EXERCISE 1 Read and translate the text, using the words after the text. The well control system prevents the uncontrolled flow of formation fluids from the well bore

The well control system prevents the uncontrolled flow of formation fluids from the well bore. When the bit penetrates a permeable formation that has a fluid pressure in excess of the hydrostatic pressure exerted by the drilling fluid, formation fluids will begin displacing the drilling fluid from the well. The flow of formation fluids into the well in the presence of drilling fluid is called a kick. The well control system permits detecting the kick, closing the well at the surface, circulating the well under pressure to remove the formation fluids and increase the mud density, moving the drill string under pressure and diverting the flow away from the rig personnel and equipment.

Failure of the well control system results in an uncontrolled flow of formation fluids and is called a blowout. This is perhaps the worst disaster that can occur during drilling operations. Blowouts may cause loss of life, drilling equipment, much of oil and gas reserves in the underground reservoir, and damage to the environment near the well.

The flow of fluid from the well caused by a kick is stopped by use of special pack-off devices called blowout preventers (BOPs). Multiple BOPs used in a series are referred to collectively as a BOP stack. The BOP must be capable of terminating flow from the well under all drilling conditions. When the drill string is in the hole, movement of the pipe without releasing well pressure should be allowed to occur. In addition, the BOP stack should allow fluid circulation through the well annulus under pressure. These objectives are usually accomplished by using several ram presenters and one annular preventer.

Modern hydraulic systems used for closing BOP's are high-pressure fluid accumulators similar to those developed for aircraft fluid control systems. The accumulator is equipped with a pressure-regulating system. The ability to change the closing pressure on the preventers is important when it is necessary to strip pipe into the hole. Stripping is most easily done using the annular preventer.

The words to be memorized:

1. formation fluid – пластовый флюид, пластовая жидкость

2. permeable formation – проницаемый пласт

3. in excess - избыточный, в избытке

4. to displace - вытеснять, замещать

5. kick – резкое повышение давления, удар

6. to detect - обнаружить

7. density - плотность

8. to divert - отводить

9. failure - отказ, поломка оборудования

10. flow - поток, выброс

11. to terminate - заканчивать

12. BOP stack - блок\комплект превенторов

13. ram – плашка противовыбросового превентора

14. ram preventer – плашечный превентор