Dorothy P. Enright

Vinyl Sulfonate Copolymers for High-Temperature Filtration Control of Water-Based Muds

This paper describes the properties of two synthetic high-molecular-weight vinyl sulfonate copolymers and their use in water-based muds for controlling high-temperature filtration properties. Vinyl sulfonate copolymers are more effective at high temperatures because they are not depolymerized by the hydrolytic and oxidative environments of the drilling mud, as are derivatives of polysaccharides, and they do not form insoluble salts in the presence of electrolytes. Laboratory tests show that these copolymers are effective filtration-control agents for water-based muds over a wide range of electrolyte concentrations and that they remain effective after aging at 350/sup 0/F (177/sup 0/C). The effectiveness of these copolymers has been demonstrated in field tests.

An Environmentally Safe Water-Based Alternative to Oil Muds

In this paper, a mechanism describing the onset of bit balling is given. On the basis of this mechanism, a new copolymer/polypropylene glycol (COP/PPG) water-based drilling fluid was developed. The properties of this fluid are described, and field test comparisons are made with water- and oil-based fluids.