Effects of high-speed pipe rotation on pressures in narrow annuli
- Mobil E and P Technical Center, Dallas, TX (United States)
Variations in annular geometry, eccentricity, and pipe rotational speed strongly affect pressure loss of a fluid flowing in the narrow annulus of a slimhole well. Due to these factors, accurately calculating and controlling pressures in slimhole wellbores are difficult. Accurate pressure calculations are crucial for safely controlling formation pressures and protecting wellbore integrity. Attempts to model non-Newtonian fluid flow in narrow annuli with high-speed pipe rotation have been hampered by the lack of quality data. The results of numerous annular flow experiments presented herein partially correct this deficit. These results supplement annular pressure data from a 2,500-ft slimhole test well and standpipe pressure data from a slimhole exploration well. Models selected from the public domain were used with varying success to calculate results from the hydraulics tests. Simple models typically used by the drilling industry calculated annular pressure loss for non-rotating cases with reasonable accuracy. However, the simple models seldom calculated absolute effects of pipe rotation even though calculated trends correctly match those in measured data. For turbulent flow, annular pressure loss increased with increasing pipe rotation. for laminar flow, annular pressure loss decreased with increasing pipe rotation. In all cases, annular pressure loss increased with increasing mud rheology and decreased with increasing eccentricity.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 93065
- Journal Information:
- SPE Drilling and Completion, Journal Name: SPE Drilling and Completion Journal Issue: 2 Vol. 10; ISSN 1064-6671; ISSN SDCOE5
- Country of Publication:
- United States
- Language:
- English
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