SUBSURFACE EQUIPMENT

The Subsurface Equipment of a flowing well consists of the tubing and various devices, serving for bringing the well into operation.

The tubing is lowered into the well, as noted in a previous section to ensure better utilization of the energy of the accompanying gas which evolves from the oil when it rises to the surface. In addition the tubing considerably simplifies and speeds up the process of starting and shutting in of a flowing well. It is possible to force out of the well through the tubing the liquid which previously filled the well and change the pressure exerted on its bottom hole by injecting air, oil water or drilling mud into the annular space.

The lower and of the tubing is arranged directly opposite the stratum which oil is produced from. This arrangement of the tubing makes it possible to wash the bottom hole. This is of especial importance when the latter is clogged with dirt and sand, and also in coning, when a column of water accumulates in the lower section of the well, creates an additional pressure on the bottom hole and prevents the inflow of fluid from the stratum.

 The diameter of the tubing is chosen depending on the expected rate of production. Tubes of smaller diameter are used in wells with low production and low formational pressure, where they permit the period of flowing to be prolonged.

In choosing tubes for a well in which paraffin may be deposited in operation, the possibility of using cleaning equipment such as scrapers inside the diameter of the tubes is so selected mat the velocity of the gas-oil flow will not be too high.

The tubes used in flowing wells are also used in wells from which oil is produced by the air – and gas-lift methods, and in pumping wells outfitted with subsurface pumps.

Taper threads with a special profile are cut on the ends of the tubes, which are joined to one another with the aid of couplings screwed on one of their ends at the manufacturing plant.

Tubing is costly equipment, and it should therefore be handled with care, preventing untimely damage and failure.

In transportation bending of tubes and sagging of their ends should be prevented. The threaded ends of tubes and couplings must be protected from damage with the, aid of metal rings and nipples which completely cover the threaded sections.

Tubes are not to be thrown down when loading and unloading then; they must be carried from place to place either by hand, holding their ends, or rolled along inclined ramps, seeing that they do not strike one another.

The threaded joints of tubes kept in storage for a long time must be given a protective coating of grease.

The preparation of tubing for lowering into a well is an important operation. It is necessary not only to measure each tube of the string, but also thoroughly check the condition of the tubes, looking for such faults as camber, the state of the internal surface and threaded joints.

The threaded joints are usually checked by external inspection. The threads must be smooth, and free of burrs, fissures, dents and other faults detracting from the strength and tightness of the joints.

When screwing tubes together see that the threaded joint is sufficiently strong. No more than two open turns of a thread are allowed on a tube screwed into a coupling. Depending on the nature of the faults serving as the cause for rejection, defective tubes are other not used at all, or are installed in less important places, for instance, in the lower section of a flowing well tubing, where the weight load on the tubes and threaded joints is not great.

Вариант V

1. Перепишите и переведите следующие предложения, обращая внимание на сложные формы инфинитива (см. образец выполнения № 1).

1. New cities are to be constructed in this region.

2. I am glad to have been invited to this party.

3. There are some problems to be solved immediately.

4. It suggested that I must have read all of the Belgian artist and writer's books.

5. A cracking noise made me think we might have brought home an unwilling creature.

6. Both experiences have made me want to experiment and challenge myself even more.

7. They made me wait 2 and half hours before a doctor finally agreed to examine me.

2. Перепишите и переведите следующие предложения. Помните, что объектный и субъектный инфинитивные обороты соответствуют придаточным предложениям (см. образец выполнения № 2).

1. We know the geological prospecting to be developing now.

2. Decreasing of volumes of oil extraction is said to continue till 1996.

3. Samotlorskoye deposit is known to be one of the top ten largest deposits of the world concerning oil reserves.

4. We know the existence of oil and gas resources in Siberia to have been predicted by I.M. Gubkin in 1934.

5. We know a laser to be a device that stimulates the electrons of a light-producing material to vibrate simultaneously.

6. Lasers are known to have found an application in the printing industry.

7. Light waves are now believed to be due to the motions of electrons themselves within the atoms.

8. Chemical investigations have shown each element to combine with another only in definite proportions.

3. Перепишите и переведите следующие предложения, содержащие придаточное условия. Определите тип условного предложения (см. образец выполнения № 3).

1. If this article were on radio-electronics we should read it without dictionary.

2. It would have been impossible to launch space rockets, if we had not had the necessary polymeric materials and synthetic fuels.

3. If oil is found in a region, the oil extractive and oil processing enterprises are created.

4. If liquids expand upon freezing, an increase of pressure lowers the freezing point.

5. If the metal had been heated slowly, the first changes in its appearance would have occurred at a temperature of 1000 К.

6. It would be impossible to determine the properties of these materials without intensive studies in our research laboratory.