Study on the Interaction Mechanism of Packer Slips and Thick Wall Casing

ABSTRACT

The slips should go into casing for certain depth to set the packer when well testing, but the casing may be damaged seriously if the setting force is too large. To make known the interaction mechanism of packer and casing, and then provide basis for the choice of hanging load of casing and shape optimization of slips, the maximum hoop stress of casing in the inner wall was deduced by the thick wall theory and the limited setting force was obtained by the strength theory. The changes of the limited setting force of casing with the variable length of packer and the face angle of slip teeth were discussed taking the general packer and casing as example. It was found that the limited setting force of casing increased with the length of slip when the packer and casing kept the same. The shorter the slip, the faster the force grows. Also, the limited setting force of casing increased non-linearly with the face angle of slip teeth. The smaller the angle, the faster the force grows.

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