1. Word usage and common errors.

1. At — Don’t use at with “an hour before”, “a week later” and ’’two years afterwards”

Y About one and a half hours later I released petroleum out of the tank.

X At about one and a half hours later I released petro­leum out of the tank.

2. A ...percentage of does not effect the noun and verb that follow.

Y Only a small percentage of the oil wells still work.

X Only a small percentage of the oil wells still works.

2. Pronunciation practice.

Gravimeter, magnetometer, seismograph, wild, extraction, sensitive, subsurface, enhance, technique, inject, percentage, compendious, throat, burst, recovery, particular, release, ex­plore.

2. Do you recognize the adjectives? Translate, please. May be you will find more of them in the text?

Subterranean, scientific, exploratory, sensitive, complex, risky, usual, compendious ...

2. Read and translate the text. Discuss possible titles for the text. Choose from: Sensitive instruments, How can I drill a well?, Offshore platforms, Extraction of oil, Oil location, My father dug a wildcat last year, Releasing the air out of the balloon.

Because of the subterranean origin of petroleum it must be extracted by means of wells. Until an exploratory well, or wildcat, has been dug, there is no sure way of knowing whether or not petroleum lies under a particular site. In order to reduce the number of exploratory wells drilled, scientific methods are used to pick the most promising sites. Sensitive instruments, such as the gravimeter, the magnetometer, and the seismog­raph, may be used to find subsurface rock formations that can hold crude oil. Drilling is a fairly complex and often risky process. Some wells must be dug several miles deep before petroleum deposits are reached. Many are now drilled offshore from platforms standing in the ocean bed. Usually the petro­leum from a new well will come to the surface under its own pressure. Later the crude oil must be pumped out or forced to the surface by injecting water, air, natural gas, steam, carbon dioxide, or another substance into the deposits. Enhanced recovery techniques have increased the percentage of oil that can be extracted from a field.

Most people think that oil is located in some underground pools, but this is not the case. Oil is located compendious in small pores between the rocks under the very big pressure. When we make a drill till the depth in which pores containing oil are located, that small drops are rushing to oil well because of the huge pressure.

T his can be compared with releasing the air out of the balloon. When we let go the balloon’s throat, the air that is pressured inside, rushes out. The same happens with oil in the well, oil under pressure rushes through the well up to the surface. Because of that in past times, it used to happen that the large amounts of oil were spilled because of the lack of the readiness. First of all, the natural pressure bursts the oil outside through the well, and after that oil companies decide to pump the oil out of the well. These two fazes of exploitation are called primary production. After that about 75% of oil’s starting amount is still in the well. That is the reason why the oil companies decide to flood oil wells with water. Through some other well they are pumping water into a well and are “washing” one part of the remaining oil with it. Thanks to this 15% more of oil’s starting amount is gained. Finally, there is about 60% of oil still in the well, which we can not pump out.