Methods, systems, devices, and products for performing well logging in a borehole intersecting an earth formation to obtain and transmit an acoustic reflection image of the formation. Methods include identifying a set of features in the acoustic reflection image substantially fitting a pattern, wherein the set of features corresponds to a portion of at least one reflecting structural interface of the formation; and using a representation of the pattern as the compressed representation of the acoustic reflection image. The features may be amplitude peaks in the acoustic reflection image, and the pattern may be a line segment therein that is obtained from the amplitude peaks. Identifying the set of features may include generating a binary image of the amplitude peaks.

A downhole device is provided that is intended to be co-located with an optical fiber cable to be found, for example by being fixed together in the same clamp. The device has an accelerometer or other suitable orientation determining means that is able to determine its positional orientation, with respect to gravity. A vibrator or other sounder is provided, that outputs the positional orientation information as a suitable encoded and modulated acoustic signal. A fiber optic distributed acoustic sensor deployed in the vicinity of the downhole device detects the acoustic signal and transmits it back to the surface, where it is demodulated and decoded to obtain the positional orientation information. Given that the device is co-located with the optical fiber the position of the fiber can then be inferred. As explained above, detecting the fiber position is important during perforation operations, so that the fiber is not inadvertently damaged.

A downhole device is provided that is intended to be co-located with an optical fiber cable to be found, for example by being fixed together in the same clamp. The device has an accelerometer or other suitable orientation determining means that is able to determine its positional orientation, with respect to gravity. A vibrator or other sounder is provided, that outputs the positional orientation information as a suitable encoded and modulated acoustic signal. A fiber optic distributed acoustic sensor deployed in the vicinity of the downhole device detects the acoustic signal and transmits it back to the surface, where it is demodulated and decoded to obtain the positional orientation information. Given that the device is co-located with the optical fiber the position of the fiber can then be inferred. As explained above, detecting the fiber position is important during perforation operations, so that the fiber is not inadvertently damaged.

An apparatus for sensing acoustic energy in a borehole penetrating the earth includes an optical interrogator and a sensing optical fiber having a length Ls optically coupled to the optical interrogator and configured to sense the acoustic energy to provide sensed acoustic data. The apparatus also includes a reference optical fiber having a length Lr optically coupled to the optical interrogator to provide reference data, wherein the optical interrogator corrects the sensed acoustic data using the reference data to provide corrected sensed acoustic data.

An apparatus for sensing acoustic energy in a borehole penetrating the earth includes an optical interrogator and a sensing optical fiber having a length Ls optically coupled to the optical interrogator and configured to sense the acoustic energy to provide sensed acoustic data. The apparatus also includes a reference optical fiber having a length Lr optically coupled to the optical interrogator to provide reference data, wherein the optical interrogator corrects the sensed acoustic data using the reference data to provide corrected sensed acoustic data.

A system for looking ahead of a drill bit includes a plane wave generator (PWG) tool deployed downhole inside a wellbore for formation evaluation and generation of reflection data, a power source providing electric power to the PWG tool for the formation evaluation and the generation of the reflection data, a surface control system receiving the reflection data from the PWG tool and generating image data of a subsurface rock formation based on the received reflection data, and a wireline that electrically couples the PWG tool to the power source and communicatively couples the PWG tool to the surface control system. The PWG tool includes a beam forming network (BFN) architecture and a plurality of antenna elements mounted to a base of the PWG tool to transmit and receive electromagnetic signals.

Methods and systems for logging a wellbore having a casing using ultrasonic logging are described. Traditional ultrasonic logging involves using a piezoelectric transducer that is spaced from the inner surface of the casing by a least a distance referred to as the “far-field” distance. Logging in the “far-field,” as traditionally done, avoids destructive interference. The methods and systems described herein allow logging in the “near-field.” Logging in the near-field using the described methods and systems overcomes several difficulties associated with acoustic logging, particularly in attenuative, dispersive, and deviated environments.

Methods and systems for logging a wellbore having a casing using ultrasonic logging are described. Traditional ultrasonic logging involves using a piezoelectric transducer that is spaced from the inner surface of the casing by a least a distance referred to as the “far-field” distance. Logging in the “far-field,” as traditionally done, avoids destructive interference. The methods and systems described herein allow logging in the “near-field.” Logging in the near-field using the described methods and systems overcomes several difficulties associated with acoustic logging, particularly in attenuative, dispersive, and deviated environments.

A combining mechanism for borehole logging tool data that employs modality merging to combine the output data of various borehole logging tools to provide a combined result and automated interpretation is provided, said mechanism comprising: at least one mechanism for assigning interpretive values to individual processed data types; at least one mechanism for combining the interpretive value data sets; and, at least one mechanism for providing an interpretation. A method of combining borehole logging tool data that employs modality merging to combine the output data of various borehole logging tools to provide a combined result and automated interpretation is also provided, said method comprising: assigning interpretive values to individual processed data types; combining the interpretive value data sets; and, providing an interpretation.

A combining mechanism for borehole logging tool data that employs modality merging to combine the output data of various borehole logging tools to provide a combined result and automated interpretation is provided, said mechanism comprising: at least one mechanism for assigning interpretive values to individual processed data types; at least one mechanism for combining the interpretive value data sets; and, at least one mechanism for providing an interpretation. A method of combining borehole logging tool data that employs modality merging to combine the output data of various borehole logging tools to provide a combined result and automated interpretation is also provided, said method comprising: assigning interpretive values to individual processed data types; combining the interpretive value data sets; and, providing an interpretation.