Rubber drillpipe protectors reduce rotary torque
- Exxon Production Research Co., Houston, TX (US)
Rubber drillpipe protectors have very low friction coefficients when they rotate against smooth or polished casing surfaces in drilling mud. A polished casing surface can be obtained by placing one protector on each joint of drillpipe run inside the casing. In this situation, casing polishing will occur in the course of normal drilling, and the resultant low friction coefficients will lead to reduced drilling torque in directional wells. The friction coefficient between casing and drillpipe protectors is controlled by the roughness of the casing surface. Coefficients range from 0.50 for badly rusted casing to 0.05 for a polished surface. The smooth casing surface needed for low friction will be obtained during 50 to 100 hours of rotation with drillpipe protectors inside the casing. A field test of this concept gave friction coefficients below 0.10 and a significant reduction in drilling torque.
- OSTI ID:
- 6775182
- Journal Information:
- SPE (Society of Petroleum Engineers) Drill. Eng.; (United States), Journal Name: SPE (Society of Petroleum Engineers) Drill. Eng.; (United States) Vol. 3:3; ISSN SDENE
- Country of Publication:
- United States
- Language:
- English
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