A study of slip/stick motion of the bit

Journal Article · Thu Dec 01 04:00:00 EST 1988 · SPE (Society of Petroleum Engineers) Drill. Eng.; (United States)

DOI:https://doi.org/10.2118/16659-PA· OSTI ID:6339769

Kyllingstad, A; Halsey, G W

This paper deals with torsional oscillations caused by slip/stick motion of the drill-collar section. This phenomenon is associated with a large-amplitude, saw-tooth-like variation in the applied torque. ''Slip/stick motion'' refers to the belief that the amplitude of the torsional oscillations becomes so large that the drill-collar section periodically comes to a complete stop and does not come free until enough torque is built up in the drillstring to overcome the static friction. A mathematical model of slip/stick motion is presented. This model includes parameters describing downhole friction effects and a simplified description of the drillstring. The effects of damping, finite rotary-table inertia, and the rotary-speed control system are discussed. Theoretical predictions are compared with measured torque signals recorded during field drilling. This kind of drilling performance is likely to be less effective than normal drilling and may also lead to fatigue problems. This paper discusses ways to avoid severe torsional oscillations by using a more sophisticated feedback system to control the rotary speed.

• Research Organization: Rogaland Research Inst., Stavanger (NO)
• OSTI ID: 6339769
• Journal Information: SPE (Society of Petroleum Engineers) Drill. Eng.; (United States), Journal Name: SPE (Society of Petroleum Engineers) Drill. Eng.; (United States) Vol. 3:4; ISSN SDENE
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
99 GENERAL AND MISCELLANEOUS
990230 -- Mathematics & Mathematical Models-- (1987-1989)
DATA
DRILL BITS
DRILLING
DRILLING EQUIPMENT
EQUIPMENT
EXPLORATORY WELLS
FATIGUE
FIELD TESTS
FRICTION
INFORMATION
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
NUMERICAL DATA
OSCILLATIONS
PARAMETRIC ANALYSIS
PERFORMANCE
ROTARY DRILLING
TESTING
THEORETICAL DATA
TORQUE
WELL DRILLING
WELLS