The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 10, 1992
Filed:
May. 09, 1990
Applicant:
Inventor:
Shawqui M Lahalih, Doha, Quatar, KW;
Assignee:
Other;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C09K / ;
U.S. Cl.
CPC ...
507117 ; 528399 ; 528259 ; 528261 ; 507103 ; 507128 ; 507130 ; 507131 ;
Abstract
A drilling fluid includes water, bentonite, a weighting agent, and an additive comprising a water-soluble polycondensate containing phosphorous and nitrogen such as phosphorylated-urea-formaldehyde or phosphorylated-melamine-formaldehyde. Such additives provide the desired rheological and filtration loss properties as well as thermal and shear stability. The additives are prepared by reacting phosphorous acid, urea and formaldehyde according to a Mannich-type reaction.