Oil and Gas Direct Exploration Technology Applied to Integrated Petroleum Systems Studies

Vladimir O. Elias¹, Paul Brooks², Tikae Takaki¹, and Giovanni Toniatti^3
1 HRT-Petroleum, Rio de Janeiro, Brazil
² HRT-Pteroleum,
³ HRT-Petroleum, N/A, Brazil

The integrated studies using geochemical, geological, geophysical and remote sensing data may provide a sharp knowledge of the primary characteristics of Petroleum Systems. In these systems exploration SGE (Surface Geochemical Exploration) technology provides the only means of investigating frontier areas. SGE technology is an important element of integrated studies because provides prediction and characterization of active petroleum systems. The characterization of oil and gas seeps are of great significance in onshore and offshore petroleum exploration and especially in ultra deep water frontier areas. The basic assumption for the use of oil and gas seeps in petroleum prospecting is that hydrocarbons from deep sedimentary sequences can migrate, either directly from source rocks or from reservoirs, to the surface. Geochemical analysis of surface and near-surface sediments in a generative basin should therefore, detect a surface expression of the underlying hydrocarbons. This paper shows examples of the application of SGE technology in the characterization active petroleum system in different basins. The traditional analytical methodology used to identify hydrocarbon seeps includes sample routine screening methods using total hydrocarbon analysis by gas chromatography (GC-FID), total scanning fluorescence (TSF) and headspace measurements. Selected samples are then analyzed by gas chromatography-mass spectrometry (GC-MS) for biomarker identification. Our experience shows that this methodology may not be applied to all basins. In Brazilian offshore areas, for example, microseeps are the main type of hydrocarbon seepage. In these areas microseeps can only be identified by a broader approach using sophisticated high resolution analytical techniques employing sorbed gases, microbiology, gas chromatography, high resolution mass spectrometry-mass spectrometry and diamondoids. The integration of these techniques allows the detection of low-levels of migrated hydrocarbons never detected before and adds critical constrains to old routine screening methods.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005