Ayoluengo’s history – Spain’s only onshore oil field
The Ayoluengo Field, commonly cited as the only onshore oil field in Spain, was discovered in June 1964 by Amospain, a joint venture of Chevron, Texaco and CAMPSA, by then the state-owned company. Ayoluengo is located about 300 km north of Madrid in the southern part of the Basque–Cantabrian Basin, a geological region where natural oil seeps, tar sands and asphalt have been recognized in outcrops since the early twentieth century. Now, 50 years after the first oil in 1967, the field has a cumulated production of 17 million barrels of oil. The 50-year production concession expired at the end of January 2017 and the field is now closed, awaiting a bidding process for a new concession to be awarded.
The Ayoluengo Field consists of a NE–SW-orientated salt-cored anticline, related to Triassic salt movements. The field is divided into two large structural blocks by a normal fault. Oil and gas production comes from a series of thin lenticular fluvio-lacustrine sandstone packages of Late Jurassic–Early Cretaceous age. More than 50 separate oil and gas sandstone beds have been identified by drilling. This multilayer reservoir, together with the structural component, means that Ayoluengo is considered to be a grouping of hundreds of small oil and gas fields.
After years of intense exploration activity, the Ayoluengo Field still, surprisingly, remains a unique oil discovery and is the only onshore commercial oil field in Spain and also the only one in the entire Iberian Peninsula. This geological singularity has resulted in recurrent discussions between petroleum geologists because it is difficult to explain why a petroleum system is working uniquely at this particular spot and nowhere else within such a vast territory.
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The history of the European oil and gas industry reflects local as well as 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. The first commercial oil wells in Europe were drilled in Poland in 1853, Romania in 1857, Germany in 1859 and Italy in 1860. The 23 papers in this volume focus on the history and heritage of the oil and gas industry in the key European oil-producing countries from the earliest onshore drilling to its development into the modern industry that we know today. The contributors chronicle the main events and some of the major players that shaped the industry in Europe. The volume also marks several important anniversaries, including 150 years of oil exploration in Poland and Romania, the centenary of the drilling of the first oil well in the UK and 50 years of oil production from onshore Spain.