PyFlow Wellbore Simulator

Abstract

Matching wellbore measurements with reservoir model results is a challenging task. In case of a single feed zone system, pressure and temperature measurement may match without additional computational effort. However, in cases of multiple feed zones, reservoir and wellbore pressure do not necessarily match (even at the feedpoints) due to interzonal flow. AUTOUGH2 and TOUGH2 geothermal reservoir simulators assume a constant bottom hole pressure and therefore their accuracy will be limited. However, numerical stability of deliverability models (DELV generators) can be increased by simultaneously coupling them with a wellbore simulator and updating the flowing bottom hole pressure. To accurately deal with those issues, a multipurpose 1-D flow solver has been developed in Python, named Pyflow. Pyflow can be used to calculate flow properties along a well, with a selection of single or multiple feed zones. Well flow tests can be modeled directly to fit both pressure and enthalpy values. Additionally, explicit, and implicit subroutines can be used to couple Pyflow with AUTOUGH2, TOUGH2 type geothermal reservoir simulators. Quite good accuracy was achieved with a standalone version of Pyflow (well flow tests) and verified by data from the Reykjanes high temperature geothermal boreholes. Explicit coupling procedure (well look-up table) was tested and verified by a model of the Kerinci geothermal system. Implicit coupling between Pyflow and AUTOUGH2 was also tested and verified, using data from the Kerinci system.