Ф 03-03 Kasymova Zh. Zh

27.2.Reading Passage

Major part of Kazakhstani oil and gas are transported by pipelines. Some pipelines are massive steel conduits more than a meter in diameter, while others are plastic tubes a few centimeters across. They form a delivery system as vast and complex as the railroads, highways or electric utilities.

A mobile assembly line moves across the landscape to lay a pipeline. Layers of soil are stockpiled separately so they can be replaced after the pipe is buried more than a meter below the ground.
The sections of pipe are welded and inspected with X-rays before being covered with a protective coating and lowered into trench. Before it goes into operation, the pipe will be filled with water at high pressure to test for leaks. Regulators set strict safety and environmental standards for pipeline construction and operation.
Cathodic protection is used to prevent corrosion of the pipe. Instrumented inspection devices called pigs are sent through pipes regularly to inspect them and check for weakness or corrosion. Sophisticated computer systems monitor pipelines continuously, and remotely operated valves can quickly isolate a section of pipe in the event of a leak. Pipelines fall into four general categories:
• gathering lines move raw oil and gas from wellheads to processing plants and transmission facilities;
• trunk lines transport crude oil, natural gas liquids and refined petroleum products to refineries and petrochemical plants, and some trunk lines transport refined products to consumer areas;
• gas transmission systems carry natural gas at high pressure from producing areas to consuming areas;
• local distribution companies deliver natural gas at low pressure to homes and businesses.
A network of gathering lines in the oilfield delivers crude oil to storage tanks. From the oil storage tanks the crude oil is then delivered to an oil pipeline. In the oil pipeline, powerful electric motors drive the centrifugal pumps. Oil travels through the pipe at four to eight kilometers per hour, and it may take a month or more to carry oil to distant places. Unlike gas transmission pipelines, which primarily carry methane, liquid trunk lines can carry different types of crude oil, natural gas liquids and refined products. 
The commodities travel through the pipe in batches, which can be many kilometers long.
Complicated networks of valves and storage tanks are used to make sure the batches get to the correct destination. Crude oil, gas liquids and refined products are also transported by truck, railway, tanker and barge. The oil tanker is the cheapest form of long-distance energy transportation, while the oil pipeline is the second cheapest.