Method for effecting controlled break in polysaccharide gels

A method of breaking a viscosified fluid introduced into a subterranean formation penetrated by a well bore comprising:

• (a) determining the temperature of the subterranean formation;
• (b) selecting a solid particulate of a condensation product of hydroxyacetic acid with up to 15 wt % cocondensing compounds containing other hydroxy-, hydroxycarboxylic-acid or carboxylic-acid moieties, the condensation product having a number average molecular weight in the range of from 200 to about 400, being substantially crystalline at the temperature of the formation and having a melting point above about 100.degree. C. and being sufficiently insoluble in the viscosified fluid at ambient temperature and degradable int ht epresence of an aqueous fluid at the temperature of the formation to form compounds capable of breaking a viscosified fluid;
• (c) dispersing a sufficient amount of the condensation product of step (b) into a viscosified fluid whereby breaking of the viscosified fluid can be achieved upon placement int he subterranean formation, said sufficient amount comprising from about 10 to about 200 pounds per 1000 gallons of said viscosified fluid;
• and
• (d) placing the viscosified fluid containing the solid particulate condensation product of step (b) into a subterranean formation whereupon said product degrades and breaking of the viscosified fluid occurs.