Abstract: An apparatus for locating a measurand anomaly, such as a hot-spot, along an optical waveguide is provided comprising: an optical waveguide, a light source configured to transmit pulsed light along the waveguide, and a first and second set of sensors provided along the waveguide. Each sensor is configured to reflect a portion of light propagating along the waveguide at a respective sensor wavelength corresponding to a measurand. The first set of sensors provides one or more groups of sensors configured to detect a measurand anomaly within that group. The second set comprises a plurality of sensors each separated from the adjacent sensor of that set by a distance along the waveguide greater than half the distance travelled by the light along the waveguide during the pulse duration. A plurality of sensors of the first set is provided between each adjacent sensor of the second set.

Abstract: A method for forming a pressure sensor is provided wherein an optical fibre is provided, the optical fibre comprising a core, a cladding surrounding the core, and a birefringence structure for inducing birefringence in the core. The birefringence structure comprises first and second holes enclosed within the cladding and extending parallel to the core. A portion of the optical fibre comprising of the core and the birefringence structure is encased within a chamber, wherein the chamber is defined by a housing comprising a pressure transfer element for equalising pressure between the inside and the outside of the housing. An optical sensor is provided along the core of the optical fibre. The cladding is internally etched by flowing an etchant through the first and second holes along a length of the portion of optical fibre which comprises the optical sensor so as to increase the width of the first and second holes. The chamber is filled with a substantially non-compressible fluid.

Abstract: A fracturing treatment optimization system using multi-point pressure sensitive fiber optic cables to measure interwell fluid interaction data, microdeformation strain data, microseismic data, distributed temperature data, distributed acoustic data, and distributed strain data from multiple locations along a wellbore. The fracturing treatment optimization system may analyze the interwell fluid interaction data, microdeformation strain data, microseismic data, distributed temperature data, distributed acoustic data, and distributed strain data, modify a subsurface fracture network model, and calculate interwell fluid interaction effects. The fracturing treatment optimization system may use the fracture network model to measure current and predict future fracture growth, hydraulic pressure, poroelastic pressure, strain, stress, and related completion effects. The fracturing treatment optimization system may enable real-time monitoring and analysis of treatment and monitoring wells.

Abstract: A method for forming a pressure sensor is provided wherein an optical fibre is provided, the optical fibre comprising a core, a cladding surrounding the core, and a birefringence structure for inducing birefringence in the core. The birefringence structure comprises first and second holes enclosed within the cladding and extending parallel to the core. A portion of the optical fibre comprising the core and the birefringence structure is encased within a chamber, wherein the chamber is defined by a housing comprising a pressure transfer element for equalising pressure between the inside and the outside of the housing. An optical sensor is provided along the core of the optical fibre. Providing the optical sensor comprises optically inducing stress in the core so that the optical sensor exhibits intrinsic birefringence. The chamber is filled with a substantially non-compressible fluid.

Abstract: An apparatus for locating a measurand anomaly, such as a hot-spot, along an optical waveguide is provided having: an optical waveguide, a light source configured to transmit light along the waveguide and a plurality of sensors provided along the waveguide. Each sensor is configured to reflect a portion of light propagating along the waveguide at a respective sensor wavelength corresponding to a measurand. The plurality of sensors is configured into one or more sets according to their sensor wavelengths, each set comprising a plurality of sensors with respective sensor wavelengths, wherein the sensors are configured such that the sensor wavelength for each sensor in a respective set is substantially equal when the measurand experienced by each of the sensors in that set is equal. The apparatus further includes a detector configured to monitor the light reflected by the sensors, and a control system.

Abstract: A fracturing treatment optimization system using multi-point pressure sensitive fiber optic cables to measure interwell fluid interaction data, microdeformation strain data, microseismic data, distributed temperature data, distributed acoustic data, and distributed strain data from multiple locations along a wellbore. The fracturing treatment optimization system may analyze the interwell fluid interaction data, microdeformation strain data, microseismic data, distributed temperature data, distributed acoustic data, and distributed strain data, modify a subsurface fracture network model, and calculate interwell fluid interaction effects. The fracturing treatment optimization system may use the fracture network model to measure current and predict future fracture growth, hydraulic pressure, poroelastic pressure, strain, stress, and related completion effects. The fracturing treatment optimization system may enable real-time monitoring and analysis of treatment and monitoring wells.

Abstract: An apparatus for locating a measurand anomaly, such as a hot-spot, along an optical waveguide is provided comprising: an optical waveguide, a light source configured to transmit pulsed light along the waveguide, and a first and second set of sensors provided along the waveguide. Each sensor is configured to reflect a portion of light propagating along the waveguide at a respective sensor wavelength corresponding to a measurand. The first set of sensors provides one or more groups of sensors configured to detect a measurand anomaly within that group. The second set comprises a plurality of sensors each separated from the adjacent sensor of that set by a distance along the waveguide greater than half the distance travelled by the light along the waveguide during the pulse duration. A plurality of sensors of the first set is provided between each adjacent sensor of the second set.

Abstract: A method for forming a pressure sensor is provided wherein an optical fibre is provided, the optical fibre comprising a core, a cladding surrounding the core, and a birefringence structure for inducing birefringence in the core. The birefringence structure comprises first and second holes enclosed within the cladding and extending parallel to the core. A portion of the optical fibre comprising of the core and the birefringence structure is encased within a chamber, wherein the chamber is defined by a housing comprising a pressure transfer element for equalising pressure between the inside and the outside of the housing. An optical sensor is provided along the core of the optical fibre. The cladding is internally etched by flowing an etchant through the first and second holes along a length of the portion of optical fibre which comprises the optical sensor so as to increase the width of the first and second holes. The chamber is filled with a substantially non-compressible fluid.

Abstract: An apparatus for locating a measurand anomaly, such as a hot-spot, along an optical waveguide is provided having: an optical waveguide, a light source configured to transmit light along the waveguide and a plurality of sensors provided along the waveguide. Each sensor is configured to reflect a portion of light propagating along the waveguide at a respective sensor wavelength corresponding to a measurand. The plurality of sensors is configured into one or more sets according to their sensor wavelengths, each set comprising a plurality of sensors with respective sensor wavelengths, wherein the sensors are configured such that the sensor wavelength for each sensor in a respective set is substantially equal when the measurand experienced by each of the sensors in that set is equal. The apparatus further includes a detector configured to monitor the light reflected by the sensors, and a control system.

Abstract: A fluid pressure monitoring apparatus for use in high temperature, harsh environment applications, is described. The apparatus comprises an elongated member, having a free end and a fixed end, and a blind bore extending through the elongated member the bore having an opening through which fluid is provided to the bore when in use. The bore is offset from a central axis of the elongated member such that the elongated member deflects in response to the pressure of the fluid when provided to the bore. The apparatus further comprises a sensing device adapted to sense the change in distance between a first position, and a second position, in response to the deflection of the elongated member.