PAIWERA – A ROBUST WELLBORE SIMULATOR FOR GEOTHERMAL APPLICATIONS

Abstract

Wellbore simulators are a key instrument for modeling the behavior and performance of geothermal wells. While a number of wellbore simulators exist for modeling geothermal well behavior they often lack robustness, i.e. they may fail to simulate well behavior under extreme thermodynamic conditions or when using a poor choice of auxiliary parameters. This is usually not a problem when studying a single well case since the modeler can manually guide the simulation. However when simulating reservoir-wellbore-surface facilities in a fully coupled model, this lack of robustness becomes very important since extreme thermodynamic conditions must be accommodated.
To address these important issues MRP has created the wellbore simulator “Paiwera” as an in-house development. Paiwera uses very robust search algorithms internally to accurately determine complex thermodynamic states and auxiliary integration parameters. Since its development Paiwera has been widely used at MRP for a variety of tasks including high-precision wellbore simulation of PTS runs; fully coupled reservoir-wellbore-surface models; batch-mode processing; and Monte Carlo simulations for well performance uncertainty modeling.
This paper gives a brief overview of the most important search strategies used in Paiwera, followed by some application examples.