Abstract: An apparatus, system, and method are provided for interrogating of optical seismic sensors in a seismic cable. According to various example embodiments of the invention, distribution, return, and amplification of optical signals is performed near sensors for improvement of modularity of construction, signal-to-nose ratios, and simplicity of operations.

Abstract: A connector is disclosed for joining two cable ends. The connector includes a load transfer plug adapted to couple to a strength member in each end of the cable. A connector insert assembly is coupled to an inner portion of each load transfer plug. Conductor terminals are disposed in corresponding openings of the insert. The terminals protrude from the insert. An alignment sleeve holder is coupled to one of the insert assemblies. The alignment sleeve holder includes alignment sleeves for receiving the protruding terminals. A housing element is sealingly coupled to an exterior of each of the plugs. The housing elements are adapted to coupled to each other and to urge the connector insert assemblies into contact with each other, and to transfer axial load between the plug coupled to each end of the cable. The housing elements have rotational and axial alignment features on corresponding surfaces. The housing elements are adapted to be removed from the plugs without uncoupling the cable from the plug.

Abstract: A method is disclosed for migrating seismic data. The method includes selecting an image point and generating an initial model of seismic velocity with respect to time. The initial model includes substantially horizontal layers each having a selected interval velocity and a selected thickness. A travel time of seismic energy is determined from at least one seismic energy source position to at least one seismic receiver position, wherein the seismic energy is reflected from the image point. A ray path is estimated from the at least one seismic source position to the image point and from the image point to the at least one seismic receiver position. The ray path is based on the source position, the receiver position and the velocity model at the image location. A two-way travel time of seismic energy through formations to the image point is then determined.

Abstract: A method is disclosed for identifying primary events in seismic data. The method includes sorting the data by frequency so that at least some primary events are separated from non-primary events, thus generating a frequency sorted gather. Amplitudes in the frequency sorted gather above a selected base amplitude are attenuated. The events are then coherency filtered and the attenuated amplitudes are replaced with amplitudes corresponding to the coherent events.

Abstract: A method of updating velocity whereby corresponding reflections are identified from P-P and P-S near-offset waves received from a seismic source and reflected by a subsurface layer to form P-P and P-S depth consistent image gathers. A joint velocity inversion in depth is performed on the P-P and P-S depth consistent image gathers to estimate a vertical depth zo, vertical P-wave velocity vpo, and vertical S-wave velocity vso of the subsurface layer. An isotropic depth migration of P-P depth consistent image gathers is determined based upon the depth zo, P-wave velocity vpo, and S-wave velocity vso to estimate a vertical isotropic depth zpp of the subsurface layer. Anisotropic parameters &dgr; and &sgr; are calculated based upon the depth zpp, P-wave velocity vp0, and S-wave velocity vso. The above steps are repeated, beginning with the joint velocity inversion, until the P-wave velocity vpo and S-wave velocity vso are substantially unchanged.

Abstract: A seismic data set is processed by selecting a set of gathers in the seismic data set. A frequency independent constraint matrix is calculated in a first gather. A model solution in at least one second gather is calculated by using the constraint matrix in a high-resolution Radon transform.

Abstract: In one embodiment the invention comprises a method for receiving an acoustic wavefield beneath the surface of the water in which at least a portion of an acoustic wavefield is received at a first position, at least a portion of an acoustic wavefield is received at a second position, and at least a portion of an acoustic wavefield is received at a third position. The first position, the second position and the third position are triangularly positioned relative to one another. The first position is not directly above or below the second position or the third position, and the second position is not directly above or below the third position.

Abstract: A method is disclosed for marine seismic surveying in which upgoing and downgoing components of a seismic wavefield at a seafloor location, and the seismic wavefield at a seismic streamer location substantially above the seafloor location are determined. The upgoing and downgoing seafloor components and the streamer seismic wavefield are used to determine a separation operator. The separation operator when applied to the streamer seismic wavefield provides an estimate of at least one of an upgoing wavefield component and a downgoing wavefield component of the determined seismic wavefield for the streamer location.

Abstract: A method of migrating seismic data is provided. The seismic data has associated therewith a wavefield at a first level. The method comprises extrapolating the wavefield from the first level to a second level; correcting the extrapolated wavefield; computing intermediate sample points for an output image between the first and the second levels; computing a contribution to the wavefield at each intermediate sample point; and summing the contributions to the wavefield at each intermediate sample point.

Abstract: A method is disclosed for controlling the quality of seismic data acquisition. The method includes generating a scattered acoustic wavefield and receiving at least a portion of the scattered wavefield. At least a portion of the received wavefield is substantially deghosting relatively near the acquisition site. The deghosting includes transforming the received scattered acoustic wavefield into the spatial frequency domain with respect to the in-line and cross-line directions, separating a ghost wavefield from the received wavefield and transforming the separated wavefield into the space-time domain. The quality of the substantially deghosted scattered acoustic wavefield below the surface of the water scattered acoustic wavefield is then evaluated.

Abstract: A method of processing data that uses an angle dependent filter from two-component sensor data allows for attenuation of free surface multiples. Typically, the sensors that are used to produce two-component ocean bottom sensor data are hydrophones and geophones. The method decomposes the recorded dual sensor data into upgoing and downgoing wavefields by combining the recorded pressure at the hydrophone with the vertical particle velocity from the geophone recorded at the ocean floor. Surface multiple attenuation is accomplished by application of an incident angle dependent deconvolution of the downgoing wavefield from the upgoing wavefield. The method uses an angle dependent filter to calibrate the geophone response so that the different coupling of the two instruments and associated noise are taken into account. In a further embodiment, a method of attenuation of multiple reflections in seismic data is provided. The seismic data comprises pressure data and particle velocity data.

Abstract: A method is disclosed for determining compressional (P) wave and shear (S) wave velocities from seismic data acquired using multiple component receivers. The method includes estimating interval velocity of P waves from earth's surface to a first reflector from P wave arrivals in the seismic data. A interval ratio of P wave to S wave velocity is estimated from earth's surface to the first reflector from P-S wave arrivals in the seismic data. An S wave interval velocity is estimated from the estimated P wave interval velocity and interval ratio. A depth is determined from the earth's surface to the first reflector using each of the P wave and S wave estimated interval velocities, the depths to the first reflector estimated using each of the P wave and S wave estimated interval velocities are balanced.

Abstract: The claimed invention is an apparatus, method and system for optimizing bandwidth utilization of demodulators in a system for seismic signal processing, wherein the apparatus comprises demodulators having bandwidths, wherein one demodulator's bandwidth is greater than another demodulator's bandwidth. The apparatus further comprises an optical switch coupled to a fringe rate detector, wherein optical fibers bear seismic signals having fringe rates detected by the fringe rate detector. The optical signals are switched among the demodulators in dependence upon the fringe rates. Further, the claimed invention is an apparatus, method and system for active gain ranging of demodulated signal outputs.

Abstract: A method and apparatus are disclosed for attenuating noise in seismic data including a plurality of input traces. The method includes transforming the seismic data from the space-time domain into the slant-stack domain. Seismic data having a preselected characteristic is excluded when the transforming into the slant-stack domain. The transformed data is inverse transformed from the slant-stack domain into the time space domain. The method and apparatus may include anti-alias filtering the seismic traces. The method and apparatus may include p-anti-alias filtering seismic traces.

Abstract: There is provided a fiber-optic hydrophone having a compliant sensing mandrel coaxial with and adjacent to a rigid reference mandrel. A first optical fiber is wound around the compliant sensing mandrel and a second optical fiber is wound around the reference mandrel. The first and second optical fibers comprise different arms of an interferometer. Flexible sealing members, such as O-rings, seal the compliant sensing mandrel to the hydrophone. One O-ring is disposed near each end of the sensing mandrel. A cylindrical support member is disposed inside the sensing mandrel. At least a portion of the support member is spaced from the sensing mandrel so as to provide a sealed cavity between the sensing mandrel and the support member. The sealed cavity is filled with air or similar compliant substance.

Abstract: In one embodiment of the present invention, a method for processing a scattered acoustic wavefield is provided. The scattered acoustic wavefield is received by at least two receivers. These receivers are offset and located at approximately the same depth. The method comprises transforming the scattered acoustic wavefield to the frequency domain. The method also comprises transforming the scattered acoustic wavefield from the frequency domain to the spectral domain. The method also comprises deghosting the scattered acoustic wavefield in the spectral domain. The method further comprises transforming the substantially deghosted transformed acoustic wavefield to the space-time domain.

Abstract: A method of migrating seismic event data in the presence of a vertically time-varying velocity field defined by a migration velocity function is provided. The method comprises approximating a migration velocity function by constant stepwise stage velocities. The seismic event data is time stretched and is then successively migrated using residual velocities. After the seismic event data is fully migrated, the effect of time stretching is removed by time unstretching the fully migrated seismic event data by a reverse operation to obtain a finally migrated seismic event data.

Abstract: A method is disclosed for attenuating acquisition geometry imprint in seismic data. The method includes raising amplitudes of the data to a predetermined power, calculating weights, selecting a time slice of the seismic data and the weights, scaling the data with the weights, stacking the scaled data, stacking the weights, and dividing the stacked scaled data by the stacked weights.

Abstract: A method for processing three-dimensional seismic data is provided. The seismic data is at least partially the result of receiving a seismic wave with a seismic receiver. At least a portion of the seismic wave is generated by a seismic source. The source and receiver are both horizontally offset and vertically offset. The method comprises binning at least a portion of the seismic data in common reflection point bins. The method comprises sorting the seismic data within the bin to create common reflection point gathers. The method further comprises analyzing velocity, and applying surface consistent statics corrections to at least a portion of the seismic data within said common reflection point gathers. The method also comprises applying a non-hyperbolic normal moveout equation to at least a portion of said seismic data, and stacking at least a portion of said seismic data within said common reflection point gathers.

Abstract: A method of migrating seismic event data in the presence of a vertically time-varying velocity field defined by a migration velocity finction is provided. The method comprises approximating a migration velocity function by constant stepwise stage velocities. The seismic event data is time stretched and is then successively migrated using residual velocities. After the seismic event data is fully migrated, the effect of time stretching is removed by time unstretching the fully migrated seismic event data by a reverse operation to obtain a finally migrated seismic event data.