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Geogas in crystaline bedrock

Abstract

Scientific literature provides conclusive evidence of gas migration through crystalline bedrock and up to the surface. In this paper, a compilation is made of significant observations of geogas. Based on these observations, and on physical and chemical principles, possible models for the behaviour of the gas are analysed and discussed. Thus, at a depth of some tens or hundreds of meters, the partial gas pressure might exceed the hydrostatic pressure, enabling the development of a gas phase. Such gas may form in fissures in the rock of perhaps 0.1 mm width. The gas deposited will attempt to minimize its surface energy. The shape assumed will depend on the geometrical constraints as well as on the specific surface energies between gas and water, gas and rock, and water and rock. For a small bubble, or a bubble of moderate size, these effects can be expected to make the bubble stay in place. The accumulation of gas into the gas pocket will lead to the exertion of pressure onto the uppermost part of the pocket. At some stage of gas accumulation, this pressure will become sufficient for the gas to penetrate upwards through the fissure. As the gas propagates, the hydrostatic pressure  More>>
Authors:
Hermansson, H P; [1]  Sjoeblom, R; [2]  Aakerblom, G [3] 
  1. Studsvik AB, Nykoeping (Sweden)
  2. National Board for Spent Nuclear Fuel, Stockholm (Sweden)
  3. Swedish Geological Company, Luleaa (Sweden)
Publication Date:
Oct 01, 1991
Product Type:
Technical Report
Report Number:
SKN-52
Reference Number:
SCA: 540230; PA: AIX-23:030392; SN: 92000709387
Resource Relation:
Other Information: PBD: Oct 1991
Subject:
54 ENVIRONMENTAL SCIENCES; ROCKS; GAS FLOW; ENVIRONMENTAL TRANSPORT; GEOLOGY; RADIONUCLIDE MIGRATION; UNDERGROUND DISPOSAL; 540230; RADIOACTIVE MATERIALS MONITORING AND TRANSPORT
OSTI ID:
10143551
Research Organizations:
National Board for Spent Nuclear Fuel, Stockholm (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Other: ON: DE92623495; TRN: SE9200028030392
Availability:
OSTI; NTIS (US Sales Only); INIS
Submitting Site:
SWDN
Size:
35 p.
Announcement Date:
Jul 05, 2005

Citation Formats

Hermansson, H P, Sjoeblom, R, and Aakerblom, G. Geogas in crystaline bedrock. Sweden: N. p., 1991. Web.
Hermansson, H P, Sjoeblom, R, & Aakerblom, G. Geogas in crystaline bedrock. Sweden.
Hermansson, H P, Sjoeblom, R, and Aakerblom, G. 1991. "Geogas in crystaline bedrock." Sweden.
@misc{etde_10143551,
title = {Geogas in crystaline bedrock}
author = {Hermansson, H P, Sjoeblom, R, and Aakerblom, G}
abstractNote = {Scientific literature provides conclusive evidence of gas migration through crystalline bedrock and up to the surface. In this paper, a compilation is made of significant observations of geogas. Based on these observations, and on physical and chemical principles, possible models for the behaviour of the gas are analysed and discussed. Thus, at a depth of some tens or hundreds of meters, the partial gas pressure might exceed the hydrostatic pressure, enabling the development of a gas phase. Such gas may form in fissures in the rock of perhaps 0.1 mm width. The gas deposited will attempt to minimize its surface energy. The shape assumed will depend on the geometrical constraints as well as on the specific surface energies between gas and water, gas and rock, and water and rock. For a small bubble, or a bubble of moderate size, these effects can be expected to make the bubble stay in place. The accumulation of gas into the gas pocket will lead to the exertion of pressure onto the uppermost part of the pocket. At some stage of gas accumulation, this pressure will become sufficient for the gas to penetrate upwards through the fissure. As the gas propagates, the hydrostatic pressure will decrease and the volume of the gas will also increase. Eventually, when the surface is reached, a burst of gas may be observed. Four mechanisms have been identified that may describe how heavy elements can be transported from considerable depths to the surface by means of gas: transport through volatile compounds that dissolve in the gas, transport by elements bonded to complexing agents that are surface active and enrich themselves onto the interface between the water and the gas, flotation (bubbles attaching themselves onto particles and lifting them) and transport by aerosols that may form when gas moves rapidly through a fracture in the rock. Finally, the paper makes some recommendations to geoscientists regarding phenomena that it may be fruitful to utilize. (31 refs., 7 figs.).}
place = {Sweden}
year = {1991}
month = {Oct}
}