In general, organic sediments buried in depths of 1,000 m to 6,000 m (at temperatures of 60 °C to 150 °C) generate oil, while sediments buried deeper and at higher temperatures generate natural gas. The deeper the source, the "drier" the gas (that is, the smaller the proportion of condensates in the gas). Because both oil and natural gas are lighter than water, they tend to rise from their sources until they either seep to the surface or are trapped by a non-permeable layer of rock. They can be extracted from the trap by drilling.
The largest natural gas field is South Pars/Asalouyeh gas field, which is shared between Iran and Qatar. The second largest natural gas field is located in Novy Urengoy, Russia.
Offshore gas fields
Like oil, natural gas is often found underwater in offshore gas fields such as the North Sea, Corrib Gas Field off Ireland, and the Scotian Shelf near Sable Island. The technology utilized to extract and transport offshore natural gas is different from land-based fields in that a few, very large, rigs are usually used, due to the cost and logistical difficulties in working over water.
See also
General
Offshore aspects
References
- Hyne, Norman J. (2001). Nontechnical guide to petroleum geology, exploration, drilling, and production (2nd ed.). Tulsa, Oklahoma: PennWell Corporation. ISBN 0-87814-823-X
External links
This article is licensed under the GNU Free Documentation License.
Last updated on Saturday June 07, 2008 at 14:56:13 PDT (GMT -0700)
View this article at Wikipedia.org - Edit this article at Wikipedia.org - Donate to the Wikimedia Foundation
Copyright © 2008, Dictionary.com, LLC. All rights reserved.