Acoustic emission measurement of geothermal reservoir cracks in Takinoue (Kakkonda) field, Japan

Crack extension caused by a shut-down operation in production wells (build-up test) in Takinoue (Kakkonda) geothermal power plant, Iwate Prefecture, Japan, has been successfully measured by an acceleration-sensitive long-distance acoustic emission measurement technique. The distribution and activity of subsurface cracks in a geothermal reservoir can be determined by the combined procedure of the pressure build-up test and AE measurements. The feasibility and importance of the measurements are demonstrated by AE data and their interpretation.