深井超深井井漏原因及堵漏技术综述OA

Deep and ultra-deep wells are highly prone to drilling-fluid loss because of geological,engineering,envi-ronmental,and human factors,which can seriously endanger drilling operations.However,current research achieve-ments on lost-circulation control in deep and ultra-deep wells are relatively scattered and lack systematic synthe-sis.Through a literature review,this paper analyzes the causes of drilling-fluid loss in deep and ultra-deep wells,summarizes progress in lost-circulation control technologies and in different categories of plugging materials,and discusses existing problems and future development directions.The study indicates that significant improvement in lost-circulation control for deep and ultra-deep wells can be achieved by organically integrating geology,engineer-ing,materials,and intelligent plugging technologies;improving the formulations and the temperature resistance,salt resistance,and pressure-bearing capacity of plugging materials.Besides,the following measures can also help,such as optimizing process parameters such as injection mode,injection pressure,and injection volumefully considering the coupled flow among the wellbore,loss zone,and formation,comprehensively utilizing reservoir plugging and plug-removal technologies,and applying artificial intelligence to perform deep learning on previous lost-circulation cases and to make intelligent decisions for plugging programs in new wells.This study provides a reference and guid-ance for the application of lost-circulation control technologies in deep and ultra-deep wells.