Japan Geoscience Union Meeting 2021

Presentation information

[J] Poster

S (Solid Earth Sciences ) » S-CG Complex & General

[S-CG44] Petrology, Mineralogy & Resource Geology

Sun. Jun 6, 2021 5:15 PM - 6:30 PM Ch.15

convener:Koichi Momma(National Museum of Nature and Science), Yu Nishihara(Geodynamics Research Center Ehime University), Tatsuo Nozaki(Submarine Resources Research Center, Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology), Nobutaka Tsuchiya(Department of Geology, Faculty of Education, Iwate University)

5:15 PM - 6:30 PM

[SCG44-P10] Experimental study on propagation of elastic wave in supercritical geothermal reservoirs

*Katsuya Mizuno1, Noriyoshi Tsuchiya1, Nobuo Hirano1 (1.Tohoku university)

Keywords:Supercritical fluid, Supercritical geothermal reservoirs, Elastic wave

Elastic wave velocity of rocks have been applied to the exploration of geothermal resources in geothermal development or the understanding of underground structures. Many laboratory scale studies have been conducted on elastic wave velocity measurements of rocks used to interpret seismic data measured in the field, but most of them were conducted under room temperature and pressure. However, Since the physical properties of rocks has changed by temperature and pressure, it is important to measure the elastic wave velocity of rocks under the in situ high temperature and pressure conditions of underground in order to achieve more accurate geothermal resource exploration. J.W. Spencer Jr & A.M. Nur, (1976), H.B. Morta & F. Wuttke, (2016) has measured elastic wave velocity in supercritical conditions of granite and amphibolite, respectively. In order to develop geothermal energy in more deep-seated regions in the future, elastic wave velocity measurements for other rocks will be necessary. The purpose of this study is to provide a new interpretation of seismic data through the measurement of elastic wave velocity of rocks under supercritical water conditions.

In this study, we started by measuring the elastic wave velocity of water as a function of temperature in order to prove that the elastic wave measurement data obtained from the experimental system for in situ measurements is correct. Then we measured the elastic wave velocity for gabbro, which is universally present in the lower crust, and compare it with the data for granite measured under the same conditions.



References



James W. Spencer Jr., Amos M. Nur, The effects of pressure, temperature, and pore water on velocities in westerly granite, JGR Vol.81, Issue5, 10 February 1976, 899-904



H.B. Morta & F. Wuttke, Temperature dependence of elastic P- and S-wave properties of rocks: Applications to geothermal reservoir evaluation, Energy Geotechnics (2016), 311-316