A long-term in-situ observation device for the deep sea bottom supported engineering geological environment is provided, including: a sediment acoustic probe, a sediment pore water pressure probe, a three-dimensional resistivity probe, a water observation instrument, a long-term observation power supply system, a probe hydraulic penetration system, a general control and data storage transmission system, an acoustic releaser, an underwater acoustic communication apparatus, and an instrument platform. The observations include the engineering properties, physical properties, mechanical properties, and biochemical properties of a seawater-seabed interface-sediment. The engineering properties and the physical and mechanical indexes of seafloor sediments are comprehensively determined by three-dimensional measurement of seafloor resistivity and acoustic wave measurements. The physical and biochemical properties of seawater are expected to be acquired by sensors. The observation probe penetrates into the sediments following the hydraulic method. Powered by seawater dissolved oxygen batteries; data transmission is achieved through sea surface relay buoys and satellite communications. The present invention provides an effective integrated, in situ and long-term observation device and method for the deep sea engineering geological environment.

A lift based acoustic source is towable in an undersea environment by a towing vessel. A controller provides a combined lift control signal and an acoustic source signal. A control cable is joined between the towing vessel and a towed depressor having an active lift control system. The combined signal is used to control the towed depressor active lift control system. The towed depressor lift fluctuates in response to the source signal to generate the undersea acoustic signal. A hydrophone or hydrophone array can be provided for measuring the generated acoustic signal for feedback and monitoring.

An acoustic logging tool may comprise a center load carrying pipe, a receiver module connected to the center load carrying pipe, one or more transmitter modules connected to the center load carrying pipe, and one or more mass modules connected to the center load carrying pipe.

A method and systems for performing a borehole operation with a borehole fluid that includes applying an amplitude oscillation deformation force to a sample of the borehole fluid over a period of time, measuring the deformation force from the sample, determining a storage modulus of the borehole fluid over the period of time based on the measured deformation force, determining a gel strength of the borehole fluid by correlation with the storage modulus, comparing the gel strength with a desired gel strength and if the gel strength is outside of an acceptable range of the desired gel strength, adjusting a drilling parameter, a composition of the borehole fluid, or a combination thereof, and using the borehole fluid in the borehole operation. Determining the storage modulus and the gel strength may be done using a processor and the force may be applied using a piezoelectric device.

Apparatus and techniques are disclosed relating to sensor housing and spacer carrier assemblies. In various embodiments, a spacer carrier provides a cavity through a body of the spacer carrier and a first alignment element positioned at a first end of the cavity. In some embodiments, a sensor housing is configured to be deployed within the cavity through the body of the spacer carrier. The sensor housing may include a housing body configured to receive a sensor and a second alignment element configured to interface with the first alignment element. In various embodiments, the first and second alignment elements are configured to maintain an orientation of the sensor housing within the cavity when the sensor housing is inserted into the spacer carrier.

An outer tubular is imaged by a pad assembly disposed within an inner tubular inserted within the outer tubular. The pad assembly is in contact with the inner tubular, and includes an acoustic pressure source, a backing mounted to a side of the acoustic pressure source, and an intervening layer between the acoustic pressure source and inner tubular. Signals generated by the pad assembly propagate radially outward from the inner tubular and reflect from the outer tubular. The generated and reflected signals travel through a medium between the inner and outer tubulars. An estimate of the distance between the inner and outer tubulars is based on the time from generation of the signal to when the reflected signal is sensed.

The disclosed embodiments include quadrupole transmitters and methods to determine wave velocities of a downhole formation. In some embodiments, the quadrupole transmitter has a first piezoelectric ring and a second piezoelectric ring that alternatively contracts and expands in opposite radial directions relative to the first piezoelectric ring in response to being simultaneously excited with the first piezoelectric ring. The quadrupole transmitter also includes a covering sleeve surrounding exterior surfaces of the two piezoelectric rings. The quadrupole transmitter further includes a windowed sleeve surrounding the two piezoelectric rings and having a first portion and a second portion adjacent to the first portion. The first portion and the second portion are formed from multiple window sections and adjacent covered sections that are positioned around different sections of the piezoelectric rings to allow transmission of quadrupole acoustic signals when the piezoelectric rings are simultaneously excited.

A sonic logging broadband impedance matching transformer modular design method and a module are related to sonic logging. The method includes the steps: obtaining component values of a multimodal equivalent circuit of a piezoelectric transducer by fitting actual impedance data of the piezoelectric transducer through a nonlinear regression method; selecting a T-type network structure composed of a matching capacitor and a matching inductor as a piezoelectric transducer impedance matching network structure; and presetting a to-be-matched frequency band and a reflection coefficient, and taking the multimodal equivalent circuit of the transducer as an artificial circuit load to optimize parameters of the piezoelectric transducer impedance matching network structure and a boosting transformer together so as to obtain final optimized parameters of the piezoelectric transducer impedance matching network structure and the transformer.

A sonic logging broadband impedance matching transformer modular design method and a module are related to sonic logging. The method includes the steps: obtaining component values of a multimodal equivalent circuit of a piezoelectric transducer by fitting actual impedance data of the piezoelectric transducer through a nonlinear regression method; selecting a T-type network structure composed of a matching capacitor and a matching inductor as a piezoelectric transducer impedance matching network structure; and presetting a to-be-matched frequency band and a reflection coefficient, and taking the multimodal equivalent circuit of the transducer as an artificial circuit load to optimize parameters of the piezoelectric transducer impedance matching network structure and a boosting transformer together so as to obtain final optimized parameters of the piezoelectric transducer impedance matching network structure and the transformer.

A well tool can be used in a wellbore that can measure characteristics of an object in the wellbore. The well tool includes an ultrasonic transducer for generating an ultrasonic wave in a medium of the wellbore. The ultrasonic transducer includes a front layer, a rear layer, backing material coupled to the rear layer, and piezoelectric material coupled to the front layer and to the backing material. The rear layer can improve signal-to-noise ratio of the transducer in applications such as imaging and caliper applications.