TRACER MONITORING BY A FIBER-OPTIC FLUOROMETER DURING A LONG-TERM CIRCULATION TEST AT THE HIJIORI HDR SITE

Abstract

A long-term circulation test has been started on 25 November 2000 at the Hijiori hot dry rock (HDR) test site. At the beginning stage of the test, two tracer experiments were conducted by NIRE to evaluate flow regime in a deep reservoir at a depth of 2,200 m and Japan Petroleum Exploration Co to validate the effectiveness of two-phase tracers. During the experiments, production fluids were continuously monitored by a fiber-optic fluoremeter to obtain real time data of fluorescein tracer concentration. We succeeded to obtain a good response curve at the second attempt after a minor modification of a flow cell. Result of two tracer experiments suggests that the volume of flow path between an injection well HDR-1 and a production well HDR-2 rapidly increased during the beginning stage of the circulation test.