Light hydrocarbons geochemistry of surface sediments from Pranhita-Godavari Basin, Andhra Pradesh

A geochemical study of surface sediments from Pranhita-Godavari Basin, Andhra Pradesh, India was carried out using light hydrocarbon compounds to assess the hydrocarbon potential of the basin. Suite of 80 soil samples were collected from the depth of 2.5 m and analyzed for adsorbed light gaseous hydrocarbons namely methane (CH 4 ), ethane (C 2 H 6 ) and propane (C 3 H 8 ) in Gas chromatograph. Compound specific Carbon isotope ratios for CH 4 and C 2 H 6 were also determined using GC-C IRMS (Gas Chromatograph Combustion Isotope Mass Spectrometer). The presence of moderate to low concentrations of methane ( : 1 to 138 ppb), ethane ( : 1 to 35 ppb) and propane ( : 1 to 20 ppb) was measured in the soil samples. Carbon isotopic composition of ranges between −27.9 to −47.1 ‰ and ranged between −36.9 to −37.2 ‰ (V-PDB) indicating that these gases are of thermogenic origin. Study of soil samples suggests the area has good potential for hydrocarbon.