A Rational and Practical Calculation Approach for Volumetric Method

Abstract

The USGS volumetric method together with Monte Carlo simulations is widely used for assessing the electrical capacity of a geothermal reservoir. However, the USGS original method appears not to be readily practicable for a liquid dominant geothermal fluid recovered at wellhead. On the other hand, some of references practice the volumetric method calculations differently from the original USGS method; in many cases rational explanations are not necessarily provided. Instead, we herein propose a rational and practical calculation method by reflecting both the steam-liquid separation process at separator and the adiabatic heat-drop process at turbine, together with a rational temperature at condenser; that can be used with Monte Carlo method also. The proposed method enables us to assess electrical capacity by clearly and rationally defined parameters for the equations; resulting in clearer understandings of the electrical capacity estimation of a geothermal reservoir. The proposed method gives larger estimation results than the ones given by the prevailing calculation method.