4. Read and translate the text.

In the past, the natural gas which was recovered in the course of recovering petroleum could not be profitably sold, and was simply burned at the oil field (known as flaring). This wasteful practice is now illegal in many countries.

Additionally, companies now recognize that value for the gas may be achieved with LNG, CNG, or other transportation methods to end-users in the future. The gas is now reinjected back into the formation for later recovery. This also assists oil pumping by keeping underground pressures higher. In Saudi Arabia, in the late 1970s, a “Master Gas System” was created, ending the need for flaring. Satellite observation unfortunately shows that some large gas-producing countries still use flaring and venting routinely. The natural gas is used to generate electricity and heat for desalination. Similarly, some landfills that also discharge methane gases have been set up to capture the methane and generate electricity.

The major difficulty in the use of natural gas is trans- portation and storage because of its low density. Natural gas pipelines are economical, but are impractical across oceans. Many existing pipelines in North America are close to reaching their capacity, LNG carriers can be used to transport liquefied natural gas (LNG) across oceans, while tank trucks can carry liquefied or compressed natural gas (CNG) over shorter dis- tances. They may transport natural gas directly to end-users, or to distribution points such as pipelines for further trans- port. These may have a higher cost, requiring additional faci- lities for liquefaction or compression at the production point, and then gasification or decompression at enduse facilities or into a pipeline.

The raw natural gas must be purified to meet the quality standards specified by the major pipeline transmission and distribution companies. Those quality standards vary from pi- peline to pipeline and are usually a function of a pipeline sys- tem’s design and the markets that it serves,

5. Write the numbers in words.

Natural gas should be within a specific range of heating value (caloric value). For example, in the United States, it should be about 1,035±5% Btu per cubic foot of gas at 1 atmosphere and 60°F (41 MJ±5% per cubic metre of gas at 1 atmosphere and 0°C).

6. Make up sentences putting the verb in a due form and fill in the table with usual pipeline quality standards.

1. delivered/at/(to be)/hydrocarbon/dew point/a speci- fied temperature

2. free of/ (to be)/solids and liquid/particulate/water

3. dehydrated/(to be)/vapor/of water/sufficiently

4. no more than/(to contain)/amounts/trace/of compo- nents

5. mercury/(to maintain)/detectable/at less than/limits

1		.. .below which some of the hydrocarbons in the gas might condense at pipeline pressure forming liquid slugs which could damage the pipeline.
2.		.. .to prevent erosion, corrosion or other damage to the pipeline.
3.		.. .to prevent the formation of methane hydrates within the gas processing plant or subsequently within the sales gas transmission pipeline.
4.		.. .such as hydrogen sulfide, carbon dioxide, mercaptans, nitrogen, and water vapor.
5.		.. .to avoid damaging equipment in the gas processing plant or the pipeline transmission system from mercury amalgamation.