Correct the statements

1. Oil and gas exist in large and small underground lakes.

2. Much of the oil began as the remains of gas.

3. Accumulation of organic matter depended upon quality of rocks.

4. Though oil was heavier than water it used to rise as water pushed it up.

5. All rocks are capable of being a reservoir rock.

6. Permeability refers to amount of pores in the rock.

7. Limestones and dolomites cannot contain oil as they are not sedimentary rocks.

8. Crude oil is called crude because it does not contain gas.

6. ANSWER THE QUESTIONS IN ENGLISH

1. What is the origin of hydrocarbons?

2. What conditions did organic matter accumulation depend upon?

3. Why did oil and gas tend to rise through the ancient sea water?

4. What two types of sedimentary rocks do you know?

5. What is porosity?

6. What is permeability?

7. What is aquifer?

8. Name reservoir rocks that you know.

9. What are hydrocarbons?

10. What states can hydrocarbons occur in?

11. What is the source of energy used to assist in pushing oil and gas out to the surface?

7. MAKE UP 5 QUESTIONS TO THE TEXT AND ANSWER THEM

LISTEN TO THE TEXT ON THE TAPE AND READ IT

NEW WORDS

1. Density -плотность

2. Drill - бурить (скважину)

3. Flow rate -уровень притока

4. Hydrocarbons -углеводородные соединения

5. Hydrostatic gradient - гидростатический градиент

6. Oil-нефть

7. Shut-in a well - закрыть скважину

8. Tubing - насосно-компрессорные трубы (НКТ)

9. Well - скважина

10. Well bottom - забой скважины

11. Wellhead-устье скважины

FLUID FLOW

Fluids move from regions of high pressure to regions of low pressure. When the well is drilled into a hydrocarbon reservoir and open at the surface, the area in the vicinity of the wellbore becomes an area of low pressure. If the reservoir has sufficient permeability, oil and gas flow from all directions into the wellbore. When fluids are flowing into the well the pressure at the well bottom is called the bottom hole flowing pressure. The pressure at surface, when the well is flowing, is called the wellhead or flowing tubing pressure. The pressure at the surface when the well is shut -in and fluids are not flowing through the tubing is called the shut-in or static tubing pressure.

The pressure within a column of fluid increases with depth and is greater at the bottom of the column than at the top. This principle can be demonstrated by the change you feel on your ears when you dive to the bottom of a swimming pool. The pressure is directly related to the depth and the density of the fluid, and is called hydrostatic pressure.

For a given height of a column of fluid, the hydrostatic pressure of liquids is much greater than the hydrostatic pressure of gas. For example, the change in pressure with depth (called the hydrostatic gradient) is about 1.0 Kpa/m in gas. In oil the gradient varies from 8.0 to 9.0 Kpa/m.

In order for fluids to flow up the wellbore, the reservoir pressure must be greater than the total of the hydrostatic and atmospheric pressure. The flow rate of oil or gas into the wellbore depends on the permeability of the reservoir rock, the area of flow into the wellbore and the viscosity of the fluid.

Дата добавления: 2015-11-14