2nd Well Bore Integrity Workshop Princeton, NJ, 28-29 March 2006
- 1 September 2006
- Event Proceedings
- Storage
There were a number of reports that indicated that well integrity may be a current issue within the oil and gas industry. A detailed study on production wells in the Gulf of Mexico indicated that up to 60% of wells had casing pressure problems, which could indicate that the integrity of the wells had been compromised. Experience from the Permian basin in the USA indicated that when fields were changed over to CO₂ flood that significant remedial work was needed to pull and re cement wells that had not seen exposure to CO₂. It was considered that many of the problems in both the Gulf of Mexico and the Permian basin resulted from poor well completions at the outset. This may be due to cases where the casings were not cleaned properly prior to CO₂ injection and the presence of residual mud in the wells led to poor seals between the cement and the formation and the cement and the casing liner (steel). Similar issues could arise due to too rapid curing of the cement, or poor cement squeezing. Where poor seals occur ingress of saline water from overlying aquifers can results in chlorine induced corrosion of the steel casing liner. The API has recognised this as a major problem and in response it is developing a new set of standards for well completions. A further set of standards for wells in CO₂ floods us also being developed but this is at an early stage.
