Using Chemically Reactive Tracers to Determine Temperature Characteristics of Geothermal Reservoirs

Abstract

The rates of most chemical reactions are very sensitive to temperature, an this property can be used to measure temperature patterns in geothermal reservoirs. Two approached are considered: reverse flush and flow through. Both of these can indicate thermal drawdown faster than the measurement of produced fluid temperature. The reverse flush approach is more difficult to carry out and gives the earlier indication of thermal drawdown and yields more information when using a single reaction. In both approaches, injecting a suite of reactants can yield bivariate time temperature distributions which give temperature distributions as functions of fluid residence time. Applications to Hot Dry Rock systems are considered throughout this paper. Result of early kinetics studies of candidate tracer reactions also are reported.