The International Energy Agency (IEA) has reported a significant acceleration in the decline rates of oil and gas fields globally.

This trend, driven by increased reliance on shale and deep offshore resources, poses challenges around maintaining current production levels.

The IEA's analysis highlights the need for continued investment to offset supply losses and ensure energy security.

The IEA report, entitled The Implications of Oil and Gas Field Decline Rates, draws on data from approximately 15,000 oil and gas fields worldwide.

It emphasises that nearly 90% of upstream investment is required annually to counteract supply losses at existing fields.

IEA executive director Fatih Birol stated: "Decline rates are the elephant in the room for any discussion of investment needs in oil and gas."

The report notes that decline rates vary significantly across different field types and regions. Onshore supergiant oil fields in the Middle East experience a decline of less than 2% per year, whereas smaller offshore fields in Europe decline by more than 15% annually.

Tight oil and shale gas fields face even steeper declines, with output falling by more than 35% in the first year without investment.

In 2010, halting upstream investment would have reduced oil supply by just under four million barrels per day (mbbl/d) annually. Today, that figure has risen to 5.5mbbl/d, with natural gas decline rates increasing from 180 billion cubic metres (bcm) per year to 270bcm. To maintain current production levels, the development of new resources is essential.

The IEA's analysis indicates that more than 45mbbl/d of oil and nearly two trillion cubic metres of gas from new conventional fields will be required by 2050. This equates to adding the total production of the top three producers combined. However, these amounts could be reduced if oil and gas demand decreases.

The report also highlights the lengthy timeline for bringing new oil and gas fields into production. It takes almost 20 years on average from issuing an exploration licence to first production, including nearly a decade for discovery and another decade for appraisal, approval and construction.