Tinsukia: Public sector giant Oil India Limited had to face a major setback after the operation to kill the well failed on Tuesday, a day after OIL succeeded in capping the blowout well at Baghjan oilfield in Assam’s Tinsukia district, which is on fire since June 9.
OIL spokesperson Tridiv Hazarika said It had been just informed from the site that the operation has been unsuccessful due to blowing out of the valve on 13.3/8” casing and the mud is going through the same profusely. “The kill mud could not be pumped to the intended zone due to the leakage; hence, mud pumping had to be stopped immediately.” “Next course of action will be decided by the global experts,” added Hazarika.
OIL had hired Canadian firm M/s Alert Damage Control, one of the few global expertize, to control the blowout at Baghjan following which a 6-member team is camping at Baghjan.
According to senior OIL sources, the fire was doused when Blowout Preventer (BoP) was closed, but when the mud was pumped to kill the well, the valve of the lowermost head developed leakage; as a result, the mud started leaking from 13.3/8″ wellhead valve. “Closing of Blowout Preventer (BoP) and pumping the mud to kill the well are a simultaneous process.” “The blowout well was again ignited to avoid spillage of condensate and gas which was a potential hazard,” sources added. They said, a valve on the casing pipe 13.3/8″, just below the wellhead, got ruptured.
A wellhead is a component at the surface of an oil or gas well that provides the structural and pressure-containing interface for the drilling and production equipment. When asked, the source said, the gas is going out through the Blowout Preventer (BoP) riser as earlier. Still, if the BoP is closed at this point of time, the gas will blowout horizontally through the leakage.
Another source in OIL said it is not clear how the experts decide to heal the rupture. “Whether the rupture can be repaired without touching the BoP or the experts have to remove the BoP to repair it needs to be seen.” The development will further delay dousing the fire, he added.
On August 17, OIL finally succeeded to cap the well after two failed attempts. The success came 83 days after the blowout occurred. Earlier, on July 31, OIL made the first attempt to install the blowout preventer, which failed after the 90-feet Athey Wagon, having a testing capacity of around 20 tonnes, toppled. The second attempt failed after inching closer to cap the well 10 days later.
The blowout occurred at gas well number 5 at Baghjan oilfield, near the Maguri-Motapung Beel and Dibru Saikhowa National Park. Work was underway to produce gas from new sand (oil and gas-bearing reservoir) at a depth of 3,729 metres, leaving natural gas and condensate oil gush to hundreds of feet into the air and spill all around. The well has been on fire since June 9.