Text 2 pipelines

Pipelines provide surface transport for both gas and liquids. They are constructed by welding together joints of large-diameter steel pipe. Most pipelines are externally coated and wrapped for protection from corrosion and abrasion. Onshore pipelines are buried. Shallow-water offshore lines are usually buried for protection, but deeper-water lines may not be buried. Single-phase pipelines transport either gas or liquid, but not both. Two-phase pipelines transport both liquid and gas. In two-phase lines, liquid builds up in the low spots and then starts moving as a slug (filling the entire line). The alternating high-volume slugs of gas and liquid emerging at the end of the line make severe demands on the separation equipment.

Pipelines are used both in gathering systems- moving produced fluids between facilities within the field- and for final transport of fluids away from the field.

Rubber swabs or spheres called pigs are periodically run through pipelines to sweep out accumulated water and debris. The pigs fit tightly, forming a seal against the inside of the line so that fluid pressure propels them. They are inserted and removed from the pressurized line through a pig launcher at the beginning of the line and a pig trap at the end of the line.

Figure 2.1 Pipeline pigging system.

Reffering to Figure 2.1, the procedure used to pig a line is:

1. The pig is loaded by closing valves A and B, bleeding off launcher pressure, opening the hatch, inserting the pig and closing the hatch

2. The pig is launched by opening valve A to provide access to the main line and then opening valve B to blow the pig out of the launcher; valve C is also open

3. The pig traverses the pipeline and lodges in the pig trap

4. The pig is recovered by closing valve C, bleeding off the pressure, opening the hatch and removing the pig

2.2 Comprehension questions:

1. What do pipelines provide?

2. How are pipelines constructed?

3. Is it important for most pipelines to be buried?

4. What is the difference between single-phase and two-phase pipelines?

5. What are the pigs used for?

2.3 Define in English:

Pipeline.

A pig.

Debris.

2.4 Translate into Ukrainian in written form:

1. When a new field is discovered, the operator normally connects it to the nearest crude oil pipeline and receives the per barrel “posted price” published by the pipeline company.

2. Gas demand is heaviest in the winter, so the pipeline operates at maximum rates during cold weather.

3. Gas processing plants extract heavier petroleum products and contaminants from the residue gas stream to prepare it for long-distance pipeline transmission.

2.5 Give Ukrainian correspondences:

associated gas; break out; coiled tubing; cryogenic; gas-to-liquids processing; pig; sweet crude; sour crude.

2.6 Make interrogative and negative sentences:

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

2. The produced fluids flow from the wellhead to central treating facilities through a flowline.

3. Gas-to-liquids processing converts methane to liquid petroleum products such as middle distillates.

2.7 Try to explain why natural gas is a highly desirable fuel.

2.8 Retell Text 2

3.1 Read and translate Text 3