Wairakei-Tauhara Pressure Regime Update

Abstract

Information from wells drilled over the last five years at Wairakei and Tauhara, together with continuous pressure monitoring has provided new insights into the pressure regimes and interconnections between Wairakei and Tauhara. Continuous pressure monitoring using capillary tubing has allowed simultaneous observations of pressure responses in several wells. This information has significantly improved the understanding of both fields. This new information confirms the long-term pressure trends observed in both systems, with the Tauhara pressure regime approximately 5 bars higher than Wairakei. The new data was also used to develop isobar contours across both systems, which together with the information from the continuous pressure monitoring, indicates that the Tauhara pressure regime extends northwest as far as Karapiti. Wells that were once considered to be part of the Wairakei system can now be considered part of Tauhara based on their pressure regime. The results also suggest a connection between Karapiti South and Tauhara, and challenge the “traditional” concept of the two systems being separated by the Waikato River.