The lumped-parameter model on two-phase and superheated geothermal reservoir

Tank models (also known as "lumped parameter" models) may be used to describe the dynamical response of a geothermal reservoir. In this paper, a generalized combined lumped-parameter model consisting of both two-phase and superheated geothermal fluid is developed. The model is inherently nonlinear and multivariate and therefore it is difficult to compute Hessian matrix (second-order partial derivatives) or Jacobian matrix. We show how the BFGS algorithm, a kind of quasi-Newton method, based on Armijo line search can be used for parameter estimation. Using this algorithm, two different scenarios are matched with data generated by tank model itself. (C) 2017 The Authors. Published by Elsevier Ltd.