Multifiber interrogation with reflectometry techniques
AssigneeSchlumberger Technology Corporation
InventorsArthur Hartog, Paul Frederick Cilgrim Dickenson
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Abstract
A system and method for simultaneously addressing multiple parallel distributed fiber optic sensors using a single interrogation instrument is disclosed. One or more of the fiber optic sensors are provided with a non-reflective delay element to prevent an overlap in time between backscatter returns from the distributed fiber optic sensors, thereby allowing the backscatter returns from each sensor to be distinguished based on round-trip transit time.
Claims20
A distributed measurement system, comprising:
- a first distributed fiber optic sensor deployed along a first measurement path;
- a second distributed fiber optic sensor deployed along a second measurement path;
- a distributed sensing interrogation instrument to simultaneously address the first and second distributed fiber optic sensor with a probe signal;
- and
- a non-reflective delay element coupled between the distributed sensing interrogation instrument and the second distributed fiber optic sensor to introduce a delay sufficient to prevent interference between backscatter returned from the first distributed fiber optic sensor and backscatter returned from the second distributed fiber optic sensor in response to the probe signal.
A method of obtaining reflectometric measurements from multiple parallel fiber optic sensors, comprising:
- providing a non-reflective delay in one of a first and a second sensor of the multiple parallel fiber optic sensors;
- and
- simultaneously addressing the multiple parallel fiber optic sensors with a probe signal generated by a distributed fiber optic sensing interrogation instrument,
- wherein the non-reflective delay prevents an overlap in time between the backscatter returns generated by the first and second parallel fiber optic sensors in response to the probe signal so that the backscatter returned from each of the first and second parallel fiber optic sensors is distinguishable by its round-trip transit time.
A distributed measurement system for obtaining measurements from a plurality of parallel distributed fiber optic sensors deployed in one or more wellbores penetrating a hydrocarbon-bearing earth formation, comprising:
- a first distributed fiber optic sensor deployed in a wellbore;
- a second distributed fiber optic sensor deployed in a wellbore;
- a distributed sensing interrogation instrument deployed at the earth surface to simultaneously address the first and second distributed fiber optic sensor with a probe signal;
- and
- a non-reflective delay element coupled between the distributed sensing interrogation instrument and the second distributed fiber optic sensor to introduce a delay sufficient to prevent an overlap in time between backscatter returned from the first distributed fiber optic sensor and backscatter returned from the second distributed fiber optic sensor in response to the probe signal.
Dependencies are inferred from the claim text.