摘要:
A method is disclosed for separating energy resulting from actuating at least two different seismic energy sources from seismic signals. The sources are actuated to provide a variable time delay between successive actuations of a first one and a second one of the sources. The method includes sorting the seismic signals such that events therein resulting from actuations of the first source are substantially coherent in all spatial directions, coherency filtering the first source coherency sorted signals, sorting the seismic signals such that events therein resulting from actuations of the second source are substantially coherent in all spatial directions, and coherency filtering the second source coherency sorted signals.
摘要:
A method for estimating seismic velocities in vertically transversely isotropic media includes generating an initial estimate of vertical interval velocity and interval normal moveout velocity with respect to depth from seismic data. An initial estimate is generated of a first anisotropy parameter with respect to depth. The first anisotropy parameter is related to the interval normal moveout velocity and the interval vertical velocity. An initial estimate is generated with respect to depth of a second anisotropy parameter. The second anisotropy parameter is related to the first anisotropy parameter and an interval anelliptic parameter. A first tomographic inversion is performed with respect to the interval normal moveout velocity and the second anisotropy parameter at a constant value of the first anisotropy parameter until travel time differentials reach minimum values. Layer depths are adjusted with the initial estimate of vertical interval velocity. Using values of the second anisotropy parameter determined in the first tomographic inversion, a second tomographic inversion is performed of interval normal moveout velocity and the first anisotropy parameter with respect to depth. The adjusted layer depths, interval normal moveout velocities and interval vertical velocities are again adjusted and interval anelliptic parameters are calculated from the second tomographic inversion.
摘要:
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.
摘要:
A method for estimating seismic velocities in vertically transversely isotropic media includes generating an initial estimate of vertical interval velocity and interval normal moveout velocity with respect to depth from seismic data. An initial estimate is generated of a first anisotropy parameter with respect to depth. The first anisotropy parameter is related to the interval normal moveout velocity and the interval vertical velocity. An initial estimate is generated with respect to depth of a second anisotropy parameter. The second anisotropy parameter is related to the first anisotropy parameter and an interval anelliptic parameter. A first tomographic inversion is performed with respect to the interval normal moveout velocity and the second anisotropy parameter at a constant value of the first anisotropy parameter until travel time differentials reach minimum values. Layer depths are adjusted with the initial estimate of vertical interval velocity. Using values of the second anisotropy parameter determined in the first tomographic inversion, a second tomographic inversion is performed of interval normal moveout velocity and the first anisotropy parameter with respect to depth. The adjusted layer depths, interval normal moveout velocities and interval vertical velocities are again adjusted and interval anelliptic parameters are calculated from the second tomographic inversion.
摘要:
A method is disclosed for processing seismic data. The method includes prestack depth migrating the seismic data to generate common image gathers using an initial velocity-depth model. Horizons in the migrated seismic data are selected. Residual migration velocity analysis in the depth-offset domain is performed with respect to each selected horizon, and the velocity-depth model is updated based on the residual migration velocity analysis.
摘要:
Marine surveys using vertically oriented sensor streamers. At least some embodiments are vertically oriented sensor streamers where each sensor streamer includes: an elongated outer jacket; a plurality of hydrophones coupled to the outer jacket, each hydrophone of the plurality of hydrophones longitudinally spaced along the outer jacket; a plurality of three-axis motion detectors, each three-axis motion detector of the plurality of three-axis motion detectors longitudinally spaced along the outer jacket; and a plurality of electrodes coupled to the outer jacket, each electrode of the plurality of electrodes longitudinally spaced along the outer jacket, and the plurality of electrodes electrically exposed outside the outer jacket. Other embodiments may also comprise a plurality of electrodes on each sensor streamer, the electrodes for measuring electromagnetic energy.
摘要:
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.
摘要:
Techniques are described for determining particle displacement or particle velocity data from particle acceleration measurements. In an embodiment, an apparatus comprises an interface configured to received particle acceleration data, one or more processors, and one or more storage media. The one or more storage media store instructions for determining one or more of particle velocity data or particle displacement data, based upon the particle acceleration data, by processing the particle acceleration data using a filter that at least approximates a Wiener filter and that uses one or more damping factors selected to provide stability in the presence of noise in the particle acceleration data.
摘要:
Techniques are described for determining particle displacement or particle velocity data from particle acceleration measurements. In an embodiment, an apparatus comprises an interface configured to received particle acceleration data, one or more processors, and one or more storage media. The one or more storage media store instructions for determining one or more of particle velocity data or particle displacement data, based upon the particle acceleration data, by processing the particle acceleration data using a filter that at least approximates a Wiener filter and that uses one or more damping factors selected to provide stability in the presence of noise in the particle acceleration data.
摘要:
A method is disclosed for determining interval anisotropic parameters. The method includes determining normal moveout (NMO) velocities and effective anelliptical parameters from seismic data traces. The NMO velocities are processed to obtain interval NMO velocities. The NMO velocities, effective anelliptical parameters and interval NMO velocities are inverted to obtain the interval anisotropic parameters. In one embodiment, the inversion includes damped least squares. In one embodiment, the inversion is preconditioned.