Cause Analysis of Not-in-place Make up of Downhole Casing

It is found that during the downhole operation,when making up,there are 3-4 threads of the Φ139.70 mm×7.72 mm J55 long-round threaded anti-corrosion casing are exposed.Relevant analysis reveals that there exist some steel balls which cause the said not-in-place make up trouble.Accordingly it is recommended to carry out thorough cleaning of the threads as per applicable construction criteria so as to avoid any foreign matter to cause the said not-inplace make-up mistake.