Attenuating water-column multiples with 3D SRME has become common practice, but interbed multiples are not attenuated with this technique since these multiples do not reflect from the free surface. Interbed multiples are often reflected between closely spaced events, giving them an effective velocity very similar to primary events. Because there is little moveout discrimination, interbed multiples do not respond to Radon multiple attenuation or other moveout-based techniques. Extending the concept of SRME to predict interbed multiples is not a new idea, but the 3D implementation was not widely applied until recently. The increase in available computing power has made 3D IME (interbed multiple elimination) a viable option. This paper will discuss a synthetic data set, a Gulf of Mexico marine data set, and an Egyptian Western Desert land data set. Attenuating interbed multiples is an important issue in exploration, especially in the Middle East, where this type of multiple is particularly problematic because the anti-multiple tools based on velocity differences do not work well in this geologic setting. In the salt provinces, attenuating interbed multiples is of particular importance as their presence greatly inhibits interpretation. In addition, removing this class of multiple is very helpful in understanding dirty salt.
Many seismic acquisition surveys today have some form of customization and specialization to reduce cost, address operational issues, or efficiently resolve a difficult geologic objective. This trend has been clearly aided in the recent past by the following: 1) Acquisition systems are more flexible and provide capability to specialize, 2) Geologic and reservoir objectives are getting more demanding and diverse, and 3) Geophysicists have more experience and expertise with acquisition opportunities. This trend of specialized acquisition will probably accelerate in the future because of: 4) Better processing tools that allow for very irregular and non-uniform acquisition, & 5) New processing tools that benefit from specialized acquisition, and 6) Better risk management tools by companies to accept unconventional acquisition. The recent discussions on "compressive sensing" shares strong parallels with specialized acquisition. Both perspectives try to find the best acquisition compromise between cost, geologic resolution, noise, and operational restrictions. Both perspectives rely on using advanced processing for successful imaging with unconventional acquisition. Modifying seismic acquisition based on the performance of new processing tools adds risk and should be done cautiously for this expensive process. But, there is a lot to be gained from finding the best acquisition compromise. Not only can costs be significantly lower, but key geologic & reservoir objectives can be resolved. The new processing methods significantly alter the considerations for the best compromise. Better risk management consideration by companies and some new aggressive risk analysis tools will aid the adoption of these specialized, unconventional acquisition & processing approaches.
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