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Analysis of Production Decline in Geothermal Reservoirs

Technical Report ·
DOI:https://doi.org/10.2172/6765221· OSTI ID:6765221

Data and analysis methods were gathered from the petroleum, geothermal, and hydrological literature. The data sets examined include: Wairakei, New Zealand -141 wells; Cerro Prieto, Mexico - 18 wells; The Geysers, USA - 27 wells; Larderello, Italy - 9 wells and groups; Matsukawa and Otake, Japan - 8 wells; and Olkaria, Kenya - 1 well. The analysis methods tested were; Arps's equations, Fetkovich type curves, Slider's method for Arps, Gentry's method for Arps, Gentry's and McCray's method, other type curves, P/z vs. Q method, Coats' influence function method, and Bodvarsson's Linearized Free Surface Green's Function method. The conclusions are: (1) The exponential equation fit is satisfactory for geothermal data. (2) The hyperbolic equation should be used only if the data fit well on a hyperbolic type curve. (3) The type curve methods are useful if the data are not too scattered. They work well for vapor dominated systems and poorly for liquid dominated systems. (4) Coats' influence function method can be used even with very scattered data. (5) Bodvarsson's method is still experimental but it shows much promise as a useful tool.

Research Organization:
Zais (Elliot) and Associates, Inc., Corvallis, OR (USA); Oregon State Univ., Corvallis (USA). School of Oceanography
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6765221
Report Number(s):
LBL-11215; GREMP-10
Country of Publication:
United States
Language:
English