Mixing models for detecting dilution, mixing and estimating reservoir temperature
Mixing diagrams are another way for determining the reservoir temperature, mixing and boiling conditions. The water in many hot springs consists of mixtures of deep hot water and shallow cold water. Partial or complete chemical equilibration may or may not occur after mixing. If chemical equilibrium is established after mixing, the chemical geothermometers indicate temperatures of the mixed water, not the hot water component.
Mixing model has two diagrams; one is silica- enthalpy and the other is an enthalpy-chloride diagram.
The procedure for applying these models is the utilizing a plot of dissolved silica or chloride versus enthalpy, as heat contents (enthalpies) of the cold and warm spring waters and draws a straight line through these points to intersect the quartz solubility in case of silica mixing model. The intersection point of mixing line and solubility curve is the original silica content of and enthalpy of the deep hot water (Fig. 1). The original temperature of the hot-water component is then obtained from steam tables.
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Figure 1 - A sample diagram of Enthalpy – Silica mixing model
Tags: boiling conditions, chemical equilibrium, detecting dilution, diagram of enthalpy, hot springs consists, hot water, mixing diagrams, mixing models, shallow cold water, warm spring waters
