Geothermal Energy Exploration

Might River Power
Nga Tamariki geothermal field
Reservoir Condensate Control System for Drilling Rig
6 months

The Nga Tamariki geothermal field (20 mins north of Taupo) was extensively drilled in the 1970’s to locate viable steam fields that could be used to generate energy for the end consumer. Unfortunately at that time technology was not advanced enough to deal with this type of field.

In recent times technology has caught up and our client had imported a drilling rig from offshore. The drilling rigs purpose was to locate the edge of the steam field and drill wells for reinjection of condensate (liquid steam).
In order for the drilling rig to perform efficiently 150,000 litres of water per day is required to be pumped down with the drilling bit.

To achieve this steam was taken out of the ground from a previously drilled well head. Through a controlled process condensate was formed and stored firstly in a settling pond and then into a 16,000,000 litre reservoir. The water is then pumped 2 kilometres to the drilling platform for use.

Our engineering team in association with Don Watson Engineering helped design and build a control solution that would safely take the steam at high pressure out of the well head and monitor the condensate on its journey through the process system to the reservoir.

At all times the control system is monitored via SCADA with live uplinks to a website where information could be evaluated remotely.

A backup system consisted of a UPS, solar arrays and an autodialler. Should the power supply be lost the system could continue to operate for a specified time period while staff rectified any problems. The autodialler contacts key personnel should any breakdown occur and certain faults can be reset remotely using the autodialler.

Work carried out included:

  • Design and build one portacom for operators to use on site. Fit out portacom with solar array on roof, switchboard and cable containment systems.
  • Design and build solar system including battery and array sizing and lighting.
  • Design and build a PLC control centre for process with back up UPS and batteries to control the automation process.
  • Freight portacom to site and locate in position.
  • Trench in all cables to field devices such as motorized valves, instrumentation transmitters, dosing pumps and other process probes.
  • Install mounting poles and mount cellular dialers and communication devices.
  • Install radio Rosemount transmitter that communicates with all remote instrumentation devices.
  • Design and build transportable solar panels to power local instruments remote from the main installation.
  • Commission installation and assist client’s automation engineers.
  • Ongoing maintenance and breakdown support.

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