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Standard classification of bits




This classification is a three-digit code. The first digit is the bit series number. The letter D before the first digit means the bit is diamond or PCD drag bit. Series D1 to D5 are reserved for diamond bits in the soft, medium soft, medium, medium hard and hard formations respectively. The second digit is the type number. Type O is for PCD drag bits. Types 1-4 designate a formation hardness classification. Feature numbers are interpreted differently, depending on the general type of bit being described.

Eight standard diamond and PCD drag bits features are: step-type profile, long taper profile, short taper profile, non-taper profile, down-hole motor type, side-track type, oil-base type, core-ejector type. The remaining feature (9) is reserved for special features.

The words to be memorized:

1. bottom of the hole -

2. drag bit

3. rolling cutter bit

4. blade - ,

5. integral -

6. body -

7. cone - ,

8. axis -

9. cutter ,

10. solid - ,

11. breakage -

12. junk ,

13. fish tail bit

14. uniformly -

15. non-brittle - ,

16. design -

17. blank - ,

18. non-abrasive -

19. gummy - ,

20. angle of attack

21. rake

22. cutter exposure

23. crown profile

24. exposed formation -

25. cutter orientation -

26. back-rake

27. side-rake

28. chip clearance -

 

EXERCISE 2 Answer the following questions.

1.What do all drag bits consist of?

2.What do rolling cutter bits consist of?

3. What is the advantage of drag bits over rolling cutter bits?

4. What are important design features of a D bit?

5. What is the most common type used in rotary drilling operations?

6. What does the drilling effect of a rolling cutter bit depend on?

7. While drilling rock, the tooth length and cone offset must be reduced to prevent tooth breakage, mustnt they?

8. What is standard classification of bits?

9. How are feature numbers interpreted?

10. Is the remaining feature reserved for special features?

EXERCISE 3 Find the proper Russian equivalent to the given English ones.

1. cone 1.

2. axis 2.

3. non-brittle 3.

4. blade 4.

5. cutter 5.

6. gummy 6.

7. junk 7.

8. rake 8. ,

9. crown profile 9.

10. blank 10.

 

EXERCISE 4 Complete the sentences.

1. Rotary drilling bits may be

2. which would leave junk in the bottom of the hole.

3. Diamond bits perform

4. Cutter orientation is defined

5. The three cone rolling cutter bit

6. The largest limitation in their design is

7. the effects of the cones.

8. are good for drilling soft formations.

9. While drilling rock

10. Feature numbers are interpreted

EXERCISE 5 Translate the sentences from Russian into English.

1. .

2. , .

3. , .

4. , - .

5. , .

6. , .

7. , .

8. .

9. .

10. .





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