OPEC will debate this week whether to cap oil output from Nigeria and Libya, which have so far been excluded from supply curbs due to falling production amid unrest, two sources with knowledge of the matter said on Wednesday.

The 14-member OPEC meets on Thursday to decide whether to extend production cuts until the end of 2018.

The sources said the idea was to cap Nigerian output at 1.8 million barrels per day and Libyan at one million bpd.

The NNPC said is looking to set up a 3.5 to five billion dollars cash-for-crude prepayment with some of the world’s top commodity traders to fund oil and gas upstream projects as well as related infrastructure, sources with direct knowledge of the matter said.

Africa’s biggest oil producer and OPEC member was hit hard by the sharp drop in global oil prices in 2014 that pushed it into its first recession in 25 years.

Already cash-strapped and weighed down by billions of dollars in old debts, NNPC has also been looking to bring in outside cash.

The sources said Standard Chartered was hired to advise on the oil prepayment and a request-for-proposal was issued a few weeks ago for a 3.5 to five billion dollars loan to be repaid with crude over five to seven years, the sources said.

A spokesman for Standard Chartered declined to comment. A spokesman for NNPC declined to comment.

The sources added that a decision was expected before the end of this year. Around seven trading firms were still in the running, one added, with top trading houses Glencore, Vitol and Trafigura as being among the active contenders.

The trading firms declined to comment.

The West African OPEC member is seeking three off takers, one of the sources said, against 70,000 barrels per day of crude.

Vitol already has a major presence in Nigeria after buying petrol stations via a joint venture with local producer Oando and private equity fund Helios.

Vitol is also among a list of majors traders, including Trafigura, that participate in a swap scheme to deliver refined products in exchange for crude.

Profit margins for trading firms have been slowly eroding over the last few years as transparency in oil markets has increased, reducing arbitrage opportunities, once based on privileged information.

Increasing traded volumes is one way to raise profits and competition is fierce for prepayment deals with state oil firms.

Nigeria’s NNPC has had cash-flow problems for years and has been chronically behind payments for its stakes in upstream joint-ventures with Shell, Chevron, Total, Eni and ExxonMobil.

After project development began to stall following the collapse in oil prices, Oil Minister Emmanuel Ibe Kachikwu reached a deal last year with its major foreign oil-producers to repay 5.1 billion dollars over five years, interest free.

NNPC has already leveraged over 300,000 barrels per day of crude to cover current fuel imports via a crude-for-product swap scheme as well as debts to traders dating back nearly a decade