A method and downhole tool is provided that uses beamforming to localize acoustic energy at a desired zone-of-interest within a wellbore traversing a subterranean formation. The tool has an array of transmitter elements configured to emit guided mode acoustic signals at variable amplitude and variable time delay, which are individually controlled by an amplitude factor and time delay assigned to respective transmitter elements. A set of amplitude factors and time delays can be assigned to the transmitter elements of the transmitter array such that the transmitter elements produce a focused acoustic beam at the desired zone-of-interest by combination of guided mode acoustic signals transmitted by the transmitter elements.

Logging of data by a downhole tool disposed in a borehole may be affected by tool wave effects. The tool waves appear in the first echo of casing wave arrivals and the amplitudes may be much larger than casing wave arrivals. The estimates of casing wave amplitude are biased due to these tool wave arrivals when using conventional cement-bond logging (CBL) processing. An automated adaptive inversion-based array processing for CBL evaluation using a downhole tool provides an improvement in the calculation of a bonding index.

Logging of data by a downhole tool disposed in a borehole may be affected by tool wave effects. The tool waves appear in the first echo of casing wave arrivals and the amplitudes may be much larger than casing wave arrivals. The estimates of casing wave amplitude are biased due to these tool wave arrivals when using conventional cement-bond logging (CBL) processing. An automated adaptive inversion-based array processing for CBL evaluation using a downhole tool provides an improvement in the calculation of a bonding index.

A soil probing device includes a probing rod with a measuring probe, a driving for penetrating the probing rod into the ground, generators for generating acoustic compression and shear waves into the ground, detectors for detecting the generated acoustic compression and shear waves. The detectors are built into the measuring probe. Also the generators are built into the measuring probe at positions that are interspaced at fixed distances in a z-direction from the detectors in the measuring probe. A processing unit CPU is provided for calculating velocities of the generated acoustic compression and shear waves that get to travel from the generators towards the detectors through local ground layers that lie adjacent the measuring probe in between the generators and detectors.

A soil probing device includes a probing rod with a measuring probe, a driving for penetrating the probing rod into the ground, generators for generating acoustic compression and shear waves into the ground, detectors for detecting the generated acoustic compression and shear waves. The detectors are built into the measuring probe. Also the generators are built into the measuring probe at positions that are interspaced at fixed distances in a z-direction from the detectors in the measuring probe. A processing unit CPU is provided for calculating velocities of the generated acoustic compression and shear waves that get to travel from the generators towards the detectors through local ground layers that lie adjacent the measuring probe in between the generators and detectors.

A method to generate a tube wave in a tubular system involves reciprocating a plunger in a chamber system to alternatingly increase and decrease net volume, drawing fluid from and returning the fluid to a tubular system and into and from the chamber system, to generate a tube wave, and guiding the tube wave to the tubular system. Also, a tube wave generator-sensor system has a chamber system, a plunger, a driver to reciprocate the plunger within the chamber system to generate a tube wave, a flow passage to guide the tube wave into a tubular system, and a sensor to receive the tube wave signal and/or response from the tubular system. The method and system can work with or without a firing valve and or accumulator, without adding or subtracting fluid from the tubular system.

A method to generate a tube wave in a tubular system involves reciprocating a plunger in a chamber system to alternatingly increase and decrease net volume, drawing fluid from and returning the fluid to a tubular system and into and from the chamber system, to generate a tube wave, and guiding the tube wave to the tubular system. Also, a tube wave generator-sensor system has a chamber system, a plunger, a driver to reciprocate the plunger within the chamber system to generate a tube wave, a flow passage to guide the tube wave into a tubular system, and a sensor to receive the tube wave signal and/or response from the tubular system. The method and system can work with or without a firing valve and or accumulator, without adding or subtracting fluid from the tubular system.

A downhole installation comprises: a first pipe layer 8, a second pipe layer 10 about the first pipe layer 8, an annulus 12 between the first pipe layer 8 and the second pipe layer, and a geological formation out-side of the second pipe layer 10. A logging system for evaluation of the downhole installation comprises: a logging tool 4 including an angled acoustic transmitter 20 for exciting a flexural wave in the first pipe layer 8, and three or more 10 angled acoustic receivers 14, 16, 38, 40, 42 spaced apart along the tool 4 such that, in use, the receivers are at different locations along the length of the pipe layers 8, 10, the receivers 4, 16, 38, 40, 42 each being for obtaining third interface echo data from the second pipe layer 10; and a processor arranged to process acoustic data from the receivers in order to: identify trends in the amplitude of the third interface echo as it propagates along the length of 1 the pipes, calculate an estimated exponential decay for the third interface echo when reinforcement from other acoustic energy is disregarded, use this estimation to predict if the material behind the second pipe layer 10 is fluid or solid, and analyse the third interface echo data in light of the determined material state in order to thereby evaluate material conditions in the annulus 12 outside the second pipe layer 10.

Movable transducer designs used in downhole environments increase the efficiency of the transmitter and receivers, thereby obtaining improved logging data. In one embodiment, the transmitter/receivers are tilted/rotated to direct the strongest acoustic wave pressure to the critical path for increasing signal strength. In other embodiments, the transmitter/receiver may be extended outwardly toward the formation, or retracted inwardly from the formation. An adaptive algorithm is provided to rotate the transmitter/receiver to match the critical angle when the formation slowness changes. Also, a transmitter/receiver port may be designed to have a cone-shape that matches the impedance of the acoustic wave to the surrounding environment.

A logging-while-drilling (LWD) tool for use within a formation. The LWD tool may include a transmitter, a receiver, and an acoustic isolator. The transmitter may be operable to transmit an acoustic signal into the formation. The receiver may be operable to receive an acoustic response from the formation. The acoustic isolator may be positioned longitudinally between the transmitter and the receiver to reduce a transfer of acoustic energy between the transmitter and the receiver through the LWD tool. The acoustic isolator may include annular chambers formed in a body of the acoustic isolator and positioned along a longitudinal axis of the acoustic isolator.