Background

Once the drilling is complete, specialized equipment manages the extraction of hydrocarbons. A wellhead at the surface of the well can withstand upward pressure of escaping gases and fluids. Natural gas, the least dense material, will often naturally rise to the surface. A “christmas tree,” a series of pipes and tubes about 6 feet high, can be installed to regulate the flow of hydrocarbons. Some crude oil and natural gas must be lifted by a special pump, called a pump jack. The underground gas is not the same as the natural gas that comes through the pipelines to our homes and businesses. It contains a variety of other trace compounds and gasses, as well as oil and water, which must be removed. In most cases, the separation of oil and gas is relatively easy and the two hydrocarbons are sent on their way for further processing. A conventional separator is where the force of gravity serves to separate the heavier liquids like oil, from the lighter gases, like natural gas, which is shipped out through an elaborate series of pipelines to processing plants or storage facilities.

The natural gas enters a compressor station to be transported through interstate pipelines, typically 24–36 inches in diameter traveling at high pressures anywhere from 200–1,500 pounds per square inch (psi). This increases the volume of natural gas being transported (up to 600 times), and propels natural gas through the pipeline. To ensure that natural gas flowing through any one pipeline remains pressurized, compressor stations are placed at 40-100 mile intervals along the pipeline. All pipelines are made of steel or plastic with corrosive protection and maintenance records are kept on all repairs.

Pigging describes various processes that allow for inspection and maintenance of a pipeline from within the pipeline itself. If maintenance is needed, specialized pigs can be used to remove debris, paraffin build-up or give a video inspection within the pipe. “Smart pigs” have become increasingly sophisticated, targeting specific types of pipeline troubles that may restrict the flow of materials through the line.

Constructing pipelines takes a great deal of planning and preparation including feasibility studies to ensure that a route provides the least impact to the environment and public infrastructure already in place. In addition, safety precautions may include aerial patrols, leak detection devices, pipeline markers, and earthquake-proof braces that allow for minor shifts in the earth.

Activities

  1. 5.1 Transporting natural gas
    How do engineers develop pipeline systems to transport oil, water, gas and other materials over long distances?
  2. 5.2 Pipeline pigging
    How can we be sure the pipeline is operating efficiently?
https://www.youtube.com/watch?v=-OV5SBM689Q

Assessment

  • After reviewing the production and transport of crude oil and natural gas, what issues need to be addressed to efficiently get the energy to the end-user?
  • What are some ways these issues can be addressed?

Digital extras