Searching for oil & gas Geological studies are the basis of all exploration
Tapping on stones, long marches on foot and climbing between steep cliffs – when our geologists are out examining rock formations in all corners of the world, they have that air of freedom and gold-rush excitement reminiscent of the people in Texas at the middle of the 19th century, when oil production began.
Crude oil and natural gas are found in the pores of deep layers of rock; they are stored there like in a sponge. Hence, the belief that these sources of energy are found in subsurface oil lakes or gas bubbles that just have to be drilled into is a myth. Most reservoirs are hidden under the earth’s surface at depths of 500 to 5,000 meters. They can only be detected by experienced geologists, who must learn as much as they can about the rock below the surface.
Just like during the search for “black gold” at the beginning of oil production, to this day finding oil and gas is still a tricky task. Back in the 19th century they could only take educated guesses at where hydrocarbon reservoirs might be, whereas today geologists have many years of know-how and cutting-edge technology at their fingertips. However, the same pioneering spirit and intuition are still needed today.
Looking back to see the future thorough analysis of existing data
Long before Wintershall begins with its own investigations on the ground, our experts mine through existing data on the region: libraries and databases, satellite images, old archives and maps. These documents help to draw conclusions about the subsurface in the area concerned. So-called “remote sensing” using satellite images is particularly important. With remote sensing the Wintershall experts don’t have to be on-site to explore a region: for example, they can identify geological structures on the images. There may be oil and gas trapped here under an impermeable layer of rock.
At the same time, with today’s technology it is possible to do much more than take images of the earth’s surface. Satellites can also measure radiation reflected by the earth such as sunlight or infra-red radiation. When scientists analyze the data from this, they find out more about the types of rock below the ground and possible reservoirs – this is also part of remote sensing.
The search for a hydrocarbon kitchen
When carrying out their painstaking and intensive preliminary research, the Wintershall geologists are looking for regions where the ground has certain properties.
For the likelihood of oil and gas to exist, a basin – a dish-shaped formation of various rock layers – should have had a sediment layer at least 2,500 meters thick. At this depth and thickness the pressure and the temperature are just right for oil and gas to form. That’s why geologists call it a “hydrocarbon kitchen”. From here the two mineral resources migrate towards the earth’s surface until they reach an impermeable layer of rock. Here, they gather and form a reservoir. Hence, geologists are interested in all types of rock that are particularly porous, and can therefore store oil and gas well.
If the initial analysis is positive, Wintershall starts its own investigations. The geologists conduct research into the rock formations on-site. A field expedition of this kind often lasts several weeks: our explorers are on the road through rough terrain for many hours every day, mastering steep and tiring ascents and taking kilos of rock samples as they go.
The Wintershall geologists can find out exactly how the layers in the ground formed on top of each other from other areas where the rock layers are recognizable at the surface. This way they can draw conclusions about possible reservoirs and determine whether there are rock strata that cover the natural resources and prevent them from escaping from the reservoir.
We don't have to undertake enormous efforts to collect rock samples - for example by drilling - to be able to examine them.Klaus Fischer
Senior Geophysical Advisor
In order to create a model of the subsurface that is as complete as possible, previous data is combined with the newly acquired data. If the results are promising, the first surveys will follow.