Packer fluid and system and method for remote sensing
AssigneeChevron U.S.A. Inc.
InventorsJames B. Bloys, Manuel E. Gonzalez
Life of this patent
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Abstract
A system, method and device for interrogating a downhole environment in a borehole beneath a surface includes a source of electromagnetic energy operable to transmit an electromagnetic signal in the borehole, a sensor module, including a passive resonating circuit including a crystal oscillator having a resonant frequency that varies with changes in the condition in the downhole environment in response to a condition in the downhole environment in the borehole and a detector positionable to receive the reflected modulated electromagnetic signal. In an embodiment, a solids-free dielectric medium is provided within an annular volume in the borehole defined by the casing through which the electromagnetic signal is transmitted.
Claims13
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.
A method of interrogating a downhole environment in a borehole beneath a surface, comprising:
- providing a substantially solids-free dielectric fluid medium within an annular volume in the borehole, the packer fluid comprising a halogenated hydrocarbon and having a density between about 9 ppg and about 20 ppg;
- transmitting an electromagnetic signal in the borehole and through the fluid medium;
- reflecting the electromagnetic signal with 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;
- modulating the electromagnetic signal in accordance with the varying resonant frequency in response to the condition in the downhole environment in the borehole;
- and
- receiving the reflected modulated electromagnetic signal.
Dependencies are inferred from the claim text.