Drilling mud

Treated and prepared drilling mud from mud pits is supplied to booster pumps, which deliver it to mud pumps. The latter pump drilling mud under high pressure through an injection line, riser, flexible arm, swivel and kelly to the wellhead. In this process a part of pump pressure is spent to overcome resistance in surface system. Then drilling mud comes through the drilling string (drilling pipes, drilling collars and downhole engine) to the bit. On this route the mud pressure decreases due to loss of energy to overcome hydraulic resistance.

Then the drilling mud, due to pressure differential inside drill pipes and on the well bottom, at high velocity comes out of the bit nozzles and washes out drilled rock from the bottomhole and the bit. Remaining part of the mud energy is spent to lift the drilled rock and overcome resistance in annulus.

Lifted to the surface used mud goes to the treatment section, where pieces of drilled rock are removed from it, and is delivered to tanks equipped with devices for restoration of its properties; then it is returned to booster pumps.

Chemical treatment of drilling mud includes addition of specific chemicals to improve its properties without significant change of gravity.

Chemical treatment provides for the following positive results:

• improves drilling mud stability;

• reduces its filtration capacity, thickness and adhesiveness of mud cake on well- bore walls;

• adjusts mud viscosity to increase or decrease it;

• provides specific properties (thermal resistance, salt resistance).

Lubricants and defoamers are also added in clay muds. Lubricating additives improve working environment of drilling string and rock crushing tools in the well. Defoamers prevent foam generation when gas phase is settled out from wash fluid.

The words to be memorized:

1. Bit nozzle –насадка долота;

2. Booster pump –подпорный насос;

3. Catcher –ловитель;

4. Core barrel –керноприемник;

5. Core breaker –кернорватель;

6. Core head –бурильная головка;

7. Core holder –кернодержатель;

8. Core lifter –керноприемная труба;

9. Corereceiver– керноприемное устройство;

10. Cuttings – шлам;

11. Defoamer–пеногаситель;

12. Downhole engine – скважинный двигатель;

13. Flexible arm– гибкий рукав;

14. Flushing channel – промывочный канал;

15. Hydroerosive impact –гидроэрозионное воздействие;

16. Injection line – нагнетательная линия;

17. Mudcake– корка бурового раствора;

18. Mudpit – емкость для бурового раствора;

19. Reference well – опорные скважины;

20. Riser – стояк;

21. Rockcutting tools –породоразрушающий инструмент;

22. Shale-shaker – вибросито.

EXERCISE 3 Answer questions about the text.

1. How is drilling mud delivered to the bit treated and prepared?

2. Why does mud pressure decrease on the way to the bit?

3. What does drilling mud do when it comes out of the bit nozzles?

4. What happens to the drilling mud when it is lifted to the surface?

5. What is chemical treatment of drilling mud?

6. What results does chemical treatment have on drilling mud?

7. Why are lubricants and defoamers added in clay muds?

EXERCISE 4 Make up sentences out of two parts from the table:

A part of pump pressure is spent …	… addition of specific chemicals.
The drilling mud at high velocity comes out of…	… the improvement of drilling mud stability.
Chemical treatment of drilling mud includes…	…to overcome resistance in surface system.
The result of chemical treatment is…	… in clay muds.
Lubricants and defoamers are also added …	…the bit nozzles and washes out drilled rock from the bottomhole and the bit.

EXERCISE 5 Make up word combinations from two columns.

Booster An injection Surface Drill Bit Drilled Chemical The overcome Downhole Drilling Well- bore Clay

Treatment Nozzles Pumps Engine System Muds Pipes Collars Walls Line Rock Resistance

EXERCISE 6 Are the following statements true or false? Correct the false ones with the right information and discuss your answers with a partner.

1. Drilling mud comes through the drilling to the bit.

2. The mud pressure increases due to loss of energy to overcome hydraulic resistance.

3. Lifted to the surface used mud goes to the treatment section, where pieces of drilled rock are removed from it, and is delivered to tanks.

4. Reduction of the thickness and adhesiveness of mud cake on well- bore walls is negative result of chemical treatment.

5. Defoamers provide foam generation when gas phase is settled out from wash fluid.

EXERCISE 7 Translate into English in written form using your active vocabulary.

1. При бурении шлам вымывается с забоя скважины буровым раствором.

2. Опорные скважины закладываются в районах, не исследованных бурением, и служат для изучения состава и возраста слагающих их пород.

3. Буровой раствор готовят в виброситах и закачивают в скважину при помощи бурового насоса.

4. Бурильная колонна состоит из утяжеленных бурильных труб и скважинного двигателя.

5. Химическая обработка бурового раствора включает добавление специфических химических веществ для улучшения свойств без значительного изменения силы тяжести.

EXERCISE 8 Read and translate the texts.