A practical implementation of subsalt Marchenko imaging with a Gulf of Mexico data set

Abstract

Marchenko redatuming allows one to use surface seismic reflection data to generate the seismic response from sources at the surface to any point in the subsurface. Without requiring much information about the earth’s properties, the seismic response generated by Marchenko redatuming contains accurate estimates of not only the primaries but also the internal multiples. A target-oriented imaging method, referred to as Marchenko imaging, was implemented for imaging complex structures of the earth using the seismic response obtained through Marchenko redatuming. Taking account of the contribution of primaries and internal multiples, Marchenko imaging produces images that contain fewer artifacts than the images obtained using conventional imaging methods (e.g., reverse time migration) with the same input data. In this study, we applied Marchenko imaging to a field data set acquired at the Gulf of Mexico to produce an image of a subsalt area. We investigated two important and practical aspects of the Marchenko framework: (1) the missing near offsets in marine shot records and (2) the calibration of the reflection data. Finally, we suggested a workflow for processing the marine towed-streamer field data set acquired at the Gulf of Mexico, and we have developed a complete theoretical and practical framework to produce a target-oriented subsalt image using the Marchenko methods. The images obtained from Marchenko imaging are consistent and comparable, for the most part, with conventional migration methods. However, Marchenko imaging achieves improvements in the continuity of the geologic structures and in suppressing the artifacts that are caused by internal multiples.