TABLE 2 / Sampling and Analytical Methods Used in Geochemical Exploration Surveys
for Oil & Gas, Helium and Mineral (U, Au, Cu, Ni, Zn, etc) Deposits

Sample Media Sampling Method Analyzed For? Analytical Method Comments
Active “Free” Soil Gas Hand probe to a minimum of 100 cm (Figure 2). C1-C4 alkanes and alkenes – methane (CH4), ethane (C2H6), ethylene (C2H2), propane (C3H8), propylene (C3H6 ), iButane (C4H10) and nButane (C4H10) and fixed gases (He, H2, CO2, CO, O2 and N2). Can search for helium, hydrocarbon and radon seeps with field portable analytical tools (see Figure 3) to map faults and to focus soil gas sampling. In the laboratory, C1-C4 alkanes and alkenes are analyzed by “Flame Ionization Detection – Gas Chromatography (GC-FID) and fixed gases are analyzed by “Thermal Conductivity Detection – Gas Chromatography (GC-TCD) and “Mass Spectrometry (MS)“. Very uniform sample media for searching for oil and gas, helium and mineral deposits (U, Au, Cu, Ni, Zn etc.). Works best in arid- to semi-arid climates with low water tables.
Soils Collection of soils at minmum depth of 50 cm with auger or spade (Figure 2). Analysis of acid-extractable and/or headspace gas for C1-C5 alkanes and alkenes – methane (CH4), ethane (C2H6), ethylene (C2H2), propane (C3H8), propylene (C3H6), iButane (C4H10) and nButane (C4H10) iPentane (C5H12) and nPentane (C5H12) and C6-C24 aromatic hydrocarbons (Figure 4). C1-C5 alkanes and alkenes are analyzed by “Flame Ionization Detection – Gas Chromatography (GC-FID) and C6-C24 aromatiocs are analyzed by Synchronous Scanned Fluorescence (SSF – see Figure 4). Method used in areas with high water tables and uniform soil cover when searching for oil and gas and mineral deposits (U, Au, Cu, Ni, Zn etc.).
Shot-hole Sediments Collection of sediments during drilling of shot-holes with an air-rotary drill (Figure 2). Acid-extractable (Occluded) and/or headspace (Sorbed) gas are analyzed for C1-C5 alkanes and alkenes including methane (CH4), ethane (C2H6), ethylene (C2H2), propane (C3H8), propylene (C3H6), iButane (C4H10) and nButane (C4H10) iPentane (C5H12) and nPentane (C5H12); Organic solvent extracts are analyzed for C6-C24 aromatics. Acid leachates can also be anlyzed for 63 major and trace elements. Acid-extractable (Occluded) and/or headspace (Sorbed) gases are analyzed for C1-C5 alkanes and alkenes by “Flame Ionization Detection – Gas Chromatography (GC-FID); Organic solvent extracts are analyzed for C6-C24 by Synchronous Scanned Fluorescence (SSF – see Figure 4); Acid leachates are analyzed for 63 major and trace elements are analyzed by Inductively Coupled Plasma Emmission Spectroscopy and Mass Spectrometry (ICP-ES/MS). Method used in conjunction with seismic surveys when searching for oil and gas deposits. Allows profiles of geochemical variables to be superimposed on seismic sections.
Lake Sediments Collection of lake bottom sediments with a gravity corer from at least 50 cm below the lake floor (Figure 2). Analysis of headspace gas for C1-C5 alkanes and alkenes – methane (CH4), ethane (C2H6), ethylene (C2H2), propane (C3H8), propylene (C3H6), iButane (C4H10) and nButane (C4H10) iPentane (C5H12) and nPentane (C5H12). Acid leachates can also be anlyzed for 63 major and trace elements. C1-C5 alkanes and alkenes are analyzed by “Flame Ionization Detection – Gas Chromatography (GC-FID). Acid leachates are analyzed for 63 major and trace elements are analyzed by Inductively Coupled Plasma Emmission Spectroscopy and Mass Spectrometry (ICP-ES/MS). Method used in regional geochemical surveys for oil & gas and mineral deposits (U, Au, Cu, Ni, Zn etc.) in remote areas with uniform lake cover (e.g. northern Canada). Large areas can be covered on a daily basis with helicopter support.
Shale Cores Collected while drilling of the well. Polar and non-polar solvent extracts of crushed core samples are C8-C40 alkanes by GC-FID and C6-C24 aromatics by SSF. Polar and non-polar solvent extracts of crushed core samples are C8-C40 alkanes by “Flame Ionization Detection – Gas Chromatography (GC-FID) for C6-C24 aromatics by Synchronous Scanned Fluorescence (SSF – see Figure 4). Method used as an inexpensive tool for estimating relative amounts of “mobile and non-mobile” oil in shale reservoirs.
Groundwater Collection of groundwater from domestic and sock water wells and from natural springs using USGS NAWQA water sampling protocols (Figure 2). Dissolved C1-C4 alkanes and alkenes – methane (CH4), ethane (C2H6), ethylene (C2H2), propane (C3H8), propylene (C3H6), iButane (C4H10) and nButane (C4H10) and dissolved fixed gases (He, H2, CO2, CO, O2and N2); Analysis for major and trace elements. Dissolved C1-C4 alkanes and alkenes are analyzed by “Flame Ionization Detection – Gas Chromatography (GC-FID) and dissolved fixed gases are analyzed by “Thermal Conductivity Detection – Gas Chromatography (GC-TCD) and “Mass Spectrometry (MS)”. Major and trace elements by Inductively Coupled Plasma Emmission Spectroscopy and Mass Spectrometry (ICP-ES/MS). Very uniform sample medium for oil & gas and mineral exploration surveys provided there is sufficient access (i.e. to water wells and springs) to groundwater for sampling.
Vegetation Tissue Collection of twigs, and leaves with pruning shears (Figure 2). Acid-digested vegetation samples (ashed or unashed) are analyzed for 63 major and trace elements. Acid-digested vegetation samples (ashed or unashed) are analyzed for 63 major and trace elements by Inductively Coupled Plasma Emmission Spectroscopy and Mass Spectrometry (ICP-ES/MS). Method used in regional geochemical surveys for oil & gas and mineral deposits (U, Au, Cu, Ni, Zn etc.) in remote areas with uniform vegetation cover (i.e. same species). Good method for mapping faults and fractures over and around oil and mineral deposits as some plants take up more metals over dilatant structures.