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 Wintershall AG
Company profile
Shaping the future.
Thinking ahead. Looking ahead. Staying one step ahead. As Germany’s largest crude oil and natural gas producer, we help meet the growing global demand for energy. We are opening up new fields, investing in new technology and expanding natural gas trading. Always in the knowledge that a sensitive approach to resources is essential for sustainable supply. We cannot predict the future. But we can prepare for tomorrow.
Wintershall. Shaping the future.
Services
In prehistoric times, the oceans and lakes of the Earth were - and still are - full of minute organisms, algae and bacteria, known collectively as plankton.
This plankton died off and sank down from the surface layers to the bottom of the water, where it mixed with clay, sand, and carbonate sediments deposited into the sea or lake by rivers. These minute organisms formed a deposit of organic silt. Often, these organic materials were embedded in this deposit so rapidly that they were shielded from the effects of oxygen and were thus preserved from natural decay. These organic deposits formed the source beds for the formation of oil and gas.
In the course of the Earth's history further layers of sediment accumulated, burying the source rock under new deposit layers several thousand meters thick. These new deposits frequently caused enormous compaction of the source beds and also generated considerable heat. Temperatures of 100° C and sometimes much higher were no rarity, since the temperature down toward the center of the Earth increases on average by 3° C every 100 m. This thermal exposure over millions of years triggered complex chemical change processes in the source rocks. Temperatures between about 60° C and 120° C led to the formation of crude oil. And wherever this oil was exposed to temperatures above 150° C, a process known as cracking took place, in which long-chain heavy oil molecules were broken down into their major components methane, ethane, propane and butane), resulting in the formation of natural gas.
Natural gas obtained from cracked petroleum or from source beds with a high proportion of organic matter derived from animals has higher concentrations of propane and methane. Gas of this kind is called "wet gas".
By far the largest quantity of natural gas was formed where the source rock contained a very high proportion of organic matter derived from plants. A natural carbonization process passing through successive stages in which the material changed into peat, lignite, bituminous coal and anthracite ultimately produced dry gas with more than 90 percent methane content. Together with minor quantities of ethane, propane and butane, natural gas almost always contains carbon dioxide and nitrogen. The best temperatures for catalytic gas formation are those between 120° C and 200° C.
However, large quantities of the natural gas produced today are a product of bacterial decomposition. In this particular case, the organic materials in the source rocks were transformed directly by bacteria to form natural gas with approximately 99 percent methane content. Unlike thermocatalytic natural gas formation requiring depths of more than 4,000 m, the bacterial formation of natural gas was not dependent on the higher temperatures caused by compaction at very low depths but frequently took place at much higher levels.
Well drilling: Still a major scientific and technical challenge
Ultimately, the only way of achieving absolute certainty about the presence of subsurface deposits is to drill an exploratory well. Even with all the preceding geophysical analysis, the success rate of these cash and material intensive undertakings is still no higher than ten percent worldwide. Up to 40 percent of the costs incurred in developing offshore fields and up to 80 percent of those incurred in developing onshore reservoirs are accounted for by exploratory wells alone.
Broadly speaking, two main methods are employed worldwide. One is rotary drilling, the other is turbodrilling. The more widely used method is rotary drilling. The drill pipe transmits the rotary motion from a turntable to the drill bit at the lower end of the drill pipe. The drill bit rotates at up to 200 rotations per minute while bearing down on the bottom of the well, thus gouging or chipping its way downward - at anything from a few centimeters to a number of meters per hour, depending on rock hardness.
To ensure the borehole remains open and the drill pipe does not get jammed, the well is tubed section by section according to the telescope principle as it is drilled. Wide tubes are used first, followed by tubes diminishing in diameter as the well gets deeper. To cool and lubricate the drill bit, a weighted fluid called drilling mud is pumped through the hollow tubing of the drill pipe. The weight of this fluid prevents unstable strata from collapsing into the hole where it has not yet been tubed and also prevents uncontrolled eruption of oil and gas should the well strike a reservoir. The drilling mud also floats the crushed rock to the surface. To prevent sudden "blow-outs", the well is equipped with a blow-out preventer at its upper end, a protective device automatically sealing a well when pressure suddenly rises excessively.
Special difficulties are involved in offshore drilling, which can extend down to water depths of more than 1,000 m as in the Campos basin off the coast of Brazil or in the Gulf of Mexico. At a depth up to 250 m, divers are employed to assemble the necessary equipment on the sea floor. At depths greater than that, the job can only be done by robots.
The second method, turbodrilling, was particularly widespread in the former Soviet Union. Today it is having something of a comeback in directional drilling. The drill bit is powered by a turbine placed directly above it. The drilling mud is pressed through the turbine at high pressure, thus powering the bit into rotation. The turbodrilling method allows for off-vertical drillings in any required direction. Today this technology has become so sophisticated that it is possible to drill horizontally through reservoir rocks over distances up to several hundred meters. Every day brings new records in this respect, the latest being approximately 5 km of horizontal drilling in reservoir rock (well no. 8, Al Shaheen, Qatar). Horizontal drilling is immensely exacting in terms of the materials used and the engineering involved. The advantage of this very expensive procedure lies in the fact that it makes it possible to extract oil and gas from reservoirs that would otherwise be commercially unprofitable, if not altogether inaccessible.
Products
The lifeline of every industrialized nation: Its energy supply
At present, about 38 percent of global primary energy demand is met by crude oil. In Germany the figure is as high as 40 percent. That puts it well ahead of other resources like bituminous coal, natural gas, nuclear power, and renewable energies. In Germany, natural gas has already outstripped coal. The largest quantities of oil, the "life-giving elixir," are consumed in the United States. The CIS states rank second, and Japan and Germany follow in third and fourth place respectively. The most important sectors where oil is used are transport (gasoline, diesel, kerosene, and engine oil), heating, and the chemical industry. Around eleven percent of the oil needed in Germany is sold to the chemical industry in the form of crude oil. Cracked into small molecules such as ethylene or acetylene, it serves as feedstock for the whole product range of organic chemistry. Whether for drugs, paints, basic materials like Vaseline for the production of cosmetics, urea for fertilizers, detergents or household cleaners, their basic components are all derived from oil. Industrial lubricants occupy a special position. The greases and oils used in industrial plants help to save energy by decreasing material wear and reducing friction in the machinery used.
But the largest product group we owe to oil is that of articles made of synthetic rubber and man-made plastics. In the field of highly sophisticated engineering, precision parts like those used in aircraft construction and in the production of electronic equipment (computers, hi-fi etc.), various kinds of engineering plastics have replaced metals because they have superior processing properties. Microfibers used in high-quality sportswear that "breathes" while at the same time protecting its wearer from environmental influences such as rain, cold or sun are another flourishing sector in plastics production. Safety helmets for cyclists, foams for mattresses and upholstered furniture, children's toys, polyester garments, shoes, lamp sockets - the list is endless.
A good example of the versatility of oil - and of plastics - is the car. If you think that it's only the engine and the gas tank of your car that contain substances produced from oil, you're far off the mark. Practically every feature of this "darling of modern society" that is not made of metal, glass or water is derived from oil: gasoline and engine oil, of course, brake fluid, coolant, anti-freeze, the coating, the dashboard, the interior lining, seats and carpets, the rubber of the tires, etc. etc. Even the laminated windscreens contain a petroleum derivative, polyvinyl butyral.
Basically, all these materials could also be produced from coal, but that would be much less cost-effective. As a starting material for chemical synthesis, petroleum has a more favorable ratio of carbon to hydrogen atoms, and chemical processing is easier too. At present, natural gas is used almost exclusively for heating purposes and power generation. And the trend is rising. The lion's share of natural gas consumption in Germany is accounted for by private households - 44 percent. More than every fourth house or apartment is heated with natural gas, and it is also used to heat water and for cooking. Now that environmental regulations have become stricter, the manufacturing industry is increasingly coming down in favor of natural gas since its combustion results in less emission of CO2 than that of other energy sources. The use of natural gas in co-generation plants is also on the increase.
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Friedrich-Ebert-Straße 160; 34119; Kassel; Germany ;
Phone: +49 561 301-0; Fax: +49 561 301-1702; |
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