Abstract With a history spanning over 50 years, the UK Continental Shelf (UKCS) is one of the most explored and mature basins in the world. Over 44 Bbbl of reserves have been recovered from over 450 fields across the UKCS, enabled by continuous improvement in seismic, drilling and development technologies. Starting in 1965 with BP's West Sole discovery in the Southern Gas Basin, every sector of the UKCS has since opened up. But it is not just the discoveries that have characterized this ultra-mature region. It has weathered a turbulent history of oil prices, fiscal changes, an ever-changing corporate environment and the industry's worst offshore disaster, which serves as a reminder of the uncompromising conditions of the North Sea. Production peaked at the turn of the millennium, and it is only since 2013 that there has been a partial reversal of the declining trend. With discoveries getting scarcer and smaller, maintaining the trend will not be easy, especially with the number of companies exiting the region for more prospective global opportunities on the rise. However, with an estimated 10–20 Bbbl yet to find in the basin, there is still a lot to play for in the coming years.

Abstract The history of the European oil and gas industry reflects local and global political events, economic constraints, and the personal endeavours of individual petroleum geoscientists, as much as it does the development of technologies and the underlying geology of the region. Europe and Europeans played a disproportionately large role in the development of the modern global oil and gas industry. From at least the Iron Age until the 1850s, the use of oil in Europe was limited, and the oil was obtained almost exclusively from surface seeps and mine workings. The use of oil increased in the 1860s with the introduction of new technologies in both production and refining. Shale oil was distilled on a commercial scale in various parts of Europe in the late eighteenth century and throughout the nineteenth century but, in the second half of the nineteenth century, the mineral oils and gas produced primarily from shale and coal could no longer satisfy demand, and oil produced directly from conventional oil fields began to dominate the European market. The first commercial oil wells in Europe were manually dug in Poland in 1853, Romania in 1857, Germany in 1859 and Italy in 1860, before the gradual introduction of mechanical cable drilling rigs started in the early 1860s. In the late nineteenth century, the northern part of the Carpathian Mountains in what is now Poland and Ukraine was one of the most prolific hydrocarbon provinces in the world. The Bóbrka Field in the Carpathian foothills of Poland, discovered in 1853, is still producing and is now the oldest industrial oil field in the world. The 1914–18 and 1939–45 world wars were both major drivers in exploration for and exploitation of Europe’s oil resources and in the development of technologies to produce synthetic fuels from the liquefaction of bituminous coal and the combination of carbon monoxide and hydrogen as the Allied and Axis governments struggled to maintain adequate supplies of fuel for their war efforts. In Britain, the first ‘accidental’ discovery of gas was made in 1875 in the Weald Basin, but it was not until 1919 that Britain’s first oil field was discovered at Hardstoft, in Derbyshire, as a result of a government-funded exploration drilling campaign, triggered by the need to find indigenous supplies of oil during World War I. The period of reconstruction after World War II was also critical for the European oil and gas industry with further successful exploration for oil and gas in the East Midlands of England resulting in Britain’s first ‘oil boom’, and the discovery and development of deep gas fields in the Po Valley in northern Italy fuelling the Italian economy for the next 50 years. Drilling technologies developed during Britain’s first oil boom, together with the extrapolation of the onshore geology of the East Midlands oil fields and of the Dutch gas fields, led to the discovery of the huge oil and gas resources beneath the North Sea in the 1960s and 1970s, which enabled Britain, Norway, Denmark and The Netherlands to be largely self-sufficient in oil and gas from the late 1970s until production began to decline rapidly in the early 2000s. Today, oil and gas production in most European countries is at an historical low. Exploration for new sources of oil and gas in Europe continues, although increasingly hampered by the maturity of many of the conventional oil and gas plays, but European companies and European citizens continue to play a major role in the global oil and gas industry.