EXERCISE 1 Read and translate the text, using the words after the text. Special equipment and procedures are required when drilling from a floating vessel

Special equipment and procedures are required when drilling from a floating vessel. It is necessary to hold the vessel on location over the bore hole and compensate for the vertical, lateral and tilting movements caused by wave action against the vessel. Vessel motion problems are more severe for a drill ship than for a semisubmersible. However, drill ships are less expensive and can be moved rapidly from one location to another.

A special derrick design must be used for drilling because of the tilting motion caused by wave action. The derrick is often designed to withstand as much as a 20' tilt with a full load of drill pipe standing in it. Special pipe handling equipment is necessary to permit tripping operations to be held safely during rough weather. This equipment permits drill pipe to be laid down quickly on a pipe rack in doubles and trebles rather than supported in the derrick. Most floating vessels are held on location by anchors. When the ocean bottom is too hard for conventional anchors, anchor piles are driven or cemented in boreholes in the ocean floor. The vessel is moored facing the direction from which the most severe weather is anticipated.

The placement technique without anchors is called dynamic positioning. The position of the vessel with reference to the borehole must be monitored at all times. Two types of aligning indicators in common use are the mechanical type and the acoustic type.

The equipment used to compensate for the horizontal and vertical movement of the vessel during normal drilling operation is as follows: A marine riser conducts the drilling fluid from the ocean floor to the drilling vessel. A flex joint at the bottom of the marine riser allows lateral movement of the vessel. The vertical movement of the vessel is allowed by a slip joint placed at the top of the marine riser. The riser is secured to the vessel by a pneumatic tensioning system.

The vertical movement of the drill string can be absorbed by a bumper sub between the drill pipe and drill collars. Heave compensators eliminate surface motion of the vessel.

A ВОР stack for a floating drilling operation is placed on the ocean floor below the marine riser. This ensures that the well can be closed even in severe weather.

The words to be memorized:

1. vessel - судно

2. to compensate - компенсировать

3. wave action – действие волн

4. semisubmersible – полупогружная платформа

5. to tilt - раскачивать

6. to withstand - противостоять

7. anchor - якорь

8. placement - размещение

9. dynamic positioning – динамическое позиционирование

10. alignment indicator – индикатор центрирования

11. marine riser – водоотделяющая колонна для бурения

12. ocean floor – дно океана

13. flex joint – гибкая муфта

14. lateral - боковой

15. slip joint – телескопическое соединение

16. to secure – надежно закрепить

17. pneumatic - пневматический

18. tensioning - затяжка, крепление

19. bumper sub – телескопический переходник-компенсатор

20. Vessel motion problems are more severe for a drill ship than for a semisubmersible - проблемы, которые создает перемещение судна, более серьезны для бурового корабля по сравнению с полупогружной платформой

21. heave compensation – компенсация вертикальной качки