07533719 is referenced by 169 patents and cites 924 patents.

Wellheads for coupling to a heater located in a wellbore in a subsurface formation are described herein. At least one wellhead may include a heater located in a wellbore in a subsurface formation; and a wellhead coupled to the heater. The wellhead may be configured to electrically couple the heater to one or more surface electrical components. The wellhead may include at least one non-ferromagnetic material such that ferromagnetic effects are inhibited in the wellhead. Systems and methods for using such wellheads for treating a subsurface formation are described herein.

Title
Wellhead with non-ferromagnetic materials
Application Number
11/788870
Publication Number
7533719 (B2)
Application Date
April 20, 2007
Publication Date
May 19, 2009
Inventor
Harold J Vinegar
Bellaire
TX, US
Richard A Hinson
Houston
TX, US
Assignee
Shell Oil Company
TX, US
IPC
E21B 34/02
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