DESIGN OF A REINJECTION WELL USING NUMERICAL MODELLING TECHNIQUES

Abstract

Re-injection of cooled geothermal brines is an urgent prerequisite to present geothermal exploitation and future developments in the Pannonian Basin, not only to maintain the reservoir pressure over a long term exploitation, but also because it is requested by the legislation in many countries in the area in order to prevent potential thermal and mainly chemical pollution.

The selected sites are located in SE Hungary and thus, from a geological point of view, in the central part of the Pannonian Basin, a group of lowlands and subdued mountains framed by the Carpathian arc, the Eastern Alps, and the Dinarides. The geothermal fluids are produced from the Upper Pannonian sandstone reservoir.

Currently efficient re-injection is practiced on limited scale due to restricted design/demonstration experience in the area.

The numerical simulation exercise carried out (using TOUGH2) reveals the most sensitive parameters that should be considered in the well design, especially when developing the filter area that interfaces the well and the reservoir.