Geothermal wellhead maintenance: A statistical model based on documented Icelandic experience

• Frequency and type of wellhead maintenance is studied.
• Waiting times between maintenance are predicted.
• Waiting times are shown to increase over time.
• The study can serve as a tool for maintenance plans.

Icelandic geothermal industry has been shown to operate in an efficient manner. We investigated how geothermal wellheads are maintained at the largest geothermal power plant in Iceland. Interviews were conducted with maintenance personnel on site, maintenance diaries were retrieved where detailed description on the maintenance activities had been recorded. Also, maintenance data was gathered from the dynamic maintenance management system (DMM). Methods of major overhauls and maintenance activities were identified, as well as the frequency of these activities. Using this data, a statistical analysis was conducted to see the estimated intervals between maintenance activities and compare them to the recommendation provided to staff. This paper concludes by recommending a wellhead maintenance management system based on the results from the statistical analysis.