Abstract: Electromagnetic field monitoring methods and systems for obtaining data corresponding to subsurface rock formations. An electromagnetic field monitoring system includes an electromagnetic transmitter located downhole in a well bore and configured to radiate electromagnetic radiation into a subsurface formation; a fiber optic cable coupled with a fiber optic interrogator, the at least one fiber optic cable and the interrogator located at the surface; and an array of electromagnetic sensors integrally formed in the fiber optic cable and configured to detect the electromagnetic radiation radiated through the subsurface formation. A method of detecting electromagnetic radiation at the surface of an oil well includes transmitting, from an electromagnetic transmitter, electromagnetic radiation into a subsurface formation; and sensing, from the subsurface formation, electromagnetic radiation at the surface of the oil well.

Abstract: Methods and systems for effectively sealing a fiber optic line to a pressure gauge device are disclosed. A pressure gauge device has an outer body, a reference volume within the outer body and a pressure sensor having a first side and a second side. The first side of the pressure sensor is exposed to a pressure inlet and the second side of the pressure sensor is exposed to the reference volume. A fiber optic line is coupled to the pressure gauge device using a feedthrough device. The fiber optic line comprises a first fiber optic line portion located within the feedthrough device, a second fiber optic line portion located within the reference volume and a third fiber optic line portion located within a cable located outside the pressure gauge device and coupled to the feed through device. The first fiber optic line portion comprises a first Fiber Bragg Grating (“FBG”).

Abstract: A well monitoring system includes a plurality of transmitter coils coupled to an exterior of a casing positioned within a wellbore, wherein one or more first transmitter coils are positioned at a first location and one or more second transmitter coils are positioned at a second location axially offset from the first location. At least one receiver coil is coupled to the exterior of the casing and positioned at the second location. A power source is communicably coupled to the one or more first and second transmitter coils. The one or more first transmitter coils generates a magnetic field detectable by the at least one receiver coil, and the one or more second transmitter coils generates a bucking signal that minimizes a direct coupling between the one or more first transmitter coils and the at least one receiver coil.

Abstract: An optical cable can include one or more graphenic elements disposed about one or more optically transmissive fibers. A graphenic element can be a coating of graphene or amorphous graphite, a ribbon of graphene or amorphous graphite, or fibers of graphene or amorphous graphite. The graphenic element provides a path for electrical conduction while the optically transmissive fiber provides a path for optical transmission. An optical cable as disclosed herein can include a plurality of electrical and optical paths with a much smaller diameter and weight than traditional cables.

Abstract: A downhole galvanic logging system including a first transmitter electrode configured to convey an exciter current into a formation and a second transmitter electrode configured to receive a return current from the formation. A first transmission line being coupled to the first transmitter electrode and configured to carry the exciter current, and a second transmission line being coupled to the second transmitter electrode and configured to carry the return current. The transmission lines can be arranged in a twisted pattern. A receiver device is positioned between the transmitter electrodes along an axial length of the downhole galvanic logging system. The receiver device can be configured to detect an electrical signal that is proportional to a resistivity of the formation. The second transmitter electrode can be coupled to one end of the receiver device with the second transmission line coupled to the second transmitter electrode through the receiver device.

Abstract: In accordance with embodiments of the present disclosure, systems and methods for triggering detonation of a perforating gun via optical signals are provided. An improved laser firing head may be used with an optical cable (e.g., fiber optic cable) run through the wellbore to trigger detonation of a perforating gun in response to an optical signal. The laser firing head may be activated, and the perforating gun fired, upon the application of an optical signal output from the surface and transmitted through the optical cable. The disclosed system using the laser firing head with the optical cable may be impervious to electrical interference, since the laser firing head may only fire the perforating gun when a properly modulated laser or light source is directed down the optical cable for a specific period of time.

Abstract: A downhole system usable with a well string is provided that can include a first resonator positioned on the well string. The system can also include a second resonator positioned to couple with the first resonator by an evanescent field. The second resonator can include a load. Further, the system can include a metamaterial positioned between the first resonator and the second resonator for amplifying or extending a range of the evanescent field.

Abstract: Reelable sensors arrays are independently fabricated separate from a downhole tubular. The sensor arrays are then reeled together onto a spool. At the well site, the sensor array is unreeled from the spool and attached to the tubular as it is deployed downhole, resulting in a fast and efficient method of sensor deployment.

Abstract: Methods and systems of electromagnetic sensing in a wellbore are presented in this disclosure for monitoring annulus fluids and water floods. An array of transmitters and one or more receivers are located along a casing in the wellbore. A transmitter in the array and one of the receivers can be mounted on a same collar on the casing forming a transmitter-receiver pair. The receiver can receive a signal originating from the transmitter and at least one other signal originating from at least one other transmitter in the array, wherein the signal is indicative of a fluid in the wellbore in a vicinity of the transmitter-receiver pair and the at least one other signal is indicative of another fluid in a formation around the wellbore. The receiver can further communicate, via a waveguide, the signal and the at least one other signal to a processor for signal interpretation.

Abstract: An electric field sensing system, in some embodiments, comprises a magnetic shield, an optical magnetometer shielded from external magnetic fields by the magnetic shield, a conductive coil proximate to the optical magnetometer, and first and second electrodes coupled to opposite ends of the coil. The electrodes are disposed outside of the magnetic shield. The conductive coil generates a magnetic field within the optical magnetometer when electrical current passes through the conductive coil.

Abstract: A downhole system usable with a well string is provided that can include a first resonator positioned on the well string. The system can also include a second resonator positioned to couple with the first resonator by an evanescent field. The second resonator can include a load. Further, the system can include a metamaterial positioned between the first resonator and the second resonator for amplifying or extending a range of the evanescent field.

Abstract: An optical cable can include one or more graphenic elements disposed about one or more optically transmissive fibers. A graphenic element can be a coating of graphene or amorphous graphite, a ribbon of graphene or amorphous graphite, or fibers of graphene or amorphous graphite. The graphenic element provides a path for electrical conduction while the optically transmissive fiber provides a path for optical transmission. An optical cable as disclosed herein can include a plurality of electrical and optical paths with a much smaller diameter and weight than traditional cables.

Abstract: A downhole galvanic logging system including a first transmitter electrode configured to convey an exciter current into a formation and a second transmitter electrode configured to receive a return current from the formation. A first transmission line being coupled to the first transmitter electrode and configured to carry the exciter current, and a second transmission line being coupled to the second transmitter electrode and configured to carry the return current. The transmission lines can be arranged in a twisted pattern. A receiver device is positioned between the transmitter electrodes along an axial length of the downhole galvanic logging system. The receiver device can be configured to detect an electrical signal that is proportional to a resistivity of the formation. The second transmitter electrode can be coupled to one end of the receiver device with the second transmission line coupled to the second transmitter electrode through the receiver device.

Abstract: Electromagnetic (EM) measurement systems and methods for a downhole environment are described herein. An example system includes an optical fiber, an EM source to emit an EM field, and a magnetic induction sensor. The magnetic induction sensor comprises a coil and an electro-optical transducer coupled to the coil and the optical fiber. The electro-optical transducer generates a light beam or modulates a source light beam in the optical fiber in accordance with a voltage induced in the coil by the EM field. An example method includes positioning an optical fiber and magnetic induction sensor in the downhole environment, the magnetic induction sensor having a coil and an electro-optical transducer coupled to the coil and the optical fiber. The method also includes emitting an EM field and generating a light beam or modulating a source light beam, by the electro-optical transducer, in the optical fiber in accordance with a voltage induced in the coil by the EM field.

Abstract: A magnetic field sensor unit for a downhole environment includes an optical fiber, a magnetic field sensor, and an optical transducer. The sensor unit also includes a sealed housing that encloses the magnetic field sensor and the optical transducer. The optical transducer is configured to generate a light beam or to modulate a source light beam in the optical fiber in response to a magnetic field sensed by the magnetic field sensor. Related magnetic field measurement methods and systems deploy one or more of such magnetic field sensor units in a downhole environment to obtain magnetic field measurements due to an emitted electromagnetic field.

Abstract: Methods and systems for effectively sealing a fiber optic line to a pressure gauge device are disclosed. A pressure gauge device has an outer body, a reference volume within the outer body and a pressure sensor having a first side and a second side. The first side of the pressure sensor is exposed to a pressure inlet and the second side of the pressure sensor is exposed to the reference volume. A fiber optic line is coupled to the pressure gauge device using a feedthrough device. The fiber optic line comprises a first fiber optic line portion located within the feedthrough device, a second fiber optic line portion located within the reference volume and a third fiber optic line portion located within a cable located outside the pressure gauge device and coupled to the feed through device. The first fiber optic line portion comprises a first Fiber Bragg Grating (“FBG”).

Abstract: Various disclosed distributed acoustic sensing (DAS) based systems and methods include embodiments that process the DAS measurements to detect one or more contrasts in acoustic signatures associated with one or more fluids flowing along a tubing string, and determine positions of the one or more contrasts as a function of time. The detected contrasts may be changes in acoustic signatures arising from one or more of: turbulence, frictional noise, acoustic attenuation, acoustic coupling, resonance frequency, resonance damping, and active noise generation by entrained materials. At least some of the contrasts correspond to interfaces between different fluids such as those that might be pumped during a cementing operation.

Abstract: A sensing system includes plurality of sensors along the lengths of input and output optical fibers. Each sensor receives broadband pulses from the input fiber, dynamically senses a plurality of physical parameters in a one-to-one correspondence with a plurality of predefined wavelength bands, and forms signal pulses from the broadband pulses by transmitting only a single wavelength within each wavelength band. Each single wavelength has a dynamically-varying peak wavelength value indicative of the corresponding sensed physical parameter. The signal pulses from the output optical fiber are directed into one or more interferometers, which produce a phase deviation corresponding to each dynamically-varying peak wavelength value.

Abstract: A tubular seismic sensing cable for use in wells and a method of deployment into wells to provide higher seismic sensitivity.

Abstract: Various embodiments include systems and methods to communicate along pipes using a conductive waveguide at quasioptical frequencies. The communication can be conducted as propagation to and from a tool at the quasioptical frequencies. A communication architecture may include a transmitter and receiver at one end of the conductive waveguide and a modulation device at an opposite end of the conductive waveguide. Additional systems and methods are disclosed.