LAUSR

Abstract Lost circulation is one of the most common and costly problems in drilling operations, but in many operational situations, wellbore strengthening is an effective and economic technique to prevent or mitigate lost circulation. While numerous experimental and modeling studies have been carried out in the last three decades, there remain differing views regarding fundamental mechanisms of lost circulation and wellbore strengthening. An extensive and critical review of achievements and limitations on these fundamental studies is needed to aid engineers and researchers in future developments in this area. This paper provides a state-of-the-art review of fundamental studies on lost circulation and wellbore strengthening. This review focuses mainly on experimental and theoretical studies, rather than field experiences, intended to illustrate limitations of current knowledge in this area and lead to new research endeavors.