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:
| 1. A part of pump pressure is spent | a) addition of specific chemicals. |
| 2. The drilling mud at high velocity comes out of | b) the improvement of drilling mud stability. |
| 3. Chemical treatment of drilling mud includes | c) to overcome resistance in surface system. |
| 4. The result of chemical treatment is | d) in clay muds. |
| 5. Lubricants and defoamers are also added | e) the bit nozzles and washes out drilled rock from the bottomhole and the bit. |
EXERCISE 5 Make up word combinations from two columns.
| 1. Booster 2. An injection 3. Surface 4. Drill 5. Bit 6. Drilled 7. Chemical 8. The overcome 9. Downhole 10. Drilling 11. Well- bore 12. Clay | a) Treatment b) Nozzles c) Pumps d) Engine e) System f) Muds g) Pipes h) Collars i) Walls j) Line k) Rock l) 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. .
2. , , .
3. .
4. .
5. .
EXERCISE 8 Read and translate the texts.
Text 1
Drilling
Oil is contained in rocks under the ground and in rocks under the sea. To find it, oilmen have to drill boreholes. The equipment for drilling these holes is the drilling rig. Drilling preparation operations include selection of location for the drilling rig, construction of an access road, arrangement of power supply, water supply and communication system. If local relief is uneven, then wellpad must be leveled.
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Rigging derrick and equipment up is performed in compliance with established for specific conditions deployment chart. Equipment must be located in a way, which provides for safe operations, suitable maintenance, low cost of construction and rigging operations and compactness in location of all drilling rig components. Most rigs work on the rotary system. A bit rotates at the end of a pipe. As the bit rotates, it cuts and crushes the rock at the bottom of the hole. The cuttings are carried to the surface by a special fluid. This fluid is called mud. Mud is a mixture of clay, water and chemicals.
Mud is not only used for carrying the cuttings up to the surface. It is also used for keeping the bit cool. The mud is pumped down through the string. It comes back up again through the annulus. The mud engineer or mud man is in charge of the mud. For example, he tells the crew how to mix the mud at the mud tanks.
Text 2
Tools for core taking
Core taking requires application of special rock cutting tools (core heads) and core receivers. Core head destructing rock on bottomhole periphery leaves in the center of a well a column of rock (core), which in the process of well deepening comes to a core receiver consisting of a housing and a core lifter (core barrel). Housing of core receiver is designed to connect core head with drilling string, accommodate core barrel and protect it against mechanical damage, and also provide access of drilling mud to flushing channels of core head.
Core barrel is designed to receive core, protect it during drilling against mechanical damage and hydroerosive impact of drilling mud and preserve it when lifting to the surface. In order to implement these functions the lower part of core barrel is equipped with core breakers and core holders, and on the top a valve, through which displaced from core barrel drilling mud passes when core barrel is filled with core. By method of installation core barrel is designed for application of core receivers with both removable and unremovable core barrels.
When drilling with unremovable core barrels the entire drilling string must be pulled out of the hole in order to retrieve to the surface core barrel filled with core. When drilling with removable core barrel there is no necessity to pull out the drilling string. Special catcher is run inside the string on a cable, by means of which core barrel is retrieved from core receiver and lifted to the surface. The same catcher is used to run in the hole with empty core barrel and install it in housing.
