Natural gas pipelines

Welded steel pipelines are the dominant mode of transporting natural gas to market. Gas pipelines are typically large diameter (20 to 40 inches) and are operated at relatively high pressures (800 to1000 psi). They are externally coated and wrapped to prevent corrosion and are usually buried for protection.

The pipeline infrastructure necessary to commercialize natural gas requires enormous investment, but yields decades of profits. Two examples of such investments that are now generating large returns are the transcontinental lines in the United States extending from the producing areas in the southwest to the major consuming areas in the northeast, and the Russian lines extending from western Siberia to western Europe. In contrast, Iran is second only to Russia in gas reserves, but produces insignificant quantities because there is no infrastructure in place.

3.2 Discuss Text 3 in the form of a dialogue with your groupmate.

3.3 Give Ukrainian correspondences:

welded steel pipelines; corrosion; the pipeline infrastructure; profit; consuming area.

3.4 Read, translate and remember

PIPE AND FITTINGS

Line pipe provides the conduits for transporting produced fluids to and through the facility. Pipe materials include:

– Steel is the most commonly used line pipe material.Its joints are usually welded or screwed together.

– Plastic pipe is used for low-pressure corrosive applications.

– For corrosive conditions at higher pressures, fiberglass-epoxy pipe is available, but very expensive.

Pipe fittings include:

– Collar, flange, and welded couplings.

– Elbow (ells) to change pipe direction and tees to join three pieces of pipe.

3.5 Define in English:

Joint.

Corrosion.

Fiberglass.

Flange.

Collar.

4.1 Read and translate Text 4

Thecomplex maze of piping, vessels, tanks, etc. that makes up the typical oilfield surface system can be baffling. These systems become easier to understand when broken down into their elements.

Text 4

PUMPS

Pumps pressurize liquids, creating a pressure differential that moves liquids through the system. Two types of pump are commonly used in the oilfield.

Centrifugal pumps consist of impellers rotating at high speed within stationary cases. The liquid enters the pump at the center of the impeller and is picked up by the impeller vanes and whirled in a circular motion. Centrifugal force flings the liquid outward, creating the pump discharge pressure.

Centrifugal pumps are best suited for high volume, low pressure applications.

They are relatively trouble-free to operate and if a downstream valve is inadvertently closed, they pump through themselves without damage.

Inexpensive single-stage (one impeller) centrifugal pumps, powered by electric motors, are routinely used for moving liquids around petroleum facilities. Expensive multi-stage centrifugal pumps, often diesel engine or turbine powered, are used for larger tasks as pipeline pumping.

Positive-displacement pumps use pistons reciprocating within closely fitting cylinders to displace the liquid.pumps consist of a gearbox converting the rotating V-belt drive to reciprocating motion and a fluid end where the pumping takes place. Prime movers usually natural gas or diesel fueled internal combustion engine.

As the crankshaft is rotated by the V-belt, the connecting rod transmits reciprocating motion to the plunger. Positive-displacement pumps are used for high-pressure, moderate to low volume applications, such as water injection. Since they are more complex than centrifugal pumps, they require more maintenance. Typical configurations are simplexes (one plunger), triplexes (three plungers), and quintuplexes (five plungers). The stroke cycles of the multiple plungers are staggered to balance the load.

4.2 Comprehension questions:

1 What do pumps create?

2 What do you know about centrifugal pumps?

3 Are single-stage centrifugal pumps powered by electric motors?

4 What is the difference between single-stage and multi-stage centrifugal pumps?

5 Why do positive-displacement pumps require more maintenance?

4.3 Give Ukrainian correspondences:

centrifugal pumps; stationary case; impeller; vane; discharge pressure; downstream valve; single-stage centrifugal pump; positive-displacement pump; gearbox; internal combustion engine; crankshaft; connecting rod; plunger.

4.4 Make all possible questions:

The large cylindrical pressure vessels seen in every producing facility are essentially enlarged sections of a pipeline.

4.5 Retell Text 4

4.6 Summarize the following: