| 摘要 |
A method of measuring an electromagnetic field in a subterranean earth formation can include installing at least one electromagnetic sensor in a well, the sensor including an optical waveguide and a material, the material changing shape in response to exposure to the electromagnetic field, and strain in the optical waveguide changing in response to the material changing shape. A well system can include an optical electromagnetic sensor installed in a well, and a transmitter which induces an electromagnetic field in an earth formation. Strain is induced in an optical waveguide of the sensor in response to the electromagnetic field. A method of monitoring an earth formation can include installing an optical electromagnetic sensor in a wellbore which penetrates the formation, and a strain being induced in an optical waveguide of the sensor in response to the electromagnetic field. |
