Online Journal for E&P Geoscientists

Wrigley, Mark J.^*1; Al Jenaibi, Mahfoud ²; Van Laer, Pierre ²; Stolpmann, Holger ¹
(1) Survey Products Group, W.L. Gore & Associates, Inc, Elkton, MD. (2) ADCO, Abu Dhabi, United Arab Emirates.

Down hole geophysics, and 2D and 3D seismic imaging, are some of the tools most often used by petroleum explorationists to find and exploit our hydrocarbon resources. Unfortunately, no single technology or tool has the current capability to answer all of the questions posed by exploration professional; each tool offers its own unique view into the subsurface and, when used together in a complementary fashion, help build a more complete picture of the petroleum system and/or the reservoir.

Amplified Geochemical ImagingSM is a complementary tool that has evolved and advanced the field of surface geochemical exploration. It has been made possible, in part, by modern advances in materials science, analytical chemistry, and computer science, adding another layer of data to the exploration picture that is not available with other techniques. Since the late 1920s, 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 counting microbial populations. 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, and resolve probable sources of the measured hydrocarbon signal

This presentation provides a basic overview of a modern surface geochemical technique, the GORE Survey, an amplified geochemical imaging technique which has overcome the limitations of prior methods. A brief summary of a recent demonstration of the capabilities of this technology near an oil field in Abu Dhabi will be presented.