Patent ID: 8575936
Filing Date: 2013-11-05
Classification: E21B,G01D,G01K,G01L

Abstract:
1. A system for interrogating a downhole environment in a borehole beneath a surface, comprising: a source of electromagnetic energy, operable to transmit an electromagnetic signal in the borehole; a pair of conducting tubes, positioned within the borehole and together defining an annular volume therebetween; a packer, arranged at a downhole end of the conducting tubes and constructed and arranged to seal a distal end of the annular volume; a substantially solids-free dielectric packer fluid, disposed within the sealed annular volume, the packer fluid comprising a halogenated hydrocarbon and having a density between about 9 ppg and about 20 ppg; a sensor module, comprising a passive resonating circuit, the passive resonating circuit comprising a crystal oscillator having a resonant frequency that varies with changes in the condition in the downhole environment to, in use, reflect the electromagnetic signal and to modulate the electromagnetic signal in response to a condition in the downhole environment in the borehole; and a detector positionable to receive the reflected modulated electromagnetic signal.