Interpretation of Nonisothermal Step-Rate Injection Tests

Abstract

Injection tests are a common method of obtaining well and reservoir data in geothermal wells. Invariably the temperature of the injected fluid is different than that of the reservoir fluid. Because of the strong temperature dependence of fluid viscosity, and to a lesser extent, fluid density, nonisothermal related pressure transients must be considered to correctly interpret the data. single rate nonisothermal injection have shown that the pressure transients can be classified by one of two cases: 1) a moving thermal front dominated problem or 2) a composite reservoir problem. Analysis methods to determine the. permeability thickness of a reservoir and the skin factor have been developed for both of these cases by Benson and Bodvarssoní. paper discusses the extension of these methods to step-rate injection tests and proposes a new method for tracking thermal fronts in injection wells.