Soil Gas Hydrocarbons: A Dual Purpose Tool Towards Perfecting the Search in Petroleum Exploration

Dale A. Sutherland and Eric L. Hoffman
Activation Laboratories Ltd, Ancaster, ON

Soil Gas Hydrocarbons (SGH) is an extractive procedure which releases organic compounds adsorbed on B-horizon soil samples. Soil acts as a long-term collector of organic compounds that migrate to the surface from hydrocarbon based plays. Soil Gas Hydrocarbon surveys are focused on the hydrocarbons in the C5-C18 range, which are very stable. Through analysis of the extracts with Gas Chromatography-Mass Spectrometry, the SGH procedure provides a highly selective and sensitive method which can detect down to the parts-per-trillion (ppt) range. Over 160 specific hydrocarbons are reported for each sample. Survey datasets are typically very clean and easily interpretable.

Geochemical anomalies of hydrocarbons over petroleum bodies have been noted in the literature for several decades. These anomalies may arise through current flows from oxidation-reduction cells involving both hydrocarbon and mineral bodies. Researchers also suggest that hydrocarbons may be able to migrate as microgas bubbles through thousands of metres of cover. SGH has the ability to vector to the vertical projection of a target as well as identify the type of buried target studied through forensically determined signatures. These capabilities have been researched and developed for over 10 years.

SGH surveys have been conducted over several fields in Southwestern Ontario and Southeastern Saskatchewan, Canada, having depth to the play at up to 3,000 metres. Some case studies will be shown in this presentation.