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Habanero incident caused by hydrogen embrittlement: Geodynamics
Monday, 24 August 2009

GEODYNAMICS has concluded the Habanero-3 well incident at the Innamincka joint venture in the Cooper Basin was caused by cracking of the casing material due to hydrogen embrittlement.

Work on the Habanero geothermal project was delayed after an incident at the well on April 24 resulted in water and steam flowing to the surface.

Investigations found that dissolved gases in the reservoir fluid such as carbon dioxide and hydrogen sulfide had reacted with the steel casing materials.

This resulted in the release of free hydrogen that was absorbed by the steel in the low temperature zone of the well under shut-in conditions.

Along with temperature fluctuations, this led to hydrogen embrittlement that made the casing steel more prone to cracking when stressed.

Armed with this information, Geodynamics and its partners have taken measures to ensure the security of existing wells that have come into contact with the reservoir fluid. The steps include installing cement plugs in Habanero-2 and 3 while work on Habanero-1 is underway.

The company added that while the investigation had complex implications for future well design, material selection and any revision of operational procedures, these were all within the bounds of general operational experience in the industry.

The work is expected to take at least eight weeks and may lead to a revision of the previously indicated delay of 6-9 months before the 1-megawatt pilot plant could be commissioned.

Geodynamics expects to be able to recover most of the costs of the well control operation from its insurance and plans to lodge a claim to cover the expected costs of drilling a replacement well for Habanero-3.