De Mient

In 1938, the Bataafse Petroleum Maatschappij (BPM), Dutch for ‘Batavian Oil Company’, now part of Shell, drilled the well Mient-01 in The Hague. It was a demonstration drilling for an exhibition on oil extraction. Read more about the history of this demonstration drilling De Mient in this blog. The hole, which had a depth of 464 metres, made an unexpected oil discovery and shone new light on the structure of the subsurface. Read the article from the first issue of Geologie & Mijnbouw (‘Geology & Mining’) for more information.

To see at the Mient

A memorial honours the first oil discovery in the west of the Netherlands. The topographic map from that time shows that the location of the drilling was already surrounded by buildings in 1938. The unexpected oil discovery created a dangerous situation since the necessary safety systems had not yet been installed. The hole was quickly closed. Seismic data reveals that a fault below the drilling site is the probable reason why oil is found so shallow here. You can consult our website,, for more information on the geological structure of the subsurface. After selecting the deep geological model (DGM-deep), you can make a few cross-sections over The Hague and the drilling site to get an idea of the structure of the subsurface in the vicinity of De Mient.

To do around the Mient area

The memorial is located on the grounds of City Farm De Gagelhoeve. If you have children, a visit to the memorial can be combined well with a visit to the city farm. The neighbouring centuries-old cemetery Oud Eik en Duinen is also worth visiting. The Eikenduinen Ruin can also be found on the cemetery grounds. This ruin is what remains of a Catholic church, the first foundations of which date back to the 13th century.

Memorial in honour of Mient-01 drilling (photo: Evert van de Graaff).
Memorial in honour of Mient-01 drilling (photo: Evert van de Graaff).

Practical information

The memorial can be found in the Vruchtenbuurt (‘Fruit District’) of The Hague, some 600 metres to the north-east of where the drilling took place.

  • The memorial is located on the grounds of City Farm De Gagelhoeve (Mient 210, 2564 KL, The Hague). 
  • Between bicycle intersection 22 and 25
  • Plan your route to De Mient

Geology in brief

It used to be thought that the lower strata from the time of the Cenozoic era (the last 66 million years) became progressively deeper towards the west. However, to the surprise of geologists, this drilling revealed that the lower marl layers of the Cenozoic were quite shallow and also contained asphalt-like oil. The existing ideas about vertical tectonic movements of the subsurface could therefore be overturned. 

Geological structure

The marl in Rijswijk is from the Landen Formation and lies at a depth of approximately 460 metres. Due to tectonic movements, reservoir rocks for oil and gas are in a favourable position in the subsurface; they are fairly shallow and in a good place to capture oil and gas. After the Second World War, the search for oil and gas in the The Hague area began. It was not until 1953 that the Nederlandse Aardolie Maatschappij (NAM), the ‘Netherlands Oil Company’, found the first producible quantity of oil near Rijswijk.