An Electromagnetic Pig for Oil and Gas Pipelines

Physical Sciences : Petroleum

Available for licensing


  • Mukul Sharma, Ph.D. , Petroleum and Geosystems Engineering

Background/unmet need

Pipelines provide the backbone infrastructure for transportation of hydrocarbons from their point of extraction to the market. Pipeline networks crisscross the country, carrying natural gas, crude oil, refined products, and gas liquids from the field to storage and further dissemination centers. Pipeline operations are a critical part of the logistics of global energy supply. Successful pipeline operations require a great deal of maintenance to ensure not only efficient operations, but personnel and public safety as well.

One important maintenance activity is the periodic removal of built-up paraffin (wax) on the inside walls of the pipeline system. These buildups, caused by temperature variations during transport combined with composition of the material being transported, must be removed in order to maintain expected flow rates and safe operating pressures. The typical process for paraffin removal consists of taking long sections of the operating line out of service, isolating them, and pumping hot oil through them to melt the paraffin buildup. This is time-consuming, costly, and reduces profitable service time of the system.

A less costly method for paraffin removal is the use of tools in-situ that physically scrape the paraffin out of the inside diameter of the pipe as they are pushed through the line between two different types of product. These cleaning tools, known as "pigs," are effective, but create non-dissolved solids in the flow stream that must be dealt with.

Invention Description

Researchers at The University of Texas at Austin have designed a new type of pipeline pigging tool. The invented design utilizes the unique property of heat generated via magnetic field flux to essentially provide a heated pig that needs no external power supply. The heated pig not only scrapes but also simultaneously melts the paraffin with which it comes into contact as it flows through the pipeline. The result is efficient and effective paraffin removal with no non-dissolved wax solids remaining. 


  • Works like the standard pipeline pigs in use for decades
  • No external power or additional equipment required
  • Heat is not concentrated at one point, but travels along the pipeline with the unit 
  • Efficient energy use, as only specific pipeline portions are heated at a given time


  • Novel design that generates heat via magnetic flux induction
  • Uses fluid pressure to heat walls and fluid locally as pig travels through pipeline
  • Heating method provides ease of paraffin removal
  • Hydrates pipeline wall ahead of the pig

Market potential/applications

Future Markets Insights estimates the intelligent pipeline pigging market to be worth $215 million in the US alone in 2015, and is expected to grow to $400 million by 2025. This increase in market revenue is accompanied by a compound annual growth rate (CAGR) of 6.3% due to increasing consumption of petroleum products and natural gas. Pipeline pigging services are essential as pipeline maintenance is expected to improve as the oil and gas industry experiences significant economic revival.

Development Stage

Lab/bench prototype

IP Status

  • 1 U.S. patent application filed