Exploration is conducted to predict where these deposits are and whether they exist in a quantity that makes them economically viable. Known as prospecting, this work involves a combination of seismic reflections, geotechnical surveys, and exploratory drilling.
Seismic reflection provides insight on the geophysical properties of the Earth’s subsurface. Seismic waves are sent underground, bounce back, and are picked up by surface sensors, providing data on potential reservoirs.
Once a deposit has been located, extraction can begin. This involves drilling a well above the underground area where the deposit is. How deep the well is, and the chosen extraction technique, depends on the depth of the hydrocarbons. For example, if oil sands are within 75 metres of the surface, surface mining techniques are used. If they’re further than 75 metres, in situ extraction is used.
Key fact: In 2019, 70% of the world’s oil and gas came from onshore sites
There are several different types of onshore gas that are produced, including tight gas, shale gas, coal seam gas, and conventional gas.
Benefits
Fewer shipping and installation costs
Greater production results
Onshore sites can be reclaimed
