Natural gas content of geopressured aquifers
It is hypothesized that free, but immobile, natural gas is trapped in pores in geopressured aquifers and that this gas becomes mobile as aquifer pressure is reduced by water production. Computer simulation reveals this hypothesis is a plausible explanation for the high gas/water ratio observed from the No. 1 sand in the Edna Delcambre No. 1 well. In this Delcambre well test, the gas/water ratio increased from the solution gas value of less than 20 SCF/bbl to more than 50 SCF/bbl during production of 32,000 barrels of water in 10 days. Bottom hole pressure was reduced from 10,846 to 9,905 psia. The computer simulation reveals that such increased gas production requires relative permeability to gas(k{sub rg}) increase from less than 10{sup -4} to about 10{sup -3} due to a decrease in fractional water saturation of pores (S{sub w}) of only about 0.001. Further, assuming drainage relative permeabilities are as calculated by the method of A.T. Corey{sup 1}, initial gas saturation of pores must be greater than 0.065. Means for achieving these initial conditions during geological time will be qualitatively discussed, and the effect of trapped gas upon long-term production will be described.
- Research Organization:
- AIME, Denver, CO
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 891252
- Report Number(s):
- CONF-771153-P1-14; TRN: US200621%%920
- Resource Relation:
- Conference: 3. geopressured geothermal energy conference, Lafayette, LA, USA, 16 Nov 1977
- Country of Publication:
- United States
- Language:
- English
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