Tiwi Geothermal Brine Injection Surface Facility Developments as Response to Changing Subsurface Conditions

Abstract

The Tiwi steam field has been in operation for the past 35 years and over the last 15 years it has witnessed changes in operating system and reservoir conditions which have ultimately affected the brine injection systems and brine disposal strategies. The influx of cool meteoric waters and injected fluids, production of acidic fluids, decline of reservoir pressures, increase in non-condensable gas concentration and enthalpy changes are some of the major challenges that have affected Tiwi and the major challenge for the injection system has been the increasing brine production in most of its producing sectors. This has been managed by instituting a number of technical and operational changes of the Tiwi surface facilities, both tactical and strategic in nature, which have included conversion of the original cold brine injection system to hot brine injection, installation of bypass and parallel lines for additional capacity and flexibility, drilling and hook-up of new injectors, conversion of idle wells as injectors and interconnection of two independent hot brine injection systems. Instituting these changes has helped the Tiwi field in maintaining a major geothermal resource, even in the face of these major operational and reservoir challenges.