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свердловина а ні газу
wet well –свердловина з незакритим caprock –покрив продуктивного пласту,
припливом ґрунтових вод покришка
seal- непроникна порода, яка покриває communicate with – сполучатись з
пласт
adjacent – суміжний, прилеглий field - родовище
reservoir- поклад нафти й газу; нафто- або level – однаковий, рівний
газоносний пласт
gradational - поступовий carrier bed – пласт, по якому можливий рух
нафти

Task 2. Read the following text, translate it into Ukrainian.
Text 1
Migration
After gas and oil are generated in shale source rock, some is expelled from the
impermeable shale. The generation of a liquid (crude oil) or gas (natural gas) from a solid
(organic matter) causes a large increase in volume. This stresses the source rock and fractures the
shale. The hydrocarbons escape through the fractures. After the pressure is released, the fractures
close, and the shale becomes impermeable again. Because gas and oil are light in density
compared to the water that also occurs in the pores of the subsurface rocks, petroleum rises. Oil
and gas can flow upward along faults and fractures. It can also flow laterally and upward along
unconformities and through carrier beds. Carrier beds are rock layers that are very permeable
and transmit fluids. The vertical and lateral flow of the petroleum from the source rock is called
migration.
If there is no trap on the migration route, the gas and oil will flow out onto the surface as
a gas or oil seep. If there is a trap along the migration route, the gas and oil can accumulate in the
trap. Of all the gas and oil that form in sedimentary rock basins, only from 0.3 to 36% is ever
trapped. On average, only 10% of the gas and oil is trapped. The rest of the gas and oil did not
get out of the source rock, was lost during migration, or seeped into the earth’s surface. Because
of migration, where the petroleum formed in the deep basin and where it ends up in the trap are
different both vertically and horizontally. This is why a reservoir of thermogenic gas that
originally formed deeply can be found at shallow depths.

Text 2
Accumulation
The trap must be in position before the gas and oil migrate through the area. If the trap
forms after the migration, no gas or oil will occur in the trap. Once the gas and oil migrate into
the trap, they separate according to density. The gas, being lightest, goes to the top of the trap to
form the free gas cap, where the pores of the reservoir rock are occupied by gas. The oil goes to
the middle of the trap, the oil reservoir. Saltwater, the heaviest, goes to the bottom.
The most common trap is a saturated pool, which always has a free gas cap on top of the
oil reservoir. The oil in the reservoir has dissolved all the natural gas it can hold and is saturated.
An unsaturated pool lacks a free gas cap. The oil has some dissolved gas, but it can hold more
and is unsaturated. Sometimes there is only a gas reservoir on water.
The boundary in the reservoir between the free gas cap and the oil is the gas-oil contact.
The boundary between the oil and water reservoir is the oil-water contact. The gas-oil and oil-
water contacts are either relatively sharp or gradational and are usually level.
The top of the trap is called the crest. The first exploratory well is usually drilled on-
structure, on the crest of the structure where the probability is highest that petroleum will be
encountered. When a well is drilled to the side of the crest, it is drilled off-structure. If a well is