Key Technology of Deepwater Tophole Drilling and Current Situation of Equipment Research and Application

Deepwater tophole drilling directly determines whether deepwater drilling operation is successful.Therefore,the problems in deepwater tophole drilling were studied.The key technologies of deepwater tophole drilling,as well as its equipment principle,technological feature,adaptability and technological difficulties,were analyzed and summarized.The key technologies include dynamic well killing,jetting conductor drilling,riserless drilling,dual-gradient drilling,artificial seabed and three-dimensional earthquake.In light of the difficulties and risks in deepwater tophole drilling,the concept of prevention first and comprehensive should be established.Research on risk prediction and monitoring should be strengthened.The technologies,such as three-dimensional earthquake,should be applied to predict shallow-layer hazards before drilling.The well position should be selected carefully.The hazards should be avoided and the accident rate should be reduced.Technologies of jetting conductor setting,dynamic well killing and rotary steering control can be combined to drill the conductor section in order to improve the success rate and quality of conductor setting.Finally,safe,high-efficiency and quality drilling can be achieved.