Aqueous based drilling fluid
Patent 5134118 Issued on July 28, 1992. Estimated Expiration Date: 
February 22, 2011. 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.
February 22, 2011. 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 References Re28474 2911365 3039529 3230201 3434970 3768565 3907927 Petroleum recovery process Drilling fluid compositions and methods of preparing same Method of producing partially hydrolyzed acrylamide polymers InventorsAssigneeApplicationNo. 659826 filed on 02/22/1991US Classes:507/121, Sulfur is attached directly or indirectly to the acrylic acid monomer or derivative by nonionic bonding (e.g., acrylamidoalkane sulfonates, etc.)507/119, Polymer derived from acrylic acid monomer or derivative507/120, Nitrogen is attached directly or indirectly to the acrylic acid monomer or derivative by nonionic bonding (e.g., acrylamide, acrylonitrile, etc.)507/140, Contains inorganic component other than water or clay526/287From monomer containing three or more oxygen atoms bonded to a single sulfur atom, e.g., sulfonate, etc.ExaminersPrimary: Maples, John S.Assistant: Sayala, C. Attorney, Agent or FirmInternational ClassesC09K 007/02C08F 228/02 AbstractThis invention relates to an improved aqueous based drilling fluid and specifically to a water soluble polymer that imparts desirable performance characteristics to the final drilling fluid. The invention also relates to the method for preparation of the polymer and drilling fluid. The water soluble polymer is especially useful in that it exhibits superior tolerance to divalent cations, salts, solids and elevated temperatures when added to aqueous drilling fluids. The polymer additive is characterized by increased viscosity at low shear rates and improved fluid loss control thereby exhibiting superior rheological and thixotropic properties. The polymer consists of reaction products of sulfonated monomers and monomers added to enhance the functional characteristics of the polymer.Other References
Field of SearchFrom metal containing monomerTransition metal containing From monomer containing three or more oxygen atoms bonded to a single sulfur atom, e.g., sulfonate, etc. Polymer derived from acrylic acid monomer or derivative Nitrogen is attached directly or indirectly to the acrylic acid monomer or derivative by nonionic bonding (e.g., acrylamide, acrylonitrile, etc.) Sulfur is attached directly or indirectly to the acrylic acid monomer or derivative by nonionic bonding (e.g., acrylamidoalkane sulfonates, etc.) |
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