(Liquefied natural gas)

Liquefying methane into LNG generates a compact, higher valued form of energy that can be economically transported around the world by ship. This allows the development of gas fields that would otherwise be economic because they are too remote from potential consumers to justify construction of a pipeline.

The purpose for changing methane from a gas to a liquid is entirely to facilitate its transportation. There is no market for the liquid as such, so it is regasified at the landing port and delivered to the consumer through conventional natural gas pipeline systems. In some cases, it is blended into a gas stream to supplement local supplies of natural gas. The problem with using LNG directly is that it must be stored at cryogenic(extremely cold) temperatures to prevent vaporization. Such heavily insulated storage is too bulky and expensive for most applications, but experimentation in direct use of LNG is ongoing. For example, its use in large trucks is being examined.

5.2 Comprehension questions:

1. What allows the development of gas fields?

2. What facilitates methane transportation?

3. Does any problem with using LNG directly exist?

5.3 Make your own sentences using the following:

to deliver, gas, a pipeline, to install, gas flow, a control system, to regulate, to construct, a shore, the liquefaction plant, to transport, two-phase flow, liquid, alternating slugs.

5.4 Make all possible questions to the extract:

Although increased pressure and reduced temperature will liquefy petroleum gases, the extreme volatility of methane dictates that cryogenic cold (-260º F) be used to liquefy and transport LNG.The liquefaction plant therefore amounts to a very large refrigeration plant. The plants are built onshore and include marine loading facilities. In the future, floating plants may be used in some protected overwater situations.

5.5 Make negative sentences. Translate them.

1. Cas moving through a piping system constantly expands and contracts from the normal variations in pressure and temperature.

2. High-gravity, low-viscosity crude oil normally separates easily from water, but lower gravity, higher viscosity crudes often form emulsions that complicate separation.

3. Produced water is considered a contaminant of crude oils, so purchasers accept only traces of sediment and water.

4. Heat reduces oil viscosity and coalesces small water droplets into bigger ones; both effects help the water to settle to bottom of the treating vessel.

5. Produced fluids enter most wash tanks through flumes designed to reduce turbulence in the tank.

5.6 Retell Text 5

6.1 Read and translate Text 6

Text 6 marine tankers

LNG is transported in specially constructed marine tankers and maintained in the liquid state by heavy insulation. Some vessels use spherical tanks set within the ship’s hull while some use tanks integrated into the ship’s hull and separated by membranes. Gas that vaporizes during the voyage is used either to fuel the vessel or is reliquefied by an onboard refrigeration unit.

There have not been any serious accidents involving LNG tankers. Nevertheless, it needs to be recognized that, given the extreme heat content and volatility of LNG, a tank-rupturing would cause an unprecedented conflagration.

The scheduling of tanker movements is quite demanding in view of

• The impracticability and therefore lack of significant LNG storage capacity between the plant outlet and the loading dock. Given the unstoppable nature of the product stream from the wells, through the pipeline, into the plant and out to the ships, the shipping operation must never be caught without a ship to receive product.

• The necessity to arrive at the destination in time to fit smoothly into the offloading operation at the end of the voyage. The product flow on the consumption end is as fully unstoppable as it was at the source. The ships must be offloaded, the LNG vaporized, the gas injected into the delivery line, and ultimately delivered to the customer without interruption or significant fluctuation.

6.2 Сomprehension questions:

1. How is LNG transported?

2. Is gas that vaporizes during the voyage used to fuel the vessel?

3. What would cause an unprecedented conflagration?

4. Why is the scheduling of tanker movements important?

6.3 Give Ukrainian correspondences:

vessel; volatility; conflagration; plant outlet; loading dock; delivery line; fluctuation.

6.4 Retell Text 6

6.5 Read “Flow lines”. Fill in the blanks using the following:

tank battery, anchors, the cellar deck, the wellhead, steel pipe, trees, a flowline, the surface, low-pressure applications.

Flow Lines

The produced fluids flow from _______to central treating facilities through ________. The fluids are driven down the line and through the treating facilities by wellhead pressure, either natural or generated by artificial lift equipment.

On land, it’s not unusual for many as 50 wells to be served by a single_______ (central treating facility). Flowlines are typically made of small diameter_________, either welded or screwed. They may either be buried or laid on _________. Coiled polyethylene is sometimes used in _________. The lines radiate inward from all directions and some may be over a mile in length.

Fields in shallow, protected waters that are developed with dispersed vertical wells and a central facilities platform use flowlines similar to those on land. They may be laid on the seafloor or buried to avoid being hooked by dragging ship________.

On deepwater offshore platforms that support multiple_________for directional wells, the flow lines are only a few feet long- just enough to reach from the trees on _________to the valve manifold on the top deck.

6.6 Comprehension questions:

1. Where do the produced fluids flow from?

2. Can 50 wells be served by a single tank battery?

3. What are flowlines made of?

4. Is it necessary for flowlines to be buried?

5. Why are the flow lines only a few feet long on deepwater offshore platforms?

6.7 Retell “Flow Lines”

7.1 Read and translate Text 7