Exxon Production Research Company

Pgs Americas, Inc.

Long Don Pham

Sen-Tsuen Chen

Yiu-Wa A Lau

Jianchao Li

Weizhong Wang

Chih-Ping J Lu

A method of migration of a seismic data is disclosed. The data include a data point having an input source location, an input receiver location, and a scatter point associated therewith. The method includes determining a projected source location, and determining a projected receiver location. The seismic data point is mapped from an input travel time to a projected travel time. A pseudo-offset is determined based on the projected travel time and the data point is mapped to the pseudo-offset.

Pseudo-offset migration

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.

Vertical cable time processing

Multiple suppression in geophysical data

A method for determining a substantially optimal NMO velocity function for use in stacking a CMP gather of seismic data traces. The method begins with an initial estimate of the NMO velocity function for the CMP gather. This initial estimate is typically determined through conventional seismic velocity analysis. The method then picks a first velocity-traveltime pair falling on the initial estimate of the NMO velocity function and conducts a two-dimensional interpolative search of trial velocity-traveltime pairs in the neighborhood of the pick to find a substantially optimal velocity-traveltime pair. This substantially optimal velocity-traveltime pair is the trial velocity-traveltime pair having the highest stack response and is substituted for the pick in the NMO velocity function. The method then proceeds to find substantially optimal velocity-traveltime pairs to replace each of the other picks on the initial estimate of the NMO velocity function. Preferably, the two-dimensional interpolative search consists of a one-dimensional parabolic interpolative search to identify the optimal velocity for each computational time within a specified time window, followed by a one-dimensional search to select one of these optimal velocities which, together with its corresponding computational time, becomes the substantially optimal velocity-traveltime pair for the pick in question.

Method for determining seismic velocities

Disclosed is a method of processing seismic data containing multiples, which method generally includes as a step, determining the two-way travel time to a suspected multiple generating event. This method includes the application of a normal moveout operation to the recorded seismic trace utilizing the primary event velocities. Once the normal moveout has been applied to the data, all of the events in the trace are shifted downward in time by an amount of time equal to the two-way travel time to the suspected multiple generating event as previously determined. Once the normal moveout operation and the two-way travel time shift have been applied to the trace, a reverse normal moveout operation is applied to the trace utilizing an extended velocity function, which is a function of the original primary and the velocity within the suspected multiple generating layer. The resulting trace is now a trace containing only multiples. Finally, the multiple noise is subtracted from the original data utilizing an amplitude scaling factor and a residual time shift.

Method of processing seismic data having multiple reflection noise

The orientation of vertical fractures in subsurface rock formations is determined. A cross-dipole logging tool collects four-component shear-wave seismic data through a formation interval of interest in a subsurface formation adjacent a well bore. A gyroscope is typically provided to indicate compass orientation of the logging tool. The collected seismic data are then transformed within a time window containing arrivals of the shear waves to a new coordinate system within which the motion of the shear waves becomes linear. In the new coordinate system, the shear wave data are processed to determine the presence and orientation of fractures in the formation.

Growing community of inventors

Houston, TX, United States of America

Long Don Pham