State oil firm NNPC has awarded 50 companies with contracts to buy Nigerian crude and more than half of them are local firms, foreign and Nigerian trading sources said.
Of the total, 32 were local companies, doubling the number of awards to Nigerian firms compared to 2017.
NNPC also awarded contracts to supply crude to 12 governments, although it was not clear how many of the deals would be handled by the companies already on the list of awards.
NNPC awards the oil purchase contracts annually, but sources said the deals this year were for two years not one year.
Contract awards were announced in January last year. Sources said the government may have delayed an announcement this time by several months as it sought to line up more local firms for awards, so it could drum up support for next year's election.
The sources said a partial list of firms awarded deals emerged on Monday, with a final list coming out on Tuesday.
This year's overall total of 50 foreign and local firms was more than the 39 listed in 2017. The list last year also included three bilateral government deals.
NNPC did not respond to calls and emailed requests for comment.
Nigeria's oil ministry said it produced more than two-million barrels a day of crude and condensate in April. Exports were expected to average 1.8-million barrels a day in the first half of 2018, up from to 1.6-million barrels a day in 2017, loading programmes showed.