The deterioration in the condition of the turret bearing on the Floating Storage and Offloading vessel (FPSO) Kwame Nkrumah has forced Tullow Oil to defer two liftings totalling over 1.6 million barrels of crude oil.
Two vessels had arrived last week to lift crude oil, only to be told on Thursday that off-take has been suspended.
As a direct consequence of the problem, crude oil production at the Jubilee fields has dropped drastically to around 40,000 barrels a day, and this is expected to be maintained till Sunday, March 20, 2016 when the FPSO Kwame Nkrumah will be shut down for maintenance.
The maintenance is estimated to last for 14 days.
In response to questions posed by The Finder, Tullow emailed this information.
“Tullow Ghana has deferred two liftings at Jubilee while we implement new operating procedures for off-take from the FPSO.
“New procedures are required following deterioration in the condition of the turret bearing.
“A planned two-week shutdown for maintenance is scheduled to begin on 20th March and oil production and gas export will continue until the planned shutdown begins.
“We are planning to recommence liftings towards the end of the shutdown once the new operating procedures and vessels are in place.
“Tullow’s 2016 production guidance is unaffected with negligible impact on short term Jubilee production”.
Lifting of crude oil from Jubilee fields is done every two weeks.
The FPSO Kwame Nkrumah has a nominal storage capacity of 1.6 million barrels of crude oil.
With an average of 100,000 barrels per day production, the two-week production, which lifting has been deferred, will mean the FPSO is full.
However, Tullow engineers explained that aside the nominal storage capacity of 1.6 million barrels, the FPSO Kwame Nkrumah has spare storage space which will be used to store the around 40,000 barrels per day till the vessel is shut down on March 20 for maintenance.
The Jubilee partners are optimistic that lifting of crude oil should resume once maintenance is completed and the vessel resumes production.
According to the company, engineers are continuing studying the deterioration in the condition of the turret bearing and when they are done, it is only then that Tullow will know what it will take to fix the problem.
Tullow identified a potential issue on the FPSO turret bearing in mid February.
The company then informed the government and its partners of a change to operating procedures at the Jubilee field’s FPSO Kwame Nkrumah.
Following an inspection of the turret area of FPSO Kwame Nkrumah, by Sofec, the original turret manufacturer, a potential issue was identified with the turret bearing.
As a precautionary measure, additional operating procedures to monitor the turret bearing and reduce the degree of rotation of the vessel were put in place.
According to Tullow, Sofec will now undertake further offshore examinations and Tullow will work with Sofec to determine what further measures will be required.
The Jubilee field was discovered in 2007 and production started in late 2010.
Tullow is the operator of the field with 35.48% interest.
Tullow’s partners are Kosmos and Anadarko, each with 24.08% interest, and GNPC and Petro SA with 13.64% and 2.73% interest, respectively.
FPSO Kwame Nkrumah has 17 modules weighing more than 12,500 tonnes installed on the vessel, including a water treatment plant, crude separation plant, chemical injection plant, gas processing and injection plant, the turret, electricity generation plant, as well as a 120-room accommodation, among others.
FPSO Kwame Nkrumah MV21 is installed in approximately 1,100 meters water depth on the Jubilee field, which is one of the largest oil fields discovered offshore West Africa in the past 10 years.
The FPSO is capable of processing more than 120,000 barrels of oil per day, injecting more than 230,000 barrels of water per day, and 160 million standard cubic feet per day (MMscfd) of produced gas.
FPSO Kwame Nkrumah perennial challenges
Various challenges have hin¬dered the delivery of a potential 120 million standard cubic feet of gas a day from the FPSO Kwame Nkrumah to the processing plant at Atuabo.
Since gas production com¬menced, Tullow Ghana has under¬taken several unplanned shutdowns of the FPSO Kwame Nkrumah as a result of faulty compressor.
Gas exports from FPSO Kwame Nkrumah to the Ghana National Gas Company’s onshore processing plant at Atuabo was temporarily halted on February 8, 2016 to fix a leak in the pump of the gas export system.
In January, a faulty compressor was reported to have similarly hindered gas supply from the Ju¬bilee field.
Regular supply of gas from the Jubilee fields has been hindered by the continuous failing of the field operator, compressor at the FPSO Kwame Nkrumah.
The compressor used by the oil company works in a similar fash¬ion as pumps.
It increases the pressure on a fluid and can trans¬port the fluid through a pipe.