This work focuses on estimating the mass (M) and energy (E) flow rates, the permeability k, and the relative permeability functions R and R associated with the naturkl verticll flow in the reservoir. To estimate M and E we used the standard 1-D vertical equations for two-phase flow, complemented with boundary conditions at the boiling and dew interfaces. These boundary conditions were derived in an earlier stage of this study that established an approximate 1-D vertical model of the reservoir. The estimated values of M and E were then used together with the previously established liquid saturation vertical profile of the reservoir, and the differential equation expresing the pressure gradient, to fit, by trial and error, the observed natural pressure profile. The accuracy of the fit depends on the assumed value for the vertical permeability and on the chosen forms for the relative permeability functions. We estimated M m- 2 s-l and E 0.2 W m- . These results lie well within the ample ranges of mass and energy flowrates per unit area found in geothermal fields worldwide. The estimated values of M and E support the previous inference that there is an extensive caprock in the reservoir. Our best fit to the natural pressure gradient imp1 ies a vert i ca 1 permeability of about 0.08 mD, residual water- and steam-saturations of about 0.04 and 0.00 respectively, and "fracture relative permeabilities" (i.e., R + =l). This work addresses aL %ajar obstacle for a succsesfull analysis of the Los Azufres geothermal reservoir, which is characterized by an extensive two-phase region: the former unavailability of reasonably re 1 iable re la t ive Permeability functions. Furthermore, the present characterization of the vertical natural flow provides kS 6.9~10-a important constraints for both lumpedand distributed-parameter models of the reservoir. Finally, this work gives information on reservoir properties that would be difficult to obtain by other means.flow provides kS 6.9~10-a important constraints for both lumpedand distributed-parameter models of the reservoir. Finally, this work gives information on reservoir properties that would be difficult to obtain by other means.

Press the Back button in your browser, or search again.

Copyright 1986, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.