Unit 9 What is an oil and natural gas reservoir.
Words to be remembered:
reservoir – коллектор
to settle - оседать, опускаться
to pile up – накапливаться
sea bottom – морское дно
over time – со временем
source rock – нефтематеринская порода
sponge – губка
to seep out – просачиваться, выходить на поверхность
permeable rock - проницаемая порода
offshore well – морская скважина
to penetrate - проходить через , проницать
gravity – 1) сила тяжести 2) плотность
to separate – отделять
gravitational separation – гравитационное разделение ( флюидов различной
плотности под действием силы тяжести)
density – плотность
solubility – растворимость
to restrict – ограничивать
Oil and natural gas were formed from the remains of prehistoric plants and animals. Hundreds of millions of years ago, prehistoric plant and animal remains settled into the seas along with sand, silt, and rocks. As the rocks and silt settled, layer upon layer piled up in rivers, along coastlines, and on the sea bottom. Over time, the layers of organic material were compressed under the weight of the sediments above them, and the increasing pressure and temperature changed the mud, sand, and silt into rock and the organic matter into petroleum. This rock containing the organic matter that turned into petroleum is referred to as source rock. The oil and natural gas are contained in the tiny pore spaces in these source rocks, similar to water in a sponge.
Over millions of years, the oil and gas that formed in the source rock deep within the earth moved upward through tiny, connected pore spaces in the rocks. Some seeped out at the surface of the earth. But most of the petroleum hydrocarbons were trapped by nonporous rocks or other barriers that would not allow it to migrate any further. These underground traps of oil and gas are called reservoirs. Reservoirs are not underground "lakes" of oil; reservoirs are made up of porous and permeable rocks that can hold significant amounts of oil and gas within their pore spaces.
Some reservoirs may be only hundreds of feet below the surface. Others are thousands, and sometimes tens of thousands of feet underground. In the U.S., a few reservoirs have been discovered at depths greater than 30,000 feet (9.15 km). Many offshore wells are drilled in thousands of feet of water and penetrate tens of thousands of feet into the sediments below the sea floor.
Most reservoirs contain oil, gas, and water. Gravity acts on the fluids to try to separate them in the reservoir according to their density, with gas being on top, then oil, then water. However, other parameters, such as fluid/rock properties and solubility will restrict complete gravitational separation. When a well produces fluids from a subsurface reservoir, typically oil and water, and often some gas will be recovered.
Questions on the text:
1) What rock is referred to as source rock? 2) Where are oil and natural gas contained? 3) How are petroleum hydrocarbons trapped? 4) What is an oil reservoir? 5) What rocks is a reservoir made of? 6) How deep below the surface are the reservoirs? 7) Why are oil, gas and water separated in a reservoir? 8) What is there on top of a reservoir? 9) What factors restrict complete gravitational separation? 10) What deposits are the easiest to locate? 11) Why are new technologies being developed? 12) What techniques have improved the odds of correctly identifying the location of smaller reservoirs? 13) Where will future discoveries of oil and gas take place?
UNIT 10 OIL AND GAS RESERVES
Words to be remembered:
pore spaces – поры
rock – горная порода
subsurface - недра
property - свойство
reservoir - коллектор ( нефти, газа, воды ), продуктивный пласт
costs – затраты, издержки to enhance – усиливать, увеличивать, повышать marginal reservoir - истощённый пласт; малорентабельный коллектор нефти deposit – месторождение, (промышленная) залежь ( полезных ископаемых );
отлагаться, осаждаться
explore – разведывать
drilling – бурение
extraction - добыча, извлечение
field – месторождение
production – добыча
to develop – разрабатывать
development – разработка
well - скважина
Oil and gas exist in the pore spaces of rock in the subsurface of the earth. How much oil or gas can be recovered from the rock depends on rock properties, technology, and economics. Even when it is technically possible to remove oil or gas from a specific reservoir, the costs may exceed the value of the oil or gas recovered. In this case, the oil or gas is uneconomic and will not be developed.
As noted above, three factors affect the amount of oil or gas that can be recovered from a known reservoir — rock properties, technology, and economics. While the industry cannot change the properties of the rock, it can develop new techniques to remove more oil from the rock. The industry has made significant advances to enhance recovery from known reservoirs. When prices rise, marginal reservoirs can be developed economically, adding to the reserve base.
Reserves will also grow as more oil and gas deposits are found around the world. Continental North America and much of continental Europe have already been explored heavily, and any new discoveries are likely to be small. But many areas of the globe are largely unexplored. Companies have experienced major success in discovering significant new oil and gas reservoirs offshore Brazil, the Gulf of Mexico, Alaska, off the western coast of Africa, Russia, and many areas of Asia and the Pacific. These are just a few of the current areas of growth. Most observers agree that significant deposits of oil and gas remain undiscovered in the Middle East.
The oil and gas industry uses advanced technology to aid in the search for the resources. Technology advances enable more accurate drilling and extraction of a higher percentage of oil and gas from each field, extending the life of each well. Advanced technology also allows development of resources that were not previously economically viable, such as deep sea fields, unconventional natural gas, and oil and gas in very deep reservoirs. Together, these new sources of oil and gas will replace production from existing wells as they decline, and help to assure adequate oil and gas supplies to meet world energy needs for the future.
Questions on the text:
1) Where do oil and gas exist? 2) How many factors affect the amount of oil or gas that can be recovered from a known reservoir? What are they? 3) What parts of the globe (земной шар) have already been explored heavily? 4) Where have companies discovered significant oil and gas reserves? 5) What aids in the search for new oil and gas sources? 6) What can technology advances enable? 7) What resources were considered (считались) not economically viable? 8) Why is it necessary to develop these resources?