Onshore fields are mature and running down. Offshore, deep-water production in the Atlantic has been rising but is being hobbled by a lack of investment, even though high oil prices usually encourage such expensive ventures.
"Nigerian oil production from currently commercial projects will be steady until around 2015-2066, but then will drop off sharply unless investment increases," energy consultants Wood Mackenzie of Edinburgh warned recently.
Growing piracy in the Gulf of Guinea, one of the hottest oil zones in the world, is becoming a serious problem for the oil industry, where offshore platforms and energy shipping are vulnerable.
In February alone, eight oil tankers were hijacked off West Africa along the coasts of Nigeria, Ghana, Ivory Coast, the Democratic Republic of Congo, Gabon all the way south to Angola, on its way to becoming a major oil producer.
That was double the January tally. At least 13 attacks have been reported in the first two months of 2012, mostly off Nigeria. There were 64 reported hijackings in 2011, but the actual total is probably higher.
Tankers are generally held for two weeks or so while oil cargoes are unloaded and transferred to smaller vessels, then sold in Nigeria or nearby Benin. High oil prices spurs on the pirates.
In the Niger Delta, the main onshore producing zone dominated by Royal Dutch Shell and Chevron, an insurgency that erupted in 2005 seems to be reigniting as a 2009 government amnesty deal that halted attacks on the oil industry falls apart because of unfulfilled promises of stipends and jobs.
Official corruption is widely blamed, with money pledged to militants who handed in their weapons -- and several thousand did -- going to politicians' pockets instead.
Hopes had been high because the reformist president, Goodluck Jonathan, is a native of the delta's Bayelsa province. But his administration, like its predecessors, is riddled with corruption and political vendettas.
In recent weeks, groups of MEND militants have launched several attacks, including the abduction of the captain and engineer of the Dutch vessel Breeze Clipper off Port Harcourt, the southern oil capital, Feb. 28.
Another group killed several military men in a speedboat attack in the delta's labyrinth of creeks and swamps.
At the peak of the delta insurgency in 2009, Nigeria's oil production was slashed by up to 40 percent, to less than 1.7 million bpd. Although Nigeria has reserves of about 38 billion barrels, production has only recovered to the 2005 level of 2.5 million bpd.
That's well short of the 4 million bpd the government had sought to achieve by 2010.
Nigeria's continental rivals, most notably Angola, on the southern edge of the West African bulge, are pushing ahead with deep-water drilling while Nigeria, the traditional leader, slips behind because of political turmoil and uncertainty.
"It's not surprising that investors currently hold back while the host nation ponders potential changes to the risk-reward equation," Ian Craig, Shell's director of sub-Saharan operations in Africa, observed in February.
Government paralysis and mismanagement, particularly the repeated failure to produce a comprehensive Petroleum Industry Bill, is seen as a critical factor in the production decline and the lack of badly needed investment to energize the oil industry.
The bill, drafted in 2008, was intended to modernize Nigeria's dysfunctional and opaque energy industry, from which an estimated $300 billion has reportedly been stolen by corrupt officials over the last decade.
The bill would also strip the National Petroleum Corp. of its regulatory powers and transform it into a purely commercial operation, boost government royalties and tighten environmental laws.
It would also for the first share oil profits with the impoverished delta communities.
"Uncertainty about the Petroleum Industry Bill is the main thing holding us all back," said Imo Itsueli, chairman of Dubri Oil, Nigeria's oldest petroleum company.
Mounting violence in the north by the Islamist Boko Haram movement, in which thousands have been killed, has added to Nigeria's growing crisis.
Indirect talks to end the bloodshed collapsed this week. No new contacts have been scheduled.