Analysis of the AAPG giant fields database reveals that there has been a step change in volumes of oil attributed to non-structural traps in the last 20 years. Why is that – and where should we be looking for them?

Rumaila–West Qurna in the Middle East is one of the world’s greatest supergiant oilfields.

The Barnett Shale gas discovery, like ‘Spindletop’ nearly 100 years prior, changed an industry by unlocking huge new volumes of oil and gas, this time from shales.

An Aging Giant

The super-giant East Baghdad oil field lies in the heavily populated outskirts of Baghdad. Can it be successfully and safely exploited?

Celebrated as the largest onshore oilfield in Western Europe (~500 MM bo), the Wytch Farm field in Dorset, southern England, is an iconic field to the thousands of geoscientists and petroleum engineers who have worked and studied there over the last four decades. It is now heading for a productive old age

Technological imaging advances and a phased development in the 15 years since discovery have begun to unlock the full potential of the Mad Dog Field, increasing its known oil-in-place nearly tenfold to up to four billion barrels of oil equivalent.

Second only to Saudi Arabia’s Ghawar, the supergiant Burgan field in Kuwait was discovered by a series of wells drilled during 1938-1952. Sitting on a huge structural anticline and occupying an area of 780 sq. km., the Cretaceous reservoirs of the Great Burgan field still account for most of Kuwait’s oil.

“We climbed for most of that day, conquering step by step the Morvarid Pass, only to drop down again, having reached the top; and as evening fell we came down on the lovely valley of Deh Diz, with its single sentinel poplar and a ruined castle in the distance, and the long ridge of the snowy Kuh-e Mangasht beyond. Our camping-place this time was in an orchard of pomegranates, beside a clear mountain stream, on a grassy terrace strewn with rocks and boulders.” Vita Sackville-West, Twelve Days in Persia: Across the Mountains with Bakhtiari Tribe (1928)

The first oil was sampled in September last year. It took several wells and one full year of detailed analyses to prove that the discovery may contain more than 2.6 billion barrels of oil.

Since the petroleum industry began in the mid-nineteenth century, numerous oil fields have been discovered and over 70,000 oil fields are still in use. Nonetheless, not all fields were created equally.

The giant Forties Field was discovered in 1970, only the second oil field to be found in the UK North Sea. Originally predicted to run dry by the early 1990, it has now produced 2.64 billion barrels – and is expected to continue for another 20 years.

Recent news of at least three dry wells and suspension of the Tupi extended well test illustrate some of the challenges facing the pre-salt play that Brazil's government has touted as having "no exploration risk." However, with the huge reserves already discovered, the frontier area remains a hot play.

The Gulf of Mexico Basin has proved to be a highly successful hydrocarbon province, and the vast untapped volume of both oil and gas ensures that the basin will continue as a major player for decades to come.

Innovative thinking and a new play concept finds a giant gas field on a lease block that had been explored for 50 years and drilled 11 times.