The average rate at which oil and gas fields' output declines over time has significantly accelerated globally, largely due to higher reliance on shale and deep offshore resources, meaning that companies must work much harder than before just to maintain production at today's levels, according to a new IEA report.
The international conversation over the future of oil and gas often focuses on demand trends while the factors affecting supply receive considerably less attention. The new IEA report, The Implications of Oil and Gas Field Decline Rates, seeks to rebalance this debate by drawing on previous groundbreaking IEA analysis on decline rates and exploring what has changed. The new analysis draws on production data from around 15 000 oil and gas fields from around the world.
"Only a small portion of upstream oil and gas investment is used to meet increases in demand while nearly 90% of upstream investment annually is dedicated to offsetting losses of supply at existing fields," said IEA Executive Director Fatih Birol. "Decline rates are the elephant in the room for any discussion of investment needs in oil and gas, and our new analysis shows that they have accelerated in recent years. In the case of oil, an absence of upstream investment would remove the equivalent of Brazil and Norway's combined production each year from the global market balance. The situation means that the industry has to run much faster just to stand still. And careful attention needs to be paid to the potential consequences for market balances, energy security and emissions."
Decline rates vary widely across field types and geographies. Onshore supergiant oil fields in the Middle East decline at less than 2% per year, while smaller offshore fields in Europe average more than 15% per year, according to the report. Tight oil and shale gas decline even more steeply: without investment, output falls by more than 35% over one year and a further 15% over a second year.
In 2010, a halt in upstream investment would have cut oil supply by just under 4 million barrels per day (mb/d) each year. Today the equivalent figure is 5.5 mb/d, while natural gas decline rates have risen from 180 billion cubic metres (bcm) per year to 270 bcm.
Against this backdrop, keeping global oil and gas production constant over time would require the development of new resources. Even with continued spending on existing fields, the IEA's analysis shows that more than 45 mb/d of oil and nearly 2 000 bcm of gas from new conventional fields would be required by 2050 to maintain production at today's levels. This would be the equivalent of adding the total oil and gas production from all of the top three producers combined. The amounts could be reduced if oil and gas demand were to come down.
The new report also highlights that it has taken almost 20 years on average to move from issuing an exploration licence for oil and gas until first production, including nearly a decade to discover new fields and a further decade for appraisal, approval and construction.
