A Comparison of Two Multiple-tracer Tests Conducted at the Geysers

Two multiple-tracer tests were conducted at The Geysers to evaluate the relative properties of various gas tracers with respect to tritiated water. In this study the geographic distribution of the tracer responses in the two tests are compared. The DV-11 test, which was conducted in 1994, used the chlorofluorocarbon R-13 and SF6. The P-1 test used the newly developed hydrofluorocarbon tracers R134a and R-23, which are five times more soluble than those used in the DV-11 test. The hydrofluorocarbons in the P-1 test displayed similar distributions and duration of recovery to the tritium tracers. The gas tracers used in the DV-11 test, in contrast, displayed somewhat different geographic distributions and shorter recovery times than the tritium tracer. Although the results of the tests may have been biased by the higher superheat in the DV11 area and a short-circuit to an adjacent production well, it seems clear that the hydrofluorocarbons R134a and R-23 are superior to the chlorofluorocarbon R-13 and SF6 as tracers in vapor-dominated systems.