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Technical Paper: Self-Healing Cement System: A Step Forward in Reducing Long-Term Environmental Impact

Society: SPE
Paper Number: 128226
Presentation Date: 2010
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Abstract

The number of wells that leak or show sustained casing pressure remains a high percentage of the total number of wells worldwide. Loss of zonal isolation, especially when the leaks are vented to surface, poses a clear environmental risk because of the potential emission of greenhouse gases such as methane.

Introduced in this paper is a new sealant developed to reduce the potential for long-term environmental issues. This cement-based material has intrinsic self-healing properties and is a responsive material activated by contact with hydrocarbons whenever the integrity of the cement sheath is compromised. It significantly reduces the risk of loss of hydraulic isolation, in existing correctly cemented annuli, during production and after abandonment.

The technology was applied to several gas storage wells in the south of France where the challenge is to ensure these wells can tolerate frequent cycling-injection followed by production. A review of operational practices confirms standard field mixing and pumping processes are adequate for properly placing such cements. None of the wells cemented during the trial phase with this self-healing cement have sustained annular casing pressure.

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