The New Zealand Code of practice for deep geothermal well drilling used by the geothermal energy industry and regulators worldwide has been revised. NZS 2403:2015 Code of practice for deep geothermal wells ensures the safe design, specification, drilling, and operation of wells that penetrate hot subsurface conditions, with a particular focus on geothermal power generation.
The Code is used by operators, drilling contractors, service companies, and regulators to improve the overall management of geothermal wells, including safety and environmental management.
A foundation document for the industry
Shanon Garden, chair of the NZS 2403 committee, says the Code is a foundation document for the NZ geothermal industry.
‘It has been fantastic to have the support of Standards New Zealand, WorkSafe NZ, and the geothermal industry to revise the Code.
‘Given the niche scale of this industry internationally, there are few, if any, comprehensive good practice guides that compare to our Code. That New Zealand has such a Code highlights the depth of geothermal expertise here.
‘The original Code, developed in 1991, has served the industry well. However, it was time to bring it into line with current safety and environmental management standards, and align it with practices used in the oil and gas sector.’
Best practice industry guidance
NZS 2403 has been revised by experts in geothermal well drilling and management, to reflect current best practice for the industry. The revision was sponsored mainly by WorkSafe NZ, with significant input from the NZ Geothermal Association and Contact Energy Ltd, GNS Science, IPENZ, Local Government New Zealand, MB Century, and Mighty River Power.
The Code is used as part of New Zealand’s regulatory regime for the management of deep geothermal wells and is considered as leading guidance in the geothermal energy industry worldwide. It covers design and work practices that have been proven in the geothermal industry since the 1950s.
Following the guidance provided in the Code will also support both safety and sound environmental stewardship.
Code reflects unique features of geothermal wells
NZS 2403 draws heavily on the standards and equipment of the onshore petroleum drilling industry. However, it covers specialised well design and drilling practices, and reflects those features that are unique to drilling and managing geothermal wells.
- provides guidance on preparing and managing the well site, drilling equipment, tools and materials, drilling techniques, and managing the well integrity
- covers all stages from design and construction through to operation and maintenance, and finally the safe abandonment of geothermal wells
- applies to continuous wireline coring, coiled tubing operations, and some non-typical methods for constructing and maintaining deep geothermal wells.