Automated Alarms for Managing Drilling Pressure and Maintaining Wellbore Stability

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 146298, ’Automated Alarms for Managing Drilling Pressure and Maintaining Wellbore Stability - New Concepts in While-Drilling Decision Making,’ by Andreas Sadlier, SPE, Chris Wolfe, SPE, Mike Reese, SPE, and Ian Says, SPE, Baker Hughes, prepared for the 2011 SPE Annual Technical Conference and Exhibition, Denver, 30 October-2 November. The paper has not been peer reviewed. With the increased complexity of wells being drilled, significant geologic uncertainty may be encountered during wellbore construction. Uncertainty can take the form of unplanned drilling events such as kicks, lost circulation, and borehole-stability problems. A more proactive effort to predict and identify trouble zones in real time could lead to a substantial reduction in nonproductive time (NPT) and safety risks. Computer systems can automate the filtering and distribution of relevant information to personnel quickly for more-rapid assessment of a situation. Introduction To assess and analyze the current risks, field engineers are tasked with monitoring various measurements and data feeds while drilling and, if potential problems occur, making recommendations for corrective actions. With an increasing volume of more-complex data available in real time, how can engineers analyze relevant information effectively and in a timely manner to mitigate risk? One way is to leverage the power in modern computer systems. Software automates the filtering and distribution of relevant information to personnel quickly for rapid assessment of a current drilling challenge. For example, in a pressure-management (PM) operation, alarms can be activated automatically to provide quick warnings on the basis of equivalent-circulating-density (ECD) measurements (in the context of the mud-weight window) and to indicate potential hazards. These alarms could help filter and interpret complex real-time data sets quickly, without relying solely on the experience of the individual pressure engineer to detect a possible drilling risk. A PM and wellbore-stability (WBS) alarming system was designed to reduce complexity and facilitate PM/WBS decision making in near real time. Background During drilling, the safe-mud-weight window ranges from the pore-pressure gradient (on the low end) to the fracture gradient (on the high end). The goal of real-time PM involves selecting and maintaining the downhole drilling-fluid pressure within the drilling-mud-weight window to reduce drilling NPT (drilling NPT attributed to pore-pressure and wellbore-instability issues is approximately 40%). To reduce this type of NPT effectively, the use of real-time PM engineers is recommended at the rigsite or from a remote monitoring center.