The economic end of the life-cycle of a well is dynamic and it varies with the oil & gas market conditions and advances in extraction technologies. If production declines or the need for a workover arises, plugging and abandonment operations are followed. In case the wellsite has encountered accidental releases, systematic abandonment and remediation becomes even more crucial to avoid further environmental damage and capital investment. This paper analyzes the Baghjan oilfield blowout of the Assam-Arakan basin and provides abandonment practices for gas wells. The mobile workover rig was stationed at the Baghjan Well-5 with the aim to plug the lower producing zone at 3871 m and complete the well in the upper Lakadong+Therria sand at a depth of 3739 m. Baghjan Gas Well No.5 blew during the temporary abandonment which was planned to mitigate the leakage in the wellhead. Improper depth for the placement of cement plug, failure to check the plug integrity, and shortcomings in the regular inspection of annular casing pressure led to the well control situation at the Baghjan gas well. While pulling out the tubing conveyed perforation gun after perforating the Lakadong+Therria I+II sand, Shut-In Tubing Pressure of 4400 psi and 3900 psi Shut-In Casing Pressure was observed which indicated a leak in the Tubing Seal Assembly. The well was killed with a 9.76 lbm/gal sodium formate brine and in the middle of pulling the tubing, leakage in the W.F. Spool was identified which changed the priority of the operations. Therefore, a temporary abandonment operation was planned to mitigate the leakage problem in the primary and secondary seals, during which the well started flowing gas profusely after nipple-down of the blowout preventer. The shortcomings of the abandonment process can be conquered by the selection of an appropriate isolation material such as resin-based sealants or bismuth and thermite, which shall act as a primary barrier and provide enhanced zonal isolation. The isolation material should mitigate micro-fractures, minimize treatment volume and fluid loss, provide ample pumping time, and not degrade in the presence of wellbore fluids. The study discusses resin-based sealants, cement slurry designs, advances in conventional, unconventional, and rigless abandonment techniques, and suggests the most efficient method for the temporary and permanent abandonment operations to avoid further such incidents in the oil and gas industry.

E&P activities are the early stage of energy production and pivotal for generating and sustaining economic growth. However, negligence and evaluating the circumstances incorrectly during these operations can lead to calamities like blowouts. This paper discusses two such tragedies, the Pasarlapudi (Krishna-Godavari) Gas Well Blowout of 1995 & Baghjan (Assam-Arakan) Oil Field Blowout of 2020, and provides possible well control measures and lessons learned. Pasarlapudi blowout incident occurred during the drilling operations. The pipe stuck-up situation at 2727m MD (Measured Depth) was detected by conducting a stretch test. Further analysis could include circulating brine, checking lost circulation and identifying casing leaks by measuring Sustained Casing Pressure (SCP), Operator-imposed Pressure (OIP), and Thermal-induced Pressure (TIP). Baghjan's gas well at the depth 3870m was producing at 2.8-3.5 MMSCFD. The aim was to plug the lower producing zone and recomplete the well in the upper Lakadong+Therria sand zone. Well was killed using brine, cement plug was placed and BOP installed. BOP was removed after the plug was set to begin the process of moving the workover rig. Well blew gas profusely during this process. Simulating a blowout and facing one, are two completely different situations. In Pasarlapudi's case, the well blew with an enormous gas pressure of 281.2 ± 0.5 kg/cm2. While drilling the production hole (8.5 inch), either differential pressure sticking, presence of water-swelling clay formation or the partial collapse of wellbore formation caused the pipe stuck-up situation. By conducting stretch test along with circulating brine, root cause of this problem could be identified. If differential sticking occurred, lost circulation could be checked & cured, while keeping the hole full. Circulating brine should solve the problem of swelling clay formation while formation collapse could have occurred due to the presence of plastic formation like salt domes. In the case of Baghjan gas well blowout during workover operations, probable safety measures could include placement of 2 or 3 backup cement plugs along with kill fluid or going for squeeze cementing before placing the cement plug & kill fluid while abandoning the lower producing zone. Attempts were made to bring the well under control by adequate water spraying, installing BOP. Water was pumped through the casing valve and a water reservoir was dug near the well plinth for the placement of pumps of 2500 gallon capacity. Proper safety measures should be used even when they're not the cheapest to avoid repetition of treatments and detrimental situations. SCP, OIP and TIP should be measured periodically whenever possible and the root cause of situations like lost circulation, pipe stuck-ups, kicks, casing leaks should be identified before proceeding towards drastic remedial operations. Innovations in countering well-control situations should be promoted invariably.