Underbalanced Drilling Optimum Methodology

Abstract

A methodology to properly screen all UBD techniques to reduce failure/misapplication and align objectives with expectations had been absent. The paper addresses the latest enhancements to better understand and screen options for UBD operations according to two aspects: formation applicability and engineering applicability. The screening tool considers a range of economic and technical parameter to provide a relative ranking for each candidate of the Underbalanced drilling (UBD) technique. As a case, the methodology was available to optimize the UBD techniques in a risky exploration well in Xinjiang oilfield, which provided guidance and technical support to screen the UBD candidate, design the drilling modeconversion, and establish the emergency schedule.