Injection and production well testing in the geothermal fields of southern Hengill and Reykjanes, SW-Iceland and Theistareykir, N-Iceland

Abstract

In this paper, different approaches and methods are used for analysing well test data. Well testing is performed in order to monitor the pressure response in a reservoir when it is subjected to injection or production. The main purpose is to evaluate the properties that govern the nature of the reservoir, flow characteristics and deliverability of the well. The project emphasis is on well completion and flow test data from Hellisheidi, Reykjanes and Theistareykir geothermal areas. An analysis of data from step-rate injection tests, temperature and pressure profiles was conducted in Hellisheidi, Reykjanes and Theistareykir geothermal areas as well as a discharge test in Reykjanes. Four wells were selected: Wells HE-04, HE-09, RN-28 and ThG-09. Well Tester software was used for the step rate injection test analysis. Temperature and pressure profiles were analysed to estimate the formation temperature and the initial reservoir pressure. The ICEBOX software was applied to get the Horner plot of rock temperature at selected depths in HE-04 and ThG-09 well, using a program called BERGHITI, and the BOILCURVE program was used to acquire the boiling curve. During the production test, measurements were made from which the fluid flow and its energy content were deduced and chemical characteristics were measured. The Russel James method can be used to determine the flow characteristics with a simple weir-box being used to measure the liquid flow.