Well cementing in permafrost
Patent 4216022 Issued on August 5, 1980. Estimated Expiration Date: 
May 18, 1999. 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.
May 18, 1999. 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 2945539 3922172 Oil well cementing process Method for execution of quick hardening cement Patent #: 4082561 InventorAssigneeApplicationNo. 06/040349 filed on 05/18/1979US Classes:106/694, Soil, diatomaceous earth, clay, shale, slate, or rock-type material containing or material for treating soil or earth (e.g., soil stabilization, etc.)106/696Organic material containingExaminersPrimary: Poer, JamesAttorney, Agent or FirmInternational ClassesC04B 28/06 (20060101)C04B 28/00 (20060101) C09K 8/42 (20060101) C09K 8/46 (20060101) AbstractA composition for use in cementing a string of pipe or other apparatus in the permafrost region of a borehole of a well which composition is a dry cementitious mix which can be mixed with water on site for pumping into the wellbore and consists essentially of from about 40 to about 60 weight percent aluminate cement, from about 20 to about 30 weight percent alkaline earth metal sulfate, from about 10 to about 30 weight percent of at least one halide salt of an alkali metal and/or alkaline earth metal, from about 3 to about 8 weight percent attapulgite, from about 0.1 to about 1 weight percent of a mixture of at least one water soluble hydroxy carboxylic acid and a sulfoalkylated lignin, and from about 0.1 to about 1 weight percent of an alkali metal citrate. | |
