Abstract:Increase in drilling depth poses higher requirements on the performance of wireline coring tool. With analysis of the research and development status, structural design feature and ultra-deep hole application of the wireline coring tool at home and abroad, this paper summarizes technical problems with the wireline coring tool for ultra-deep hole drilling, such as fishing reliability of the latching mechanism, signal reliability of the landing mechanism, working stability of the core jamming indicating mechanism, service life of the swivel mechanism. The causes of the above problems are also examined. All these lay a good foundation for the optimum design of the wireline coring tool used for 5000m ultra-deep holes.