000			01880nab a2200205 4500
005			20260520001830.0
008			260224s2010 xxu
245	0	0	_aOn the end-effect correction for Couette type oil-field direct-indicating viscometers for Newtonian and non-Newtonian fluids
260			_a _b _cmar. 2010
270			_a12/07/2010 ; 12/07/2010
300			_a10 p. ; 37-46
520			_aTranscripción del resumen del autor. Analysis and experimental results are presented which quantify the magnitude of end-effects for direct- indicating, narrow gap, rotating cylinder viscometers used extensively in oil- eld, for Newtonian and non- Newtonian uids. Such viscometers have already embedded at manufacturing stage an end-effect correction and give directly the shear stress which does not allow end-effect quanti cation in a straight forward manner. The presented analysis resolves this problem by estimating the embedded correction, which has been determined as 6.69% of the torque developed along the cylindrical part of the stationary bob of this viscometer. Experimental results with Newtonian and non-Newtonian uids show that there is no additional end-effect from the bottom of the stationary bob. However, there is additional end-effect contribution from the top section of the bob, which has not been taken into account in the design and manufacturing of the instrument. Its magnitude ranges from 5 to 6% for the Newtonian uid and the high shear rate range for the non- Newtonian uid, to 12% for the low shear rate range for the non-Newtonian uid tested, while the impact on drilling situations is also discussed.
581			_a1-2
773	0		_tJournal of Petroleum Science & Engineering _g71
942			_cARTICULO
100	1		_aKelessidis, V.C. _938573
100	1		_aMaglione, R. _945600
100	1		_aBandelis, G. _945601
999			_c174936 _d174936