New Theory Predicts Location Of Oil And Gas Reserves
ScienceDaily (Oct. 21, 2007) — Researchers in Stavanger, Norway, have developed a theory which can be important for future oil and gas exploration.
The Golden Zone is the name of a an underground zone where temperatures range between 60 and 120 C. The name refers to a new discovery that 90 per cent of the world's oil and gas reserves are to be found just there.
The theory has been tested and verified against a global database containing 120 000 oil fields under production, This gives geologists a tool that makes it simpler and cheaper to find new offshore oil and gas reserves.
The theory of the Golden Zone has come as a surprise to the petroleum industry. The theory has been developed over a period of ten years by the former senior researcher, now dean, Per Arne Bjørkum at the Faculty of Technology and Science at the University of Stavanger, and the researchers Paul Nadeau and Olav Walderhaug at Statoil.
This tool makes the work easier because the companies can now concentrate their resources on exploration at this temperature range. Outside this interval of 60 to 120 C, particularly above 120 C, the chances of finding oil and gas are much slimmer.
Earlier it was assumed that the formation of oil and gas was related to temperature. The new discovery is that temperature decides where most of the lighter oil and gas is trapped in the reservoirs.
The fact that oil and gas coexist within the same temperature zone is a new discovery and a surprise. Gas is formed at higher temperatures than oil. Consequently it has been a standard rule that there should be more gas than oil the deeper one drilled into the reservoir. The reason why this is not the case is covered by the new theory which predicts that both oil and gas escape through fissures formed at 120 C. But nobody had checked it, Bjørkum says.
Obviously it had to be like that according to the new theory, he says.
Adapted from materials provided by University of Stavanger.