A. Comprehension

Answer the questions:

1. There are many different theories as to the origins of fossil fuels. What does the most widely accepted theory say about fossil fuels formation?

2. Why is natural gas usually associated with oil in deposits that are 1 to 2 miles below the earth's crust? And where can we find pure methane?

3. What is biogenic methane? How is it usually formed?

4. What is landfill gas?

5. What is the third way in which methane (and natural gas) may be formed? Describe it shortly.

6. Are the processes of natural gas formation identical to the processes of oil formation?

7. What geological formations ‘trap’ gas under the ground?

8. How must a hole be drilled to bring fossil fuels to the surface successfully?

9. Is recovery of gas or recovery of oil a more efficient process ? Why?

10) In practice, only about 75- 80 percent of the in-place gas can be recovered. Explain why.

2. Vocabulary practice

1. Give the Russian equivalents for:

1) to become an inanimate mixture of gases; 2) to be found underneath the surface of the earth; 3) to be formed when organic matter is compressed under the earth; 4) to put a great deal of pressure on the organic matter; 5) tiny methane producing microorganisms; 6) void of oxygen; 7) close to the surface of the earth; 8) to be lost into the atmosphere; 9) to be formed through abiogenic processes; 10) to interact with minerals that exist underground ; 11) to form elements and compounds that are found in the atmosphere; 12) loose, shale type rock; 13) geological formations that 'trap' the gas under the ground; 14) to shift down to trap natural gas; 15) 'dome' shape; 16) to contain more recoverable energy; 17) differences in the physical and chemical properties; 18) initial low concentration and high dispersibility; 19) deep or shallow drilling; 20) to occur throughout and below the oil window; 21) different physical variations affecting reservoir performance and recovery; 22) to recover nearly all of the in-place gas; 23) the encroachment of water in the sedimentary rock formation; 24) actual gas recovery; 25) associated gas.

2. Give the English equivalents for:

1) различные теории, объясняющие образование ископаемого топлива; 2) образовываться из органических частиц, покрытых илом и другими осадками; 3) метан-продуцирующие микроорганизмы; 4) химически разрушать органическое вещество; 5) газ из органических отходов; 6) абиогенные процессы; 7) процессы, происходящие в отсутствии кислорода; 8) реакции, в результате которых образуются новые элементы и соединения; 9)газы, богатые водородом; 10) подвергаться высокому давлению в процессе продвижения к поверхности земли; 11) обладать низкой плотностью; 12) сланцевая порода; 13) рассеиваться в атмосферу; 14) захватывать большое количество природного газа, образуя резервуар; 15) бурить отверстие через непроницаемую породу; 16) обладая меньшей плотностью, располагаться ближе к поверхности; 17) газ, находящийся в резервуаре под давлением; 18) мигрировать и скапливаться в ловушках; 19) возместимая энергия; 20) более эффективный процесс; 21) сдвиг породы; 22) образовываться над «нефтяным окном», встречаться в самом «нефтяном окне» и под ним; 23) сбросить давление в достаточной степени; 24) добывать лишь 80 % от содержащегося в резервуаре природного газа; 25) попутный газ, добываемый вместе с нефтью.

3. Fill in the appropriate word(s) from the list below into the extracts and translate them into Russian:

1. Organisms, carbon bonds, harmful, to be composed, natural gas, fuels, origin, microorganisms, compression, sediment, mud, electricity, explanation, pressure, theories, heat, conveniences, chemical, source, to be buried.

When we use … powered heaters and stoves in our homes, we usually neglect to ponder the fact that these modern … are made possible by a natural substance of ancient … . Even the … supplied by utility companies often relies on natural gas for production. Natural gas, which … primarily of methane, is an important … of energy in the world today, burning cleaner and producing less … emissions than other … . With the widespread use and reliance on natural gas, one can easily forget that this key source of energy originated from … which lived millions of years ago.

Several differing … attempt to explain the true origin of natural gas, though the most widely accepted … is that natural gas forms from the remains of ancient … as well as plant and animal matter that have undergone conditions of extreme … and … over very long periods of time. As such organic matter … by increasing amounts of … and … over time, the resulting pressure forces it further underground, compressing the matter and subjecting it to the high temperatures that exist deep within the earth. Intense … and high temperature conditions cause … in the organic matter to break down, a … transformation resulting in the formation of natural gas and other fossil fuels.

b) escape, methanogens, closer, impermeable, reservoir, oxygen, depths, rock, natural, extraction, energy, atmosphere, microscopic, resistance, low, drilling intense, atop, byproduct, to be treated, escaping.

Another way natural gas is formed is by microorganisms known as … . Methanogens are … organisms which live in environments devoid of … and chemically decompose organic matter, creating methane as a … . Contrary to the natural gas formed by compression of organic matter under … pressure at great …, methane created by methanogens is typically found … to the earth’s surface where the organisms live.

Once natural gas forms within the earth, its … density causes it to rise through the path of least…, often escaping the earth’s crust and dissipating into the … . But natural gas deposits that are sought for … by different companies form when … rock “traps” the natural gas within the earth, preventing it from … and causing it to collect, creating a … .

Natural gas is usually located within such reservoirs floating … oil deposits, which have formed reservoirs in much the same way. However, deposits containing only natural gas are not unusual. Both the oil and natural gas may be extracted by … into the impermeable rock restricting the fossil fuels to the reservoir. The … pressure already present within the reservoir allows the fossil fuels to … on their own once the … containing them is penetrated.

Once natural gas is extracted from the earth, it … (if necessary) and distributed to supply the … on which much of the world relies.

c) scientists, criteria, to be drilled, impurities, gasoline, hydrocarbons, reservoirs, formations, buried, rock, hold, refine, useful, well, rivers, subterranean.

Oil and Gas Reservoirs.

Hydrocarbons and their associated … occur in rock … that are usually … thousands of feet or metres below the surface. … and engineers often call … formations that hold hydrocarbons "… ."

Oil does not flow in underground … or pool up in … lakes, contrary to what some people think. And, as you've learned, … and other refined … do not narurally occur in pockets under the ground, just waiting … for. Instead, crude oil and natural gas occur in buried rocks and, once produced from a …, companies have to … the crude oil and process the natural gas into … products. Further, not every rock can … hydrocarbons. To serve as an oil and gas reservoir, rocks have to meet several … .

d) suitable, pores, permeable, to flow, to produce, voids, to occur, locked, microscope, to contain, economically, porosity, sandstone, to move out, to be connected, solid.

Characteristics of Reservoir Rocks.

Nothing looks more … than a rock. Yet, choose the right rock - say, a piece of … or limestone - and look at it under a … . You see many tiny openings or … . Geologists call these tiny openings "…" (fig. 1). A rock with pores is "porous" and a porous rock has "…." Reservoir rocks must be porous, because hydrocarbons can … only in pores.

A reservoir rock is also … - that is, its pores … (fig. 2). If hydrocarbons are in the pores of a rock, they must be able … of them. Unless hydrocarbons can move from pore to pore, they remain … in place, unable … into a well. A … reservoir rock must therefore be porous, permeable, and … enough hydro­carbons to make it … feasible for the operating company to drill for and … them.

Fig 1. Connected pores give a rock permeability.

Fig 2. A pore is a small open space in a rock.

4. Match the following terms with their definitions, give their Russian equivalents and make up your own sentences with them:

trap, sedimentary basin, dome, accumulation, reservoir, migration, water encroachment, layer.

1. A depression in the crust of the Earth formed by plate tectonic activity in which sediments accumulate.

2. The movement of hydrocarbons from their source into reservoir rocks.

3. The phase in the development of a petroleum system during which hydrocarbons migrate into and remain trapped in a reservoir.

4. A configuration of rocks suitable for containing hydrocarbons and sealed by a relatively impermeable formation through which hydrocarbons will not migrate.

5. The movement of water into a producing formation as the formation is depleted of oil and gas by production.

6. A geologic structure resembling an inverted bowl. A short anticline plunging on all sides.

7. A slab of reservoir rock bounded above and below by another layer in vertical hydraulic communication.

8. A subsurface body of rock having sufficient porosity and permeability to store and transmit fluids.

5. Explain the following terms using a specialized dictionary and glossary, give their Russian equivalents and make up your own phrases with them:

shallow deposits, geological formations, biogenic methane, landfill gas.

VI. Give English translation for:

1. Единого мнения о происхождении нефти и газа в настоящее время пока не существует. Имеются гипотезы неорганического и органического происхождения нефти и газа.

2. Многие ученые придерживаются гипотезы неорганического происхождения нефти и газа в недрах земли в результате химических реакций между водородом и углеродом в условиях воздействия высоких температур и давления ( и при отсутствий органических веществ).

3. Гипотеза органического происхождения нефти предполагает образование нефти и газа из остатков животных и растительных организмов в условиях высоких температур при отсутствий кислорода.

4. Живые организмы, в основном, планктон и водоросли, отмирая, опускались на дно морей, затем в течение миллионов лет их заносило песком и илом, таким образом, они оказывались погребенными глубоко под осадочными породами.

5. Температура земной коры увеличивается ближе к центру земли, поэтому останки растений и животных подогревались, постепенно превращаясь в нефть и газ.

6. Нефть образуется при температуре от 50 до 175 градусов Цельсия, при более высоких температурах из останков образуется природный газ.

7. Метан образуется из трех источников: при термическом разложении органического материала, из небиологических реакций простых неорганических соединений или через метаболическую активность метаногенных бактерий.

8. Газ метан также может образовываться и при невысоких температурах на небольшой глубине под землей. Например, в болотах при разложении растений и других органических останков образуется болотистый газ - метан.

9. В залежах угля, образованного из останков древних деревьев, погребенных глубоко под землей, тоже образуется метан.

10. Для формирования месторождений нефти и газа в залегающих в глубинах земли отложениях, необходимы следующие условия: наличие соответствующих пород-коллекторов и относительно непроницаемых покрышек и ловушек, которые предотвращают утечку углеводородов к земной поверхности.

11. Для того чтобы стать коллектором, порода должна обладать пористостью и проницаемостью. Те же свойства необходимы для сохранения нефти и газа, а также запасов подземных вод.

12. Для образования залежей необходимо, чтобы пористые и проницаемые породы-коллекторы перекрывались породами, которые препятствуют последовательной миграции нефти и газа вверх.

13. Когда газ обнаруживают вместе с месторождениями нефти, его называют попутным газом, который раньше сжигался в факелах как бесполезный побочный продукт.

14) В отличие от природного газа попутный нефтяной газ содержит в своем составе кроме метана и этана большую долю пропанов, бутанов и паров более тяжелых углеводородов. Во многих попутных газах, в зависимости от месторождения, содержатся также неуглеводородные компоненты: сероводород и меркаптаны, углекислый газ, азот, гелий и аргон.

15) Сегодня нефтяной попутный газ является ценнейшим иcтoчником cыpья для пpoизвoдcтва pяда xимичеcкиx продуктов, источник получения дешевой электрической и тепловой энергии.

С. Discussion

Topics:

1. Oil and gas migration.

2. Accumulation of oil and gas.

3. Reservoir rocks.

Unit 4. Unconventional Gas Reservoirs

Active Vocabulary

1.	coalification	карбонизация, обуглероживание; обугливание; углефикация
2.	joint	трещина
3.	blanket	поверхностный / защитный слой, отложение, пласт, слой; нанос
4.	devonian	девон, девонский период
5.	lattice	структура, кристаллическая решётка
6.	flow rate	1. расход жидкости; количество жидкости, протекающей в единицу времени 2. производительность (насоса, компрессора) 3. дебит (скважины или промысла)
7.	outlook	1. (for) перспективы, виды на будущее 2. точка зрения, взгляд
8.	hydrate	гидрат, гидроксид
9.	shale gas	сланцевый газ
10.	coal-bed/ coal seam	угольный пласт
11.	coal-bed gas	газ угольных пластов
12.	ascent	повышение, подъём
13.	clathrate	хим. клатрат
14.	spin	осевое вращение
15.	iridescent	радужный, переливчатый, переливающийся
16.	tight	плотный, герметичный, тугой
17.	resultant	получающийся в результате чего-либо
18.	plentiful	изобилующий, изобильный, обильный
19.	feasible	возможный; выполнимый; осуществимый
20.	to spin	вращать (ся) , свинчивать; развинчивать (бурильные или насоснокомпрессорные трубы), скручивать, закручивать
21.	to confine	ограничивать
22.	to revert	возвращаться (в прежнее состояние)
23.	to encounter	(неожиданно) встретиться, столкнуться , натолкнуться
24.	to unleash	развязывать, высвобождать, давать волю
25.	to entrain	1. увлекать за собой, 2. помещать (жидкость, газ; куда-л.)
26.	to exploit	пользоваться,использовать, эксплуатировать
27.	to complement	дополнять; составлять; комплектовать
28.	to supplant	выжить, вытеснить; занять (чьё-л.) место
29.	to squeeze/ to squeeze out	сжимать; сдавливать; стискивать/ выдавливать, выжимать, вытеснять
30.	lenticular sand	линзовидный пласт
31.	unconventional gas	природный газ нетипичного происхождения
32.	hydraulic fracturing	гидравлический разрыв
33.	carbon cycle	углеродный цикл
34.	geopressurized gas	газ зон геодавлений
35.	in situ	1. на месте естественного залегания 2. на месте проведения работ
36.	USGS	(United States Geological Survey) Геологическая служба США
37.	darcy	дарси, D (внесистемная единица проницаемости пористых сред)

Substantial amounts of gas have accumulated in geologic environments that differ from conventional petroleum traps. This gas is termed unconventional gas and occurs in "tight" (i.e. relatively impermeable) sandstones, in joints and fractures or absorbed into the matrix of shales (often of the Devonian Period about 360,000,000 to 408,000,000 years old), dissolved or entrained in hot geopressured formation waters, and in coal seams. Unconventional gas sources are much more expensive to exploit and have to be produced at much slower rates than conventional gas fields. Moreover, recoveries are low. In all likelihood, unconventional gas will continue to complement conventional gas production but will not supplant it.

Deep Natural Gas

Deep natural gas is exactly what it sounds like - natural gas that exists in deposits very far underground, beyond 'conventional' drilling depths. This gas is typically 15,000 feet or deeper underground, quite a bit deeper than conventional gas deposits, which are traditionally only a few thousand feet deep, at most.

Deep gas has, in recent years, become more conventional. Deep drilling, exploration, and extraction techniques have substantially improved, making drilling for deep gas economical. However, deep gas is still more expensive to produce than conventional natural gas, and as such, economic conditions have to be such that it is profitable for the industry to extract from these sources.

Tight gas

Tight gas occurs in either blanket or lenticular sandstones that have an effective permeability of less than 1 millidarcy (or 0.001 darcy, which is the standard unit of permeability of a substance to fluid flow). These relatively impermeable sandstones are reservoirs for considerable amounts of gas that are mostly uneconomical to produce because of low natural flow rates. The outlook for increased production of gas from tight sandstones has been enhanced by the use of massive hydraulic fracturing techniques that create large collection areas in low-permeability formations through which gas can flow to a producing well. A fractured well in a tight gas formation usually produces at a lower rate than a conventional gas well but for a longer time. About 2 percent of the gas production in the United States comes from tight sandstones.

Devonian shale gas

Devonian shale gas was generated from organic mud deposited during the Devonian Period. Subsequent sedimentation and the resultant heat and pressure transformed the mud into shale and also produced natural gas from the organic matter contained therein. Some of the gas migrated to adjacent sandstones and was trapped in them, forming conventional gas accumulations. The rest of the gas remained locked in the nonporous shale. The production history of Devonian shale gas indicates that the recovered gas occurs in well-connected fracture porosity. Production is generally at low flow rates but is long-lasting. The factor of greatest importance in commercial production is the presence of natural fractures, but wells can be stimulated by explosives or by hydraulic fracturing, which sometimes enhances gas production. About 1 percent of the gas produced in the United States comes from Devonian shales.

Coal-bed gas

Considerable quantities of methane are trapped within coal seams. Although much of the gas that formed during the initial coalification process is lost to the atmosphere, a significant portion remains as free gas in the joints and fractures of the coal seam and as adsorbed gas on the internal surfaces of the micropores within the coal itself. Since coal is relatively impermeable, any methane recovered usually must flow through existing fracture systems. Therefore, coal seams that are highly fractured appear to be the best sources of coal-bed methane.

Geopressurized Zones

Geopressurized zones are natural underground formations that are under unusually high pressure for their depth. These areas are formed by layers of clay that are deposited and compacted very quickly on top of more porous, absorbent material such as sand or silt. Water and natural gas that is present in this clay is squeezed out by the rapid compression of the clay, and enters the more porous sand or silt deposits. This natural gas, due to the compression of the clay, is deposited in this sand or silt under very high pressure (hence the term 'geopressure'). In addition to having these properties, geopressurized zones are typically located at great depths, usually 10,000-25,000 feet below the surface of the earth. The combination of all of these factors makes the extraction of natural gas in geopressurized zones quite complicated. However, of all of the unconventional sources of natural gas, geopressurized zones are estimated to hold the greatest amount of gas. Most of the geopressurized natural gas in the U.S. is located in the Gulf Coast region. The amount of natural gas in these geopressurized zones is uncertain. However, experts estimate that anywhere from 5,000 to 49,000 Tcf of natural gas may exist in these areas! Given the current technically recoverable resources are around 1,100 Tcf, geopressurized zones offer an incredible opportunity for increasing the nation's natural gas supply.

Methane Hydrates

Methane hydrates were only discovered in the late twentieth century, and thus constitute the last unconventional gas resource to appear. They are also, very probably, the largest resource, and, along with geopressurized zone gas, the best means of prolonging the carbohydrate age of energy. Methane hydrates, also known as clathrates or gas hydrates, are potentially a huge resource, which by the most generous estimates stores thermal energy equivalent to that of 100 trillion barrels of oil.

Methane hydrates are unstable compounds formed from water and methane in which the water molecules form a sort of cage or lattice around the methane molecules and the two establish weak chemical bonds with one another. Clathrates only appear under conditions of intense pressure and extreme cold and are found in arctic permafrost and in the depths of the sea. Interestingly, submarine clathrates are not confined to regions of cold surface waters, but are quite abundant in the Gulf of Mexico, and presumably elsewhere in warm regions of the globe. This may be explained by the fact that the temperature of abyssal waters is normally just above freezing at all latitudes.

Methane hydrates look like chunks of ice, although frequently they are shot through with bursts of iridescent colors representing minor impurities. Upon being exposed to normal atmospheric pressures they revert very rapidly to their constituents, methane and water.

A number of techniques have been proposed for harvesting methane hydrates, and at least a couple has been attempted on an experimental basis. Whatever technique is utilized, the gas has to be released in situ, at or immediately adjacent to the area where the methane hydrate deposit occurs. If one attempts to bring the clathrates up from the sea floor or from an excavation in the permafrost, most of the methane will be lost in transit.

А. Comprehension

Answer the questions:

1) What gas is termed unconventional gas?

2) What is deep natural gas?

3) Where does tight gas occur?

4) How was devonian shale gas generated?

5) What is coal-bed gas?

6) Why do coal seams appear to be the best sources of coal-bed methane?

7) What is geopressurized gas?

1. Why are methane hydrates the best means of prolonging the carbohydrate age of energy?

2. Explain why the recovery of unconventional gas is considered to be unprofitable.

3. What methods are used to enhance the production of gas from unconventional gas sources?

B. Vocabulary practice

9. Give English equivalents for:

1. значительное количество газа; 2) отличаться от традиционных нефтегазовых ловушек; 3) природный газ нетипичного происхождения; 4) плотные песчаники; 5) глубокое бурение; 6) методы разведки и добычи; 7) встречаться в поверхностных и линзовидных пластах; 8) эффективная проницаемость; 9) относительно непроницаемый песчаник; 10) газ, неэкономичный для добычи; 11) использовать метод гидроразрыва пласта; 12) последующая седиментация: 13) мигрировать в прилегающие песчаники; 14) газ, заблокированный в плотном глинистом сланце; 15) наличие естественной трещиноватости (породы); 16) увеличивать добычу газа; 17) газ, образовавшийся в процессе формирования угля; 18) свободный газ в трещинах угольного пласта; 19) протекать через существующую систему трещин; 20) газ, залегающий в зонах геодавлений; 21) превышать все запасы газа вместе взятые; 22) нестабильные соединения, образованные из молекул воды и метана; 23) образовываться в условиях сильного давления и экстремального холода; 24) потенциально огромные запасы; 25) распадаться на составляющие при нормальном атмосферном давлении.

II. Give Russian equivalents for:

1) geologic environments that differ from conventional petroleum traps; 2) to occurs in "tight" sandstones; 3) to be much more expensive to exploit; 4) not to supplant conventional gas production; 5) beyond 'conventional' drilling depths; 6) deep drilling; 7) to be profitable for the industry; 8) to occur in either blanket or lenticular sandstones; 9) to have an effective permeability of less than 1

millidarcy; 10) low natural flow rates; 11) massive hydraulic fracturing techniques; 12) to be generated from organic mud deposited during the Devonian Period; 13) to transform the mud into shale; 14) to migrate to adjacent sandstones and to be trapped in them; 15) to remain locked in the nonporous shale; 16) the factor of greatest importance in commercial production; 17) to enhance gas production; 18) to be trapped within coal seams; 19) the initial coalification process; 20) to remain as adsorbed gas on the internal surfaces of the micropores within the coal itself; 21) to flow through existing fracture systems; 22) to be the best sources of coal-bed methane; 23) unusually high pressure; 24) commercially feasible extraction technique; 25) to form a sort of cage or lattice around the methane molecules; 26) appear under conditions of intense pressure and extreme cold; 27) to be released in situ.

III. Fill in the appropriate word(s) from the list below into the extracts and translate them into Russian:

a) to disintegrate, soft, shale, to exist, conventional, properties, to contain, extraction, mud

Natural gas can also … in Devonian shale deposits. Devonian shales are formed from the … of shallow seas that existed about 350 million years ago (during the Devonian period of the Paleozoic era). … is a very fine-grained sedimentary rock, which is easily breakable into thin, parallel layers. It is a very … rock, but does not … when it becomes wet. These shales can … natural gas, usually when two thick, black shale deposits 'sandwich' a thinner area of shale. Because of some of the … of these shales, the … of natural gas from shale formations is more difficult (and thus expensive!) than extraction of … natural gas.

b) global, wells, drillings, high, deposits, to be found, conventional, commercially, to exceed, depths, to be exploited, resource

Geopressurized zones are … of natural gas under unusually … pressure, and occupying layers of sand or silt located at … of between fifteen and twenty-five thousand feet. These zones may … either under dry land or beneath sea beds. Total … resources of geopressurized gas are believed … all other … and unconventional gas resources put together with the exception of methane hydrates.

Given the size of the … and the continued ascent of natural gas prices, we believe that geopressurized zones will … in time, but the time is not yet. No … feasible extraction technique has been developed to date, and only exploratory … have been made. There are no commercially producing … today.

c) activities, industry, to be trapped, conditions, digging, seams, fossil, methane, leaks, threat, coal

Coal, another … fuel, is formed underground under similar geologic … as natural gas and oil. These coal deposits are commonly found as … that run underground, and are mined by … into the seam and removing the coal. Many coal seams also contain natural gas, either within the seam itself or the surrounding rock. This coal-bed methane … underground, and is generally not released into the atmosphere until coal mining … unleash it. Historically, coal-bed methane has been considered a nuisance in the coal mining … . Once a mine is built, and … is extracted, the methane contained in the seam usually … out into the coal mine itself. This poses a safety …, as too high a concentration of … in the well create dangerous conditions for coal miners.

d) natural gas, atmosphere, has increased, energy, latticelike, temperatures, to be discovered, permafrost, conventional, inexpensively, energy, drill, unstable, control, to explode, to encounter, to underlie, to cause

What do you get when you combine water and swamp gas under low … and high pressures? You get a frozen … substance called methane hydrate, huge amounts of which … our oceans and polar …. This crystalline combination of a … and water (known technically as a clathrate) looks remarkably like ice but burns if it meets a lit match.

Methane hydrate … only a few decades ago, and little research has been done on it until recently. By some estimates, the … locked up in methane hydrate deposits is more than twice the global reserves of all … gas, oil, and coal deposits combined. But no one has yet figured out how to pull out the gas …, and no one knows how much is actually recoverable. Because methane is also a greenhouse gas, release of even a small percentage of total deposits could have a serious effect on Earth's … .

Research on methane hydrate … in the last few years, particularly in countries such as Japan that have few native … resources. As scientists around the world learn more about this material, new concerns surface. For example, ocean-based oil-drilling operations sometimes … methane hydrate deposits. As a … spins through the hydrate, the process can cause it to dissociate. The freed gas may …, causing the drilling crew to lose … of the well. Another concern is that … hydrate layers could give way beneath oil platforms or, on a larger scale, even … tsunamis.

IV. Match the following terms with their definitions and give their Russian equivalents and make up your own sentences with them:

in situ, hydraulic fracturing, shale, darcy, tight, gas hydrate, coal, geopressure

1. A carbon-rich sedimentary rock that forms from the remains of plants deposited as peat in swampy environments. Burial and increase in temperature bring about physical and chemical changes called coalification.

2. The pressure within the Earth, or formation pressure.

3. A standard unit of measure of permeability.

4. A crystalline solid consisting of water with gas molecules in an ice-like cage structure.

5. A stimulation treatment routinely performed on oil and gas wells in low-permeability reservoirs.

6. A dark fine-grained laminated sedimentary rock formed by compression of successive layers of clay-rich sediment

7. In the original location or position, such as a large outcrop that has not been disturbed by faults or landslides.

8. Having very low permeability.

V. Explain the following terms using a specialized dictionary and glossary, give their Russian equivalents and make up your own phrases with them:

unconventional gas reservoirs, conventional gas reservoirs, devonian, clathrate, geopressurized gas

VI. Give English translation for:

Исторически сложилось, что традиционные месторождения природного газа всегда являлись простыми для разработки. Однако, с продвижением технологий, добыча природного газа из нетрадиционных источников начинает составлять все больший процент от общего объема добываемого газа.

Что же такое «нетрадиционный газ»? Точный ответ на этот вопрос трудно найти. «Нетрадиционный природный газ» - это газ, который труднее и экономически менее выгодно добывать, в основном из-за того, что технологии, применяемые для добычи такого газа, либо развиты не до конца, либо слишком дороги. Например, до 80-х годов прошлого века, залежи природного газа, находящиеся очень глубоко под землей, были практически нетронутыми. Добывать такой газ было экономически невыгодно. Однако, с развитием глубокого разведочного и эксплуатационного бурения, добыча газа с большой глубины перестала быть чем-то «нетрадиционным».

На сегодняшний день выделяют шесть основных категорий «нетрадиционного газа». Это газ, добываемый с больших глубин, плотный газ, сланцевый газ девонского периода, газ угольных пластов, газ зон геодавлений и гидраты метана.