Exxon Mobil Corporation (NYSE:XOM) said today it added 1 billion oil-equivalent barrels of proved oil and gas reserves in 2015, replacing 67 percent of production, including a 219 percent replacement ratio for crude oil and other liquids.

At year-end 2015, ExxonMobil's proved reserves totaled 24.8 billion oil-equivalent barrels. Liquids represented 59 percent of proved reserves, up from 54 percent in 2014. ExxonMobil’s reserves life at current production rates is 16 years.

In 2015, reserves were added in Abu Dhabi, Canada, Kazakhstan and Angola. Liquid additions during 2015 totaled 1.9 billion barrels. Natural gas proved reserves were reduced by 834 million oil-equivalent barrels primarily in the United States reflecting the change in natural gas prices. The company expects this gas to be developed and booked as proved reserves in the future.

Over the past 10 years, ExxonMobil has replaced 115 percent of the reserves it produced, including the impact of asset sales.

“ExxonMobil has a successful track record of proved reserves replacement over the long term, demonstrating the strength of our global strategy to identify, evaluate, capture and advance high-quality opportunities,” said Rex W. Tillerson, chairman and chief executive officer.

“Our proved reserves represent a diverse portfolio that positions us to create shareholder value as we supply long-term energy demand growth. We will continue to apply our disciplined, paced investing approach as we develop our industry-leading resource base.”

Reserves additions in 2015 reflect new developments as well as revisions and extensions of existing fields resulting from drilling, studies and analysis of reservoir performance. The annual reporting of proved reserves is the product of the corporation’s long-standing, rigorous process that ensures consistency and management accountability in all reserves bookings. Consistent with SEC requirements, ExxonMobil reports reserves based on the historic average market prices on the first day of each calendar month during the year.

Resource Base

During 2015, ExxonMobil added 1.4 billion oil-equivalent barrels to its resource base through by-the-bit exploration discoveries, undeveloped resource additions and strategic acquisitions.

ExxonMobil’s by-the-bit exploration success in 2015 included a significant oil discovery offshore Guyana and additional discoveries in Iraq, Australia, Romania and Nigeria. Strategic unconventional resource additions were made in the Permian Basin in West Texas, Canada and Argentina.

Overall, the corporation’s resource base totaled more than 91 billion oil-equivalent barrels at year-end 2015, taking into account field revisions, production and asset sales. The resource base includes proved reserves, plus other discovered resources that are expected to be ultimately recovered.