000			01850nab a2200193 4500
005			20260520002034.0
008			260224s2011 xxu
245	0	0	_aStructural recovery behavior of barite-loaded bentonite drilling muds
260			_a _b _cagos. 2011
270			_a11/04/2012 ; 11/04/2012
300			_a7 p. ; 552 - 558
520			_aTranscripción del resumen del autor Freshly prepared barite-loaded bentonite suspensions take more than a day to reach surface chemical equilibrium. These suspensions prepared 24 h earlier also display structural recovery with time of rest after structural breakdown by stirring, where the yield stress increased with time of rest. The Nguyen–Boger model and the so-called Leong model were quite accurate in predicting the structural recovery behavior of these suspensions. The time scale of structural recovery of barite–bentonite suspensions in the mass ratio 1:1 (13.1 wt.% solids), 2:1 (18.4 wt.%) and 3:1 (23.1 wt.%) based on the Leong model is ~ 4 h. In the presence 0.2 dwb% pyrophosphate and triphosphate, this time scale was increased to more than 20 h and ~ 10 h respectively. Both these additives also reduced the yield stress. The loading of barite on a 7 wt.% bentonite slurry up to 5 wt.% produced a weakened flocculated network structure. Then the resultant structure began to gain strength but very gradually until barite loading of 30 wt.% was achieved. Above 30 wt.% barite, the yield stress increased exponentially. The large increase in the particle concentration by the added barite now produces a much stronger network structure with the bentonite particles.
581			_a2
773	0		_tJournal of Petroleum Science & Engineering _g78
942			_cARTICULO
100	1		_aYap, Jack _952396
100	1		_aLeong, Yee-Knong _952397
999			_c187039 _d187039