| Abstract |
An extensive study of the Thermal Shallow Reservoir at The Geysers was performed in 1982 to improve our understanding of the source ana flow patterns of steam in the shallow anomaly and how they relate to the Thermal 4 blowout. This project includea gathering and analyzing pressure transient, enthalpy, tracer and chemical data and developing a reservoir model that was consistent with this data. Following the pressure transient testing and analysis, a convectionplume with lateral-flow model was proposed. Subsequent analysis of enthalpy, tracer and chemical data corroborated this model. The high flowrate wells - Thermal 4, Thermal 10, Thermal 11 and Magma 1 - produce from the high-pressure, high-permeability upflow zone. The source of this upflow is a limited fracture system connecting the shallow anomaly with the underlying main reservoir. The outlying low-pressure, low-permeability wells are supplied by lateral flow of steam from the central area. The pressure gradient from the core to the periphery is caused by condensation in the flanks. |