Ecobank Transnational, which has operations in dozens of West African countries, said oil producers like Nigeria "had a window of opportunity" when Libyan oil production was shut down by war in 2011, the Financial Times reports.
The newspaper adds that Libya's return presents a "major problem" for Nigeria at the same time shale developments in North America gain momentum.
Ecobank, the Financial Times reports, estimates that Nigerian crude oil exports to the United States could fall from 800,000 barrels of oil per day in 2012 to as low as 580,000 bpd in 2013.
An editorial in Nigerian newspaper Business Day this week warned that the shale oil and natural gas boom in the United States means diversity is central to Nigerian development.
Nigeria gets 75 percent of its revenues from oil. The country is the No. 7 oil producer among the 12 members of the Organization of Petroleum Exporting Countries.
OPEC said Nigerian oil production fell last year from its 2.1 million bpd on average for 2011. At the same time, OPEC said it expected to see major oil and natural gas growth from North American producers given new technologies used in shale operations.