Nigeria's national oil company said it secured more than $1 billion in financing for onshore and offshore drilling operations from a Chevron subsidiary.

An agreement signed during the weekend in London envisions $1.2 billion for the development for 23 onshore and 13 offshore wells in Nigeria.

The Nigerian National Petroleum Corp. said the funding is an integral part of an exploration and production financing program meant to address "the perennial challenge" on the part of the government's support for upstream activities.

The company said the projects could combine for between $2 billion and $5 billion in revenue for the federal government.

Stage one, consisting of 19 wells, could deliver up to 21,000 barrels of oil and 120 million cubic feet of natural gas per day through 2016. Stage two development could yield 20,000 bpd and 7 milion cubic feet of gas per day through 2018.

The Organization of Petroleum Exporting Countries said member state Nigeria was among those contributing most to the group's overall gains in output. Production in August was 1.85 million bpd and around 4 percent higher than the previous month, though still below the historic high of 2.1 million bpd in 2011.

Nigeria's oil minister in February said OPEC member states were uncomfortable with the low price of oil. Royal Dutch Shell this year completed the sale of its stake in a Nigerian oil field for $737 million as part of a strategic review of onshore assets there.

An early 2015 report from analytical firm IHS said crude oil production in Nigeria will drop from 2 million bpd in 2011 to less than 1.5 million bpd by 2020 without substantial investments in the offshore sector.