Buoyant ball sealers

Settling rate in 15% HCl, for example, can vary from about 24 feet per minute (ft/min) for a 1.1 s.g. ball to almost 90 ft/min for a 1.4 s.g. ball. For buoyant ball sealers, or floaters, the settling rate will be negative— meaning that the ball will rise, rather than sink or settle. In 15% HCl, a 0.9 s.g. ball will have a rise rate of about 65 ft/min, while the rise rate of a 1.0 s.g. ball would be about 42 ft/min. One benefit of using floaters is that the rise rate can usually be easily overcome. For example, in 2%" tubing, the velocity of acid movement at 1 bpm is 173 ft/min (5.615 cubic feet per minute divided... 

Gabriel, G. A., and S. R. Erbstoesser. 1984. The design of buoyant ball sealer treatment. Paper SPE 13085, presented at the Society of Petroleum Engineers Annual Technical Conference and Exhibition, Houston. 

The minimum injection rate also depends on the ball density relative to the acid. Ball densities typically vary from about 0.9 specific gravity (s.g.) to about 1.4 s.g. Ball sealers with densities less than 1.0 s.g. are called buoyant hall sealers ot floaters. Newer ball sealer products are of the floater or neutral density variety. The concept was developed at Exxon. Ball sealers with specific gravities greater than water or acid (>1.1 s.g.) are called sinkers for obvious reasons. Older ball sealers are of the sinker variety. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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