Development of Techniques to Create and Estimate Multifractures at the Akinomiya Site, Japan

Abstract

CRIEPI has proposed some new techniques to create and estimate man-made fractures in the hot dry rock since 1986. A hydraulic fracturing operation with Casing Reamer Sand Plug (CRSP) method was performed at Akinomiya site in Japan in a well at depth of about 400m in 1987. The distribution of Acoustic Emission(AE) indicated the growth of a set fracture sloping downward toward N45?W at about 45?NW inclination. Three(3) fractures (1 or 2mm in width) on the inside wall of the well could be observed by using a Borehole Television Scanner (BTVS) system. The strike and the inclination of these fractures were consistent with the distribution of AE. These results gave suggestions that CRIEPI's techniques may be proper to make a multi fracture system at different depth in a well and would be necessary for the geothermal energy extraction system.