Borehole sensor apparatus and methods. The borehole sensor apparatus includes at least one sensor and a first elastomer portion in operable contact with the at least one sensor and configured to be connected to a production tube of a borehole. The elastomer portion is further configured to expand upon exposure to a fluid and move, via the expansion, the sensor away from the production tube to operably contact a casing

Borehole sensor apparatus and methods. The borehole sensor apparatus includes at least one sensor and a first elastomer portion in operable contact with the at least one sensor and configured to be connected to a production tube of a borehole. The elastomer portion is further configured to expand upon exposure to a fluid and move, via the expansion, the sensor away from the production tube to operably contact a casing

A distributed acoustic system (DAS) method and system. The system may comprise an interrogator and an umbilical line comprising a first fiber optic cable and a second fiber optic cable attached at one end to the interrogator. The DAS may further include a downhole fiber attached to the umbilical line at the end opposite the interrogator and a light source disposed in the interrogator that is configured to emit a plurality of coherent light frequencies into the umbilical line and the downhole fiber. The method may include generating interferometric signals of the plurality of frequencies of backscattered light that have been received by the photo detector assembly and processing the interferometric signals with an information handling system.

A distributed acoustic system (DAS) method and system. The system may comprise an interrogator and an umbilical line comprising a first fiber optic cable and a second fiber optic cable attached at one end to the interrogator. The DAS may further include a downhole fiber attached to the umbilical line at the end opposite the interrogator and a light source disposed in the interrogator that is configured to emit a plurality of coherent light frequencies into the umbilical line and the downhole fiber. The method may include generating interferometric signals of the plurality of frequencies of backscattered light that have been received by the photo detector assembly and processing the interferometric signals with an information handling system.

Methods and apparatus for automatic recognition of environmental parameters with azimuthally distributed transducers. For example, a toolstring is disposed in a cased portion of a borehole penetrating a subsurface formation. The toolstring comprises a module comprising azimuthally distributed acoustic transducers each operable to emit and receive acoustic signals. The module is operated to emit an acoustic signal into fluid surrounding the module in the casing and record data indicative of receipt, by a plurality of the transducers, of acoustic waveforms resulting from interaction of the emitted acoustic signal with the casing, including at least a non-specular diffraction head wave excited by a guided wave that is excited by diffraction of the acoustic signal propagating in the casing metal. Acoustic velocity of the guided wave in the casing metal is determined utilizing the recorded data and geometric parameters of the module.

Methods and apparatus for automatic recognition of environmental parameters with azimuthally distributed transducers. For example, a toolstring is disposed in a cased portion of a borehole penetrating a subsurface formation. The toolstring comprises a module comprising azimuthally distributed acoustic transducers each operable to emit and receive acoustic signals. The module is operated to emit an acoustic signal into fluid surrounding the module in the casing and record data indicative of receipt, by a plurality of the transducers, of acoustic waveforms resulting from interaction of the emitted acoustic signal with the casing, including at least a non-specular diffraction head wave excited by a guided wave that is excited by diffraction of the acoustic signal propagating in the casing metal. Acoustic velocity of the guided wave in the casing metal is determined utilizing the recorded data and geometric parameters of the module.

Methods and devices for imaging wells using phased array ultrasound imaging devices is described. The devices enable high resolution real-time imaging of a well during various operations in the well, including during completions, fracturing, milling, fishing and drilling operations. The phased array ultrasound imaging devices may be integrated with other well tools, such as a bottom hole assembly (BHA), fishing tools, milling tools, fracturing tools, and drilling tools, in order to integrate imaging capabilities into such tools.

Methods and devices for imaging wells using phased array ultrasound imaging devices is described. The devices enable high resolution real-time imaging of a well during various operations in the well, including during completions, fracturing, milling, fishing and drilling operations. The phased array ultrasound imaging devices may be integrated with other well tools, such as a bottom hole assembly (BHA), fishing tools, milling tools, fracturing tools, and drilling tools, in order to integrate imaging capabilities into such tools.

An immersible ultrasonic transmitter consists of an end element of a first type, an end element of a second type and at least one transmitting member. The end element of the first type comprises a first cylindrical transmitter, a stack of piezoelectric elements, a second cylindrical transmitter and a coupling element with a threaded connection for coupling together the two cylindrical transmitters. The transmitting member contains a stack of piezoelectric elements, a cylindrical transmitter of a transmitting member, and an element with a threaded connection for coupling together the cylindrical transmitter of a transmitting member and the cylindrical transmitter of an adjacent transmitting member, or the second cylindrical transmitter of the end element of the first type. The end element of the second type comprises a first cylindrical transmitter, a stack of piezoelectric elements and a coupling element with a threaded connection for coupling together the cylindrical transmitter and the cylindrical transmitter of an adjacent transmitting member.

A distributed acoustic system (DAS) may comprise an interrogator and an umbilical line attached at one end to the interrogator, a downhole fiber attached to the umbilical line at the end opposite the interrogator. The interrogator may further include a proximal circulator, a distal circulator connected to the proximal circulator by a first fiber optic cable, and a second fiber optic cable connecting the proximal circulator and the distal circulator.