An acoustic logging tool includes a support structure and a set of acoustic transducers coupled to the support structure. The set of acoustic transducers includes a first acoustic transducer and a second acoustic transducer facing the same direction. Each of the first and second acoustic transducers includes a substrate having a first end, a second end, a first side, and a second side. Each acoustic transduce further includes a first piezoelectric element coupled to the first side of the substrate and a second piezoelectric element coupled to the second side of the substrate. The first and second ends of the substrate extend beyond the first and second piezoelectric elements and are fixed to the support structure.

A Transducer in a downhole environment with an increased amplitude of the transducer output at lower frequencies. A transducer may include a bender bar, wherein the bender bar may include a first piezoelectric layer disposed on one surface of the bender bar, a second piezoelectric layer disposed on the opposite surface of the bender bar, and a metallic substrate disposed between the first piezoelectric layer and the second piezoelectric layer. The transducer may further include a first fixed end is attached to the bender bar and connects the bender bar to a base, a second fixed end opposite the first fixed end that attaches the bender bar to the base, and a compartment disposed within the base.

A downhole tool for operation within a wellbore and including a transmitter array and first and second receiver arrays. The transmitter array includes a plurality of transmitters azimuthally distributed around a longitudinal axis of the downhole tool at a first axial location of the downhole tool. The first receiver array includes a plurality of first receivers azimuthally distributed around the longitudinal axis at a second axial location axially offset from the first axial location. The second receiver array includes a plurality of second receivers azimuthally distributed around the longitudinal axis at a third axial location axially offset from the first and second axial locations.

An apparatus includes a marine seismic source having a volume of gas and a gas reservoir, and the marine seismic source and the gas reservoir are coupled to permit a resonating gas flow to pass therebetween. The apparatus may be a component of a marine seismic survey system. The apparatus may be utilized in a method of marine seismic surveying.

A bender bar acoustic transducer capable of exciting at least three resonance modes is provided. The provided bender bar acoustic transducer may be capable of exciting a second resonance mode by configuring a first portion of a piezoelectric element to contract while a second portion of the piezoelectric element expands when voltage is applied to electrodes coupled to the piezoelectric element. The bender bar acoustic transducer may be further configured such that the first portion and the second portion of the piezoelectric element both contract and/or expand to excite a first resonance mode. The bender bar acoustic transducer may be used in downhole and well logging applications.

A sensor system for use in a wellbore is provided that can include a piezoelectric transducer for transmitting an acoustic wave into a fluid medium positioned in the wellbore by repeatedly bending between two positions in response to an actuation signal. The piezoelectric transducer can include at least four piezoelectric layers stacked on top of one another. Each of the four piezoelectric layers can be coupled to an adjacent layer via a bonding material. Each of the four piezoelectric layers can include a piezoelectric material, a top electrode coupled to a top surface of the piezoelectric material, and a bottom electrode coupled to a bottom surface of the piezoelectric material. The sensor system can also include a hydrophone for detecting a reflection or a refraction of the acoustic wave off an object in the wellbore and transmitting an associated signal to a processing device.

A variable inductor includes a three-limbed core first section having an inductor winding wound about a medial limb. An air gap is disposed in the medial limb. The inductor includes a second section having a control limb in which a first end of the control limb is connected to a first outer limb of the three-limbed core, and a second end of the control limb is connected to a second outer limb of the three-limbed core. A control winding is wound about the control limb. The inductor may be used in a control circuit to control a power signal driving a transducer. The inductor may be controlled by a signal derived from a comparison of a voltage phase of a power signal to the transducer and a phase of the current traversing the transducer. A system may include the control circuit, including the variable inductor, and the transducer.

An apparatus is disclosed which may include a plurality of marine seismic sources. According to some embodiments, these marine seismic sources may include a plurality of piezoelectric components. Such an apparatus may provide a useful sound pressure level for conducting marine seismic surveying. According to some embodiments, a conduit may be coupled between the plurality of marine seismic sources and a gas reservoir external to the plurality of marine seismic sources. The conduit may in some embodiments have at least one adjustable dimension for changing a frequency of the apparatus. The apparatus may be used in a method of marine seismic surveying.

Systems and methods for deploying and using a controlled-frequency downhole seismic source are provided. A downhole seismic source may be placed into a borehole in a geological formation and coupled rigidly to the geological formation via an edge of the borehole. A controlled-frequency seismic signal may be generated sufficient to enable a seismic measurement of the geological formation.

A system may include a conduit coupled between a marine seismic source and a gas reservoir external to the seismic source. The conduit may have at least one adjustable dimension for changing a resonance frequency of the system. The system may be utilized in a method of marine seismic surveying.