Artificial lift

When pressures in the oil reservoir have fallen to the point where a well will not produce by natural energy, some method of artificial lift must be used.

Used for this purpose are downhole pumps, which are divided into three general groups: pumps at the bottom of the hole run by a string of rods, pumps at the bottom of the hole run by high-pressure liquids, bottom-hole centrifugal pumps. Another method of artificial lift uses high-pressure gas to lift the oil from the reservoir.

The pumping unit is a complete set of surface equipment necessary to impart an up-and-down motion to the sucker-rod string, to which the bottom-hole pump is con­nected.

Speed reduction between the prime mover and the pitman crank is accomplished by a combination of a V-belt drive and gear reducer. With an engine of 600 revolutions per minute (RPM), a speed reduction ratio of 30 to 1 is necessary to operate the unit at 20 strokes per minute. The crank is rotated by the slow-speed shaft of the speed reducer. With one end of the pitman connected to the crank and the other end to the walking beam, the rotation is changed to the up-and-down motion of the walking beam necessary to operate the pump.

A set of weights, attached to the crank or to one end of the walking beam, coun­terbalances the weight of the rods and part of the weight of the fluid, which are suspend­ed from the opposite end of the walking beam and helps the power plant lift rods and fluid on the upstroke. The rod string is lifted by means of a cable looped over the horsehead and connected to the carrier bar to support the polished-rod clamp.

Pumping wells need a means of sealing off the pressure inside the tubing to prevent leakage of liquid and gas outside the polished rod. Stuffing boxes consist of flexible mate­rial or packing housed in a box, which provides a method of compressing the packing. The stuffing-box packing is replaced when it becomes worn.

The words to be memorized:

1. Beam pump – станок-качалка

2. Maintenance – техническое обслуживание

3. Thermal processes – тепловые процессы

4. Down hole pump – глубинный насос

5. Sucker-rod pump – штанговый насос

6. Water injection – закачка, нагнетание воды

7. Bubble point– точка начала высвобождения газа

8. Gas-to-liquid ratio– коэффициент содержания газа в жидкости

9. Pump intake – всасывающее отверстие насоса

10. Slippage – переходная зона

11. Oil reservoir – коллектор нефти

12. Bottom-hole centrifugal pumps–глубинные центробежные насосы

13. The prime mover – первичный двигатель

14. The pitman crank– рычаг соединительной тяги

15. Underground formations – подземные формации

16. Oil-producing operations- нефтедобывающие операции

17. Producing formation – продуктивный пласт

EXERCISE 3 Answer questions about the text.

1. When must methods of artificial lift be used?

2. What groups are downhole pumps divided into?

3. What does the pumping unit consist of?

4. What must be done to prevent leakage of liquid and gas outside the polished rod?

5. What provides a method of compressing the packing?

EXERCISE 4 Insert the omitted word from the text

1. When pressures in the __________have fallen to the point where a well will not produce by __________, some method of __________ must be used.

2. The __________ is a complete set of surface equipment necessary to impart an__________ to the sucker-rod string, to which the __________ is con­nected.

3. Speed reduction between the __________ and the __________ is accomplished by a combination of a V-belt drive and gear reducer.

4. The __________ is lifted by means of a cable looped over the horsehead and connected to the carrier bar to support the __________ clamp.

5. __________wells need a means of sealing off the pressure inside the tubing to prevent leakage of __________ and __________ outside the polished rod.

Prime mover, bottom-hole pump, rod string, liquid, polished-rod, natural energy, oil reservoir, pumping unit, artificial lift, up-and-down motion, gas, pitman crank, pumping.

EXERCISE 5 Are the following statements true or false? Correct the false ones with the right information and discuss your answers with a partner.

1. Method of artificial lift uses low -pressure gas to lift the oil from the reservoir.

2. With an engine of 6000 revolutions per minute (RPM), a speed reduction ratio of 30 to 1 is necessary to operate the unit at 20 strokes per minute.

3. The rod string is lifted by means of a cable looped over the horsehead and connected to the carrier bar to support the polished-rod clamp.

4. A set of weights, attached to the crank, coun­terbalances the weight of the rods and part of the weight of the fluid, which are suspend­ed from the opposite end of the walking beam and helps the power plant fall rods and fluid on the downstroke.

5. Stuffing boxes consist of flexible mate­rial or packing housed in a box, which provides a method of compressing the packing.

EXERCISE 6 Connect the terms with their definitions.

Artificial lift	a down-hole oil pump located on the bottom of the tub­ing on a beam well. The sucker-rod pump is activated by the sucker-rod string rising and falling in the tubing thus pulling plunger up and down.
Natural lift	a tool used to measure temperature in a well at a specific depth.
Pressure differential	a mechanical method that is used to assist in lifting crude oil in a well to the surface. The most common methods are sucker-rod pump, hydraulic pump, gas lift and electric submersible pump.
Bottom-hole thermometer	the flow of formation fluids out of a well without artificial lift. The reservoir pressure is sufficient to lift the fluids to the surface.
Sucker-rod pump	difference between pressures in the well bore and reser­voir or in the well bore intervals.

EXERCISE 7 Make up your own sentences using the following words:

Beam pump, injection, thermal processes, sucker-rod pump, gas-to-liquid ratio, pressure.

EXERCISE 8 Translate into English in written form.

1. Скважинные насосы подразделяются на три группы: глубинные насосы, спускаемые в скважину на колонне штанг, глубинные насосы, которые работают в результате воздействия высокого давления скважинных флюидов, глубинные центробежные насосы.

2. Метод механизированной добычи – это метод, при котором для поднятия пластовой нефти используется газ под высоким давлением.

3. Снижение скорости между первичным двигателем и рычагом соединительной тяги осуществляется при помощи клиноременной передачи в комбинации с редуктором.

4. Коленчатый рычаг поворачивается низкоскоростным валом редуктора.

5. Нагрузка на коленчатом рычаге или одном конце балансира служит противовесом для колонны штанг и части жидкости на другом конце балансира и помогает силовой установке поднимать штанги и жидкость при ходе поршня вверх.

6. Гидравлический сальник изготовляется из гибкого материала или набивки, которая находится в корпусе, что позволяет уплотнять набивку.

7. Набивку сальника заменяют по мере износа.

EXERCISE 9 Read and translate the texts.