Abstract: Allyl end-capped propylene terephthalate polyester oligomers are sulfonated in an aqueous system in the presence of a free radical initiator by a process in which only a part (about 15% to 40%) of the source of bisulfite is added at the start of the sulfonation step with the remainder being added later in that step, in such increments as will permit maintaining a clear single phase, to give sulfinate-containing sulfonated products, following which the sulfinate content is oxidized to give sulfonated end-capped propylene terephthalate polyester oligomers.

Abstract: Oil field chemicals are incorporated in polymeric particles of the condensation product of hydroxyacetic acid or the co-condensation product of hydroxyacetic acid and other compounds containing hydroxy-, carboxylic acid-, or hydroxycarboxylic acid moieties. The particles are introduced into an oil well bore and/or subterranean oil formation where the polymeric particles dissolve over a period of time and release the oil field chemicals.

Abstract: A melted polymer of hydroxyacetic acid with itself or with other hydroxy-, carboxylic acid-, or hydroxycarboxylic acid-containing moieties is subjected to high shear and injected into an organic liquid which is inert to the polymer to form an organic liquid dispersion of very fine polymer particles. In one aspect the melted polymer is combined with the organic liquid and the combination is thereafter subjected to high shear to form the fine particle polymer dispersion. A dispersion agent may also be used to aid in dispersing the particles. The dispersion is used for fluid loss control and gel breaking in subterranean formations.

Abstract: Hydroxyacetic acid condensation product is used as a fluid loss material in a well completion or workover process in which a fluid comprising a hydrolyzable aqueous gel is used. The hydroxyacetic acid condensation product degrades at formation conditions to provide hydroxyacetic acid which breaks the aqueous gel, thereby restoring full formation permeability without the need for separate addition of gel breaker.

Abstract: Hydroxyacetic acid condensation product is used as a fluid loss material in a formation fracturing process in which a fracturing fluid comprising a hydrolyzable aqueous gel is used. The hydroxyacetic acid condensation product degrades at formation conditions to provide hydroxyacetic acid which breaks the aqueous gel, which provides restored formation permeability without the need for separate addition of gel breaker.

Abstract: This invention relates to a composition and method of temporarily reducing the permeability of subterranean formations penetrated by a wellbore. In particular, it relates to an inexpensive, low molecular weight condensation product of hydroxy acetic acid with itself or compounds containing other hydroxy-, carboxylic-acid-, or hydroxycarboxylic-acid moieties and method for preventing fluid loss during well treatment.