Nigeria: Bayelsa Spill - Abrupt Wellhead Leak Impossible Without Interference, Experts Insist

29 December 2021

Experts involved in the liquidation of the Santa Barbara Wellhead in Nembe, Bayelsa State, have argued that only deliberate interference with the equipment could have caused a disruption to its normal functions.

The spillage at the wellhead, which has now been stopped, the engineers stated, could only have emanated from tampering with the device.

Specifically, they concluded that it was impossible for a wing valve installed on a wellhead to become detached so abruptly, saying such can only happen if the facility has been altered by unauthorised persons.

The wing valve is a piece of flow-control equipment used in oil and gas operations and is part of a Christmas tree used to shut in flow from an oil well.

The professionals corroborated pronouncements by the Nigerian Upstream Petroleum Regulatory Commission (NUPRC) and the National Oil Spills Detection and Response Agency (NOSDRA), two critical federal agencies, which earlier linked the leak to sabotage.

During a Joint Investigation Visit (JIV) to the Santa Barbara River, Nembe, both organisations, based on their on-site assessment of the wellhead, had agreed that unknown persons would have been tampered with the wing valve, leading to the leak that caused the blowout.

The representative of the NURPC, Mr. Adetoyinbo Adeyemi, stated that the physical examination of the failed wellhead, from an engineering point of view, indicated that the pressure from the equipment was not of a sufficient level to cause a blowout. He explained that the wind valve was designed to withstand extremely high pressure and could not have failed if it had not been tampered. He said the fact that the facility was not even producing meant the internal well pressure would have been quite low at the time.

Adeyemi stated, "We are here to establish the cause of the incident that happened at the Santa Barbara well 1. From the findings, you can see that there's no spill anymore. Where the spill came out from is from the wing valve.

"The wing valve has been replaced now. That means that the wing valve, the way it was, is not designed to fail like that because there are bolts surrounding it, well designed to keep the pressure in place.

"So, if it had not been taken off, there is no way it could have moved from there. When it was reported initially, there was no valve in that place, and none was found. So, to us, it is an act of sabotage."

He said the valve was designed to take care of any pressure from the well, insisting that the fact that the well had not been producing for a long time meant there was no pressure to take off the valve.

"They are called the barriers to ensure that such an environment where it has been installed is not affected," the NURPC representative said. He added, So, if you are trying to compare an apple with an orange, it's going to be a wrong thing.

"Another thing is that if you can go back and read, you will find out the valve is not designed to fail except somebody goes there to mess it up."

NOSDRA's Ismail Baba-Ahmed traced the leak to the same cause, stressing that from his expertise in fluid mechanics, his own physical examination at the site, and his interactions with the wellhead experts who plugged the leak, only vandalism could have led to the blowout. Baba-Ahmed explained that he had ascertained that the threading on the wellhead casing where the valve was removed was not worn out, a situation that suggested that the detachment of the valve was not caused by pressure.

He stated, "The engineer that killed the well, I asked specifically that after killing the well, before fixing the valve, what were the circumstances of the thread? This is because if those valves were pulled out under pressure, the threads would be worn out and he answered emphatically that the threads were intact.

"The most likely cause that could remove those valves was external influences. If those valves were removed under internal pressure, the thread would wear out because it will pull out."

Another NOSDRA representative, Olubunmi Akindele, also corroborated his colleague's position.

Akindele stated, "If this thing wasn't worn out and it was a sudden thing, then it's a surge. In addition, if it had not been building for some time, it cannot come off suddenly. That corroborates what my colleague has said."

Chief Executive Officer of Kenyon International, the company that undertook the sealing of the leak, Victor Ekpenyong, in his comments, insisted that wing valves were designed to be sturdier than the pressure they are meant to withstand.

Ekpenyong said, "In seismic studies, before a well is designed or drilled, there are a lot of parameters that are put into consideration. One of them is the reservoir pressure. So, when the reservoir pressure is determined, the pressure that is going into the design for the well must be able to withstand the reservoir pressure.

"There's no way you have a reservoir pressure of 5,000 PSI and you design an equipment of 2000 PSI. In fact, you design a higher PSI. There's no way you drill a well and the pressure will remove the Xmas tree designed based on the seismic report.

"So, it's not correct to say that the pressure from the reservoir pulled out the Xmas tree. This well was not drilled by Aiteo, it was drilled by Shell. Shell is an international company with high reputation worldwide. Aiteo inherited the well from Shell.

"Everything that has to do with this well was well designed and taken care of. There's no chance that the pressure can pull out the valve. In industry best practices, a well needs first line and second line maintenance. Aiteo has a procedure, which I have seen."

Ekpenyong further explained that the stud the community alleged was tampered with in the process of fixing the leak was the anti-theft device.

Global Group Director/Coordinator, Asset Protection/Security Services and Community Matters, Aiteo, Andrew Oru, also reiterated that beyond emotions and sentiments, the facility had spilled about 16,000 barrels, as against a loss of two million barrels that had been promoted by certain individuals.

Oru said, "Total barrels recovered is 16, 000. Nobody in Aiteo said two million barrels had been recovered from this place and this place is not even capable of producing two million barrels in 20 years. That's not the position, not the science. Let's forget emotions and sentiments."

Another Aiteo engineer, Glory Odita, disclosed that the well had been in existence for about 20 years, saying that wing valves do not detach on their own.

According to him, the reservoir pressure determines the pressure valve, which he estimated to be about 6,500 PSI, adding that that kind of pressure was not possible with a well that was not in production and had been shut-in as well.

The leak, which was reported on November 5, was plugged on December 8.

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