Abstract
This paper presents the innovative planning methods and highlights of the operations completed for the abandonment of a gas producer well suffering from integrity problems thereby restoring the integrity of the platform and putting the other wells on production. The integrity problems were oil/gas bubbles seen on the sea bed around the conductor pipe and high sustained pressures in the outer cemented annuli of 18 5/8" × 13 3/8" and 13 3/8" × 9 5/8". The entire tower/ platform was considered highly dangerous and unsafe under these conditions and the tower was risk ranked No. 1. Consequently, the wells on this platform were secured in January 2001.
A task force was formed to investigate the problem and propose solution. The team proposed to permanently abandon the gas well to restore the integrity of the tower. The possible source of leak was identified by monitoring the annuli pressures, measuring fluid samples, running noise and temperature logs and leak rate tests. After analyzing all the problems, the team agreed to isolate the source of leaks by remedial squeeze jobs through selected perforated intervals with additional barriers like bridge plug. International standards were adopted in planning for the abandonment of this well.
There were several challenges involved in the abandonment of the well like identifying the possible leak sources, perforation against 4 casings, adopting international standards for abandonment, choosing the type of barriers, cement type, ensuring the integrity of the barriers etc. Finally, the team through continuous effort and hardwork overcame these challenges, produced a robust plan and executed the operation safely in cost effective manner.
The paper serves as a good reference for the abandonment of gas wells following international standards and other areas include perforation against four casings.
