| Popis: |
The traditional solution for capping abandoned oil and gas wells is to fill portions of the open well with cement. However, cement is not ideal for plugging or capping because it often results in an ineffective seal. Cement proves ineffective due to shrinkage, inability to bond to steel casing, degradation over time, and a large carbon footprint in production. To be a solution for greenhouse gas (GHG) emissions from abandoned wellbores, plugging must be effective indefinitely. Moreover, the effectiveness must be documented over time. Thus, the conventional approach of plugging with cement and walking away offers no documented proof of GHG emission mitigation. In this work we suggest the use of a proprietary polymer-based sealant for plugging and abandonment. The sealant, referred to TSN-20, has superior flowability, excellent bond strength to steel and rock, is very ductile, and is thermally stable. TSN-20 sealant can penetrate, flow into and seal extremely thin microcracks (< 30 microns) where cement and most other sealants cannot flow. These small microcracks are problematic leakage pathways for methane and other GHGs. Further, unlike cement, TSN-20 bonds to steel and rock, is very ductile, thermally stable, and resist harsh downhole conditions, including acids and hydrocarbons. Tests showed TSN-20 can dramatically reduce the flow rate after one sealant injection. TSN-20 sealant can be used to mitigate methane gas emissions in abandoned oil and gas wells. |
