D5.6 - Integrity analysis of all existing wells, Zalecze & Zuchlow site

S. Nagy, L. Klimkowski, K. Polański, T. Włodek, M. Mazurowski

The analysis of the integrity of wells located in the Zalecze & Zuchlow reservoirs were performed by AGH based on the data provided by PGNiG to mitigate and consequently reduce the risk of injected CO₂ escaping up abandoned wells. Because of data obtained were incomplete. This was due to reasons beyond the control of the project contractors. This was mainly related to the quality of records and the poor quality of existing measurements. That was why due to the lack of technical work on selected holes abandoned the implementation of the experiments. It was impossible to carry out their other openings due to the need to set new auctions, so abandoned in this part of the experimentation.

Laboratory experiments performed by AGH show that CO₂ corrosive atmosphere reduces the strength of hardened sealing slurries. Drop resistance to all tested sealing slurries characterized by insignificant value for the 180 days of storage time and the values of 50% to 90% of bending strength value measured for cement kept in H₂O  for 360 days. The impact of the water - cement ratio on the reduction of the strength of the tested samples is specific to the types of cement. The results are presented in D5.6 Report. Quantitative analysis of CO₂ leakage through well showed that overall amount of CO₂ leaked through one leaking well is not of high significance. However, mitigation practices should be developed.