Geo Well Well integrity and risk assessment for

Geo. Well: Well integrity and risk assessment for high temperature geothermal wells – lessons learnt Eric P. Ford, Erlend Randeberg, Hans Petter Lohne, Mohammad Mansouri Majoumerd NORCE (formerly IRIS) The Geo. Well project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No

Outline • Project background • Well integrity • Risk assessment approach • Recommendations and outlook

High-temperature geothermal wells • Challenges • High temperatures and aggressive nature of geothermal fluids (casing and cement failures) • High thermal strains on casing and cement • High investment and maintenance costs of geothermal wells • Identified needs • • Innovative casing technology and optimised cementing procedures Novel casing materials and innovative material solutions Monitoring of well integrity Solutions for extended lifetime of geothermal wells Risk management

Example: Icelandic HT well failures 136 production wells 60% of wells have no registered failures 40% of wells have one or more registered failures 75 failures in total Nearly all failures related to casing

Risk assessment work package • Increased temperatures means increased risk • Risk assessment as methodology • Tasks include • Mapping of status, similarities and differences compared to petroleum • Recommendations on use/applicability of different methods/techniques • Foundations for well integrity and risk assessment • Reliability study of Geo. Well technologies/solutions 4 reports Focus – Technical Barriers in Drilling Completion Production Maintenance P&A

Geothermal “well risk” management • Often focused on economic risks • A wide range of practices in industry • Risk approach, methodology, tools… • Lack of standards for geothermal wells • NZ code of practice frequently referred to • In strong contrast to petroleum wells • Consequences are different • Less comprehensive regulations

Risk assessment framework ISO 31000: 2009 NORSOK Z-013 (Oil & Gas NCS) Geothermal ? Generic framework Implementations

“Well integrity” approach • Fluid migration as a challenge • Petroleum vs. geothermal • Barrier approach • Well barrier elements • Failure modes • Consequences of barrier failures • HSE, technical, economic • Major incidents (petroleum industry experience)

Proposed risk assessment framework

Proposed risk assessment framework Example of proposed activities Identify well barriers Identify relevant legislation

Proposed risk assessment framework Example of proposed activities Selection of appropriate QRA methods Identify relevant modes of failure for well barrier elements

Proposed risk assessment framework Example of proposed activities Establish relevant model parameters for selected QRA method(s) Analysis of model results, e. g. load/strength cases for materials

Proposed risk assessment framework Example of proposed activities Comparison of risk analysis results with risk acceptability criteria

European geothermal well risk protocol? • Lack of specific regulations/guidelines • Currently no common practice between regions • Methodology undefined • Streamlining code of practice • Common definitions (e. g. barriers) • Common foundation for well (integrity) risk assessment • Categorization of wells/fields • Stakeholders • Industry, regulatory bodies, R&D community • Compliance with existing regulations • Across regions • Value-creating element • Benefits vs. cost

Thank you for your attention WP 6 reports are available at http: //geowell-h 2020. eu/ The Geo. Well project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No