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Controlled pressure drilling (CPD) is an emerging, multi-component drilling application that can improve drilling time and reduce previously recorded lost time on offset conventionally drilled wells—when applied appropriately. In addition, specific drilling techniques offered within CPD technology not only improve the time it takes to reach total depth (TD), but also have been proven to optimize reservoir section productivity and maximize economically recoverable reserves. CPD is composed of three main techniques: air drilling, underbalanced drilling, and managed pressure drilling. This paper provides an updated discussion of CPD techniques, the nonproductive time that it can address and screening methodology. A methodology to properly screen CPD techniques to reduce failure/misapplication and align objectives with expectations had been lacking. This paper addresses the latest refinements in an expert system developed to better understand and screen options for CPD operations. The Internet-based selection tool provides guidance by using key indicator questions, beginning with the primary objective(s) for the given wellbore section. If the specific CPD technique is known, the user can activate the online screening tool. The online screening tool considers a range of economic and technical parameters, which are applied to algorithms and logic rules, to provide a relative ranking for each CPD candidate. This paper will also address modifications that have been made to reduce cost related sensitivity when screening air and managed pressure drilling, which previously made the screening process less consistent. Sensitivity analysis can also be performed to determine the impact of key uncertainty parameters. Additional expert-user screening and selection can be incorporated upon the completion of the online CPD candidate selection process. Lastly, the paper will also include supporting case histories. |
