Radon Transect and Emanation Studies

Abstract

Radon transient analysis has been demonstrated as a means of examining mass transport in geothermal reservoirs (Warren and Wger, 1979). The relationships between observed wellhead radon concentration and emanating power, flowrate, and reservoir volume were explored by Stoker and Kruger (19751, using linear and radial flow conditions, and D'Amore and Sabroux (1976) for the extremes of pipe flow and diffuse flow through the reservoir. Warren and Kruger (1979) extended the analysis of radon concentration transient with abrupt change in flowrate using a conical flow pattern in vapor-dominated systems characterized by a constant boiling front at depth. Analysis of several test cases showed for single flowing wells that the model provided reasonable estimates of reservoir pore volume and permeabilitythickness. However, it was also noted transients in multiple flowing well systems could be more difficult to interpret because of the effects of (1) interference of flow between wells when only one is partially shut in, and (2) changes in emanating power of the reservoir formation due to the resulting pressure changes.