Practice and application of uninterrupted circulation system for extended reach Well in offshore oil fields
In the world,the well with water vertical ratio≥2 and sounding depth greater than 3000 meters or the well with horizontal displacement of more than 3000 meters is generally called extended reach well.Long reach drilling and completion technology is a high technology in the field of international drilling engineering,and it is also a difficult frontier technology that challenges the limit of rotary drilling.With the increasing horizontal displacement and water-vertical ratio,long reach drilling and completion face many serious challenges.Borehole cleanliness is directly related to the instability and safe extension limit of large inclination and long open hole,pressure loss control of hydraulic circulation[1],the severity and control ability of downhole friction and torque,the difficulty and wear severity of long casing strings,and the limitation and comprehensive application ability of drilling equipment,etc.Through the field application and practice of uninterruptable continuous circulation system,The stable equivalent circulation density value of the whole well interval during the drilling of the extended reach well has a good reference value for maintaining stable equivalent circulation density control and safe operation of offshore extended reach well.
Large displacementEquivalent circulation densityContinuous circulation system
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