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Patents

Referenced by

Citing PatentFiling dateIssue dateOriginal AssigneeTitle
US397145031 Jan 197527 Jul 1976Engineering Enterprises, Inc.Well drilling tool
US401959231 Dec 197526 Apr 1977Engineering Enterprises, Inc.By-pass tool
US404906619 Apr 197620 Sep 1977Apparatus for reducing annular back pressure near the drill bit
US42601674 Sep 19797 Apr 1981Engineering Enterprises, Inc.Well drilling tool
US454301928 Jul 198224 Sep 1985Tokyo Shibaura Denki Kabushiki KaishaBoring tool
US47444262 Jun 198617 May 1988Apparatus for reducing hydro-static pressure at the drill bit
US498967922 Dec 19885 Feb 1991Institut Francais du PetrolCentering device that can be engaged or disengaged, specifically for a drilling assembly
US504260023 Mar 199027 Aug 1991Conoco Inc.Drill pipe with helical ridge for drilling highly angulated wells
US739587726 Sep 20068 Jul 2008Weatherford/Lamb, Inc.Apparatus and method to reduce fluid pressure in a wellbore
US80747171 Aug 200713 Dec 2011Shell Oil CompanyDrilling method and downhole cleaning tool

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