Apparatus for deflecting a drill string
This patent describes a method of corrosion inhibition in an electromagnetic heating system for a mineral fluid well, the heating system including a heating circuit comprising a heating electrode located downhole in the well, and an electrical power source connected to the heating circuit and operating to maintain a high amplitude A.C. heating current in the heating circuit. It comprises: applying a low D.C. bias voltage to the heating circuit, in addition to the high amplitude heating current, with a polarity to inhibit corrosion of the downhole heating electrode; sensing the D.C. bias current in the heating circuit; and adjusting the D.C. bias voltage to maintain the D.C. bias current sensed in step B below a given minimum level. This patent also describes an electromagnetic heating system for an oil well or other mineral fluid well, including a main heating electrode located downhole in the well at a level adjacent a mineral fluid deposit, and a return electrode at a location remote from the main electrode so that an electrical current between the electrodes passes through and heats a portion of the mineral fluid deposit. It comprises: a A.C. power source for generating a high amplitude A.C. heating current, of a least fifty amperes; a D.C. bias source for generating a low amplitude D.C. bias current having a polarity such as to inhibit corrosion at the main electrode; and connection means for applying both the A.C. heating current and the D.C. bias current to the electrodes of the well heating system.
- Assignee:
- Amoco Corp., Chicago, IL (USA)
- Patent Number(s):
- US 5012877; A
- Application Number:
- PPN: US 7-443768
- OSTI ID:
- 5116379
- Resource Relation:
- Patent File Date: 30 Nov 1989
- Country of Publication:
- United States
- Language:
- English
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