Assessing the Quantitative Value of Seismic Data in a Mature Production Setting
Authors: Reilly Joseph M. 
Published: July 2010

It is widely accepted that surface seismic surveys are essential to hydrocarbon exploration, development and production. Furthermore, advances in acquisition, processing, computing hardware and theory continue to enhance seismic-image quality. However, since major 3D seismic projects often require large financial commitments, easily reaching $100M's, an investment decision should be based upon a reasonably quantifiable expected value.

In most settings, clearly 2D and 3D seismic data are critical for efficient prospect generation and evaluation during the exploration stage, and a baseline 3D survey can easily be justified for most major development projects. Demonstrating seismic value in these cases is often relatively simple, since the unknowns (or uncertainty) are very large without seismic information, and total project costs generally dwarf the seismic expense. In these situations, the valuation exercise need not be extensive and can leverage the current " best practice?? in a given area; i.e., " same basin, same geology, same project maturity, same seismic solution??.

Similarly, in the appropriate setting, a repeat seismic survey (4D) can be of great benefit in the efficient exploitation of a reservoir. Deepwater West Africa Tertiary clastic reservoirs are one example of a setting in which repeat surveys have a proven record of minimizing development costs and optimizing resource extraction.

Determining whether additional investment in seismic acquisition would provide significant added value late in the life of a field is more problematic. In some cases, reprocessing existing data using recently developed algorithms can mitigate deficiencies in older acquisition technologies and/or design. However, in many instances, reservoir challenges cannot be addressed simply by acquiring a new survey or applying the " most current?? seismic technology to an existing data set. Alternative acquisition and processing strategies must be considered to replace more conventional approaches and/or to prepare the data so that they conform to the physics assumed by our modern imaging algorithms. In other situations, wellbore-based geophysics, passive seismic or other (non-seismic) technologies may be more effective.

The optimum technology usually depends upon the specific reservoir objective. For example, geophysical solutions for monitoring a deepwater clastic reservoir are very different from those required for a shallow-water carbonate reservoir. In these situations it is critical for us to avoid relying upon " faith-based?? assumptions, such as " newly acquired data are always better than existing data??, or " a modern processing flow?? will solve the problem.

To be successful, we must objectively assess the fundamental reservoir problems that need to be resolved and develop a clear and explicit understanding of how additional seismic investment can address those issues. The estimate of future value should be calculated as an addition to the " base case?? scenario, which would include all existing seismic dataset(s) as well as all the available borehole data. This last point is critical, since the new seismic information must effectively " compete?? with information that is already available from direct well measurements and the extrapolation of those measurements into the geologic model. This is perhaps the most difficult concept for the practicing geophysicist to understand and accept.