Stepan Company

Douglas Hillshafer

Sarah Wolek

Ronald Anthony Masters

George Magnus

Christopher A Gariepy

Andrew Guo

A hydraulic fracturing method for recovering oil from a low-temperature subterranean oil formation is disclosed. Before, during, or after inducing hydraulic fracturing within the formation, a particulate, degradable polyester diverting agent is introduced into the formation in an amount effective to improve oil production from the formation. The diverting agent is allowed to degrade, and oil is recovered. The diverting agent has a melting point greater than the average temperature of the formation and is selected from: (i) ethylene glycol succinates; (ii) acid-terminated ethylene glycol succinates; (iii) acid-terminated polyglycolic acids; (iv) acid-terminated polylactic acids; and (v) mixtures of any of (i) through (iv) with a half acid ester.

Polyester diverting agents for low-temperature oil wells

A hydraulic fracturing method for recovering oil from a low-temperature subterranean oil formation is disclosed. Before, during, or after inducing hydraulic fracturing within the formation, a particulate, degradable polyester diverting agent is introduced into the formation in an amount effective to improve oil production from the formation. The diverting agent is allowed to degrade, and oil is recovered. The diverting agent has a melting point greater than the average temperature of the formation and is selected from: (i) ethylene glycol succinates; (ii) acid-terminated ethylene glycol succinates; (iii) acid-terminated polyglycolic acids; (iv) acid-terminated polylactic acids; (v) mixtures of any of (i) through (iv) with a half acid ester; and (vi) mixtures of polylactic acids or polyglycolic acids with a half acid ester. These easily synthesized classes of particulate polyester diverting agents degrade more effectively than polylactides under the conditions present in low-temperature wells and should help to enhance well productivity.

A method for producing a polyester polyol is disclosed. The method comprises reacting phthalic anhydride with a diol selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,6-hexanediol, polyethylene glycols having a number average molecular weight within the range of 200 g/mol to 600 g/mol, and mixtures thereof at a diol to phthalic anhydride molar ratio within the range of 1.1 to 1.6. The resulting o-phthalate polyester polyol has a hydroxyl value in the range of 18 to 400 mg KOH/g, an acid value in the range of 0.2 to 5.0 mg KOH/g, and 1 wt. % or less of cyclic esters.

Method for producing &#x3bf;-phthalate polyester polyols with low cyclic ester content

Hydrophilic, multi-arm urethane polymers are described that are dispersible and/or soluble in water, and provide wetting, foaming and cleaning benefits for aqueous cleaning products, including hard surface cleaners, machine dishwash, and liquid hand dishwash compositions.

Multi-arm hydrophilic urethane polymers, methods of making them, and compositions and processes employing them

Disclosed are polyester-ether polyols and their use in urethane prepolymers, urethane foams and non-foam urethane coatings, adhesives, sealants and/or elastomers. Methods for producing such polyester-ether polyols are disclosed, along with methods for producing urethane prepolymers. The polyester-ether polyols of the instant invention are preferably the reaction product of phthalic anhydride, diethylene glycol, and propylene oxide. These polyester-ether polyols are useful as either the primary polyol in urethane compositions or in combination with conventional auxiliary polyester- and/or polyether-based polyols. The polyester-ether polyols impart greatly improved solubility and compatibility to mixtures of either polyether and/or polyester polyols. The polyester-ether polyols of the instant invention are desirably of lower viscosity than their precursor intermediate polyester polyols and are generally soluble in either polyester- and/or polyether-based polyols. Additionally, the polyester-ether polyols generally provide improved hydrolytic stability to CASE materials in which they are utilized.

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Western Springs, IL, United States of America

Douglas Hillshafer