Method, source array and seismic vibro-acoustic source element for seismic data acquisition. The number of beams of acoustic energy to be generated for the seismic data acquisition are determined or selected. A different pilot signal is generated for each of the number of beams of acoustic energy. A plurality of drive signals are generated using the different pilot signals. An array of source elements are driven using the plurality of drive signals to generate the two or more beams of acoustic energy.

The present disclosure belongs to the technical field of monitoring landslide mass geological disasters, and discloses a multi-state triggered system and method for remote automatic monitoring and early warning of a landslide mass. The multi-state triggered system for remote automatic monitoring and early warning of a landslide mass includes: a landslide mass monitoring module, a data preprocessing module, a communication module, a central control module, a displacement monitoring module, a stability evaluation module, an abnormality early warning module, a power supply module, a data storage module and a display update module. In the present disclosure, through the displacement monitoring module and the stability evaluation module, long-term automatic monitoring of the landslide mass can be realized, and the displacement change of the landslide mass can be grasped so as to evaluate the stability of the landslide mass.

A method for imaging a wellbore in a spiral wave imaging mode using a phased array ultrasonic radial imaging probe having an annular transducer array comprising a plurality of elements, the method comprising the steps of a) pulsing a first element in the transducer array that forms part of a first sequence of elements, b) pulsing a second element that forms part of the first sequence of elements, c) repeating steps a) and b) for each element in the first sequence with a time delay between steps a) and b), d) receiving signals for each element in the first sequence, e) applying time delays to the received signals to achieve virtual beamforming and form imaging data, f) repeating steps a) to e) for additional sequences of elements in the transducer array, and g) coherently summing the imaging data from each sequence to form a 3D image of the wellbore.

A marine survey acquisition system. The system may include a vessel for towing a marine survey spread. The marine survey spread may include streamers, marine vibrators and a cable. The cable may be coupled to a respective streamer from among the streamers and one of the marine vibrators. The cable may power the respective streamer and the one of the marine vibrators. The one of the marine vibrators may emit energy at a high frequency range.

Source element of a source subarray can be individually actuated according to an actuation sequence. The actuation sequence can be at least partially based on a relative position of each of the source elements within a particular geometry of the source subarray with respect to a previously actuated source element and a towing velocity of the source subarray.

A method for use in marine seismic surveying includes: towing at least a portion of a marine seismic survey spread; imparting a composite swept seismic signal from the marine seismic survey spread, the composite swept seismic signal including a plurality of randomized subsweeps having different frequencies relative to one another and being emitted in parallel; and receiving a respective return for each of the subsweeps.

A method for marine seismic surveying includes separating up-going and down-going wavefields from seismic energy emitted by at least one marine seismic energy source. The separated up-going and down-going wavefields are propagated from the at least one marine seismic energy source to at least one of a water surface and a common reference depth. One of the up-going and down-going wavefields is phase shifted 180 degrees. The propagated, phase shifted up-going and down-going wavefields are summed.

A method for selecting parameters of a seismic source array comprising a plurality of source elements each having a notional source spectrum is described, the method comprising calculating a ghost response function of the array; calculating directivity effects of the array; and adjusting the parameters of the array such that the directivity effects of the array are compensated by the ghost response to minimize angular variation of a far field response in a predetermined frequency range. A method for determining a phase center of a seismic source array is also related, the method comprising calculating a far field spectrum of the array at predetermined spherical angles, and minimizing the phase difference between the farfield spectra within a predetermined frequency range by adjusting a vertical reference position from which the spherical angles are defined.

There is a method for finding a best distribution of source elements that form a vibratory source array. The method includes inputting plural constraints for the source elements; generating plural distributions of the source elements that fulfill the plural constraints; calculating for each distribution a performance index characterizing the source array; and selecting the best distribution from the plural distributions based on a value of the performance index.

During a seismic survey, shots located close to one another are fired at a time interval shorter than an echo time interval and longer than a closest receiver time interval. During the echo time interval which follows a first shot, receivers located within a predetermined distance from the first shot location detect seismic reflections related to the first shot. During the closest-receiver time interval which follows the first shot, at least one seismic receiver located closest to the first shot location detects all the reflections from the first shot reaching this seismic receiver.