Abstract: A method for determining a fault in a seismic air gun includes comparing a near field seismic signal measured during operation of the air gun to a reference near field signal and determining the existence of a fault in the air gun when a difference between the measured near field signal and the reference near field signal exceeds a selected threshold.

Abstract: Particle motion sensor signals and the pressure sensor signals data from a towed marine seismic streamer are combined to generate an up-going pressure wavefield component and a down-going particle motion wavefield component. The down-going particle motion wavefield component is extrapolated from the receiver position depth level to the source position depth level. The up-going pressure wavefield component is multiplied by the extrapolated down-going particle motion wavefield component, generating a first product. Then, nth order surface related multiples in the pressure wavefield are iteratively calculated utilizing a product of (n?1)th surface related multiple free data and the extrapolated down-going particle motion wavefield component. The calculated nth order surface related multiples are iteratively subtracted from the recorded pressure wavefield, generating the nth order surface related multiple free data.

Abstract: A marine seismic streamer section has at least one strength member positioned in the streamer section, a solid material, which may be a soft compliant solid material, substantially filling the marine seismic streamer section around the strength member; and means for mechanically decoupling the strength member from the solid material.

Abstract: A seismic data acquisition telemetry system includes a seismic vessel including a data recording system thereon. The system includes a seismic data gathering unit in operative connection with at least one seismic sensor. The system includes a first antenna disposed on the seismic vessel and a second antenna disposed on the data gathering unit, at least one of said first and second antennas being directional. Means are included for orienting a sensitive direction of the directionally sensitive antenna toward the other of said first and second antennas.

Abstract: A method for characterizing function of an air gun includes measuring, with respect to time, a parameter related to pressure in a charge chamber portion of the air gun. The measurements with respect to time are used to characterize the function of the air gun.

Abstract: A seismic streamer includes a jacket covering an exterior of the streamer. At least one strength member extends along the length of the streamer and is disposed inside the jacket. At least one seismic sensor is disposed in a sensor spacer affixed to the at least one strength member. An encapsulant is disposed between the sensor and the sensor spacer. The encapsulant is a substantially solid material that is soluble upon contact with a void filling material. A void filling material is disposed in the interior of the jacket and fills substantially all void space therein. The void filling material is introduced to the interior of the jacket in liquid form and undergoing state change to substantially solid thereafter.

Abstract: A marine seismic energy source includes a seismic tow cable configured to be towed by a vessel from one end and at least one seismic source coupled proximate another end of the tow cable. The at least one seismic source is associated with a depth controller. The depth controller is configured to move the seismic source to a selectable depth in a body of water.

Abstract: An electromagnetic sensor cable includes at least one strength member configured to be coupled to a vessel for towing in a body of water and extending along the length of the cable. A jacket covers the strength member and extends along the length of the cable. At least one electrode mounting sleeve is disposed along the jacket and is coupled at its longitudinal ends to one end of a segment of the jacket. The longitudinal ends of the sleeve are configured to mate with a corresponding end of the jacket segment. The sleeve includes a passage therethrough for the at least one strength member. The sleeve includes a mounting surface for a fiber electrode material thereon disposed between the longitudinal ends of the sleeve. At least one electrical contact surface is disposed on the mounting surface. Electrically conductive fiber electrode material is disposed on the mounting surface and is in electrical contact with the electrical contact surface.

Abstract: A method is disclosed for migrating seismic data which includes determining travel time of a compressional wave from a source location to a scatter point, taking into account ray bending. Travel time of a shear wave from the scatter point to a receiver location is determined, taking into account ray bending at the interfaces between subsurface strata. The determined travel times are then used to migrate the seismic data. In one embodiment, the travel times take account of vertically transversely isotropic media with a vertical symmetry axis.

Abstract: A cleaning device for a seismic streamer includes a housing placeable the exterior of the streamer. A turbine is associated with the housing and is configured to be rotationally driven by movement of the streamer through a body of water. A drive element is associated with the housing and is configured to convert rotational motion of the turbine to motive power to move the housing along the streamer. At least one cleaning element is associated with the housing and is cooperatively engaged with the exterior of the seismic streamer. A method for cleaning a streamer includes towing the streamer through the water. Motion of water is converted into motive power to move a cleaning device along the streamer.

Abstract: A paravane for a marine seismic survey system includes a float and at least one diverter operatively coupled to the float. The diverter is configured to redirect flow of water past the paravane with respect to a direction of motion of the paravane through water. The paravane also includes a steering device. The steering device is configured to controllably redirect the flow of water so as to control an amount of lateral force generated by the paravane.

Abstract: A connector for a seismic data acquisition cable includes a molded plastic connector body. The connector body has inserted therein at least one electrical contact for mating with a corresponding electrical contact. The connector body has an internal opening for receiving an electrical cable. The connector body has a mating surface adapted to contact a corresponding connected structure. The internal opening is filled with a curable compound which upon cure forms a substantially interface free bond with the connector body and an external jacket of the electrical cable.

Abstract: Systems and methods are disclosed to construct subsurface images from diffuse seismic energy. Various disclosed system embodiments include multiple seismic sensors that each convert received seismic energy into one or more seismic signals. One or more processor combine the seismic signals to determine a subsurface map. As part of determining the map, the processor(s) systematically focus the array of seismic sensors on each bin in the subsurface volume of interest. In this manner each bin becomes a focal point of the array. For each bin, the processor(s) analyze the seismic wave travel time to each seismic sensor and apply a corresponding time shift to align the seismic signals with a uniform travel time. The time-shifted seismic signals are then combined to determine an intensity value for seismic energy radiating from the focal point. A subsurface map can then be derived from the intensity value as a function of position.

Abstract: A system comprises a plurality of acoustic transmitters, mounted inside the streamers, adapted to transmit broadband signals having low cross-correlation between the signals of different transmitters; a plurality of acoustic receivers, mounted inside the streamers, adapted to receive the signals from the transmitters; at least one processor adapted to cross-correlate the signals received at the receivers with copies of transmitter signals to determine identities of the transmitters of the received signals and to determine travel times of the received signals; and a main processor adapted to convert the travel times to distances between the identified transmitters and the receivers and to determine relative positions of the streamers from the distances.

Abstract: Signals of pressure sensors and particle motion sensors located in marine seismic streamers are combined to generate pressure sensor data and particle motion data with substantially the same broad bandwidth. The noisy low frequency part of the motion signals are calculated from the recorded pressure signals and merged with the non-noisy motion signals. The two broad bandwidth data sets can then be combined to calculate the full up- and down-going wavefields.

Abstract: An optical accelerometer includes means for changing the length of at least one optical fiber in response to acceleration functionally coupled to the at least one optical fiber. The fiber and the means for changing length are enclosed in a pressure compensated housing. The housing is filled with a substantially incompressible fluid or gel.

Abstract: Seismic data sets representative of a marine seismic streamer survey are constructed with test coverage holes in the data sets. The data sets are processed and data quality degradation in the processed data due to the test coverage holes is evaluated. Maximum acceptable coverage holes for the survey are determined from the evaluation of data quality degradation.

Abstract: An up-going wavefield and a down-going wavefield are calculated at a sensor position from a pressure sensor signal and a particle motion sensor signal. Then, an up-going wavefield is calculated at a water bottom position substantially without water bottom multiples from the up-going and down-going wavefields at the sensor position. In one embodiment, the up-going wavefield at the sensor position is backward propagated to the water bottom, resulting in an up-going wavefield at the water bottom. The down-going wavefield at the sensor position is forward propagated to the water bottom, resulting in a down-going wavefield at the water bottom. The up-going wavefield at the water bottom without water bottom multiples is calculated from the backward propagated up-going wavefield at the water bottom, the forward propagated down-going wavefield at the water bottom, and a reflection coefficient of the water bottom.

Abstract: A seismic streamer includes a jacket covering an exterior of the streamer. At least one strength member extends along the length of and is disposed inside the jacket. At least one seismic sensor is disposed in a sensor spacer mounted to the at least one strength member. The streamer includes means for retaining the at least one sensor spacer to the at least one strength member. The means for retaining provides substantial acoustic isolation between the at least one spacer and the at least one strength member.

Abstract: Prestack seismic data is imaged by calculating an individual reflectivity for each frequency in the seismic data. Then, a mean reflectivity is calculating over the individual reflectivities. A variance is calculated for the set of reflectivities versus frequency. A second variance is calculated for the upgoing wavefield, using the mean reflectivity. A spatially varying pre-whitening factor is then calculated, using the variance for the reflectivities and the variance for the upgoing wavefield. A reflectivity is calculated at each location, using the spatially varying pre-whitening factor.