Year: 1978
Type: conference-paper
Abstract: Radon transient analysis is being developed as a method complementary to pressure transient analysis for evaluation of geothermal reservoirs. The method is based on the observations of Stoker and Kruger (1975) that radon concentration in produced geothermal fluids is related to geothermal reservoir type, production flow rates, and time. Stoker and Kruger showed that radon concentrations were markedly different in vapor-dominated and liquid-dominated systems, and varied not only among wells of different flow rate in an individual reservoir, but also varied timewise in individual wells. The potential uses of radon as an internal tracer for geothermal reservoir engineering were reviewed by Kruger, Stoker, and Umana (1977). Also included were results of the first transient test performed with rapid flow rate change in a vapor-dominated field. The results of the next four radon-flow rate transient experiments were summarized by Kruger (1978) in which effects of well interference and startup production in a new well were demonstrated. Four of these first five radon transient experiments have been carried out in vapor-dominated reservoirs at The Geysers in California and Serrazzano in Italy. The systematics of the transients of radon concentration following abrupt changes in flow rate is being evaluated by Warren and Kruger (1978). The fifth test was at the HGP-A well in Hawaii, the first transient test in a liquid-dominated reservoir. Three additional radon transient tests have been carried out, each in a different type of geothermal resource. The first test was in a petrothermal resource, the reservoir created by hydraulic fracturing by LASL in the hot, dry rock experiment in New Mexico. The results of this first 75-day production test of continuous forced circulation, during January-April, 1978, are given by Tester, et al (1978). The results of the radon concentration measurements made during this test are summarized by Kruger, Cederberg, and Semprini (1978). The second test was a second transient test at the HGP-A well in the liquid-dominated reservoir at Pohoiki, Hawaii, and the third test was a second transient test at the Grottitana well in the Serrazzano field at Larderello, Italy. The general observations of these tests are listed in Table 1. A summary of each of these three tests follows. During the LASL hot dry rock flow test, five samples of recirculating production fluid were obtained by wellhead sampling. Two samples were obtained during the following shutin and venting periods of the test, and one sample of makeup water was analyzed during the test.
Authors: P. Kruger, Lewis Semprini, G. Cederberg, Lucas A. Macias
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1605896846