Crude Oil means a mixture of mainly pentanes and heavier hydrocarbons that may be contaminated with sulphur compounds, which is recovered or is recoverable at a well from an underground reservoir. It is liquid at the conditions under which its volume is measured or estimated, and includes all other hydrocarbon mixtures so recovered or recoverable except raw gas, condensate or crude bitumen. For production measurement and reporting purposes, crude oil is deemed to be "heavy" if it has a density of 900 kg/m3 or greater, and "light & medium" or "conventional" if it has a density of less than 900 kg/m3.
Crude Oil is sold between countries in quantities called barrels (bbl). There are approximately 159 litres (42 US gallons) of oil in a barrel.
Crude postings are generally indicative as to how the market values certain crudes. Postings are posted by refineries and tend to be more like a bid to buy than an offer to sell and therefore are generally lower than market price.
Tight light oil, also known as tight shale oil, is found in sedimentary rock formations that are characterized by very low permeability. The flow of oil from the rock to the well bore is limited by the largely impermeable fine-grained nature of the oil-hosting rock thus the basis for the term “tight”. While some tight light oil plays produce oil directly from shales, most tight oil is produced from low-permeability siltstones, sandstones, limestones and dolostones that are associated with the shales from which the oil has been generated. Oil trapped in these relatively impermeable rock units requires well stimulation techniques including horizontal drilling and hydraulic fracturing.
International Energy Agency’s (IEA) monthly reports can be accessed from this site:
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