|AIST > Geological Survey of Japan > Geo-Resources & Environment > Geomicrobiology Research Group > Glossary|
Anaerobic oxidation of methane
Methane oxidation mainly occurs in anoxic sediments. Most of the methane produced in the marine sediments is consumed by this process. However, little is still known about the microbes involved in the process.
Depleted oil field
An oil field from which most of the recoverable oil has already been produced. Using current technologies, it is about half of the reservoirfs original crude oil that is economically recoverable. For effective utilization of the remaining crude oil, a new EOR (Enhanced Oil Recovery) technology is to be developed.
A region where there is natural gas underground. It forms by the accumulation of natural gas in folded strata, and often overlaps with oil field. In Chiba and Niigata Prefectures, there are dissolved-in-water type gas fields, whose natural gas is dissolved in the formation water.
Geopollution (subsurface contamination)
Contamination of subsurface air, water, and sediments. Contamination of groundwater is a global environmental problem.
Solid crystal in which molecules of methane are trapped within a clathrate structure of water. It exits under low temperature and high pressure conditions. Many methane hydrate was found in deep marine sediments around Japan.