Characterizing Feed Zones in Geothermal Fields: Integrated Learnings from Completion Testing, Image Logs and Continuous Core

Abstract

The Wairakei and Tauhara geothermal fields lie within the Taupo Volcanic Zone in the North Island of New Zealand. Both fields are currently utilised by Contact Energy Ltd for electricity generation since the 1950’s. There is a resulting wealth of information in the form of completion testing data including pressure, temperature and fluid velocity profiles which has been the traditional way of understanding feed zones. More recently, this understanding has been enriched by combining it with acoustic formation imaging logs or continuous core. Integrating these two additional datasets refines the understanding of the feed zones which are the ultimate fuel source for power generation. It is critical to enhance the understanding of existing feed zones in order to utilise them more effectively and also for future well targeting.