Abstract: A sensor assembly for passive detections of downhole well features. Embodiments include a casing collar locator assembly that utilizes fiber optics in combination with a magneto-responsive sensor to detect casing collars and provide real-time location information in a well. The sensor may be configured to work with a poled monolithic structure that is dimensionally responsive to voltage in a way that substantially eliminates noise during detections. Additionally, the sensor may be intentionally imbalanced, utilizing multiple fibers of different lengths and multiple wavelength monitoring so as to provide enhanced directional information as well as allow operators to decipher and address circumstances of polarization fade.

Abstract: A fiber optic distributed vibration system for detecting seismic signals in an earth formation is provided. The system includes a fiber optic cable deployed in a borehole that extends into the earth formation and which is configured to react along its length to a seismic wave incident on the fiber optic cable from outside the borehole. An optical source launches an optical signal into the fiber optic cable while the seismic wave is incident thereon. A receiver detects coherent Rayleigh noise (CRN) produced in response to the optical signal. A processing circuit processes the detected CRN signal to determine characteristics of the earth formation.

Abstract: A sensor assembly for passive detections of downhole well features. Embodiments include a casing collar locator assembly that utilizes fiber optics in combination with a magneto-responsive sensor to detect casing collars and provide real-time location information in a well. The sensor may be configured to work with a poled monolithic structure that is dimensionally responsive to voltage in a way that substantially eliminates noise during detections. Additionally, the sensor may be intentionally imbalanced, utilizing multiple fibers of different lengths and multiple wavelength monitoring so as to provide enhanced directional information as well as allow operators to decipher and address circumstances of polarization fade.

Abstract: A fiber optic distributed vibration system for detecting seismic signals in an earth formation is provided. The system includes a fiber optic cable deployed in a borehole that extends into the earth formation and which is configured to react along its length to a seismic wave incident on the fiber optic cable from outside the borehole. An optical source launches an optical signal into the fiber optic cable while the seismic wave is incident thereon. A receiver detects coherent Rayleigh noise (CRN) produced in response to the optical signal. A processing circuit processes the detected CRN signal to determine characteristics of the earth formation.

Abstract: A fiber optic distributed vibration sensor provides a highly sensitive measurement of a measurand with a high degree of linearity. The distributed vibration sensor includes subsections configured to have a high sensitivity to a measurand of interest interspaced in an alternating manner with subsections having a low sensitivity to the measurand. The distributed vibration sensor is interrogated such that a phase difference between the backscattered signals generated in low sensitivity subsections surrounding a high sensitivity subsection can be determined. Characteristics of the measurand may then be determined based on the phase difference.

Abstract: A fiber optic distributed vibration system for detecting seismic signals in an earth formation is provided. The system includes a fiber optic cable deployed in a borehole that extends into the earth formation and which is configured to react along its length to a seismic wave incident on the fiber optic cable from outside the borehole. An optical source launches an optical signal into the fiber optic cable while the seismic wave is incident thereon. A receiver detects coherent Rayleigh noise (CRN) produced in response to the optical signal. A processing circuit processes the detected CRN signal to determine characteristics of the earth formation.

Abstract: A fiber optic sensing tool assembly is deployed in a wellbore that penetrates a hydrocarbon-bearing formation of interest to measure fluid composition and other fluid characteristics. This measurement is implemented by deploying the tool in a region in which there is substantially no fluid flow and by heating the tool through an optical delivery system. Parameters of the fluid are monitored as a function of the heating of the tool to derive information that is indicative of fluid composition and other fluid characteristics.

Abstract: A fiber optic distributed vibration system for detecting seismic signals in an earth formation is provided. The system includes a fiber optic cable deployed in a borehole that extends into the earth formation and which is configured to react along its length to a seismic wave incident on the fiber optic cable from outside the borehole. An optical source launches an optical signal into the fiber optic cable while the seismic wave is incident thereon. A receiver detects coherent Rayleigh noise (CRN) produced in response to the optical signal. A processing circuit processes the detected CRN signal to determine characteristics of the earth formation.

Abstract: A fiber optic sensing tool assembly is deployed in a wellbore that penetrates a hydrocarbon-bearing formation of interest to measure fluid composition and other fluid characteristics. This measurement is implemented by deploying the tool in a region in which there is substantially no fluid flow and by heating the tool through an optical delivery system. Parameters of the fluid are monitored as a function of the heating of the tool to derive information that is indicative of fluid composition and other fluid characteristics.

Abstract: A fiber optic distributed vibration system for detecting seismic signals in an earth formation is provided. The system includes a fiber optic cable deployed in a borehole that extends into the earth formation and which is configured to react along its length to a seismic wave incident on the fiber optic cable from outside the borehole. An optical source launches an optical signal into the fiber optic cable while the seismic wave is incident thereon. A receiver detects coherent Rayleigh noise (CRN) produced in response to the optical signal. A processing circuit processes the detected CRN signal to determine characteristics of the earth formation.

Abstract: To provide a polarization-diverse, heterodyne optical receiving system, a light signal is transmitted into an optical fiber having a plurality of optical sensors that are distinguishable using a multiplexing arrangement. A return light signal from the optical fiber is mixed with an optical local oscillator light signal, where the mixing outputs plural output signal portions having different polarizations. A birefringence of a particular optical sensor is determined based on the plural signal portions.

Abstract: Methods and apparatus for use in a well. A first component made of a first material and a second component made of a second material are provided. The first and second materials are dissimilar to each other. An adaptor is also provided, where part of the adaptor is made of or compatible with the first material, and another part of the adaptor is made of or compatible with the second material. The first component is connected to the adaptor, as is the second component. The combined adaptor and first and second components are deployed into a downhole well system.

Abstract: A fiber optic sensor employs at least two flexural discs that are spaced apart from one another along a central axis. A fiber optic coil is affixed to at least one of the flexural discs. A proof mass is disposed between the flexural discs. A first stop member is disposed between the proof mass and one flexural disc. A second stop member is disposed between the proof mass and the other flexural disc. The first and second stop members are sized to provide space between the proof mass and the corresponding flexural disc to allow for normal motion of the flexural discs, while interfering with movement of the flexural discs to prohibit unwanted extreme motion. The fiber optic sensor can be used for OTDR measurements of acceleration for real-time oilfield monitoring applications as well as other fiber-based interferometric measurement applications. A coupling structure preferably couples the outer edges of the flexible disks, the mass being attached to the coupling structure.

Abstract: To treat a surface of an optical fiber cable structure, substantially an entire length of the optical fiber cable structure is moved through an inline plasma treatment system. As the optical fiber cable structure is moved through the inline plasma treatment system, the surface of the optical fiber cable structure is continually exposed to plasma. Exposing the surface of the optical fiber cable structure to plasma modifies a characteristic of the surface of the optical cable structure to improve an ability of the surface of the optical fiber cable structure to adhere to a target material.

Abstract: A fiber optic distributed vibration sensor provides a highly sensitive measurement of a measurand with a high degree of linearity. The distributed vibration sensor includes subsections configured to have a high sensitivity to a measurand of interest interspaced in an alternating manner with subsections having a low sensitivity to the measurand. The distributed vibration sensor is interrogated such that a phase difference between the backscattered signals generated in low sensitivity subsections surrounding a high sensitivity subsection can be determined. Characteristics of the measurand may then be determined based on the phase difference.

Abstract: A fiber optic distributed vibration system for detecting seismic signals in an earth formation is provided. The system includes a fiber optic cable deployed in a borehole that extends into the earth formation and which is configured to react along its length to a seismic wave incident on the fiber optic cable from outside the borehole. An optical source launches an optical signal into the fiber optic cable while the seismic wave is incident thereon. A receiver detects coherent Rayleigh noise (CRN) produced in response to the optical signal. A processing circuit processes the detected CRN signal to determine characteristics of the earth formation.

Abstract: An assembly for passive detection of features at known locations of a conduit. The assembly is a sensor assembly particularly well suited for detection of casing collars at known locations of cased wells, such as segmented hydrocarbon wells. Thus, the assembly is able to provide real time positioning information relative to any tool coupled thereto which is being advanced in the well pursuant to a well application. Given that the detection takes place in a passive manner via the combination of a magneto-responsive sensor and voltage responsive device, no separate dedicated power source or additional electronics are required.

Abstract: To provide a polarization-diverse, heterodyne optical receiving system, a light signal is transmitted into an optical fiber having a plurality of optical sensors that are distinguishable using a multiplexing arrangement. A return light signal from the optical fiber is mixed with an optical local oscillator light signal, where the mixing outputs plural output signal portions having different polarizations. A birefringence of a particular optical sensor is determined based on the plural signal portions.

Abstract: A fiber optic sensor employs at least two flexural discs that are spaced apart from one another along a central axis. A fiber optic coil is affixed to at least one of the flexural discs. A proof mass is disposed between the flexural discs. A first stop member is disposed between the proof mass and one flexural disc. A second stop member is disposed between the proof mass and the other flexural disc. The first and second stop members are sized to provide space between the proof mass and the corresponding flexural disc to allow for normal motion of the flexural discs, while interfering with movement of the flexural discs to prohibit unwanted extreme motion. The fiber optic sensor can be used for OTDR measurements of acceleration for real-time oilfield monitoring applications as well as other fiber-based interferometric measurement applications. A coupling structure preferably couples the outer edges of the flexible disks, the mass being attached to the coupling structure.

Abstract: A fiber optic sensor employs a central support structure and at least two flexural discs spaced apart from one another along a central axis. Radially-inner portions of the flexural discs are rigidly attached to the central support structure. A fiber optic coil is affixed to one of the flexural discs. At least one proof mass is disposed between the flexural discs. Coupling means rigidly connects together radially outer edge portions of the flexural discs and rigidly connects the at least one proof mass to such outer edge portions. The flexibility of the axially-aligned outer-edge-connected flexural disc arrangement, together with the outer-edge-connected proof mass, provide for a relatively large response to axial forces. The radial stiffness of the axially-aligned outer-edge-connected flexural disc arrangement minimizes the response to non-axial forces. By limiting the response to non-axial forces, unwanted cross-axis sensitivity of the device is reduced and unwanted resonances are eliminated.