What is tar sand, or oil sand, and how is it extracted and converted to heavy oil? What are some environmental problems related to the use of this energy resource? What is shale oil and how is it produced? What are the major advantages and disadvantages of using heavy oils produced from tar sand and shale oil as energy resources?

The oil wells are drilled into the gas deposits to remove it from the ground. In this, the oil may fall into the reservoir under the reservoir's natural pressures. Few other techniques are required to maintain this operation, such as horizontal drilling, water flooding, and gas injection along with the artificial raise.

Through extracting the sand filters from the heavy oil fields and processing the sand with the oils to its limit, the oil sand is processed into heavy oils.

Air pollution, land use (which removes large numbers of trees), the use of massive amounts of water, and greenhouse gas emissions are the environmental issues with this.