Well completion and worкover operations

EXERCISE 1 Read and translate the text "Completion", using the words after the text.

Completion

After drilling and casing the well, it must be 'completed'. Completion is the process in which the well is enabled to produce oil or gas. In a cased-hole completion, small holes called perforations are made in the portion of the casing which passed through the production zone, to provide a path for the oil to flow from the surrounding rock into the production tubing. In open hole completion, often 'sand screens' or a 'gravel pack' is installed in the last drilled, uncased reservoir section. These maintain structural integrity of the wellbore in the absence of casing, while still allowing flow from the reservoir into the wellbore. Screens also control the migration of formation sands into production tubulars and surface equipment, which can cause washouts and other problems, particularly from unconsolidated sand formations in offshore fields.

After a flow path is made, acids and fracturing fluids are pumped into the well to fracture, clean, or prepare and stimulate the reservoir rock to produce hydrocarbons into the wellbore. Finally, the area above the reservoir section of the well is packed off inside the casing, and connected to the surface via a smaller diameter pipe called tubing. This arrangement provides a redundant barrier to leaks of hydrocarbons as well as allowing damaged sections to be replaced. Also, the smaller diameter of the tubing produces hydrocarbons at an increased velocity in order to overcome the hydrostatic effects of heavy fluids such as water.

In many wells, the natural pressure of the subsurface reservoir is high enough for the oil or gas to flow to the surface. However, this is not always the case, especially in depleted fields where the pressures have been lowered by other producing wells, or in low permeability oil reservoirs. Installing a smaller diameter tubing may be enough to help the production, but artificial lift methods may also be needed. Common solutions include downhole pumps, gas lift, or surface pump jacks. The use of artificial lift technology in a field is often termed as "secondary recovery" in the industry.

The words to be memorized:

artificial lift methods – методы механической добычи

cased-hole completion – заканчивание скважины посредством обсадной колонны

completion – заканчивание скважины

depleted field – истощенное месторождение

formation sand – песок из пласта

fracturing fluid – жидкость для гидроразрыва

gravel pack – гравийный фильтр

hole completion - заканчивание скважины

leak – утечка, течь

permeability - проницаемость

to produce – добывать

producing well – добывающая скважина

production tubular – эксплутационная скважина

perforation – перфорационное отверстие

production zone – продуктивная зона

production tubing – эксплутационная насосно-компрессорная колонна

redundant – излишний, избыточный, резервный

reservoir rock – порода- коллектор

reservoir section – коллекторская порода

screen – фильтр

secondary recovery – вторичное извлечение

unconsolidated sand – неуплотненный песок

washout – размыв, отверстие в бурильной трубе

EXERCISE 2 Read and translate the text "Fishing tools", using the words after the text.

Fishing tools

Sometimes items of drilling or production equipment get lost in the borehole. When an item of equipment is lost in the hole, it is called a “fish”. A lost item is also called “junk”. Operations in the wellbore cannot continue until the fish or the junk is recovered from the hole. To recover the lost item, a fishing job is necessary. Special fishing tools are used for latching on to the fish and pulling it out to the surface. There are many types of fishing tools. For example, there is a type of fishing tool called a “junk basket”, and there is another type called a “spear”. These fishing tools are very different. The spear is used to recover lost tubing. The spear enters the bore of the lost pipe. The diameter of the spear, therefore, must be smaller than the diameter of the pipe in the hole. When the spear enters the pipe, its teeth push out and grip the inner sides of the pipe tightly. Then it is usually possible to pull the fish out of the hole.

The junk basket is used for latching on to smaller pieces of junk. It is used for recovering lost pieces of equipment, for example. The bottom part of the basket is a shoe with hard-faced teeth. The shoe has a hole in its center. The fish is forced through the hole and enters the barrel of the basket. Spring-loaded fingers prevent the fish from dropping out of the barrel and falling back into the well.

Before fishing can begin, the string must be tripped out of the hole. The string is broken out in stands and the stands are stood back in the derrick. After that the fishing can begin.

The words to be memorized:

1. Annual – ежегодный

2. Borehole – буровая скважина

3. Coil tubing – гибкие трубы

4. Displacement of down hole fluid – замещение внутри скважинной жидкости

5. Downholetubing – скважинный трубопровод;

6. Fishing jobs – ловильные работы

7. Fishing tools – инструменты для ловли

8. Fluid – жидкость

9. Junk basket – шламоловка

10. Junk – металлические обломки

11. Latch on – прикреплять

12. Maintain – позволить, поддержать

13. Mandatory – принудительный

14. Production rate – дебит

15. Reserve – обратный

16. Solvent – растворитель

17. Spear – внутренняя труболовка

18. Spring-loaded fingers – подпружиненные пальцы.

19. Squeeze – сжатие

20. Treatment – обработка

21. Water-sensitive – чувствительный к воде

22. Well killing – глушение скважины

23. Wire line technique – канатная техника

EXERCISE 3 Answer questions about the text.

1. Why is a junk basket hollow?

2. Why are there many types of fishing tools?

3. What is a spear used for?

4. What is a junk basket used for?

5. How is usually an item lost in the hole called?

6. What is the purpose of fishing jobs?

7. On what condition can fishing jobs start?

EXERCISE 4 Are the following statements true or false? Correct the false ones with the right information and discuss your answers with a partner.

1. To recover the lost item, a fishing job isn't necessary.

2. A lost item is also called “fish''.

3. Before fishing can begin, the string mustn't be tripped out of the hole.

4. Sometimes production equipment get lost in the borehole.

5. The diameter of the spear must be bigger than the diameter of the pipe in the hole.

EXERCISE 5 Insert the omitted word from the text

1. The junk __________ is used for latching on to smaller pieces of junk.

2. The shoe has a hole in its __________.

3. The fish is forced through the __________and enters the barrel of the basket.

4. Spring-loaded fingers prevent the__________ from dropping out of the __________and falling back into the well.

5. Operations in the wellbore cannot __________until the fish or the junk is recovered from the hole.

6. The __________is used to recover lost tubing.

7. The spear enters the bore of the lost __________.

8. The bottom __________of the basket is a shoe with hard-faced teeth.

Barrel, center, basket, hole, part, spear, pipe, continue, fish

EXERCISE 6 Make up sentences out of two parts from the table:

1. The shoe…	a) … there is another type called a “spear”.
2. Operations in the wellbore cannot continue …	b) … than the diameter of the pipe in the hole.
3. There is a type of fishing tool called a “junk basket”, and …	c) … has a hole in its center.
4. Spring-loaded fingers prevent the fish from …	d) … a shoe with hard-faced teeth.
5. When an item of equipment is lost …	e) … dropping out of the barrel and falling back into the well.
6. The bottom part of the basket is …	f) … until the fish or the junk is recovered from the hole.
7. The diameter of the spear, therefore, must be smaller …	g) … in the hole, it is called a «fish».

EXERCISE 7 Connect the terms with their definitions.

1. Fish	a) tools are used for latching on to the fish and pulling it out to the surface.
2. Junk basket	b) a combination of operations required to free wellbore of foreign objects (lost pipes, engines, etc.) to resume normal operations.
3. Spear	c) a tool used to collect metal cuttings and pieces at a well bottom after work with a mill.
4. Fishing tools	d) A lost item is also called.
5. Junk	e) when an item of equipment is lost in the hole, it is called.
6. Fishing jobs	f) type of fishing tools which used to recover lost tubing.

EXERCISE 8 Read and translate the texts.

Text 1

Well killing fluids

Well killing fluids include foam, methanol, diesel, crude oil, emulsions and water with different additives.

Oil and oil emulsions can be successfully applied as killing fluids in formations with water-sensitive clays under specific geological conditions. However they are flammable and difficult to prepare. Methanol and diesel are also not common due to similar and other reasons.

If a fluid simultaneously having properties of a squeeze fluid and capable to dissolve paraffin's and asphaltenes is applied for well killing, then bottom hole treatment can be combined with work over operations. Taking into account that on average each well annually is worked over, application of such kill fluid will provide for annual cleaning of bottom hole, which in its turn, will allow maintaining hydrocarbon production rate.

Such process fluid is reverse emulsion containing required amount of hydrocarbon solvent capable to filter out without breaking emulsion. Efficiency of producing formation bottom hole treatment with reverse emulsion with dissolving properties is much higher than efficiency of formation treatment with pure hydrocarbon solvent. A specific of well killing technology in this case is mandatory pumping of kill fluid to the bottom of the well.

Text 2

Well workover

Well work over is associated with pulling out of the hole and running in the hole with equipment, tools, various instruments, and also injection of process fluids in the well. For this purpose the following work over methods are applied:

- with the help of down hole tubing assembled of individual pipes;

- with the help of coil tubing wound on a drum;

- using wire line technique or cable.

Well work over can be performed both with open and closed or sealed wellhead.

In the first case the well must be stopped by means of killing or displacement of down hole fluid with safe fluid in order to mitigate its aggressive impact on work over crew and the environment. As a rule, well killing makes the state of bottom hole area significantly worse and may result in its production rate decrease.

In the second case work over is performed without well killing, which does not result in its production rate decrease after performed work over, improves work over crew working conditions and mitigates potential pollution of the environment. However this requires application of complicated costly equipment capable to provide for hermetic running of tubing with collars. Moreover, opposite to work over with open wellhead, where running of equipment takes place by its own weight, it is necessary to use special devices on the wellhead, which provide for creation of axial load on tubing to push tubing string into the well at high pressures.

EXERCISE 9 Answer questions about the text.

1. How can oil and oil emulsions be applied as?

2. What properties must fluid possess to be used for well killing?

3. What is reserve emulsion?

4. What is well work over associated with?

5. What methods of well work over do you know?

6. Where can well work over be performed?

7. What are the drawbacks of well killing?

8. What are the advantages of well work over with the help of coil tubing wound on a drum?

EXERCISE 10 Connect the English equivalents to the Russian words combinations from the box.

1. Дизельное топливо

2. Уровень производства углеводородов

3. Глушение скважины жидкостями

4. Сжатие

5. Чувствительная к воде глина

6. Огнеопасный

7. Ежегодный

8. Капитальный ремонт скважины

9. Углеводородный растворитель

10. Скважина

11. Забой

12. Принудительный

13. Обработка

14. Закачка

15. Эмульсия

16. Эффективность

17. Геологические условия

Well killing fluids, diesel, emulsions, bottom, pumping, hydrocarbon solvent, squeeze, water-sensitive clays,well work over, flammable, annual, hole, mandatory, efficiency, geological conditions, hydrocarbon production rate, treatment

EXERCISE 11 Connect the terms with their definitions.

1. Well work over	a) operations to make holes in casing in the interval of a pay zone.
2. Methods with the help of down hole tubing assembled of individual pipes	b) word over is performed without well killing, which does not result in its production rate decrease after performed work over.
3. Methods with the help of coil tubing wound on a drum	c) major repairs of down hole equipment (casing repairs, cement squeeze job, re-perforation, fishing jobs).
4. Perforating job	d) the well must be stopped by means of killing or displacement of down hole fluid with safe fluid.
5. Logging tool	e) a metal instrument package containing both transmitting and receiving equipment that is run in a well to make a wire line well log.