Origin of Oil and Gas (4200)
1. Learn the words and word combinations before reading:
decay - [dI'keI]– распад, разложение
trap - [trxp] – n трапп, ловушка(нефти или газа), моноклиналь; v улавливать, поглощать, отделять, останавливать, задерживать, удерживать
yield - [jJld] – n урожай, добыча, выход; прогиб; поддувание (почвы); v давать какой то результат, производить, выпускать
algae ['xldZJ] pl от alga - водоросли
kerogen - bituminous material occurring in shale and yielding oil when heated
to be mature – подоспеть, прийти (о сроке), созреть
protein - ['prqutJn] - белок, протеин
trigger - ['trIgq] - вызывать, играть роль спускового механизма, инициировать
squeeze - [skwJz] - сжимать, сдавливать, выжимать
expel - [Ik'spel]– выталкивать, выбрасывать
fracture - ['frxktSq] - перелом, разрыв, трещина
blob - [blPb] - капля, шарик
tarry - ['txrI] - дёгтеобразный, смолистый, просмолённый
viscous - ['vIskqs] - вязкий, вязкостный
2. Read and translate the text:
Oil and gas are derived almost entirely from decayed plants and bacteria. Energy from the sun, which fuelled the plant growth, has been recycled into useful energy in the form of hydrocarbon compounds - hydrogen and carbon atoms linked together.
Of all the diverse life* that has ever existed comparatively little has become, or will become oil and gas. Plant remains must first be trapped and preserved in sediments then be buried deeply and slowly 'cooked' to yield oil or gas. Rocks containing sufficient organic substances to generate oil and gas in this way are known as source rocks.
Whether oil or gas is formed depends partly on the starting materials. Almost all oil forms from the buried remains of minute aquatic algae and bacteria, but gas forms if these remains are deeply buried. The stems and leaves of buried land plants are altered to coals. Generally these yield no oil, but again produce gas on deep burial.
On burial the carbohydrates and proteins of the plant remains are soon destroyed. The remaining organic compounds form a material called kerogen. Aquatic plants and bacteria form kerogen of different composition from woody land plants.
The processes of oil and gas formation resemble those of a kitchen where the rocks are slowly cooked. Temperatures within the Earth's crust increase with depth so that sediments, and kerogen which they contain, warm up as they become buried under thick piles of younger sediments.
As a source rock, deposited under the sea or in a lake, becomes hotter (typically >100oC), long chains of hydrogen and carbon atoms break from the kerogen, forming waxy and viscous heavy oil. At higher temperatures, shorter hydrocarbon chains break away to give light oil and then, above about 160oC, gas.
Once a source rock has started to generate oil or gas it is said to be mature. The most important products generated are gas, oil, oil containing dissolved gas, and gas containing dissolved oil which is called gas condensate. Condensate is the light oil which is derived from gas condensates to be found at high underground temperatures and pressures.