The plugging of lost circulation in deep fractured formations: A review

Abstract

Lost circulation in fractured formations represents a significant technical challenge that hinders the safe drilling of deep geothermal and petroleum reservoirs. Improving the once plugging success rate in deep fractured formations is essential to achieve a safe, efficient, and economical drilling. This paper provides an overview of the foundation theory of fluid loss and lost circulation control in fractured formations, introduces the application of various lost circulation materials (LCMs) in the loss control of fractured formation., and elaborates on the experimental devices and methods currently used to study the mechanism of fracture plugging. Disparities among these devices and methods can yield differing evaluation results, potentially leading to more conservative perspectives on fracture plugging. Additionally, it examines the current research status and shortcomings regarding the formation and structural evolution mechanisms of the fracture plugging zone. Focusing on three key aspects—plugging mechanisms, LCMs, and plugging formulations—this study outlines the future directions for the development of plugging technologies tailored for deep fractured formations. These efforts will support the intelligent advancement of plugging technology.