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Audit of StatoilHydro: Sleipner CO2 injection

Audit: The Petroleum Safety Authority Norway (PSA) conducted an audit of StatoilHydro on 18 April 2008. The audit was mainly related to Sleipner CO2 injection and possible applicable for other StatoilHydro fields.


Background for the audit
We perceive CO2 injection to be a new technology, and consequently we see the need for a more thorough review. The audit included CO2 well design for Sleipner, Troll and Snøhvit with field development plans for large-scale CO2 injection.

Purpose of the audit
The purpose of the audit was to illustrate the challenges relating to transportation, storage and monitoring in connection with CO2 injection. The task included a review of StatoilHydro's requirements and actions in connection with this kind of activities.

Result of the audit
It is our impression that StatoilHydro has carried out a comprehensive qualification program for establishing CO2 injection wells on Sleipner, Snøhvit and the Troll field.

During the audit, it was noted that there is a need for guidelines for personnel who handle CO2 during the process at the facility, and for personnel who operate pressure control equipment in connection with well intervention.

During the audit we emphasised challenges relating to choice of materials and well design.  CO2 injection wells will require development of new logging methods and improvements in attaching the well to the formation. In connection with future well design for CO2 injection, new metering methods should be developed for well integrity, as well as methods to measure the dispersion of CO2 in the formation.

There is a need for technological development relating to CO2 injection as regards the quality of the injection medium. Measuring and adjusting the pH value, purity and water content in the flow medium is important for the lifetime of the process facility, pipelines, injection wells and nearby wells.

During the audit we identified the following areas with potential for improvement:

  • Personnel safety
  • Choice of material
  • Well integrity

Reference is made to Chapter 5 of the report for a more detailed description of potential improvements.