Amplified geochemical imaging: an enhanced view to optimize outcomes

Harry S. Anderson of W. L. Gore & Associates describes the benefits of amplified geochemical imaging in a variety of context including environmental and oil and gas applications. Before surgeons begin any delicate operation, they use state-of–the-art imaging to afford an enhanced view into the human body. Without question, the accuracy and detail of a CAT scan or MRI increases their chance of a successful surgical outcome. With a resource so precious, who wouldn’t use the best technology? Likewise today’s earth scientists have sophisticated imaging tools available that provide them with the enhanced view they need to focus their efforts, save time and money, and generate more reserves and profits. 3D seismic imaging is the tool we often think of first in petroleum exploration but recent advances have made possible a complementary technique: amplified geochemical imaging. This advanced geoscience tool is used in diverse applications such as environmental site assessment and pipeline integrity management, as well as petroleum and mineral exploration. Since 1930, earth scientists have used surface geochemical techniques to explore for hydrocarbons. These techniques look for the effects of minute levels of hydrocarbons that migrate through the imperfect seals that cover every reservoir and migrate either as macroseepage via faults or as microseepage vertically through the reservoir overburden. (Klusman, 1993, Coleman et al., 1977) Some of these early techniques were crude and included soil analysis, active soil gas analysis, iodine mapping, and microbial counting. Unfortunately, exploration results using these early geochemical techniques were often disappointing. This is a direct result of several fundamental factors: - Inability of the sampling method to cope with heterogeneous soil characteristics including permeability, moisture, and organic content - Heavy losses in compounds due to sampling techniques (Hewitt and Lukash, 1996) - Monitoring indirect effects (like microbes or iodine) rather than direct effects - Poor sensitivity (ppm rather than ppb or ppt) - Severely limited set of compounds not representative of the target (C1-C6 only) - Failure to use statistical tools to clearly differentiate noise from signal