THE CHALLENGE
The operator needed to run 7”- 32.0#/ft liner into 9 1/2” OH passing through the 8.535” restriction of the 9 5/8” – 53.5#/ft casing with a TD of 3,600m and a whipstock window. The customer was also expecting washouts.
The operator was concerned that rotating with low quality, weak, hinged bow spring centralizers could destroy them and create serious problems.
THE SOLUTION
55 x 7” x 9 ½” Centek UROS centralizers designed to be both strong and flexible and developed for use in restrictions.
THE RESULT
The liner has to be pulled due to hole conditions 40m short of TD. OWS and the cementers inspected all the centralizers/collars and the only damage that could be seen was bending of some of the set screw sockets.
During the re-run, the liner was partially rotated in the open hole on the way in, and it was rotated for approximately 12 hours at 20rpm in the cased hole on the way out.
The Centek UROS single piece construction gives it robustness and strength which exceeds that of competitor products. Although Centek does not recommend the re-use of centralizers when pulled out of hole this case study proves that even when subjected to extreme stresses the unique design of Centek centralizers meant that they remained in good condition and could be re-run.
