Proceedings, Twenty-Second Workshop on Geothermal Reservoir Engineering
Stanford University, Stanford, California, January 27-29, p. 309-316, 1997

Application of inverse modeling to geothermal reservoir simulation

S. Finsterle1, K. Pruess1, D. P. Bullivant2 and M. J. O'Sullivan2

1 Lawrence Berkeley National Laboratory, Earth Sciences Division
University of California, Berkeley, CA 94720

2 Department of Engineering Science
University of Auckland, Auckland, New Zealand

Abstract. We have developed inverse modeling capabilities for the non-isothermal, multiphase, multicomponent numerical simulator TOUGH2 to facilitate automatic history matching and parameter estimation based on data obtained during testing and exploitation of geothermal fields. The iTOUGH2 code allows one to estimate TOUGH2 input parameters based on any type of observation for which a corresponding simula-tion output can be calculated. Furthermore, a detailed residual and error analysis is performed, and the uncer-tainty of model predictions can be evaluated. Automatic history matching using iTOUGH2 is robust and efficient so that model parameters affecting geothermal field performance can reliably be estimated based on a variety of field measurements such as pressures, temperatures, flow rates, and enthalpies. The paper describes the methodology of inverse modeling and provides a detailed discussion of sample problems to demonstrate the application of the method to data from geothermal reservoirs.