Abstract: The disclosure provides neutrally-buoyant tools for seismic data collection. The tools may range from several hundred meters to several kilometers in length and have integrated sensors which move along with the borehole fluid in response to a passing seismic wave. The disclosure also provides methods of deploying neutrally-buoyant tools, which includes using a tractor, adding a weight or both to the tool in order to overcome the difficulty of lowering a neutrally buoyant tool into a borehole, and optionally occasionally clamping the tool to the borehole to alleviate tension in the tool. This disclosure also provides methods of acquiring seismic data, which involves positioning a neutrally-buoyant tool in a borehole such that the tool is able to move relatively freely along with the borehole fluid in response to a seismic wave passing through the fluid, firing a seismic source, and using the sensors to collect seismic data generated thereby.

Abstract: A multiple axis sensor assembly includes an enclosure and encapsulated microelectromechanical system (MEMS) sensors. The encapsulated sensors are disposed inside the enclosure and are mounted in different orientations, which correspond to different axes of the sensor assembly. A controller of the sensor assembly is disposed in the enclosure and electrically coupled to the MEMS sensors.

Abstract: A technique includes obtaining first measurements acquired by sensors of a towed seismic streamer, which are indicative of an inclination of the streamer. Based at least in part on the measurements, a shape of the streamer while in tow is determined.

Abstract: A technique includes receiving first data indicative of a pressure measurement and measurements of components of a particle motion vector acquired by sensors disposed on at least one cable; and processing the first data to generate second data indicative of a constructed an in-line component of the particle motion vector. The technique includes processing the first and second data in a geophysical processing operation that relies on at least three components of the particle motion vector.

Abstract: Measurement data acquired by at least one sensor in a cable structure towed through a body of water is received. A torsional vibration noise component in the measurement data is estimated. The torsional vibration noise component is used to estimate a rotation angle of the at least one survey sensor with respect to a reference coordinate system of the cable structure.

Abstract: Apparatus and methods for acquiring seismic data using a seabed seismic data cable positioned on a seabed are described, including correcting for the effect of one or more sensor non-linear motions, which improves accuracy of seismic data. One or multiple non-linear movements of the sensor may be corrected for. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: A technique includes receiving data indicative of acoustic measurements acquired by receivers disposed on a seismic receiver spread including at least one streamer. The technique includes processing the data in a machine to determine a depth and/or shaped of the spread.

Abstract: A seismic sensor module includes sensing elements arranged in a plurality of axes to detect seismic signals in a plurality of respective directions, and a processor to receive data from the sensing elements and to determine inclinations of the axes with respect to a particular orientation. The determined inclinations are used to combine the data received from the sensing elements to derive tilt-corrected seismic data for the particular orientation.

Abstract: According to one or more aspects of the invention, a marine seismic survey method comprises towing at least two streamers below a sea surface forming a survey spread, each streamer comprising a survey sensor and a profiler; and at each profiler, emitting an acoustic signal; recording an echo of the emitted signal at the profiler; and determining a parameter from the recorded echo, the parameter comprising at least one selected from the group of a distance between the profiler and the sea surface, a water current vector and a sea surface slope.

Abstract: A seismic cable for use in land applications is described. The cable includes seismic sensors for measuring seismic signals reflected from subterranean or subsea formations. The cable may be deployed in trenches dug in the survey region to provide adequate sensor coupling to ground. Sensor units may be inline with the cable and may further be disposed in slim casings, thus facilitating handling and deployment.

Abstract: To calibrate an accelerometer, a seismic cable that carries the accelerometer is rotated. Data measured by the accelerometer as the seismic cable is rotated is received, and at least one calibration parameter according to the received data is computed. The at least one calibration parameter is for use in calibrating the accelerometer.

Abstract: A technique facilitates collection and use of data on subterranean formations. The technique comprises creating a distributed sensor network having multiple sensors arranged in a desired pattern. The distributed sensor network is employed to collect seismic data from the multiple sensors. Additionally, the distributed network and sensors are designed to collect gravity data from the multiple sensors. The sensors may be arranged in a variety of environments, including land-based environments and seabed environments.

Abstract: A technique includes designing a streamer, which includes a cable and seismic sensors based at least in part on a relationship between vibration noise and a bending stiffness of the cable.

Abstract: Measurement data is received from first and second seismic sensors, where the first and second seismic sensors are oriented in opposite directions. Each of the first and second seismic sensors has a sensing element responsive to pressure and particle motion. The signals can be combined to remove the particle motion component of the measurement data and obtain pressure-only data. Alternatively, the signals can be combined to deghost the received measurement data.

Abstract: A technique facilitates collection and use of data on subterranean formations. The technique comprises obtaining gravity measurements through the use of seismic streamers. At least one streamer is provided such that each streamer has multiple sensors, e.g. accelerometers. The at least one streamer is towed with a tow vessel, and gravity data are accumulated via the multiple sensors during towing.

Abstract: A technique includes obtaining different sets of data, which are provided by seismic sensors that share a tow line in common. Each data set is associated with a different spatial sampling interval. The technique includes processing the different sets of data to generate a signal that is indicative of a seismic event that is detected by the set of towed seismic sensors. The processing includes using the different spatial sampling intervals to at least partially eliminate noise from the signal.

Abstract: Seabed sensor units, systems including same, and methods for acquiring seabed data are described, one seabed sensor unit comprising a base, the base containing at least one sensor able to detect a seismic signal, electronics comprising a clock and one or more electronic components enabling the sensor to communicate seismic data to one or more memory modules, and a local autonomous power source. This abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: A housing for a seismic sensing element (3) for use on the earth's surface comprises connecting means (5) for connecting the housing (3) to a support cable (2) so as to allow relative movement between the sensor housing (3) and the cable (2). This de-couples the sensor housing from the support cable, and improves the fidelity of the sensor. The connecting means (5) preferably comprises resilient connecting elements, to prevent the transmission of vibrations between the support cable and the sensor housing. The sensor housing (3) preferably has a flat base (1), so that there is good coupling between the sensor housing and the earth. Alternatively, the sensor housing can be fitted with a base member ((24a, 24b, 24c) that has at least one flat face (26, 26a, 26b, 26c).

Abstract: A technique includes disposing a particle motion sensor on a spread of at least one streamer and using the particle motion sensor to acquire a measurement of a signal, which is transmitted from an acoustic transmitter. The technique includes determining a heading of the particle motion sensor based at least in part on the measurement.

Abstract: A technique includes receiving data indicative of a first measurement acquired by a rotation sensor on a seismic streamer and based on the first measurement, estimating a torque noise present in a measurement acquired by a second sensor on the streamer. The technique includes attenuating the torque noise based on the estimate.