Flow rate decline of steam wells in fractured geothermal reservoirs
Decline curves are commonly used at The Geysers geothermal field to assess the generating capacity of a producing lease. It is generally assumed that wells will initially be drilled using 40-acre (400 m) spacing, with infill drilling used later to provide additional producing wells as needed. It is commonly believed that the final well spacing should not be less than 10 acres (200 m). Decline curves are used with this approach to estimate the number of make-up wells during a project lifetime (up to 30 years), as well as the appropriate plant size (MWe). A rather simple two-dimensional model was used to investigate the factors that control flow rate decline in steam wells. The effects of parameters such as fracture spacing and permeability are considered, as well as the effects of permeability, porosity and initial liquid saturation in the rock matrix. Also, the conventional P/z method that is commonly used in analyzing gas well production is investigated in terms of its applicability to fractured vapor dominated systems.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5986804
- Report Number(s):
- LBL-18439; CONF-850107-10; ON: DE85008681
- Resource Relation:
- Conference: 10. annual workshop on geothermal reservoir engineering, Stanford, CA, USA, 22 Jan 1985
- Country of Publication:
- United States
- Language:
- English
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Decline curve analysis of production data from The Geysers geothermal field
Decline Curve Analysis of Production Data from the Geysers Geothermal Field