Seismic Reflection in the Ohaaki-Broadlands Geothermal Field

Abstract

In 1984 a seismic reflection survey was conducted over the Ohaaki-Broadlands geothermal field. The processing of the resulting data produced a very noisy result, with very few continuous reflectors, and made interpretation extremely difficult. Since then the data has been used as a proof that the seismic reflection method does not work in geothermal fields, because of the complicated geology and energy absorption and channelling in the near surface layers. At the beginning of 1996 I started to reprocess the data and found them to be much maligned. It was difficult to process and required a lot of time, but it can produce a surprisingly good quality final section that does aid in the understanding of the Ohaaki-Broadlands geothermal field. The reprocessed data shows that contrary to popular belief, the seismic reflection method that is commonly used in the Oil Industry does work in geothermal field investigations and can provide good quality data to aid the resource extraction