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Deepwater Exploration Geophysics Challenges

Deepwater Exploration Geophysics Challenges post image

Frontier deepwater exploration in the Gulf of Mexico is becoming more difficult as we enter deeper water, much deeper reservoirs and potential under salt. As a result, we are faced with prospects that are supported by little to no amplitude, tiny seismic bandwidth as well as flat amplitude variation with offset (AVO) that sit in high pressure and high temperature environments. Every industry class, talk, symposium and workshop I have attended in the past year present software, workflows and case studies that address happy direct hydrocarbon indicators (Class IIp and III AVO) and merry time-lapse amplitude analysis (4D) in the Gulf of Mexico shelf or the North Sea, West Africa and Northern Australia deepwater where these anomalies are abundant and detectable.

Yesterday, I asked an industry expert on 4D about its application in hard sands, deep sands with flat or Class IV AVO, reservoirs with low to no acoustic impedance contrast and subsalt and FINALLY we started to talk as a group about time shifts and seismic data of low peak frequency. This is where seismic acquisition and processing technology is headed with finer acquisition and processing grid spacing, spectral decomposition and (somewhat) full waveform inversion, but not at the interpretation workflow level because these now address the planning of offset gas wells on land (Poisson’s ratio cubes, Class III, Poisson’s ratio cubes, elastic impedance, ZZZzzzzz).

Some day soon, when the romance with quick-and-easy onshore gas is over, we will re-enter the ultra-deepwater in earnest to pick apart the tiniest of changes in frequency, acoustic impedance and [insert new property here]. Three questions: 1) Who is already doing this and well? 2) Is it worth it, given the cheap cost of computing (plus) and ultimate project economics (minus)? and 3) Are we ready?


1 comment… add one
  • mineralphys May 17, 2013, 12:38 PM

    Many years ago, I gave a talk on the behavior of salt at high pressures and temperatures–density, elastic properties, and strength. A manager for an oil company manager was at the talk, and he gave me his card and said “Let me know when you want to come work with us. Houston is a great place to live.” I was a postdoc, and tempted, but in the end got my current faculty job. I still think about the road(s) not traveled.

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