MICROBIOLOGICAL STUDIES ON PETROLEUM AND NATURAL GAS

VI. MICROFLORA OF NIIGATA AND MOBARA GAS-FIELDS IN JAPAN

Abstract

Microbiological studies on the Niigata and Mobara gas-fields in Japan were carried out. A considerable number of aerobic bacteria, mainly belonging to genus Pseudomonas, were isolated from the gas-brines of a depth of 300m to 800m, but few or no microorganisms were found in depth over 1, 000m. Taxonomic studies revealed that a succession in the microflora took place in the gas wells during the three years from only a few microorganisms to a large number of pseudomonads of the fluorescent group. It was deduced from these facts that large amounts of fresh water may invade into the gas-layers from the outside, and that the water may flow from the north-east to the south-west in the Niigata gas-field. In comparison with the oil-brines, it was interesting that no kerosene-utilizing bacteria or anaerobic sulfate-reducers were found in the gas-brines in the Niigata gas-field. No microorganisms were found in the gas-brines in the Mobara gas-field. The use of bacterial tracers for natural gas mining, as well as for petroleum mining, is suggested.