The SEAM Phase I Subsalt Earth Model is a 3D representation of a deepwater Gulf of Mexico salt domain, complete with fine-scale stratigraphy and fluid-filled reservoirs. The model measures 35 km east-west by 40 km north-south by 15-km depth. A pictorial overview of the model is shown in file PhIEarthModelReport_Day_ AM2009.ppt, which was presented at the SEAM workshop in October 2009.
SEAM’s mission is to produce earth models and simulations on those models to advance the state of the art in multiple disciplines over a multiyear period. Phase I pushed the limits of model building. The model is not only large, but it also is highly complex with realistic faults, overturned beds, overhanging salt, density diffractors to generate diffracted multiples, turbidite fans, and braided stream channels reservoirs. Some compromises had to be made due to limitations of model-building tools available. (See “Model Construction Methodology” for details.) There was some limited progress in this area during Phase I, but much more could be done. We tried to make the best model we could for the SEAM project, given the limitations in hardware, software, and time available. The following sections point out the areas where compromises were made and where there are open areas for development. There is a joke about cabinetmakers that goes something like this: The difference between a professional and an amateur is that the professional does not point out his mistakes in a project. If our goal as an industry is to learn and improve, then we need
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SEAM Phase I: Challenges of Subsalt Imaging in Tertiary Basins, with Emphasis on Deepwater Gulf of Mexico
“SEAM is a collaborative industrial research effort dedicated to largescale, geophysical numerical simulation projects. The projects are designed to provide the geosciences exploration community with earth models and simulated data that represent significant geophysical challenges of high business value to the petroleum resource industry. The Phase I project produced a deepwater subsalt earth model designed to capture as much physics and realism as possible in a 3D model that was relevant to oil and gas exploration. The 3D model covers a 40 õ 35 õ 15 km area and includes a complex salt intrusive in a folded Tertiary basin. The primary deliverable was the seismic data set of variable density acoustic simulations consisting of 200 TB of uncompressed traces for over 60,000 shots. Also delivered to the participants were several smaller compressed subsets of these data (“classic” data sets) intended for easier handling, simpler distribution to third parties, and easier comparison of imaging tests results. This report covers how the prime objectives of Phase I were met. Details are outlined in chapters on Model Development, Numerical Design and Vendor Qualification, Acquisition Design, Production Simulations, Quality Control, and Data Storage and Distribution.”