Lessons Learnt in Annuli Cure of Gas Storage Well

Gas production and storage are becoming crucial to Oil & Gas industry in clean energy development and transportation. Shale gas wells and gas production and storage wells are often casing completed. B/C/D annuli are cemented for well integrity. After a period of production, annuli may find pressure build up. It is often caused by channeling and micro-channeling from shallow gas or formation gas reservoir. Kill or shut off annuli pressure is important to maintain a safe production. This paper describes a new approach to deploy resin chemical to cure the annuli pressure. Job was deployed and performed. First shut off was not successfully. Further operation was suspended due to poor weather condition. Job result was further investigated to gain more understanding of annuli status in the following aspects: (1) Annuli pressure environment for correct sealant selection. (2) Annuli temperature environment for correct sealant selection. (3) Annuli geometry and its relation to crosslink. (4) Annuli fluid that influences the gravity fall and crosslink. Annuli condition was far more complicated than originally thought. Carefully investigation and analysis to annuli and wellhead condition is the priority before any job is prepared. A successful operation must select a reliable resin system with an appropriate recipe.