Title:
CASING DRILLING CONNECTOR WITH LOW STRESS FLEX GROOVE
Document Type and Number:
WIPO Patent Application WO2002036923
Kind Code:
A3
Abstract:
An oilfield tubular string (10, 60, 60A) comprising a plurality of elongated joints having one or both ends threaded. The joints may be connected by a coupling including a generally sleeve-shaped coupling body having a tapered upstream thread profile and a tapered downstream thread profile for threaded engagement with a mating profile of a respective joint. The coupling body includes a low stress flex groove (30) having a selected box thread runout bevel angle, and all transitions in the flex groove between surfaces are radiused to greater than 0.100 inches to minimize stress risers. A pin-in-box connection between tubular joints includes mating tapered threads (72), engagement of end shoulder (74, 76, 78, 80), and a low stress flex groove (82). The present invention allows the elongate joints to be used as both a casing string and a drill string, thereby saving significant time and expense.
Inventors:
DELANGE RICHARD W
EVANS MERLE EDWARD
GRIFFIN RICHARD
EVANS MERLE EDWARD
GRIFFIN RICHARD
Application Number:
PCT/US2001/050537
Publication Date:
September 12, 2002
Filing Date:
November 01, 2001
Export Citation:
Assignee:
GRANT PRIDECO LP (US)
International Classes:
E21B17/042; F16L15/00; (IPC1-7): F16L25/00
Foreign References:
| US2825585A | 1958-03-04 | |||
| US6050610A | 2000-04-18 | |||
| US5931511A | 1999-08-03 | |||
| US5681059A | 1997-10-28 | |||
| US5505502A | 1996-04-09 |
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