1. Dimitrios Mendrinos Centre for Renewable Energy Sources and Saving
Seismic velocity & rock modulus of elasticity vs temperature in Los Humeros: provisional analysis and methodology
Dimitrios Mendrinos
Centre for Renewable Energy Sources and Saving

2. Background
Dependence of seismic velocities vp and vs to temperature has been known since the 70s and 80s
Johnes et al (1980)
The temperature dependence of vp and vs to temperature has been experimentally verified by lab experiments in Icelandic rocks
Jaya et al (2010)
There have been efforts to establish an empirical Vp-T relationship in geothermal fields
Iovenitti et al. (2013)

3. 1-D Seismic velocity profile in Los Humeros
Vp = 6 km/s at 30 km depth
Data from Urban and Lehrmo 2013

4. 1-D Temperature profile in Los Humeros
Data from Gutiérrez-Negrí and Izquierdo-Montalvo, 2010: boiling-point-to-depth down to 2200 m,
max recorded temperature at 2400 m

5. Seismic velocity correlation to temperature

6. Density profile from Gravity inversion in Los Humeros
Source: Garcia-Estrada, 1992

7. Elastic modulus correlation to temperature

8. Conclusions of 1-D analysis
Provisional 1-D analysis of published data from Los Humeros indicate an exponential relation between seismic velocity and elastic modulus to temperature:
Vp = 0,7392· e0,0049· T, R² = 0,9920
p = 8· 108· e0,0113·T, R² = 0,9868

9. GEMex approach 3-D analysis will be performed
Seismic velocities will be calculated from passive seismic survey carried out by geophysical (seismic) groups
Density profiles will be calculated from gravity survey carried out by geophysical (gravity) groups
Temperature distribution will be calculated by modelling carried out by geology/reservoir groups
Statistical analysis will be carried out by CRES team

10. Calculations scheme ρ μp & μs Passive seismic analysis
Reflection seismic survey
Refraction seismic survey
Gravity survey
Vp & Vs ρ
μp,s = ρ vp,s2
μp & μs

11. Correlations scheme μ T Measured Temperatures Modelled Temperatures
Boiling Point to depth
Conductive
Convective
Activity index
Seismic / Gravity surveys μ T
“μ correlates to T”
statistical evaluation by
linear & non-linear regression
SPSS IBM package
Definition of empirical equations:
linear, polynomial, logarithmic, exponential

12. References
Garcia-Estrada G.H. (1992) “Study for the development of new interpretative criteria for gravity studies of geothermal area – Case study of Los Humeros Pue., Mexico”, Geothermal Resources Council Transactions, Vol. 16, October 1992.
Gutiérrez-Negrí L.C.A. and Izquierdo-Montalvo G., (2010) “Review and Update of the Main Features of the Los Humeros Geothermal Field, Mexico”, Proceedings World Geothermal Congress 2010, Bali, Indonesia, April.
Iovenitti J., Sainsbury J., Tibuleac I., Karlin R., Wannamaker P., Maris V., Blackwell D., Thakur M., Ibser F.H., Lewicki J., Kennedy B.M., Swyer M. (2013) “EGS exploration methodology project using the Dixie Valley geothermal system, Nevada, status update, Proceedings, Thirty-Eighth Workshop on Geothermal Reservoir Engineering Stanford University”, Stanford, California, February 11-13, 2013, SGP-TR-198
Johnes T., Merphy W, Nur, A., (1980) “Effects on temperature and saturation on the effects of velocity and attenuation of seismic waves in rocks: application to geothermal reservoir evaluation”, rock physics project, Department of Geophysics, Stanford University.
Jaya M.S., Shapiro S.A., Kristinsdóttir L.H., Bruhn D., (2010) “Temperature dependence of seismic properties in geothermal rocks at reservoir conditions”, Geothermics 39, 115– 123.
Urban E. and Lehrmo J.F. (2013) “Local seismicity in the exploitation of Los-Humeros geothermal field, Mexico”, Proc. Thirty-Eighth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, February 11-13, SGP-TR-198.