Evaluation of geothermal reservoir cracks by shear-wave splitting of acoustic emission

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Geothermics (International Journal of Geothermal Research and its Applications); (United States)

DOI:https://doi.org/10.1016/0375-6505(91)90032-Q· OSTI ID:7239590

Sato, M; Matsumoto, N; Niitsuma, H ^[1]

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1. Dept. of Resources Engineering, Faculty of Engineering, Tohoku Univ., Sendai 980 (JP)

This paper reports that shear-wave splitting of acoustic emissions (AE) was analyzed to obtain a description and evaluation of subsurface cracks in a natural geothermal reservoir. During shutdown operations of production wells in 1984-1986 at the Kakkonda (Takinoue) geothermal power plant, Japan, several thousand, AE events were located with a downhole tri-axial AE sonde. A total of 145 of these events showed shear-wave splitting and they were used to estimate depth and crack density of multiple layers in the reservoir. The shear-wave polarization was used to determine the orientation of the cracks, and crack density was calculated from delays between shear-wave polarization-anomalies. The reservoir was divided into three zones based on observed characteristics of the shear wave splitting. These zones are identified as the injection, production and intermediate zones.

• OSTI ID: 7239590
• Journal Information: Geothermics (International Journal of Geothermal Research and its Applications); (United States), Journal Name: Geothermics (International Journal of Geothermal Research and its Applications); (United States) Vol. 20:5; ISSN GTMCA; ISSN 0375-6505
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150301* -- Geothermal Exploration & Exploration Technology-- Geophysical Techniques & Surveys
150904 -- Geothermal Engineering-- Geothermal Reservoir & Well Performance
ACOUSTIC EMISSION TESTING
ACOUSTIC TESTING
CRACKS
GEOLOGIC STRUCTURES
GEOTHERMAL FIELDS
GEOTHERMAL SYSTEMS
KAKKONDA GEOTHERMAL FIELD
MATERIALS TESTING
NONDESTRUCTIVE TESTING
SEISMIC S WAVES
SEISMIC WAVES
TESTING