NM12 Pipeline

Mighty River Power

May 2014

Ngatamariki, Waikato

Length: 1.3km

Size: 600NB

The NM12 pipeline is located to the South West of the Ngatamariki Power Station on State Highway 5, between Rotorua and Taupo.

A new production well (NM12) was drilled in the Ngatamariki Steam Field to increase the available fuel supply to the station.

Warner Construction won the tender to be the main contractor to connect the well to the power station in addition to all of the works associated with the connection.

Warner Construction constructed the two-phase (steam and gas) production pipeline (the NM12 pipeline), approximately 1300m long and 600NB diameter, along with the wellhead pipework 500NB and 450NB.

In addition, a minimum flow system including silencer, cooling channels and brine storage pond was constructed to allow the well to continue to flow at reduced rates in the event of pipeline isolation for maintenance and/or plant shutdown.

The storage pond is emptied through a pumped system via a 200NB HDPE buried pipeline that was installed beside the NM12 pipeline where it was tied into the existing cold brine system.

In addition along the NM12 pipeline route there is two low points cold brine ponds for draining of the pipeline.

An 11kv cable and fiber cable was also buried alongside the pipeline in a separate trench to provide power to the well head instrumentation.

Warner Construction completed the NM12 pipeline on time, to budget, of high quality standard and with an excellent safety record with over 30,000 man hours worked incident free.

The rig and pipeline sites were visited by the High Hazards Unit and Work Safe NZ respectively, with both bodies commenting favorably on what was observed.