A mechanical transducer for the detection of acoustic and/or seismic signals is indicated, comprising a continuous or discrete coupled mass-spring network with varying masses and/or spring constants. The mass-spring network is adapted to transform a comparatively small-dimensioned motion parameter of a first mass element into a comparatively large-dimensioned motion parameter of a further mass element. Between the first mass element and the further mass element, the mass-spring network comprises one or more intermediate mass elements, which are coupled to the first mass element and the further mass element by means of spring elements.

A mechanical transducer for the detection of acoustic and/or seismic signals is indicated, comprising a continuous or discrete coupled mass-spring network with varying masses and/or spring constants. The mass-spring network is adapted to transform a comparatively small-dimensioned motion parameter of a first mass element into a comparatively large-dimensioned motion parameter of a further mass element. Between the first mass element and the further mass element, the mass-spring network comprises one or more intermediate mass elements, which are coupled to the first mass element and the further mass element by means of spring elements.

In some embodiments, an apparatus and a system, as well as a method and article, may operate to determine a change in fracture volume in a geological formation over a selected time period. Further activities may include determining injected fluid loss as an amount of lost fluid over the selected time period, based on the change in fracture volume, selecting a fluid loss model as a selected model based on the amount of lost fluid, and operating a controlled device based on the selected model. Additional apparatus, systems, and methods are disclosed.

A method and geophysical acceleration sensor (100) for measuring seismic data and also for protecting the sensor from shock. The sensor includes a housing (102); a flexible beam (104) having a first end fixedly attached to the housing; a piezoelectric layer (108) attached to the flexible beam; a seismic mass (112) attached to the flexible beam; and a first movement limiter (130) connected to the housing and configured to limit a movement of the flexible beam. A distance between a tip of the first movement limiter and the flexible beam is adjustable.

Sensors for imaging boreholes via the detection of electrical and optical properties may be subject to harsh conditions downhole, such as from pressure and temperature. In addition, these sensors may be subject to impact, such as tension, elongation, and compression forces, along the wall of the borehole. The harsh conditions downhole and impacts on the sensor can lead to premature wear and even breaking. The present disclosure generally relates to an apparatus for measuring electrical and optical properties of the borehole and methods for manufacturing the apparatus.

It is proposed a seismic data acquisition device (400) intended to be placed on an ocean bottom floor, comprising a polymeric casing (412) defining a chamber that houses at least art of a data acquisition system (440, 444, 445); and a metallic device (414) in which the polymeric casing (412) is trapped, the metallic device (414) comprising two metallic beams (4141, 4142) that extend on opposite sides of the polymeric casing (412).

It is also proposed a method for assembling such a device and a corresponding method for seabed seismic data acquisition.

The present disclosure belongs to the technical field of an ultrasonic sound field measuring system, and relates to a manual acoustic axis aligning method for an ultrasonic sound field measuring system. The method comprises: obtaining an intersection between a current acoustic axis and a plane by scanning two detection planes, and calculating an inclination angle of the current acoustic axis; judging whether the inclination angle is less than an adjustment threshold. The method does not depend on the specific mechanical implementation of adjusting an acoustic axis angle. The iterative algorithm combined with geometric information can converge quickly. The criterion of intersection between the acoustic axis and the plane used is not limited to the amplitude criterion, and other criteria can be introduced by increasing the distance between two planes to increase the robustness of measuring the acoustic axis angle.

A seismic data acquisition unit includes circuitry to detect and digitize a seismic signal, and timing circuitry to control a time of acquisition of each sample of the seismic signal. The timing circuitry include a voltage controlled oscillator (VCO), a local clock incremented by the VCO, and a reference time receiver. The timing circuitry powers on the reference time receiver to generate a reference time value based on signals received from a reference time source, and measures time deviation of the local clock from the reference time value. The timing circuitry determines an adjustment value to apply to the VCO over a time interval during which the reference time receiver is not powered on. The adjustment value is selected to gradually bring the local clock into synchronization with the reference time source over the time interval at a time that the reference time receiver is to be next powered on.

A seismic data acquisition unit includes circuitry to detect and digitize a seismic signal, and timing circuitry to control a time of acquisition of each sample of the seismic signal. The timing circuitry include a voltage controlled oscillator (VCO), a local clock incremented by the VCO, and a reference time receiver. The timing circuitry powers on the reference time receiver to generate a reference time value based on signals received from a reference time source, and measures time deviation of the local clock from the reference time value. The timing circuitry determines an adjustment value to apply to the VCO over a time interval during which the reference time receiver is not powered on. The adjustment value is selected to gradually bring the local clock into synchronization with the reference time source over the time interval at a time that the reference time receiver is to be next powered on.

This invention provides a system apparatus and method for ship-towed deployment of a non-linear volumetric array of hydrophones, allowing line-intersect or line-transect sampling of marine mammal populations through passive acoustic monitoring, enabling unambiguous real-time three-dimensional localization of single sounds received through a low-cost, modular, robust, stable, small, light, neutrally to slightly negatively buoyant volumetric array having low self-noise and low flow noise, that avoids putting high tension on the tow cable and that is compatible with standard hydrophones, instrumentation, cabling, and analytical software.