| Abstract |
Before Wairakei Geothermal Field was liquidwith a near-hydrostatic pressure gradient, 260 C, flowed up fissures and intersected the boiling point curve at about depth. temperatures at shallower depths. hydrothermal fluid mixed with cold meteoric water in deposits. tho Formation prevented infiltration of surface waters to greater depth. emerged in topographic l o w s Geyser Valley, Lower Waiora Valley, and along the Waikato River), whereas the separated steam to emerge in topographic (and highs the Upper Waiora and thermal areas.) A small -pour-dominated zone, along tho jointed upper surface of a rhyolite sill in the of Pield, may have fed the Blowhole") in the Karapiti Thermal Area. Water, at Saturation conditions controlled aquifer 100 to 200 depth, the the underlying lacustrine mudstones of water from the deep system When exploitation began in 1951, the natural hoat flow from the Field was 430 borefield exceeded the natural heat flow in 1955, and increased to a of 2800 MW during 1964. 1650 today. Heat through walls in the production It has subsequently declined to about |