4. Give the adequate Russian variants for the following word combinations:

To drill by gouging and scraping; to contain compacts; to be composed of; abra­sion resistance; the tungsten carbide's durability; to make long bit runs; to result in signifi­cant cost savings; to be reusable.

5. Agree or disagree with the following statements:

1. The original rotary drilling bit was a diamond bit.

2. A drag bit has no moving parts and drills by gouging and scraping.

3. New drag bits contain milled teeth composed of diamond crystals and tungsten car­bide.

4. Polycrystalline diamond bits combine the diamond's hardness and abra­sion resistance with the tungsten carbide's durability to make long bit runs.

5. Drag bits always require serious repair.

6. Answer the questions:

1. What compacts do modern drag bits contain?

2. What drag bit characteristics have resulted in signifi­cant cost savings?

3. What advantages do these bits offer?

You’ve got acquainted with the different bit types. To revise the information you’ve read earlier, do the given tasks:

7. Find in the texts the English equivalents for the following words and word combinations and learn them by heart:

Выбор долота, изнашиваться, свойства горной породы, шарошечное долото, карбидвольфрамовые вставки, фрезерованные зубья, образование сальника на долоте, скорость проходки, покрытие, штыревое долото, прочный, спускоподъемная операция, смещение осей шарошки, промывочный канал, направлять поток бурового раствора, шлам/металлические обломки, лопастное долото/долото режущего типа, прочность на истирание.

8. Match the words with their definitions and give their Russian equivalents:

compressive strength	the teeth or tungsten carbide inserts in the outermost row on the cones of a bit, so called because they cut the outside edge of the hole and determine the hole's gauge or size.
gauge	the material in which the diamonds on a dia­mond bit are set.
gauge cutters	the degree of resistance of a material to a force acting along one of its axes in a manner tending to collapse it; usually expressed in pounds of force per square inch (psi) of surface affected or in kilopascals.
matrix	a cylindrical object, rounded or chisel-shaped on one end and usually made of tungsten car­bide, that is inserted in the cones of a bit to form the cutting element of the bit.
insert	the diameter of a bit or the hole drilled by the bit.

9. Scan the texts and find the words which correspond to the given definitions:

1. Wearing away by friction.

2. The cutting or boring element used in drilling oil and gas wells. It consists of a cutting and a circulating element.

3. An extremely hard material, usually crushed tungsten carbide, that is applied to the out­side surfaces of tool joints, drill collars, stabilizers, and other rotary drilling tools to minimize wear when they are in contact with the wall of the hole.

4. Metal debris lost in a hole. It may be a lost bit, pieces of a bit, milled pieces of pipe, wrenches, or any relatively small object that impedes drilling and must be fished out of the hole.

5. A hole inside a bit through which drill­ing fluid from the drill stem is directed.