Loss-of-well-control (LOWC) events are generally defined as uncontrolled flow of formation or other fluids to either the surface or another subsurface formation. Such events are also known as blowouts. Blowouts can result in the loss of human life, catastrophic damage to ecosystems, and substantial economic losses. Many blowouts start with a "kick event", where the formation pore pressure becomes greater than the wellbore pressure, causing formation fluid to flow into the wellbore and combine with the drilling fluid (i.e., mud). Detecting a kick as early as possible is key to preventing a blowout. Conventional kick detection methods (e.g., monitoring mud pit returns, monitoring wellbore liquid levels) are usually time-consuming, resulting in delays during which the kick may grow in intensity and efforts required to re-establish well control may become more extensive. Some, more sophisticated kick detection techniques use instrumentation that can be costly. In this paper, an alternative, lower-cost, early kick detection method is proposed.
Here a kick detection method is proposed that uses measurements from the instrumentation deployed on the drillstring to provide real-time information on the wellbore. Specifically, bulk density, acoustic (compressional wave) velocity, and electrical resisitivity are considered for use as detection parameters. These fluid mixture (combined formation and drilling fluid) properties as a function of kick fluid volume are estimated. Theoretically, these parameters are found to be sufficiently responsive to be used for kick detection. However, additional work is needed to determine how these parameters respond in experimental or field conditions.