Optimized optical fiber for enhanced scatter in downhole environments
AssigneeBaker Hughes Oilfield Operations LLC
InventorsPaul F. Wysocki, Dan Raymond Provenzano
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Abstract
An apparatus for sensing a value of a property in a borehole having hydrogen gas penetrating a subsurface formation includes an optical fiber configured to be disposed in the borehole having the hydrogen gas and comprising a core having a fiber Bragg grating that is responsive to the value of the property and a cladding disposed about the core, wherein (i) the core is doped with a first dopant that is photo-sensitive for writing the fiber Bragg grating and that has a concentration in the core of 2 Mole % or less and (ii) the cladding is doped with a second dopant that lowers an index of refraction of the cladding.
Claims16
An apparatus for sensing a value of a property in a borehole having hydrogen gas penetrating a subsurface formation, the apparatus comprising:
- an optical fiber configured to be disposed in the borehole having the hydrogen gas and comprising a core having a fiber Bragg grating that is responsive to the value of the property and a cladding disposed about the core, wherein (i) the core is doped with a first dopant that is photo-sensitive for writing the fiber Bragg grating and that has a concentration in the core of 2 Mole % or less and (ii) the cladding is doped with a second dopant that lowers an index of refraction of the cladding.
A method for sensing a value of a property in a borehole having hydrogen gas penetrating a subsurface formation, the method comprising:
- disposing an optical fiber in the borehole having the hydrogen gas, the optical fiber comprising a core having a fiber Bragg grating that is responsive to the value of the property and a cladding disposed about the core, wherein (i) the core is doped with a first dopant that is photo-sensitive for writing the fiber Bragg grating and that has a concentration in the core of 2 Mole % or less and (ii) the cladding is doped with a second dopant that lowers an index of refraction of the cladding;
- and
- interrogating the fiber Bragg grating with light using an optical interrogator optically coupled to the optical fiber to determine the value of the property.
Dependencies are inferred from the claim text.