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US 5,174,340 AGranted
Apparatus for preventing casing damage due to formation compaction
AssigneeShell Oil Company
InventorsJames L. Peterson, Romulo Gonzalez
Life of this patent
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Abstract
A method and apparatus for preventing casing damage due to high axial loading in a well as a result of compaction of the surrounding earth formations. The method consists of providing specially sized and located grooves on both the inside and outside diameters of a section of well casing. The grooves are designed and spacers may be used in some grooves to ensure symmetrical deformation of the casing when subjected to a compressive loading.
Claims8
A special well casing section, said casing section comprising:
- (a) a section of tubular well casing and
- (b) a means allowing axial loading of said well casing without buckling said well casing, said means comprising
- (i) a plurality of first annular grooves, said first grooves being formed on the outer surface of said well casing, said first grooves being equally spaced;
- (ii) a plurality of second annular grooves, said second grooves being formed on the inner surface of said well casing, said second grooves being equally spaced between said first grooves;
- and
- (iii) said first and second grooves having substantially identical U-shaped cross sections, the depth of said first and second grooves being sufficient to allow the bottom of said grooves to overlap and the axial spacing between adjacent first and second grooves being substantially equal to substantially twice the width of said grooves and the width of the grooves being such that as axial loading occurs, ends of the U-shaped grooves substantially close and convert the U-shaped grooves into teardrop-shaped grooves.
3 more elements
Dependencies are inferred from the claim text.