Assignee
DUHN OIL TOOL INC
US·11 granted patents·247 citations·filing 1989–2008
Technology mixE21B11
Top patents by PatentIndex Score
11 records- 0193US7322407B2Wellhead isolation tool and method of fracturing a wellDUHN OIL TOOL INC·Filed 2005·Granted Jan 29, 2008·36 cites·41 claims
- 0286US7416020B2Wellhead isolation tool, wellhead assembly incorporating the same, and method of fracturing a wellDUHN OIL TOOL INC·Filed 2007·Granted Aug 26, 2008·18 cites·31 claims
- 0380US6920925B2Wellhead isolation toolDUHN OIL TOOL INC·Filed 2003·Granted Jul 26, 2005·56 cites·88 claims
- 0477US7520322B2Wellhead isolation tool and method of fracturing a wellDUHN OIL TOOL INC·Filed 2007·Granted Apr 21, 2009·10 cites·27 claims
- 0575US7726393B2Wellhead isolation tool and wellhead assembly incorporating the sameDUHN OIL TOOL INC·Filed 2008·Granted Jun 1, 2010·9 cites·28 claims
- 0672US6199914B1Drilling quick connectorsDUHN OIL TOOL INC·Filed 1999·Granted Mar 13, 2001·48 cites·51 claims
- 0760US6543533B2Well tubing rotatorDUHN OIL TOOL INC·Filed 2001·Granted Apr 8, 2003·24 cites·42 claims
- 0849US7493944B2Wellhead isolation tool and method of fracturing a wellDUHN OIL TOOL INC·Filed 2004·Granted Feb 24, 2009·11 cites·55 claims
- 0949US6588510B2Coil tubing hanger systemDUHN OIL TOOL INC·Filed 2001·Granted Jul 8, 2003·13 cites·20 claims
- 1033US5303774ARing seal packerDUHN OIL TOOL INC·Filed 1992·Granted Apr 19, 1994·14 cites·23 claims
- 1130US4974676AGround subsiding wellheadDUHN OIL TOOL INC·Filed 1989·Granted Dec 4, 1990·8 cites·19 claims
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