Abstract: A one-pass centrifuge separator for mixtures of two liquids which may also contain gas. The centrifuge uses separation zones on a rotor's inner wall to improve separation efficiency and minimize turbulent mixing. The zones consist of surface and interface vanes, and baffle plates to control flow at the fluid interface. The zones also retain an open concept to facilitate washing by cleaning fluids which are provided by nozzles installed on a stationary feedpipe mounted along the rotational axis of the centrifuge. A fluid accelerator gradually accelerates the fluid from the feedpipe to the inner wall of the rotor.

Abstract: A method of migrating seismic data using offset checkshot survey measurements. The offset checkshot survey measurements involve raypaths similar to the migration raypaths for the seismic data, and are used to determine direct arrival traveltimes to receivers in a borehole. Embodiments of the invention provide for direct use of the traveltimes in migration, or indirect use of the traveltimes in migration via construction of a migration velocity model. The velocity model embodiments further provide for either traveltime error correction via use of interpolated error functions or construction of migration error tables. The invention can be employed for time, depth or Kirchhoff migration, in either two or three dimension, and in either prestack or poststack applications. The invention may be used to migrate any type of seismic data, including compressional-wave, shear-wave, and converted-wave seismic data.

Abstract: A frequency domain method of processing geophysical data on a computer having massively parallel processors. The method involves assigning data slice partitions to each processor, precomputing a velocity model corresponding to the geophysical data, and migrating the data on each slice within each processor using a one-pass, split wave equation finite difference technique for depth migration and either phase shift or recursive techniques for time migration. A sequence of transforms and transpositions between processors assigned partitions on each frequency slice transforms into the frequency-wavenumber domain and allows the migration calculations to be directly performed by each processor to be independent of each other processor. The transforms and transposes also allow for depth migration error correction and filtering in the frequency-wavenumber domain.

Abstract: A method of determining traveltime fields for use in processing geophysical data. The method is implemented on a computer having massively parallel processors. The input to the method is a three-dimensional velocity model of a volume of the subsurface of the earth. The method assigns the traveltime calculations to groups of processors, which calculate traveltimes for individual shots. A preliminary simulation of the traveltime calculation process is performed to determine the number of processors required in each group. The groups of processors perform the traveltime calculations independent of the other groups. Calculations are performed in spherical coordinates, with traveltimes interpolated to a rectangular grid for storage and subsequent use. The final traveltimes are compressed in a differential format to reduce data storage and transfer requirements.

Abstract: A method of processing seismic data on parallel processors, preferably on a massively parallel processor. The input ot the process is seismic data from one or more of a number of seismic lines. The end product of the invention is a DMO corrected, zero-offset seismic image of the subsurface. By repeating the method on different input offsets, the variation in reflection strength of a reflector as a function of the angle of incidence can be examined. The method includes a two stage parallelization. First, a parallelization over the incoming traces generates a suite of DMO-corrected partial images for each point on each incoming trace. Secondly, a parallelization over output locations accumulates and combines the partial images, and produces output traces.

Abstract: A method of migrating seismic data using offset checkshot survey measurements. The offset checkshot survey measurements involve raypaths similar to the migration raypaths for the seismic data, and are used to determine direct arrival traveltimes to receivers in a borehole. Embodiments of the invention provide for direct use of the traveltimes in migration, or indirect use of the traveltimes in migration via construction of a migration velocity model. The velocity model embodiments further provide for either traveltime error correction via use of interpolated error functions or construction of migration error tables. The invention can be employed for time, depth or Kirchhoff migration, in either two or three dimension, and in either prestack or poststack applications.

Abstract: A method of processing geophysical data on a parallel processor. The method involves decomposition of an analysis cube into depth slices, a second decomposition of a data acquisition cube into traveltime slices, and determination of a variably dimensioned analysis aperture. Precomputed traveltimes are stored in packed format to minimize storage volume and data bandwidths. The method relies on staged access of traveltime fields from high speed mass storage to disk storage and via input/output processors to analysis processor memory. The input/output processors monitor analysis processor memory to optimize the direct scatter download of traveltime fields to the analysis processors. The seismic trace data download is also staged, preferably from tape storage to disk storage to processor memory. A control processor preprocesses the trace data while downloading the trace data from disk storage to processor memory.