Key drilling technologies for the ultradeep extended reach well in East China Sea Oil and Gas Field

In order to stabilize the oil and gas production of East China Sea Oil and Gas Field, one ultradeep extended reach well is deployed in one fault block. Extended reach wells are characterized by high torque, large friction resistance, oil-based drilling fluid leakage, difficult casing running and limited electric logging cement quality technology. To deal with these difficulties, the corrected catenary profile was selected by means of multiple objective optimization based extended reach well trajectory design method and hole trajectory and casing program were optimized in the design stage. And in the process of well drilling, a series of key drilling technologies for extended reach wells were adopted, including torque and drag monitoring while drilling, ECD control and rotary liner hanger, and consequently this well is drilled successfully with well depth of 6 866 m, horizontal displacement of 5 350.49 m, HD/VD of 1.7, open hole section of 3 614 m and 75° holding section of 4 134 m. It is indicated that the key drilling technologies applied in this well can satisfy the drilling requirements of ultradeep extended reach wells, and they are promising in popularization and application prospect.