Geosteering in thin sandstones — planning and operating a duo-lateral well in the Mittelplate oilfield, offshore Germany

Abstract

The Mittelplate oilfield is located in the German Wadden Sea National Park about 8 km west of the coastline of Schleswig-Holstein and 100 km northwest of Hamburg. For 30 years DEA Deutsche Erdoel AG has operated the field together with Wintershall Holding GmbH as its partner. Some 37 million m³ (232 million bbl.) have been produced from middle Jurassic sandstone reservoirs until by 2017 with 21 producing wells from the Mittelplate island and seven extended reach wells from Dieksand land station. The Busum Dogger 1 well discovered the field in 1966 and in 1980 and 1981 the wells Mittelplate 1, 2 and 3 confirmed Germany’s largest oil accumulation. In 1985 the construction of the worldwide unique drilling and production island Mittelplate started. The Mittelplate field has been producing since 1987 with a current daily production of 4000 m³. The German Wadden Sea was declared a national park in 1985 and in 2009 the entire Wadden Sea area was dedicated as a Unesco World Heritage Site. Therefore, the development of the field has been limited to the existing offshore structure – the existing artificial drilling and production island Mittelplate A. A concept of multi-lateral wells has been successfully to optimise the limited number of available slots and reservoir exposure per well.