Around one quarter of all oil and gas reserves are under water (offshore), in Europe the proportion is as high as 90 percent. For this reason, oil companies start at an early stage to look for deposits far from the mainland. Wintershall is involved in exploration projects, particularly in the North Sea. ,One such example is the oil discovery of the “Maria” exploration well which was one of the largest discoveries in Norway in 2010 and some 200 kilometers off the Trondheim coast.. In addition, Wintershall was also a partner in a number of other successful well discoveries.  For example in the Catcher field in the British sector of the North Sea, was one of the largest discoveries of the past few years.

Seismic technology plays the leading role in exploring the high seas, whereby rather than vibrotrucks, it is the ships that trigger the vibrations. In the past, explosive charges were also used at sea, however today the sound waves are generated by airguns. The sound waves propagate through the water, penetrate the layers of rock below, and are reflected back in the same way as during onshore exploration. The ship tows a large number of “underwater microphones” (hydrophones) on long streamers (collectively known as a towed sonar array) and uses them to capture the reflections.

Once the seismic surveys have indicated a deposit, test wells are drilled using drilling platforms and or drillships. Using the same methodology as on land, drill bits and drill rods are used to drill into the rock below the seabed reaching water depths of more than 3,000 meters. To get the maximum from a reservoir and make efficient use of the drilling platforms and drillships, the experts create dozens of wells into the seabed that extend into all directions.

When analyzing seismic data and drill cores, Wintershall’s experts use the same techniques as in onshore exploration. With the help of the latest technology, the experts often succeed in gaining new information about undiscovered reservoirs from old data records.  This investigative information gathering process allowed Wintershall to be involved in six of Norway’s twelve largest crude oil discoveries. This is especially significant as before these discoveries the North Sea had long been regarded as virtually fully explored.