Pilot test of carbon dioxide (CO2) injection into a saline aquifer has been conducted under cooperation of Research Institute of Innovative Technology for the Earth (RITE) and Engineering Advancement Association of Japan (ENAA) in Nagaoka-City, 200km north of Tokyo. One injection well and three observation wells were drilled in the site. Totally 10405 ton of CO2 was injected into the aquifer. In order to grasp the movement of CO2 and to evaluate properties of the aquifer for simulation study, several kinds of well tests have been carried. Tests include three water production tests and two step rate tests for the purpose of evaluation of permeability of the aquifer and injectivity of the injection well, spinner survey in order to investigate injection profile of the perforated interval of the injection well and formation fluid sampling and their analysis so as to see fluid distribution in the formation behind the observation well. With these tests, CO2 movement was clearly understood and several formation properties were quantified and introduced to the simulation model.
