In 2004 Eni Exploration and Production (E&P) launched the GreenHouse
Gases (GHG) Project to develop technologies and select fields suitable for
geological sequestration of carbon dioxide (CO2).
For the well area, the project includes
- Well-integrity assessment: Verify and (if necessary) reinstate the
structural integrity of the existing wells.
- Well-integrity assurance: Establish the technical requirements to ensure
the integrity of new CO2-injection wells.
Well-integrity assessment has been carried out by developing and
implementing an operational methodology for three Italian fields:
Cortemaggiore, Palino-Ascoli-Candela-Satriano (PACS), and
Giaurone-Armatella-Gela. This methodology includes the comparison between the
sustained casing pressures (SCPs) measured in the annuli and the relevant
maximum allowable pressures (MAPs) to estimate how close each well is to losing
its safety conditions. Then, the methodology foresees specific investigations
for the critical wells to identify the magnitude and possible causes of the
SCPs occurrence. Finally, it includes the preparation of suitable remedial
and/or monitoring plans.
Stress-analysis studies supported these activities by calculating the
mechanical resistance, under the planned operational conditions, of production
casings and tubings of the CO2-injection wells.
As for well-integrity assurance, technical requirements for new
CO2-injection wells have been established on the basis of the
project for Well Cortemaggiore 157 Dir, constructed to carry out the pilot test
for the injection of CO2 in a depleted level of the Cortemaggiore
Specific studies have been carried out for the PACS and
Giaurone-Armatella-Gela fields. The former is a gas field with high
CO2 content--CO2 will be separated and reinjected. The
latter is an oil field--CO2 injection will be used as an effective
means for enhancing oil recovery.
This paper describes the operational approach followed for these activities
and describes the main requirements for the new CO2-injection
© 2011. Society of Petroleum Engineers
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- Original manuscript received:
29 October 2010
- Meeting paper published:
23 September 2010
- Revised manuscript received:
15 January 2011
- Manuscript approved:
20 January 2011
- Published online:
25 March 2011
- Version of record:
16 May 2011