(Ecofin Agency) - Nigeria's major crude oil stream, Qua Iboe, is to remain under force majeure for one month while repairs on a leak on the pipeline feeding the terminal are ongoing.

The damage has affected Nigeria’s oil production, which has reduced due to militant attacks and another accident at the Qua Iboe terminal at the beginning of this year.

ExxonMobil which is the operator declared a force majeure on the crude last week, because of a system anomaly discovered during a routine check.

Sources this week said that the pipeline lost pressure while loading a cargo of crude oil and the company afterwards discovered a leak on the underwater pipeline.

The sources added that the renovation works were more extensive than earlier supposed and would not commence this week. Thus, the force majeure is likely to remain in place for a minimum of one month.

In fact, the force majeure on exports of Qua Iboe crude is the second this year with the first being the Shell-operated Forcados crude oil exports which was shut down since a militant attack on its subsea pipeline in February.

Till date the cause of the leak is still unclear, but the force majeure was declared days after the Niger Delta Avengers claimed responsibility for bombing a pipeline related to Qua Iboe, Reuters reports.

Anita Fatunji