and can actually decrease the risk of differential sticking. Instead of shifting MW or changing other drilling parameters, MPD adjusts the required ECD and/or equivalent static density (ESD) based on formation pore pressure gradient. Additionally, MPD directly lowers SBP in the event of mud losses due to high ECD/ESD to decrease the BHP without the need to reduce MW. This paper discusses hydraulic simulation software used to model the drilling development plan. The software optimizes MW and SBP while drilling, making pipe connections, and completing the well. Furthermore, it discusses the sensitivity effects of each parameter on wellbore pressure and provides guidelines for managing pressure by adjusting these variables.

Meeting Name

SPE Oil and Gas India Conference and Exhibition 2017 (2017: Apr. 4-6, Mumbai, India)

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Drilling; Well drilling; Kick detection

International Standard Book Number (ISBN)

978-151084202-1

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2017 Society of Petroleum Engineers (SPE), All rights reserved.

Publication Date

01 Apr 2017

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