Using drill-bit noise to create a seismic image while drilling promises valuable real-time information. The technique can locate the bit on a surface seismic section and provide instant check-shot data. Yet, seismic-while-drilling service has so far failed to take off. We look at two new developments that may help the technique succeed.
Looking for new hydrocarbons in frontier areas, geologists and geophysicists use every trick in the book-plate tectonics, magnetic and gravity data, plain old geological horse sense and lots of seismic data. We follow an interpretation team as they pick their way through a seismic survey shot in offshore Congo, searching for those areas-the plays-that show the greatest promise.
Today explorationists are finding reservoirs that just a few years ago escaped detection. Massively parallel computing, expanded seismic workstation capabilities, and faster data processing methods are turning former blind spots into new prospects. Here is an introduction to structural imaging, one of the fastest evolving seismic techniques.
In addition to a structural and stratigraphic interpretation, seismics offers the possibility of identifying pore fluid. Fluids are determined by analyzing how seismic reflection amplitude varies with shooting offset, a technique called AVO. With synthetic and real examples, we show how AVO works. We then review the processing and interpretation challenges geophysicists must still address to make the technique reliable.
Until recently, the geologic processes that create reservoirs, source rocks and seals were interpreted as purely local events. Experts now take a more global view, realizing that the processes are cyclical and follow the rise and fall of the oceans. This is the basis for sequence stratigraphy, a global framework for integrating seismic, well log and fossil data. In the right situations, it provides a quantum leap in our ability to interpret seismic sections.
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