Research on Dynamic Continuous Monitoring and Early Warning Technology for Kick and Loss in Ultra-Deep Wells

In deep and ultra-deep well drilling, formation pressure systems become increasingly complex, making pre-drilling pressure prediction more challenging and significantly increasing the risk of well control incidents caused by influxes and losses. Currently, overflow and loss monitoring mainly relies on single-point liquid level sensors in the mud tank, with operators judging wellbore conditions based on experience. This approach is hindered by poor timeliness and a high false alarm rate. Therefore, a monitoring and early warning for kick and loss in ultra-deep wells was established. Firstly, the liquid level data of each mud tank is obtained through distributed sensors. By comprehensively considering the effects of solid control equipment losses, complex wellbore filtration losses, working fluid evaporation, and maintenance related impacts on the total volume, dynamic continuous monitoring of mud volume under drilling fluid circulation conditions has been achieved, meeting the requirements for rapid and accurate identification of overflow conditions. Then, based on a self-developed wellbore annulus liquid level measurement device, various algorithms such as acoustic signal filtering, wellbore fluid level localization, signal cycle detection, and echo data correction were constructed. It can realizes dynamic tracking of the wellbore liquid level and volume change rate when the wellbore pressure is greater than the formation pressure, meeting the continuous monitoring requirements of the leakage and overflow conversion state. Finally, an integrated monitoring and early warning for kick and loss technology is established, incorporating both mud tank and annular fluid level monitoring. In addtion, Field testing demonstrates the system’s effectiveness in enhancing the safety and reliability of deep and ultra-deep well drilling operations.