Spacer fluids
Patent 5030366 Issued on July 9, 1991. Estimated Expiration Date: 
November 27, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 27, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorsAssigneeApplicationNo. 441853 filed on 11/27/1989US Classes:507/228, Monomer contains benzene ring and sulfonate group166/291, With piston separator507/211, Carbohydrate is polysaccharide507/216, Hydroxyalkylcellulose (e.g., HEC, etc.)507/225, Nitrogen is attached directly or indirectly to the acrylic acid monomer or derivative by nonionic bonding (e.g., acrylamide, acrylonitrile, etc.)507/226, Sulfur is attached directly or indirectly to the acrylic acid monomer or derivative by nonionic bonding (e.g., acrylamidoalkane sulfonates, etc.)507/229, Hetero nitrogen ring is attached directly or indirectly to the ethylenic monomer by nonionic bonding507/262, Organic component contains a carbocyclic group507/928Spacing slug or preflush fluidExaminersPrimary: Stoll, Robert L.Assistant: Geist, Gary Attorney, Agent or FirmForeign Patent References
International ClassesE21B 033/16F17D 001/12 AbstractSpacer fluids providing an effective buffer between drilling fluids and cement slurries during well completion. The spacer fluids comprise a sulfonated styrene copolymer dispersant and one or more additional components such as surfactants, viscosifiers and weighting materials to form a rheologically compatible fluid between the drilling fluid and the cement slurry.Field of SearchWith piston separator |
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