Oilfield Glossary:
slug
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2. n. [Well Workover and Intervention]
A small volume of fluid, often of a higher density than the main body of fluid, within the circulating or production-fluid system that influences the flow or production characteristics of the well. A slug may be placed to ensure that fluids are naturally drained from a tubing string as it is pulled from the wellbore. The term may also be applied to a small volume of liquid produced from a gas well. Similarly, it is used to describe the flow characteristics that occur when a mixture of liquid and gas result in a sporadic production regime as the liquids are unloaded erratically.
( http://www.glossary.oilfield.slb.com/Display.cfm?Term=slug )


„Slugs in line. (Technology Focus).
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Offshore drillers often use a single pipeline to carry a mix of liquid hydrocarbons, gas, and water from satellite wells to a central production platform.
Using a single pipeline is cheaper, but the flow of liquid and gas can cause problems. The gas flows faster than the liquid. Liquid tends to accumulate in the dips and inclined pipe sections. From time to time, large volumes of liquid, known as slugs, build up in the pipeline.“
( http://www.allbusiness.com/professional-scientific/scientifi... )


Blacktip Gas Project - Glossary:
Slug catcher - A devise that removes slugs of liquid from natural gas pipelines. "Slug Catchers" dissipate the energy of the liquid slugs that intermittently propagate through a gas pipeline.
( http://www.nt.gov.au/nreta/environment/assessment/register/b... )


Mihalidi A. i M, Hemijsko-tehnološki rečnik:
slug - začepljenje, prepreka; slag (engleska tehnička jedinica mase); ingot metala; spori