Lost circulation status in deepwater of South China Sea and preventive measures

Compared with the case in shallow water drilling, the handling of lost circulation in deepwater drilling is more difficult, making it particularly important to prevent lost circulation. To address the status of frequent lost circulation in deepwater of the South China Sea, the complex conditions of the drilled wells are investigated and the leakage status is analyzed, including the operating conditions for easy leakage and the nature of leakage. In combination with the typical leakage cases in the South China Sea, the main causes for lost circulation in this area are analyzed: small deepwater pressure vessel, extremely high ECD, etc. prevention and treatment measures are proposed according to the causes and characteristics of deepwater wells leakage in the South China Sea in hope of providing some reference for the prevention and treatment of future deepwater wells lost circulation in this area.