c g x E n e r g y I n c

	Onshore \| Microseepage

	Visible seeps of hydrocarbons have been reported in the Berbice Block, even though surface conditions are such that few would be expected. Extensive thickness of very porous and permeable sands at surface enables ground water from abundant rainfall to disperse what would otherwise have been a visible show. In addition, visible seeps have often migrated laterally over long distances.

	Several technologies can measure minute traces of hydrocarbon microseepage to identify the possible presence of hydrocarbon reservoirs. Hydrocarbons trapped at depth leak in varying but detectable quantities to the surface. A geochemical anomaly at surface represents the end of a petroleum migration path, often with little areal dispersion from an underlying trap. Surface geochemical expression takes many forms:
		Anomalous hydrocarbon concentrations in sediment, soil, water and the atmosphere
		Microbial anomalies
		Anomalous non-hydrocarbon gases like helium and radon
		Mineralogical changes such as calcite, pyrite, uranium, elemental sulphur and certain magnetic iron oxides and sulfides
		Clay mineral alterations
		Geobotanical anomalies
		Altered acoustical, electrical and magnetic properties of soils and sediments

	Microseepage Model

	Hydrocarbon migration from reservoir traps induces chemical, mineralogical and biological changes at surface. ON used GeoMicrobial Technologies (GMT), whose low-cost process searches for microseepage by measuring the concentration of microbes that thrive on butane. We also used the sorbed soil gas method to directly measure hydrocarbons. It's a quantitative determination of methane (C1), ethane (C2), propane (C3), butane (C4) and heavy components (C5) sorbed to soil particles or within soil cements. The sorbed gas anlysis confirmed the hydrocarbons were from a thermomagnetic source, such as the Canje source kitchen, rather than a biogenic source, such as the decay of near-surface organic material. Staatsolie is using Gore Technologies, the same company that developed Goretex, to directly identify seepage of specific released hydrocarbons.



	Microbial Soil Sampling (MOST) is easily done in most terrains. All samples are checked at day's end to maintain quality control and prepare for subsequent stabilization for the trip to analytical labs in Ochelata, Oklahoma.