Method and apparatus for avoiding mutual coupling between receivers in measurement while drilling

US5869968A · kind A · utility

Assignee

• Baker Hughes Holdings LLC · US

Inventors

• Andrew Brooks · Thiensville, US
• MacMillian M. Wisler · Kingwood, US
• Larry W. Thompson · Willis, US
• Jian-Qun Wu · Kingwood, US
• Wallace H. Meyer · Spring, US
• John W. Harrell · Waxahachie, US

Key dates

• Filing date: Sep 18, 1996
• Grant date: Feb 9, 1999
• Expiry date: Sep 18, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G01V3/30
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An arrangement of two closely spaced transmitters and two spaced apart receivers symmetrically disposed about the transmitters in a measurement while drilling tool avoids the effects of mutual coupling between the receivers. In one method of operation of the transmitters, each transmitter is sequentially activated while the other transmitter is decoupled to eliminate mutual coupling, and the recorded signals processed to take advantage of reciprocity relations. In another method of operation, both transmitters are operated simultaneously with one relative polarity and then with another relative polarity, to eliminate the effects of mutual coupling and to take advantage of reciprocity relations.