and-other-formation-stimulation-technologies-shale-gas-0) This method is now widely used world-wild, ensuring the US and Canada to have constant gas supply for 100 years and has presented an opportunity to generate electricity at half the CO2 emissions of coal. (https://www.bbc.co.uk/news/uk-14432401) Steam-assisted gravity drainage (SAGD) is another method used to open up large deposits below the surface and produce heavy crude oil and bitumen. It is an advanced form of steam stimulation in which a pair of horizontal wells are drilled into the oil reservoir, one a few meters above the other. High-pressure steam is continuously injected into the upper wellbore to heat the oil and reduce its viscosity, causing the heated oil to drain into the lower wellbore, where it is pumped out. Similar to fracking, SAGD consumes large quantities of water and natural gas – 20 times more than conventional oil drilling, which makes it very expensive to operate. A possible alternative would be cyclic steam stimulation (CSS) and high-pressure cyclic steam stimulation (HPCSS). (https://en.wikipedia.org/wiki/Steam-assisted_gravity_drainage) Oil and gas in the Arctic Among the greatest uncertainties concerning future energy supply is the volume of oil and gas remaining to be found in high northern latitudes. According to the United States Geological Survey (USGS), there are about 30% of the world’s undiscovered gas and 13% of the world’s undiscovered oil may be found in the Arctic Circle. The recent retreat of polar ice makes petroleum exploration and development much easier. Petroleum is highly associated with sedimentary rocks. The map provided the basis for defining assessment units (AUs), which are mappable volumes of sedimentary rocks that share similar geological properties. The Circum-Arctic Resource Appraisal (CARA) defined 69 AUs, each containing more than 3 km of sedimentary strata, the probable minimum thickness necessary to bury source rocks sufficiently to generate significant oil and gas.>