Stick-free running of 244.5 mm casing in Chenghai 1-1 block second-spud
In the large displacement wells of the Dagang oilfield Chenghai block,problems such as difficult casing running and frequent casing sticking should be urgently solved.A statistical analysis is conducted on the casing sticking accidents in the Chenghai 1-1 block of Dagang oilfield in recent years and find that pressure difference is the main reason for sticking.Integrated with differential pressure sticking mechanism,a differential pressure sticking prediction model based on the pipe string/mud cake contact model is constructed,and the solution is studied.Through the analysis,the mechanism obtained was to prevent sticking by reducing the casing weight and thereby reducing the contact area with the borehole wall.The mechanism has been applied in Chenghai 1-1-XX and Chenghai 1-1-YY wells,achieving safe running of the 244.5 mm casing in this extended reach well.The sticking mechanism from prevention analysis is proved to be correct and the technology was feasible.Floating 2 846 m,Chenghai 1-1-XX well breaks the China National Petroleum Corporation's record of 244.5 mm casing floating section length.Besides,among all the wells of CNPC,the Chenghai 1-1-YY well is the first to realize full floating 244.5 mm casing running at an extended reach well.
casing runningpressure differential stickingfloatingextended reach horizontal well
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