Statics Solutions
At PGS we have developed a complete range of tools to analyze and solve for velocity anomalies present in the Earth. These tools utilize a basic principle that if one can measure the travel time physically from the data, then one can also construct a model of the velocity structure within the Earth. By estimating the travel time through the model, and then comparing this to the actual travel time, and then based on certain assumptions, update the model to better reflect the actual travel time. This process is iterated and replicated for many possible raypaths, until a solution is reached.
Refraction Statics (STRATUS)
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STRATUS is a PGS proprietary utility that utilizes the timing of refractors measured from the seismic data to construct and update a velocity model of the subsurface.
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Stack sections showing before/after the application of refraction static solutions.
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Stack sections showing before/after the application of high frequency refraction static solutions.
TOMOSTATICS
TOMOSTATICS is a PGS utility that allows for the analysis and solution of complex velocity layering.
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Initial velocity model (left) and the final solution after TOMOSTATICS (right).
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The stacks above show the imaging before (left) and after the application of the TOMOSTATICS solution (right).
Reflection Statics (CUMULUS)
CUMULUS is a PGS proprietary utility which utilizes the timing of reflection events to analyze and solve for surface consistent velocity anomalies.
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The images above are screen captures from the interactive CUMULUS interface.
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The stack images above are before (left) and after (right) the application of CUMULUS reflection statics.
Water Column Statics
In areas where the water column is dynamic, a more complex static problem arises. This is due to the fact that there is no longer a surface consistency to the solution, and instead there is a time dependency. PGS utilizes a proprietary methodology to solve this problem. It has been used successfully on several large 3D surveys.
The solution is broken out into two phases. The first phase analyzes the timing error from the seismic data valume and calculates a correction to be applied to each shot and receiver based on the time it was acquired.
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These diagrams illustrate the nature of the error and its solution. The image on the left is from a Brazil 3D survey. The "bust" in the contours of the water bottom reflection event is evident. The image to the right is a gradient of the same surfaces, which is used to accentuate the seams in the surface.
Once a solution has been determined, it is applied using a dynamic correction which accommodates the differential length of the raypath within the water column as a function of offset and depth.
