Geological features
Oil basins
Suitable conditions for the formation and accumulation of oil exist in the down warped segments of the earth’s crust where layers of sediment have accumulated to great thickness, thickest in the middle and thinner towards the edges. Such areas are called ‘sedimentary basins’ and are considered as potential ‘oil basins’ worth investigating for the presence of oil until its absence is definitely proved. Topographically they are generally low and many occur along the continental margins and in the foothills and lowlands bordering mountain chains.
Oil occurs in various formations, although all the oil probably originated from only one formation, the Mesozoic, which covers the floor of the basin.
Several oil basins extend seaward as part of the continental shelf bordering the continents, the limit of which is roughly defined by the 200 metre water depth contour. Exploration of continental shelves has progressed considerably. For example, in the Gulf of Mexico oil has been found 60 miles off the US coast and the search now extends to about 100 miles. Boundaries between states whose coasts are either adjacent or opposite to each other are generally agreed on to be the median line, i.e. a line formed by points equidistant from the nearest points of the coast line of either state.
Rock types
Rocks are divided into three main groups: igneous rocks, which include granite and volcanic rocks, consolidated from hot liquid material; sedimentary rocks, either fragments of other rocks deposited on land or under the sea by wind and water, or chemically deposited, for instance as evaporation products, or of organic origin; metamorphic rocks, which occur when igneous and sedimentary rocks are exposed to great heat and pressure thus melting and becoming magma.
Igneous and metamorphic rocks cover immense areas of the earth’s crust, forming the central nuclei of the continents, called shields, or they occur as smaller masses (massifs) located all over the world. Their nature normally prevents their bearing oil but if fractured they can act as reservoirs for oil that has migrated from overlying sedimentary rocks.
The oil geologist is mainly concerned with the sedimentary deposits filling all the world’s potential oil basins, which comprise about a tenth of the land area of the earth.
Sedimentation
The products of denudation or erosion of the higher parts of the earth’s surface are carried away by water, ice and wind in the form of pebbles, sand, silt, mud, etc., and are deposited as sediment in the valleys and plains and in the surrounding seas where they may attain thicknesses of many thousands of feet. Though slow, the action of running water and the like has brought about immense changes during the many millions of years of geological time. The eroded material is washed away by streams and rivers which carry it eventually into the sea where it may be distributed over enormous areas by ocean currents.
Under arid climatic conditions salt and anhydrite deposits called evaporites may form by evaporation of sea water, for instance in lagoons. Shallow seas of warm clear water favour the growth of corals and algae which are important contributors to the formation of carbonate rocks such as limestone and dolomite. Where vegetable matter accumulates, peat, lignite, and eventually coal beds may form.
The beds of sedimentary rocks deposited in this way are seldom uniform in thickness, composition or texture. The variations may be small or large depending on many factors
Geological age and oil occurrence
By the study of fossils, both large and microscopic, the geologist is able to assign relative ages to sediments and so to determine the succession of beds one above the other. The absolute age of the rocks can be determined from a study of radioactive minerals.
6.3. Answer the questions on the text:
1. Where do suitable conditions for the formation and accumulation of oil exist? 2. How are such areas called? 3. What are the main groups of rocks? 4. What do igneous rocks include? 5. How are sedimentary rocks formed? 6. When do metamorphic rocks occur? 7. What do igneous and metamorphic rocks form? 8. What deposits is the oil geologist mainly concerned with? 9. What deposits may form by evaporation of sea water under arid climatic conditions? 10. What favours the growth of corals and algae? 11. How can the geologist assign relative ages to sediments?
Give the English equivalents to the following word combinations from the text:
подходящие условия; стоящий того, чтобы исследовать; горные цепи, дно бассейна, простираться к морю, подвергаться действию тепла и давления, занимать огромные территории, быть заинтересованным в основном осадочными горными породами, вносить важный вклад, в зависимости от многих факторов.
6.5. Match the words in the left column (A) with their equivalents on the right (B):
A B
1. presence 2. expose 3. assign 1. develop 2. substance 3. stretch
4. immense 5. occur 6. progress 4. name 5. separate 6. behave
7. locate 8. comprise 9. call 7. border 8. be found 9. determine
10. matter 11. extend 12. divide 10. subject to 11. availability 12. huge
13. boundary 14. act 13. situate 14. consist of
6.6. Match each word on the left (A) with a word on the right (B) to make a word combination. Put them down and translate into Russian.
A B
1. mountain 2. continental 3. water 1. rocks 2. currents 3. minerals
4. igneous 5. organic 6. central 4. surface 5. time 6. ages
7. earth’s 8. ocean 9. geological 7. shelves 8. chains
9. contour
10. relative 11. radioactive 12. potential 10. origin 11. basins 12. nuclei
6.7. Match the words in the left column (A) with their opposites on the right (B):
A B
1.thick 2. presence 3. normally 1. above 2. opposite 3. cold
4. towards 5. adjacent 6. small 4. indefinite 5. exact 6. enormous
7. warm 8. include 9. under 7. backwards 8. exclude 9. thin
10. definite 11. rough 10. seldom 11. absence
6.8. Translate the following sentences into Russian in writing:
1. The nature of igneous and metamorphic rocks covering immense areas of earth’s crust normally prevents their bearing oil but if fractured they can act as reservoirs for oil that has migrated from overlying sedimentary rocks.
2. Oil may be generated in sedimentary rocks of almost any age, but the older rocks will naturally have lost more of their oil than have the younger ones through seepages, cracks, erosion or heat from igneous or volcanic rocks.
6.9. Choose the only correct variant to fill in the gaps:
Topographically oil basins are normally …….and may occur along continental margins.
a) high b) low c) small d) enormous
2. Exploration of ……… has progressed considerably.
a) depth contours b) groups c) continental shelves d) boundaries
3. Sedimentary rocks are exposed to …….
a) volcanic rocks b) hot liquid materials c) evaporation products
d) heat and pressure
4. If fractured igneous rocks act as ……… for oil.
a) median line b) reservoirs c) shields d) areas
5. Evaporites may form by ……… of sea water.
a) accumulation b) denudation c) evaporation d) erosion
6. Shallow seas …… … the growth of corals and algae.
a) favour b) decrease c) slow down d) cover
7. The geologist is able to assign relative ages to ………
a) composition b) texture c) sediments d) currents
6.10. Summarize the contents of the text in a few sentences.
UNIT 7 OIL TRAPS
Remember the meaning of the following words:
density - плотность
survey – изыскания, исследования
bear witness - свидетельствовать
offshore areas – прибрежные районы
assume - предполагать
displace – вытеснять
interrupt - прерывать
folding - складчатость
faulting - образование сбросов
fault trap – ловушка, обусловленная наличием сбросов
salt dome – соляной купол
ductile crustal deformation – упругая деформация земной коры
flank - склон
closure – замкнутая структура
underlay – залегать ниже
brittle crustal deformation – хрупкая деформация земной коры
updip – вверх по восстанию пласта
intrusion - внедрение
deep-seated – глубоко залегающий
punch - пробивать
truncate - усекать
plug - пробка
remnant - остаток
lateral – боковой, поперечный
laterally – горизонтально, вбок
lenticular sand – линзовидный песок
fissure - трещина
cavern – пещера, каверна
unconformity – несогласное напластовывание
tilt – наклон
exploration drilling - разведочное бурение
development well - эксплуатационная скважина
7.2. Read and translate the text using a dictionary:
Oil traps
Hydrocarbons are of lower density than formation water. Thus, if no mechanism is in place to stop their upward migration they will eventually seep to the surface. On seabed surveys in some offshore areas we can detect craters which also bear witness to the escape of oil and gas to the surface. It is assumed that throughout the geologic past vast quantities of hydrocarbons have been lost in this manner from sedimentary basins.
The direction of movement of oil from the place it was formed to where it accumulates because its further movement is blocked by a trap, is thought to be upward. Oil or gas (or both) rises as it displaces the sea water which originally filled the pore spaces of the sedimentary rock. Its progress is interrupted when it reaches a barrier of impervious rock that traps or seals the reservoir.
Oil traps are of many kinds divided broadly into 'structural' and 'stratigraphic' traps.
Structural traps
Structural traps result from some local deformation such as folding, faulting or both, of the reservoir rock and a cap rock. Typical examples are anticlinal and fault traps and traps connected with salt domes.
In an anticlinal trap which is the result of ductile crustal deformations a reservoir sand and a reservoir limestone are capped by impervious beds which also cover the flanks of both reservoirs, providing closure and preventing the horizontal escape of oil and gas The upper part of each reservoir contains gas underlain by oil-saturated rock; the pore space of the lower part is filled with salt water.
A fault trap which is the result of brittle crustal deformations provides closure for the sand reservoir by bringing an impervious layer alongside it on the updip side but not for the limestone reservoir m which oil and gas could not accumulate because they would escape updip through the sand.
Traps are sometimes formed by the local intrusion of deep-seated rocks into overlying sediment. Rock salt is a frequent intruder forming ’salt domes’ – cylindrical, steeply conical or mushroom-shaped masses of rock salt, formed when salt was forced to flow plastically under very high pressure, punching its way up from deep-seated beds through the overlying layers. Porous formations, if present, have been truncated and effectively sealed by the salt plug. Oil may accumulate against the plug or above it in reservoir formations that have been folded by the rising plug, or in the porous remnant of older strata pushed up on top of the salt.
Stratigraphic traps
Sedimentary layers may change laterally in lithologic composition or may die out and reappear elsewhere as a different type of rock. Such changes often cause a lateral decrease in porosity and permeability, and the more porous section of the layer may form a ‘stratigraphic’ trap. Oil accumulations also occur in traps formed by lenticular sand masses completely enclosed in tight sediments.
Limestone in itself is often impervious but may contain fissures and caverns that can form stratigraphic traps. The remains of an ancient coral reef buried by impervious sediments can also form a stratigraphic trap.
A different kind of a stratigraphic trap may be formed by unconformities when a succession of layers, including a potential oil reservoir, have been uplifted, tilted, cut by erosion, and finally overlaid by impervious sediments that act as cap rock
Oil accumulations may result not only from any one of the above-mentioned types of trap, but from a combination of two or more types. Some traps are not easy to recognize and it is not surprising, therefore, that even the most modern geophysical methods may fail to give an indication of their presence, in which case only exploration drilling can provide sufficient information, at a cost considerably high than that of other exploration methods.
Even after the initial discovery of an exploitable oil accumulation, geological conditions may be so complicated that it may take years to drill many development wells before the detailed pattern of oil occurrence in the area is fully understood.
7.3. Answer the questions on the text:
1. When is movement of oil interrupted? 2. What do structural traps result from? 3. What are typical examples of structural traps? 4. How are traps formed sometimes? 5. What can form stratigraphic traps? 6. What may oil accumulation result from? 7. Why do modern geophysical methods fail to give an indication of traps presence? 8. How can sufficient information be provided?
7.4. Give English equivalents to the following word combinations from the text:
таким образом, в конце концов, огромное количество, возникать в результате, заставлять насильно, исчезать и появляться вновь, заглубляться под действием, вышеупомянутые типы, предоставить достаточно информации, разрабатываемая залежь нефти.
7.5. Match the words in column A with their equivalents in column B:
A B
1. thus 2. quantity 3. lose 1. beside 2. bed 3. in this manner
4. broadly 5. remnant 6. form 4. famous 5. enough 6. waste
7. finally 8. recognize 9. sufficient 7. widely 8. supply 9. remainder
10. provide 11. connect 12. layer 10. put together 11. amount
13. alongside 14. well-known 12. identify 13 eventually 14. join
7.6. Choose the only correct variant to fill in the gaps:
Structural traps result from some ………
a) combination b) deformation c) accumulation d) sedimentation
2. A reservoir sand and a reservoir limestone are capped by …
a) permeable layers b) overlying sediment c) impervious beds d) pores
3. A fault trap provides …. for the sand reservoir.
a) closure b) salt dome c) sediment d) salt
4. Rock salt is a frequent …. forming salt domes.
a) strata b) intruder c) mass d) kind
5. Such changes often cause a lateral ….. in porosity and permeability.
a) increase b) failure c) cavern d) decrease
6. Limestone is often …. but may contain fissures and caverns.
a) permeable b) cut c) impervious d) buried
7. Some traps are not easy to ……..
a) change b) bury c) form d) recognize
7.7. State whether the sentences are true (T) or false (F):
1. Hydrocarbons are of much higher density than formation water.
2. The progress of oil and gas is interrupted when they reach a barrier of
impervious rock.
3. Anticlinal and fault traps are connected with associated water.
4. Rock salt seldom intrudes in formation of salt domes.
5. A stratigraphic trap can be formed by the remains of an ancient coral reef.
6. Oil accumulations may result only from one type of traps.
7.8. Retell the text using the following word combinations as a plan:
The direction of movement, to block by a trap, to be upward, impervious rock, types of traps, to result from, oil accumulations, a combination of, to fail to give, exploration drilling development wells.
UNIT 8 WHAT IS NATURAL GAS?
8.1. Remember the meaning of the following words and word combinations:
combustible – горючий
fossil fuels – ископаемые виды топлива
to emit = to give off - выделять, испускать
harmful byproducts - вредные побочные продукты
primarily – в основном, главным образом
chart - таблица
composition - состав
carbon dioxide - углекислый газ
hydrogen sulfide - сероводород
trace - след
to deliver - доставлять
commonly – обычно
associated with - (зд.) сопровождающие, попутные
to remove - удалять
reservoir - коллектор
deposit - месторождение
to search for - искать
once - как только
to refine - очищать
impurities - примеси
compound - соединение
to exist - существовать
to measure - измерять
in a number of different ways – по-разному, различными способами
volume - объем
cubic feet - кубические футы
British thermal unit (Btu) - британская тепловая единица
pound - фунт (0,453 кг)
gas utility - газовая коммунальная служба
billing - выписка счета
8.2. Before reading the text check the pronunciation of the following words:
Carbon, hydrogen, hydrocarbons, sulfur, oxygen , nitrogen, carbon dioxide,
hydrogen sulfide, methane, ethane, propane, butane, argon, neon, helium, xenon
8.3. Read and translate the text using a dictionary.
What is Natural Gas?
Natural gas, in itself, might be considered a very uninteresting gas - it is colorless, shapeless, and odorless in its pure form. Quite uninteresting - except that natural gas is combustible, and when burned it gives off a great deal of energy. Unlike other fossil fuels, however, natural gas is clean burning and emits lower levels of potentially harmful byproducts into the air. We require energy constantly, to heat our homes, cook our food, and generate our electricity. It is this need for energy that has elevated natural gas to such a level of importance in our society, and in our lives.
Natural gas is a combustible mixture of hydrocarbon gases. While natural gas is formed primarily of methane, it can also include ethane, propane, butane and pentane. The composition of natural gas can vary widely, but below is a chart outlining the typical makeup of natural gas before it is refined.
Typical composition of natural gas
Methane (CH4) - 70-90%
Ethane (C2H6) - 0-20%
Propane (C3H8) - 0 - 5%
Butane (C4H10) - 0 - 5%
Carbon dioxide (CO2) - 0 - 8%
Oxygen (O2) - 0-0.2%
Nitrogen (N2) - 0 - 5%
Hydrogen sulfide (H2S) - 0 - 5%
Rare gases Ar, He, Ne, Xe trace
In its purest form, such as the natural gas that is delivered to your home, it is almost pure methane. Methane is a molecule made up of one carbon atom and four hydrogen atoms, and is referred to as CH4.
Ethane, propane, and the other hydrocarbons commonly associated with natural gas have slightly different chemical formulas, which can be seen here.
Natural gas is considered ‘dry’ when it is almost pure methane, having had most of the other commonly associated hydrocarbons removed. When other hydrocarbons are present, the natural gas is 'wet'.
Natural gas has many uses, residentially, commercially, and industrially. Found in reservoirs underneath the earth, natural gas is commonly associated with oil deposits. Production companies search for evidence of these reservoirs by using sophisticated technology that helps to find the location of the natural gas, and drill wells in the earth where it is likely to be found. Once brought from underground, the natural gas is refined to remove impurities like water, other gases, sand, and other compounds. Some hydrocarbons are removed and sold separately, including propane and butane. Other impurities are also removed, like hydrogen sulfide (the refining of which can produce sulfur, which is then also sold separately). After refining, the clean natural gas is transmitted through a network of pipelines, thousands of miles of which exist in the United States alone. From these pipelines, natural gas is delivered to its point of use.
Natural gas can he measured in a number of different ways. As a gas, it can be measured by the volume it takes up at normal temperatures and pressures, commonly expressed in cubic feet. Production and distribution companies commonly measure natural gas in thousands of cubic feet (Mcf), millions of cubic feet (MMcf), or trillions of cubic feet (Tcf). While measuring by volume is useful, natural gas can also be measured as a source of energy. Like other forms of energy, natural gas is commonly measured and expressed in British thermal units (Btu). One Btu is the amount of natural gas that will produce enough energy to heat one pound of water by one degree at normal pressure. To give an idea, one cubic foot of natural gas contains about 1,027 Btus. When natural gas is delivered to a residence, it is measured by the gas utility in 'therms' for billing purposes. A therm is equivalent to 100,000 Btu's, or just over 97 cubic feet, of natural gas.
. Answer the questions on the text:
1) In what way is natural gas an uninteresting gas? 2) How does natural gas differ from other fossil fuels? 3) Where do we use it? 4) What is natural gas? 5) What is the composition of the typical natural gas? 6) What is the difference between the ‘dry’ and ‘wet’ natural gas? 7) Why is natural gas refined? 8) What happens to natural gas after refining? 9) What happens to impurities like propane, butane and sulfur? 10) How do production and distribution companies measure the volume of natural gas? 11) How is natural gas measured as a source of energy? 12) What is one Btu? 13) How does the gas utility measure natural gas?
8.5. Give English equivalents to the following word-combinations from the text:
бесцветный, бесформенный и без запаха; в чистом виде, обычный
состав (2), редкие газы, называться, считаться ‘сухим’, почти чистый метан,
признаки (наличия) коллектора, сложная технология, удалять примеси, отдельно, после очистки, перекачивать по сети трубопроводов, доставлять до места использования; компании, занимающиеся добычей и распределением , источник энергии, нагреть один фунт воды на один градус
8.6. Match the words in list A with their equivalents in list B and translate them:
List A
1) combustible 2) to give off 3) makeup 4) commonly 5) to transmit
6) a great deal of 7) to elevate 8) to search for 9) to refine 10) odorless
List B
a) usually b) much/many c) to remove impurities d) inflammable e) to raise
f) without smell g) to emit h) to move i) composition j) to look for
8.7. Choose the only correct variant to fill in the gaps:
Natural gas is ………………….. in its pure form.
a) not combustible b) separate c) without odor d) useless
2) The main component of natural gas is ……………. .
a) propane b) methane c) butane d) ethane
3) Methane is a molecule made up of ……. carbon atom and ……. hydrogen
atoms.
a) one , six b) two , six c) four, ten d) one, four
4) When natural gas consists of almost pure methane it is called …………… .
a) ‘wet’ b) ‘clean’ c) ‘dirty’ d) ‘dry’
5) Natural gas is produced from …………… under the earth.
a) reservoirs b) impurities c) refineries d) pipelines
6) Water, other gases, sand and other compounds that are removed from natural
gas are called …………. .
a) reservoirs b) impurities c) mixtures d) fluids
7) The measurement of natural gas by the volume is expressed in …………… .
a) liters b) thermal units c) cubic feet d) tons
8) The measurement of natural gas as a form of energy is expressed in ……….. .
a) British thermal units b) tons c) cubic feet d) liters
8.8. Give the summary of the text about natural gas using the following word
combinations:
in its pure form, combustible mixture of hydrocarbon gases, typical composition, ‘wet’, ‘dry’, many uses, to remove impurities, to transmit through pipelines, to measure by the volume, in cubic feet, be measured as a source of energy, British thermal units, one Btu
UNIT 9 THE FORMATION OF NATURAL GAS
9.1. Remember the meaning of the following words and word-combinations:
essentially - по сути
remains - останки
origin theory - теория происхождения
widely accepted - широко признанный
organic matter –органическое вещество
to compress – сжимать
be referred to - называться
thermogenic methane - термогенный метан
mud - грязь, ил
sediment - осадок
debris - обломки
to pile on - скапливаться над
carbon bonds - углеродные связи
relative to – (зд.) относительно
tiny - мельчайший
biogenic - биогенный
to break down - разрушать, разрывать
be void of – быть лишенным чего-либо, без чего-либо
intestines - кишечник
to take place – происходить
to be trapped – попадаться в ловушку
landfill gas - газ из органических отходов
to allow - позволять
abiogenic - абиогенный
to interact - взаимодействовать
absence - отсутствие
to result in - приводить к ч-л
9.2. Read and translate the text using a dictionary:
The Formation of Natural Gas
Natural gas is a fossil fuel like oil and coal. This means that it is, essentially, the remains of plants and animals and microorganisms that lived millions and millions of years ago. But how do these once living organisms become an inanimate mixture of gases?
There are many different theories as to the origin of fossil fuels. The most widely accepted theory says that fossil fuels are formed when organic matter (such as the remains of a plant or animal) is compressed under the earth, at very high pressure for a very long time. This is referred to as thermogenic methane. Similar to the formation of oil thermogenic methane is formed from organic particles that are covered in mud and other sediment. Over time, more and more sediment and mud and other debris are piled on top of the organic matter. This sediment and debris puts a great deal of pressure on the organic matter, which compresses it. This compression, combined with high temperatures found deep underneath the earth, break down the carbon bonds in the organic matter. As one gets deeper and deeper under the earths crust, the temperature gets higher and higher. At low temperatures (shallower deposits), more oil is produced relative to natural gas. At higher temperatures, however, more natural gas is created, as opposed to oil. That is why natural gas is usually associated with oil in deposits that are 1 to 2 miles below the earth's crust. Deeper deposits, very far underground, usually contain primarily natural gas, and in many cases, pure methane.
Natural gas can also be formed through the transformation of organic matter by tiny microorganisms. This type of methane is referred to as biogenic methane. Methanogens, tiny methane producing microorganisms, chemically break down organic matter to produce methane. These microorganisms are commonly found in areas near the surface of the earth that are void of oxygen. These microorganisms also live in the intestines of most animals, including humans. Formation of methane in this manner usually takes place close to the surface of the earth, and the methane produced is usually lost into the atmosphere. In certain circumstances, however, this methane can be trapped underground, recoverable as natural gas. An example of biogenic methane is landfill gas. Waste-containing landfills produce a relatively large amount of natural gas, from the decomposition of the waste materials that they contain. New technologies are allowing this gas to be harvested and used to add to the supply of natural gas.
A third way in which methane (and natural gas) may be formed is through abiogenic processes. Extremely deep under the earth's crust, there exist hydrogen-rich gases and carbon molecules. As these gases gradually rise towards the surface of the earth, they may interact with minerals that also exist underground, in the absence of oxygen. This interaction may result in a reaction, forming elements and compounds that are found in the atmosphere (including nitrogen, oxygen, carbon dioxide, argon, and water). If these gases are under very high pressure as they move towards the surface of the earth, they are likely to form methane deposits, similar to thermogenic methane.
Answer the questions on the text:
1)What is the source of natural gas? 2) How many theories of the origin of fossil fuels are described in the text? 3) How is thermogenic methane formed? 4) What puts a great deal of pressure on the organic matter? 5) Why is natural gas usually associated with oil in deposits that are 1 to 2 miles below the earth’s crust? 6) Why do deeper deposits contain primarily natural gas? 7) What type of methane is called biogenic? 8) Where can we find such microorganisms? 9) Where does the formation of this type of methane usually take place? 10) Is it possible to use biogenic methane? 11) How can methane be formed through abiogenic processes?
9.4. Give English equivalents of the word-combinations from the text:
происхождение ископаемых видов топлива, быть сжатым под землей, со временем, оказывать большое давление, в сочетании с ч-л, разрывать углеродные связи, в отличие от нефти, под земной корой, мельчайшие микроорганизмы, быть лишенным кислорода, таким образом, близко к поверхности, при определенных обстоятельствах, мусорные свалки, собирать, постепенно подниматься, похожий на
. Complete the sentences in column A choosing the proper ending from
column B:
A B
1) Natural gas like oil and coal is … a) a great deal of pressure on the
organic matter
2) Fossil fuels were formed from b) more oil is produced
organic matter compressed …….
3) Over time sediment and debris puts…... c) to produce methane
4) At low temperatures …….. d) by tiny microorganisms
5) At higher temperatures …… e) under the earth at very high pressure
6) Methanogens chemically break f) a fossil fuel
down organic matter ……
7) Biogenic methane is formed ….. g) in the absence of oxygen
8) Hydrocarbon compounds are h) more natural gas is created,as
formed ……. opposed to oil
. Match the words in list A with their definitions in list B. There are two extra
definitions in list B which you do not need to use:
List A List B
natural gas a) the result of decomposition of
organic matter under great pressure
without air for a long time
a reservoir b) gaseous mixture of hydrocarbons
to remove impurities c) to produce in great volumes
one Btu d) the result of transformation of
organic matter by tiny
microorganisms
fossil fuels e) to increase the temperature
biogenic methane f) to refine gas from water, sand and
associated hydrocarbons
g) an underground trap made up of
porous and permeable rocks
h) the amount of gas that will give
energy to heat one pound of water
by one degree at normal pressure
. Give the summary of the text about natural gas formation using the following word-combinations:
theories of the origin of fossil fuels, thermogenic methane, sediment and debris, break down the carbon bonds, at low temperatures, at higher temperatures, biogenic methane, tiny microorganisms, without oxygen, landfill gas, abiogenic processes, interact with minerals; result in a reaction, forming nitrogen, oxygen, carbon dioxide and other elements
UNIT 10 WHAT IS AN OIL AND NATURAL GAS RESERVOIR?
10.1 Remember the meaning of the following words and word-combinations:
reservoir – коллектор
to settle - оседать, опускаться
silt – ил, наносы
layer – слой
to pile up – накапливаться
sea bottom – морское дно
geologic shift – геологический сдвиг
to result in – приводить к ч-л
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
to locate – определять место, местонахождение
mature - старое, давно разрабатываемое (месторождение)
to access – доходить до, достигать
band – слой
seismic technique – метод сейсмической разведки
3D = 3 dimensional - трехмерный, объемный
odds - шансы
remote areas – отдаленные территории
10.2 Read and translate the following text using a dictionary:
What is an Oil and Natural Gas Reservoir?
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. Geologic shifts resulted in some of these layers being buried deep in the earth. 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 is 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. The properties of these rocks allow the oil and natural gas within them to flow through the pore spaces to a producing well.
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.
The larger subsurface traps are the easiest deposits of oil and gas to locate. In mature production areas of the world, most of these large deposits of oil and gas have already been found, and many have been producing since the 1960s and 1970s. The oil and gas industry has developed new technology to identify and access smaller, thinner bands of reservoir rock that may contain oil and gas. Improved seismic techniques (such as 3D seismic) have improved the odds of correctly identifying the location of these smaller and more difficult to find reservoirs. There is still a lot of oil and gas left to be discovered and produced. Future discoveries will be in deeper basins, and in more remote areas of the earth. There will also be a lot of small reservoirs found in existing oil and gas areas using advanced technologies.
10.3. Answer the questions on the text:
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?
10.4. Give English equivalents of the following word-combinations from the text:
накапливаться слой за слоем, со временем, называться нефте-
материнской породой, мельчайшее поровое пространство, перемещаться дальше, морские скважины, в зависимости от плотности, растворимость; территории, где давно ведется добыча (нефти/газа), распознавать и доходить до, более тонкие пласты, усовершенствованная техника, отдаленные территории
10.5. Complete the sentences in column A choosing the correct ending from
column B:
A B
1) Oil and natural gas were formed from … a) large amounts of fluids in their
pore spaces.
2) The layers of organic material were com- b) in remote areas of the earth.
pressed ……..
3) The source rock within the earth has c) according to their density.
got ………..
4) Underground traps of oil and gas are d) the remains of prehistoric plants
called ……….. and animals.
5) Reservoirs can hold ……….. e) reservoirs.
6) Fluids in a reservoir are separated ……. f) tiny pore spaces that contain oil
and natural gas.
7) New technologies allow to identify and g) under the weight of the sediments
access ………….
8) Future discoveries will take place …… h) thinner bands of reservoir rock.
10.6. Choose the only correct variant to fill in the gaps:
1) Rocks and silt settled layer upon layer over …………… .
a) tiny pore spaces b) the remains of plants and animals
c) the source rock d) permeable rock
2) The source rock contains oil and natural gas in ………….. .
a) underground lakes b) a sponge
c) tiny pore spaces d) geological shifts
3) Below the surface the petroleum hydrocarbons …………. by nonporous rocks.
a) are produced b) are allowed c) are penetrated d) are trapped
4) ………. reservoirs have been discovered at 9 kilometers depth.
a) a lot of b) some c) many d) plenty of
5) Fluids are separated in the reservoir because of …………. .
a) gravity b) water c) pressure d) temperature
6) In a reservoir …….. is usually on top, then ……, then ……. .
a) water, gas, oil b) oil, water, gas
c) gas, water, oil d) gas, oil, water
7) 3D seismic allows production engineer to identify and access …………. .
a) the sea floor b) thinner bands of reservoir rocks
c) remote areas of the earth d) mature production areas
10.7. Give the summary of the text about oil and natural gas reservoirs using the
following word-combinations:
Remains of prehistoric plants and animals, be compressed under the weight of sediments, source rock, be trapped by nonporous rocks, to form a reservoir, of different depth, gravity, to separate according to density, to locate subsurface traps, to develop new technologies, to identify and access thinner bands of reservoir rock, remote areas of the earth.
UNIT 11 EXPLORATION METHODS AND TECHNIQUES
11.1. Remember the meaning of the following words:
anticline - антиклиналь, антиклинальная складка (куполовидная складка,
крылья которой падают в противоположных направлениях)
survey - изыскание; съёмка; разведка; профилирование; картирование;
геофизические исследования; производить съёмку
exploration - поисково-разведочные работы; разведка месторождения;
изыскательские работы
gravity anomalies – гравитационные аномалии
magnetic anomalies - магнитная аномалия
seismic grid - сетка сейсмических профилей
public domain - всеобщее достояние; государственная собственность accumulation - аккумуляция; скопление; накопление; залежь;
месторождение (нефти, газа); формирование залежи
investigation - изучение; исследование; обследование (месторождения)
validity – истинность; достоверность; обоснованность; доказанность
onshore seismics - наземная сейсмическая разведка
offshore – морской
folded – складчатый
mapping - составление карты, картографирование, картирование; геодезическая съёмка
prospect - перспективная площадь; разведка; изыскание
wildcat - скважина, заложенная без предварительного геолого-
геофизического обоснования; опорно-геологическая скважина;
разведочная скважина
crude – нефть, «сырая нефть»
lead - продуктивный пояс месторождения
mud - буровой раствор; промывочная жидкость; буровая грязь
play - длина нефтеносного пласта
to develop - подготавливать месторождение к эксплуатации; разрабатывать
(месторождение)
environmental impact assessment - экологическая экспертиза, оценка
воздействия на окружающую среду
11.2. Read and translate the text using a dictionary.
Exploration Methods and Techniques
From the drilling of Drake's well in Pennsylvania in 1859 until far into the twentieth century, wells were sunk close to seepages - what is now known as "seepage drilling” - but there was no exploration in the modern sense until geology was applied to the finding of oil in the late nineteenth century. In 1885 several new fields were discovered on the basis of the theory that oil accumulates in the crests of folded rock layers, known to geologists as anticlines.
The first employment of a geologist by an oil company appears to have been in 1897, but not until the discovery of the Cushing Field, Oklahoma, in 1912 as a result of geological survey did geologists enter the industry in any numbers. Soon afterwards, however, many hundreds were roaming all over the USA and other countries in search of anticlines. The period from 1912 to 1925, during which most of the principal anticlines in the USA were discovered, is known as the "anticlinal period", the end of which marks the beginning of modern scientific exploration.
The objective of any exploration venture is to find new volumes of hydrocarbons at a low cost and in a short period of time. Exploration budgets are in direct competition with acquisition opportunities. If a company spends more money finding oil than it would have had to spend buying the equivalent amount "in the market place" there is little incentive to continue exploration. Conversely, a company which manages to find new reserves at low cost has a significant competitive edge since it can afford more exploration, find and develop reservoirs more profitably, and can target and develop smaller prospects.
The usual sequence of activities once an area has been selected for exploration starts with the definition of a basin. The mapping of gravity anomalies and magnetic anomalies will be the first two methods applied. In many cases today these data will be available in the public domain or can be bought as a "non exclusive" survey. Next, a coarse two-dimensional (2D) seismic grid, covering a wide area, will be acquired in order to define leads, areas which show for instance a structure which potentially could contain an accumulation. A particular exploration concept, often the idea of an individual or a team will emerge next. Since at this point very few hard facts are available to judge the merit of these ideas they are often referred to as "play". More detailed investigations will be integrated to define a prospect; a subsurface structure with a reasonable probability of containing all the elements of a petroleum accumulation.
Eventually, only the drilling of an exploration well will prove the validity of the concept. A wildcat is drilled in a region with no prior well control. Wells may either result in discoveries of oil and gas, or they find the objective zone water bearing in which case they are termed "dry".
Exploration activities are potentially damaging to the environment. The cutting down of trees in preparation for an onshore seismic survey may result in severe soil erosion in years to come. Offshore, fragile ecological systems such as reefs can be permanently damaged by spills of crude or mud chemicals. Responsible companies will therefore carry out an Environmental Impact Assessment (EIA) prior to activity planning and draw up contingency plans should an accident occur.
11.3. Answer the questions on the text:
1. When was geology first applied to the finding of oil? 2. Why is the period from 1912 to 1925 known as the “anticlinal period”? 3. What does the end of the "anticlinal period" mark? 4. What is the objective of any exploration venture? 5. Are exploration budgets in direct competition with acquisition opportunities? Why? 6. What is the usual sequence of exploration activities? 7. What are the first two methods applied? 8. What is acquired in order to define leads? What is a lead? 9. What is often referred to as "play"? 10.What is a prospect? 11.What proves the validity of the exploration concept? 12. Why are exploration activities potentially damaging to the environment?
11.4. Translate the following words and phrases into English:
на основе теории; сводовая часть складки; путешествовать, скитаться, странствовать; цель любых поисково-разведочных работ; по низкой цене; приобретение, покупка; стимул; конкурентное преимущество, отличие; гравитационные и магнитные аномалии; быть общедоступным; неопровержимые факты; месторождение нефти; обычная последовательность действий; двухмерная сетка сейсмических профилей; разведочная скважина; наземная сейсмическая разведка; привести к сильной эрозии почв, разлив нефти; химикат, химический продукт, химреагент; составлять план работ в аварийной ситуации.
11.5. Complete these sentences with a suitable word or phrase from the text:
1. Responsible companies carry out ________prior to activity planning.
2. _______, covering a wide area, is acquired in order to define leads.
3. A prospect is a subsurface structure with a reasonable probability of containing all the elements of __________.
4. The cutting down of trees in preparation for _______survey may result in severe soil erosion in years to come.
5. Only the drilling of _______proves the validity of the exploration concept.
6. ________ are areas which show a structure which potentially could contain an accumulation.
7. The first two exploration methods are_________.
8. The objective of any exploration venture is to find new volumes of ______at a low cost and in a short period of time.
9. Not until the _______of the Cushing Field, Oklahoma, in 1912 as a result of geological survey did geologists enter the industry in any numbers.
10. In 1885 several new fields were discovered on the basis of the theory that oil accumulates in the crests of folded rock layers, known to geologists as_______.
11.6. Say whether the following sentences are true (T) or false (F).
1. From the drilling of Drake's well in Pennsylvania in 1859 until far into the twentieth century, wells were sunk close to seepages - what is now known as "anticlinal period".
2. An oil company first employed a geologist in 1897.
3. Exploration budgets are related to acquisition opportunities.
4. A coarse three-dimensional (3D) seismic grid, covering a wide area, is acquired in order to define leads.
5. An exploration well is drilled in a region with no prior well control.
6. Responsible companies carry out an Energy Information Assessment (EIA) before activity planning and draw up contingency plans if an accident occurs.
7. Exploration activities may cause damage to the environment.
8. The drilling of an exploration well always results in discoveries of oil and gas
11.7. Retell the text, using the questions from exercise 3 as a plan.
UNIT 12 DRILLLING THE WELL
Remember the meaning of the following words and word-combinations:
round-the-clock - круглосуточный
spudding in – забуривание (скважины)
completion – заканчивание нефтяной скважины, вскрытие (нефтяного пласта) drilling foreman = toolpusher – буровой мастер
crew - бригада
eight-hour shift - восьмичасовая смена
be in charge of - отвечать за
cuttings - шлам
core – керн
to supervise – наблюдать за ч-л
productive formation - продуктивный пласт
drilling fluid = mud – буровой раствор, промывочная жидкость
treatment - технологическая обработка, очистка
stuck pipe – прихват трубы
kelly – ведущая бурильная труба
rotary table - буровой ротор, стол бурового ротора
weight on the bit - нагрузка на долото
weight indicator - индикатор нагрузки на буровой инструмент
drill string - колонна бурильных труб, бурильная колонна
to descend - опускать, спускать
joint – стык, соединение
to screw on - привинчивать
the first tool joint - первое замковое соединение, первый бурильный замок
to insert wedges – вставлять зажимные плашки
rotary slips – плашки для зажима бурильных труб в роторе
recess – паз, выемка, желобок
table bushing – втулка (вкладыш) роторного стола
derrick – буровая вышка, установка
tongs – трубный ключ, захваты
to resume – начинать снова
to replace – заменять
stand - свеча бурильных труб
to stack – укладывать правильными рядами
derrick man – верховой рабочий
out –подъем, извлечение
running in - спуск
round trip – рейс, спускоподъемная операция
rig – буровая установка (включая вышку)
12.2. Read and translate the text using a dictionary:
The technique of drilling.
The drilling of a well is a round-the-clock operation and usually continues uninterruptedly from the moment of drilling the first foot (spudding in) until completion. Under the supervision of a drilling foreman (toolpusher), three crews, each comprising a driller and four men, work three eight-hour shifts. A mechanic attends to the engines and other specialists are called in as required.
While the drillers are responsible for the mechanical operations of drilling, the engineer in charge has to see that the drilling programme is carried out to best advantage. He may examine drill cuttings and cores before sending them to the laboratory for more detailed examination; he may supervise production tests of potentially productive formations; he will repeatedly test the drilling fluid to ensure its proper consistency and performance, and will see that it receives any necessary chemical or mechanical treatment. This is most important, because neglected or improperly treated mud can seriously impede progress, or even lead to loss of well control, stuck pipe or equally serious hazards.
When the drilling string has been run to bottom and the kelly connected, the mud pumps are started and when normal circulation is achieved the rotary table is put into motion and drilling proceeds. The weight on the bit, as shown by the weight indicator, is kept at the required value by gradually lowering the string until the kelly has descended through most of its length and another joint has to be screwed on. The kelly is then raised until the first tool joint shows above the rotary machine when the weight of the string is taken up by inserting wedges (rotary slips) around the drill pipe. These slips fit into a recess in the rotary table, known as the table bushing. The kelly is then unscrewed by means of mechanically operated tongs and is placed to one side of the derrick. A 30 ft joint of drill pipe is screwed on the kelly is replaced and drilling is resumed.
At intervals, generally because a bit has to be replaced, the entire string is pulled and unscrewed in 90 ft stands which are stacked in a nearly upright position on one side of the derrick floor with the help of the derrick man. This man occupies a rather precarious position on a platform high up in the derrick, to which he is attached by a safety belt.
Pulling out and running in a long, heavy drilling string (the entire operation is called a 'round trip') is a lengthy business in spite of efficient handling methods and powerful equipment. On a well organized rig drilling at 15 000 ft, it may take 51 hours to pull out and 31 hours to run back in again, the pulling out taking longer on account of the great weight (about 100 tons) to be lifted in the early stages.
12. 3. Answer the questions on the text:
1) How long does the drilling of a well last? 2) Who supervises the work of a drilling crew? 3) What are the drillers responsible for? 4) What is an engineer in charge of ? 5) Why is chemical and mechanical treatment of the drilling fluid necessary? 6) What device shows the weight on the bit? 7) Does the drill string consist of several joints? 8) Why is it necessary to make intervals during the drilling operations? 9) How long are the stands which are stacked on one side of the derrick floor? 10) Who helps to carry out this operation? 11) Is a ‘round trip’ a lengthy business? 12) How long does it take and why?
12.4. Give English equivalents of the following word-combinations from the text:
Продолжаться непрерывно, по мере необходимости, наилучшим образом, подробное исследование, гарантировать необходимую стабильность и функционирование бурового раствора, препятствовать продвижению вниз, серьёзная опасность, бурение начинается, поддерживается на нужном уровне, постепенно опуская, подходить к ч-л, развинчивать (отвинчивать), почти в вертикальном положении, предохранительный пояс, несмотря на , мощное оборудование, из-за
Match the words in list A with their equivalents in list B and translate them into Russian:
List A
1) round-the-clock 2) to supervise 3) pulling out and running in 4) wedges 5) drilling the first foot 6) drilling foreman 7) drilling mud 8) to change 9) to impede
List B
a) ‘round trip’ b) spudding in c) drilling fluid d) twenty-four-hour e) toolpusher f) to replace g) to prevent h) to control i) slips
Choose the only correct variant to fill in the gap:
1) The drilling of a well begins with spudding in end finishes with ………… .
a) round trip b) pulling out c) completion d) a shift
2) …………. is responsible for the uninterrupted work of engines.
a) A mechanic b) A toolpusher c) A derrick man d) A mud engineer
3) …………… helps to cool the bit and to carry the cuttings to the surface.
a) Drilling foreman b) Spudding in
c) Drilling fluid d) Drilling string
4) A ‘round trip’ operation is necessary to replace …………. .
a) the kelly b) the slips c) the tongs d) the bit
5) The kelly is ……………. by means of mechanically operated tongs.
a) is unscrewed b) is descended c) is controlled d) is raised
6) The man who occupies a position on a platform high up in the derrick is called
……………… .
a) a toolpusher b) a derrick man c) a foreman d) an engineer
7) Replacement of a bit is a lengthy operation ……….. the great weight of the
string.
a) in spite of b) by means of c) because of d) because
Give the summary of the text.
UNIT 13 HOW ARE OIL AND GAS PRODUCED?
13.1 Remember the meaning of the following words and word-combinations:
to produce – добывать
to recover – добывать, извлекать
production – добыча
producing well = production well – эксплуатационная скважина
once – как только
reservoir – коллектор, нефтеносный или газоносный пласт
reservoir rock – коллекторская порода
to assess - оценить (потенциал коллектора)
pore spaces – поровое пространство, поры
to part - (зд.) отдавать, расставаться с ч-л
to stabilize a borehole – cтабилизировать скважину, выравнивать перепад
давлений между стволом скважины и пластом
casing – обсадные трубы, крепление обсадными трубами
to cement – цементировать
to pass through – проходить через ч-л
to contaminate – загрязнять
tubing string – насосно-компрессорная колонна
wellbore – cкважина
wellhead – устье скважины
bottom of the wellbore – забой скважины
packer – сальник, трубный пакер
valve – клапан, вентиль, задвижка
to install – устанавливать, монтировать
depending on – в зависимости от
insufficient - недостаточный
be referred to - ( зд.) называться
predictable – предсказуемый
decline curve – кривая падения (добычи), кривая истощения ( пласта)
“workover” – 1) ремонт скважины; 2) операции по увеличению дебита
скважины (дополнительное углубление, прострел, кислотная
обработка)
to age – стареть
waterflooding - заводнение ( нефтяного месторождения)
to convert – трансформировать, превращать
injection well – нагнетательная скважина
enhanced oil recovery (EOR) – добыча нефти вторичным методом
per se – сам по себе, по существу
to remove impurities – удалять примеси
feedstock – исходное сырьё, перерабатываемое сырьё
consumer – потребитель
gas-to-liquids (GTL) – технология перевода из газообразного в жидкое
состояние
liquefied natural gas (LNG) – cжиженный природный газ
facilities – оборудование, аппаратура, средства
Read and translate the text using a dictionary:
How are Oil and Gas Produced?
Once an oil or gas reservoir is discovered and assessed, production engineers begin the task of maximizing the amount of oil or gas that can ultimately be recovered from it. Oil and gas are contained in the pore spaces of reservoir rock. Some rocks may allow the oil and gas to move freely, making it easier to recover. Other reservoirs do not part with the oil and gas easily and require special techniques to move the oil or gas from the pore spaces to a producing well. Even with today's advanced technology, in some reservoirs more than two-thirds of the oil in the reservoir rocks may not be recoverable.
Before a well can produce oil or gas the borehole must be stabilized with casing, which is lengths of pipe cemented in place. The casing also serves to protect any fresh water intervals that the well passes through, so that oil cannot contaminate the water. A small-diameter tubing string is centered in the wellbore and held in place with packers. This tubing will carry the hydrocarbons from the reservoir to the surface.
Reservoirs are typically at elevated pressure because of underground forces. To equalize the pressure and avoid the "gushes" of the early 1900s, a series of valves and equipment is installed on top of the well. This wellhead, or "Christmas tree," as it is sometimes called, regulates the flow of hydrocarbons out of the well.
Early in its production life, the underground pressure will often push the hydrocarbons all the way up the wellbore to the surface, much like a carbonated soft drink that has been shaken. Depending on reservoir conditions, this "natural flow" may continue for many years. When the pressure differential is insufficient for the oil to flow naturally, mechanical pumps must be used to bring the oil to the surface. This process is referred to as artificial lift. In the U.S., above-ground pumping units are often called "horsehead" pumps because of their unique shape and movement.
Most wells produce in a predictable pattern called a decline curve. Production will increase for a short period, then peak and follow a long, slow decline. The shape of this decline curve, how high the production peaks, and the length of the decline are all driven by reservoir conditions. Some wells may stop producing in economic quantities in only a few years. In the U.S., 8 oil and gas fields have been producing for more than 100 years.
Engineers can do a variety of things to affect a well's decline curve. They may periodically perform an operation called a "workover", which cleans out the wellbore to help oil or gas move more easily to the surface. They may fracture or treat the reservoir rock with acid around the bottom of the wellbore to create better pathways for the oil and gas to move through the subsurface to the producing well.
As a field ages, the company may choose to use a technique called waterflooding. In this case, some of the wells in the field are converted from production wells to injection wells. These wells are used to inject water (often produced water from the field) into the reservoir. This water tends to push the oil out of the pores in the rock toward the producing well. Waterflooding will often increase production from a field.
In more advanced cases, the company may use more sophisticated techniques, collectively referred to as enhanced oil recovery (EOR). Depending on reservoir conditions, various substances [from steam to nitrogen, carbon dioxide to a surfactant (soap)] may be injected into the reservoir to remove more oil from the pore spaces and increase production. Throughout their productive life, most oil wells produce oil, gas, and water. This mixture is separated at the surface. Initially, the mixture coming from the reservoir may be mostly oil with a small amount of water. Over time, the percentage of water increases. On average in the United States, oil wells produce 8 barrels of water for each barrel of oil. Some older wells may produce as much as 100 barrels of water for each barrel of oil. This produced water varies in quality from very briny to relatively fresh. In arid areas of the western U.S., produced water may be used for agricultural purposes, such as livestock watering or irrigation. Where it cannot be used for other purposes, this produced water may be reinjected into the reservoir — either as part of a waterflooding project or for disposal (returning it to the subsurface).
Natural gas wells usually do not produce oil, per se, but do produce some amount of liquid hydrocarbons. These natural gas liquids are removed in the field or at a gas processing plant (which may remove other impurities as well). Natural gas liquids often have significant value as petrochemical feedstocks. Natural gas wells also often produce water, but the volumes are much lower than is typical for oil wells.
Once it is produced, oil may be stored in a tank and later moved by means of truck, barge, or ship to where it will be sold or enter the transportation system. Most often, however, it goes from the separation facilities at the wellhead directly into a small pipeline, which then, feeds into a larger pipeline. Often, pipelines are used to bring the production from offshore wells to shore. Pipelines may transfer oil from a producing field to a tanker loading area for shipping. Pipelines also may be used to move oil from a port area to a refinery to be processed into gasoline, diesel fuel, jet fuel, and many other products.
Natural gas is almost always transported through a pipeline. Because of the difficulty in moving it from where it exists to where potential consumers are, some known gas deposits are not currently being produced. Many years ago, the gas may have been wasted as an unwanted byproduct of oil production. The industry recognizes the value of clean-burning natural gas and is working on improved technologies for getting gas from the reservoir to the consumer. Gas-to-liquids (GTL) is an area of technology development that will allow natural gas to be converted to a liquid, transported by tanker. Some countries have installed facilities to export gas as liquefied natural gas (LNG), but the number of countries with facilities to use LNG is still limited.
13.3. Answer the questions on the text:
1) Where are oil and gas contained? 2) What must be done before a well can produce oil or gas? 3) What is casing and what does it serve to? 4) Why are reservoirs often at high pressure ? 5) What is done to avoid “gushers”? 6) How long may a natural flow of the hydrocarbons continue? 7) What is an artificial lift and when is it applied? 8) What can engineers do to affect a well’s decline curve? 9) When is the technique of waterflooding used? 10) Describe the waterflooding technique. 11) What is enhanced oil recovery (EOR)? 12) How much water is produced from oil wells in the USA? 13) How is this water used? 14) Was natural gas considered for many years as an unwanted by-product of oil production? 15) What happens to produced natural gas today? 16) What technologies are developed to transport natural gas by tankers?
13.4. Give English equivalents to the following word-combinations from the text:
Передовая технология, загрязнять воду, повышенное давление, избегать выброса нефти “фонтаном”, устанавливать вентили (задвижки), устье скважины, забой скважины, выталкивать углеводороды, недостаточный, искусственный подъем (нефти), станок-качалка в форме «головы лошади», товарное количество (нефти), влиять на кривую падения добычи из скважины, обрабатывать кислотой, сложные (усовершенствованные) технологии, в среднем, соленый, пресный, газоперерабатывающий завод, установка по отделению, отгрузка, нефтеперерабатывающий завод, газовое месторождение, не использовать.
13.5. Match the words from list A with the words from list B and translate them into Russian:
List A
1. to discover and assess 2. to stabilize 3. to contaminate 4. to center 5. to avoid 6. artificial 7. to affect a well’s 8. to treat 9. to remove 10. to convert
List B
a) the water b) the “gushers” c) decline curve d) with acid e) impurities
f) an oil or gas reservoir g) to a liquid h) a borehole with casing
i) a tubing string in the wellbore j) lift
13.6. Choose the only correct variant to fill in the gaps:
1) The task of production engineers is …………… the maximum amount of oil
from the reservoir.
a) to assess b) to discover c) to recover d) to contaminate
2) Due to elevated underground pressure the hydrocarbons are………. up the
borehole.
a) treated b) pushed c) referred d) installed
3) Mechanical pumps are used to lift the oil to the surface if natural pressure is
……………. .
a) insufficient b) wasted c) liquefied d) high
4) An operation of cleaning out the wellbore to help oil or gas move more easily
is called ……………. .
a) “gushers” b) “horsehead” c) “workover” d) “Christmas tree”
5) ……………. can be used to move oil from a production area to the consumer.
a) Feedstock b) Facilities c) A refinery d) Pipelines
6) Natural gas wells produce …………… .
a) a lot of water b) oil c) liquid hydrocarbons d) impurities
7) The volumes of water produced from natural gas wells are ………….. than
those from oil wells.
a) lower b) higher c) the same d) much higher
13.7. Give the summary of the text about oil and gas production using the following word-combinations:
The pore spaces of reservoir rock, to drill and stabilize a borehole, to avoid the ‘gushers’, natural flow, artificial lift, to produce in economic quantities, waterflooding, injection wells, enhanced oil recovery (EOR), to produce water, to remove impurities, to transmit through pipelines.