Text 7 Looking for Oil and Gas?

 

Petroleum refers to any naturally occurring hydrocarbon found beneath the surface of the earth, no matter whether that hydrocarbon is solid, liquid or gas. The solid and semi-solid forms of petroleum are called asphalt and tar. When liquid, petroleum is called crude oil if it is dark and viscous, or condensate if it is clear and volatile. And of course there is natural gas, which can be associated with oil or found entirely by itself.

Mankind has used the various forms petroleum for centuries. The Babylonians used asphalt to pave paths and caulk boats, and the ancient Egyptians used tar to prepare their mummies. In fact, mummy is a derivation of the Arabic word for tar. Condensate was an essential ingredient of Greek fire, the secret weapon of Byzantium, and the ancient Chinese used natural gas to light their imperial palaces. These ancient cultures found petroleum by simply looking for oil or gas seeps and hoping that an adequate source was nearby, but the search for oil and gas today is much more complicated.

Several geologic elements are necessary for oil and gas to accumulate in sufficient quantities to create a pool large enough to be worth producing. These elements include an organic-rich source rock to generate the oil or gas, a porous reservoir rock to store the petroleum in, and some sort of trap to prevent the oil and gas from leaking away. Traps generally exist in predictable places - such as at the tops of anticlines, next to faults, in the updip pinchouts of sandstone beds, or beneath unconformities.

To find a convergence in the subsurface of the geologic elements necessary to form an oil or gas pool requires a careful blend of science and art. To discover what geometries and lithologies rocks might possess underground, geologists examine the rocks where they are exposed in surface outcrops, or they examine aerial photographs and satellite images when surface access is limited. Geologists also work closely with geophysicists to integrate seismic lines and other types of geophysical data into their interpretations.

The collection of seismic data involves sending shock waves into the ground and measuring how long it takes the subsurface rocks to reflect the waves back to the surface. Shock waves are generated by pounding the earth with a vibrator truck or by exploding small dynamite charges in shallow holes. Boundaries between the rocks reflect the waves back, and the arrival times of the waves at the surface are detected by listening devices called geophones. Computers then process the geophone data and convert it into seismic lines, which are nothing more than two-dimensional displays that resemble cross-sections.

Seismic lines in the old days were just two-dimensional lines created by laying the geophones out in single line. But today, the data is commonly collected as an intersecting grid of seismic lines referred to as 3-D seismic volume. Data collected in this fashion may even be used to help create 3-D computer models of the underground geometries of the rocks.

Geologic and geophysical clues are enticing, but drilling is the only way to learn if an oil or gas field really exists. Once a well is drilled, well logs yield data on the types of rock present and, most important, what fluids these rocks contain. The information interpreted from the logs is used to decision whether a well should be completed and used to produce oil and gas, or filled with cement and abandoned. The logs are also used to update the geologic models originally used to locate the well.

Today, the average wildcat well has only one chance in ten of finding an economic accumulation of hydrocarbons. A rank wildcat, if drilled in a frontier area, stands only one chance in forty of success. The odds are much better for a development or extension well, but nothing is a sure bet in the oil business. Thus, even though explorationists (oil and gas prospectors) of today have better tools than their ancient predecessors, luck remains a significant factor in the search for oil and gas. The reality is that most wildcats turn out to be dry holes and not every development well becomes a producer.

SUPPLEMENTS

 

Приложение 1

 

Список глаголов, встречающихся в учебнике, требующих употребления определённого предлога

 

arm with вооружать (чем-л.)

attach to придавать (кому-л.)

belong to принадлежать, входить в состав (чего-л.)

bring…into вводить в

carry out выполнять (задачу), проводить (разведку)

consist of состоять из

cross into переправлять на (плацдарм)

depend on зависеть от

divide into делить на

equip with оснащать, вооружать (чем-л.)

fire at, on стрелять, вести огонь по

inflict…on наносить (потери, удар) (кому-л.)

lead to вести к

listen to слушать (кого-л., что-л.)

look at смотреть на

look through просматривать (напр. книгу, газету)

make up составлять (что-л.)

prepare for готовить(ся) к

prevent from мешать, препятствовать (кому-л., чему-л.)

provide for обеспечивать, снабжать (кого-л., чего-л.)

reinforce with усиливать (чем-л.)

speak to, with говорить с

wait for ждать (кого-л., чего-л.)

work at работать над

 

Приложение 2

 

Список английских глаголов, после которых

Не употребляются предлоги

 

answer отвечать (на)

approach подходить к, приближаться к

cross переправляться, переходить через

enter поступать в (учебное заведение) входить в

join вступать в, присоединяться к

leave уезжать из, уходить из

meet встречать (ся) с

play играть в

reach выходить к (на)

 

Приложение 3

 

Префиксы

Dis-

to appear v – to disappear

armament n – disarmament

to disagree, to disconnect, to dislike; disagreement, disorder

Im-

possible adj – impossible

immovable, improbable

Re-

to appear v – to reappear

to rearrange, to rebuild, to re-do, to re-examine, to remake,

to rename, to reopen, to re-read, to retell, to rewrite

Un-

comfortable adj – uncomfortable

expected – unexpected

to tie v – to untie

unconquerable, unemployed, unhappy, unhealthy, unimaginable,

unimportant, uninteresting, unknown, unlawful, unnatural, unpleasant,

unskilled, unusual, unwelcome; to undress, to undo

 

Приложение 4

 

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