Computer Science
Scientific paper
Dec 1986
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1986gecoa..50.2847p&link_type=abstract
Geochimica et Cosmochimica Acta, Volume 50, Issue 12, p. 2847-2853.
Computer Science
1
Scientific paper
Helium isotope ratios in Sacramento basin natural gas wells show a strong mantle signal. The3He/4He ratios range from 0.11 times the atmospheric ratio (0.11 RA) in the Rio Vista field to 2.75 RA in the Moon Bend field, indicating that 1% to 34% of the helium is mantle-derived. 3He/4He versus CH4/4He ratios provide evidence of two-component mixing between crustal and magmatic end-members. Extrapolation of the linear regression line to CH4/4He = 0 gives a hypothetical magmatic end-member 3He/4He ratio of 3.84 RA, half the typical mantle ratio. This indicates that the magmatic end-member may actually represent a mixture of mantle and crustal helium. Gases which deviate from the simple two-component mixture can be explained by addition of pure methane, radiogenic 4He, or a high N2-He component with 3He/4He = 0.6 Ra to 1.0 RA. The CH4/3He ratio of the magmatic end-member remains poorly constrained (0 to 3 × 109) and one cannot rule out the possibility that a significant proportion of the methane in some fields may be of deep-earth origin. However, fields with the highest 3He/4He ratios are associated with buried Plio-Pleistocene intrusives which have up-arched sediments to form hydrocarbon traps. The methane in these fields may have been produced by rapid thermal alteration of the intruded sediment. Elsewhere, the methane appears either to have migrated from deeply-buried sediments in the western basin or to have been produced by local microbial activity.
Craig Harmon
Jenden P. D.
Kaplan Isaac R.
Poreda Robert J.
No associations
LandOfFree
Mantle helium in Sacramento basin natural gas wells does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Mantle helium in Sacramento basin natural gas wells, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mantle helium in Sacramento basin natural gas wells will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1123873