Rethinking Event Detection and Drilling Processes Using High-Speed Downhole Telemetry and MPD Know-How

Abstract

Abstract Objectives/Scope The objective of this paper is to describe how high-speed downhole telemetry and technologies developed for managed pressure drilling (MPD) may be combined to overcome the limitations of conventional surface-based event detection systems. This paper will discuss equipment and control system considerations in the exposition of a downhole event detection system. Methods/Procedures/Processes An evaluation of high-speed downhole telemetry in the context of an MPD operation was performed, uncovering the limitations of conventional and MPD event detection systems. Using simplified fluids physics models, this paper describes how a surface-based event detection system is disadvantaged in identifying changing or deteriorating downhole conditions. Examples include cases of gas solution following an influx and undiagnosed wellbore instability events. Downhole event detection systems and methods, which aid in the early detection of the events, are shared along with a discussion of applications of MPD technologies in non-MPD wells. Result/Observations/Conclusions This paper is a demonstration of the shortcomings of conventional event detection approaches. Nearly all contemporary event detection systems are surface-based, consuming surface-acquired data. The drawback of this approach is that downhole events grow in magnitude or scope undetected until an instrument detects a change at the surface. This may allow the downhole conditions to significantly depart from what the rig crew thinks is happening based on what they can see at the surface. By combining downhole high-speed telemetry technology and certain components developed for MPD operations, a downhole event detection system can compare measured values from downhole tools with expected values from an online model. The downhole measurements represent the well as it is, whereas the estimates represent the well from the surface vantage point. Deviation between these two viewpoints occurs during key contingency events, implying that a change has occurred downhole that cannot be physically measured at the surface. As such, a deviation alarm may be set, which is triggered significantly before any surface-based event detection systems. Detecting problems and responding to the well early is essential to reduce the occurrence and impact of unplanned events. Novel/Additive Information Other information is shared regarding event detection system design and integration with other systems onboard the rig. Visualizations that simplify the interpretation of downhole-acquired data are shared. Additional considerations for rig integration are also discussed.