“Axial vibration” caused technical issues with Liza Destiny compressor – Exxon


United States oil giant ExxonMobil has attributed the vibration of the axial rotor to the failure of its compressor on the Liza Destiny vessel, which has resulted in the company having to temporarily increase flaring above pilot levels in order to maintain safe operations.

In a statement on January 29, the oil major said it is experiencing a technical issue with a seal on Liza Destiny’s gas compressor and that the faulty part has been shipped to Germany for diagnostic and repairs at the manufacturer’s workshop.

Giving an update on the issue today, Exxon’s Government and Public Affairs Advisor Janelle Persaud, said technical experts at the MAN Energy Solutions workshop in Germany continue to reassemble the internal components of the flash gas compressor.

Exxon’s Government and Public Affairs Advisor Janelle Persaud

“A detailed assessment of the compressor has found an axial vibration of the compressor rotor was the initiating event of the technical issue experienced on January 27.  The resulting vibration within the compressor was the cause of the mechanical seal failure initially reported,” she noted.

Persaud further explained that the experts have completed the adjustment of all sealing components for the suction and have moved forward with the assembly and alignment of the seals and the bearings on the discharge side.

“A key component of the assembly, the discharge silencer, which was transported to Germany separately based on the disassembly sequence on the FPSO, is under evaluation and assessment to determine the scope of repairs required,” she added.

Meanwhile, reinstatement could take up to eight weeks.

Nevertheless, Persaud assured that Exxon is conducting comprehensive root cause analyses of the issues and will take full action to incorporate lessons learned for the FPSOs employed in future projects, including Liza Phase 2 and Payara.

The failure of the compressor led to Exxon flaring 16 million cubic feet of gas per day, which sparked considerable criticism.

Flaring on Liza Destiny (Annette Arjoon)

While some have called for the Environmental Protection Agency (EPA) to take action, their hands are in fact tied.

At a recent press conference, Vice President Bharrat Jagdeo had pointed out that Exxon is limited to flaring 14 Billion cubic feet of gas based upon the approved impact assessment.

However, he had described the company’s current routine flaring as unacceptable.