Sour crude oil is crude oil containing more than 0.5% sulfur impurities (by weight). The impurities need to be removed before this lower-quality crude can be refined into petrol, thereby increasing the cost of processing. This results in a higher-priced gasoline than that made from sweet crude oil.
Current environmental regulations in the United States strictly limit the sulfur content in refined fuels such as diesel and gasoline.
Western Canadian Select (WCS) is a heavy sour blend of crude oil that is one of North America's largest heavy crude oil streams and, historically, its cheapest. It was established in December 2004 as a new heavy oil stream by EnCana (now Cenovus), Canadian Natural Resources, Petro-Canada (now Suncor) and Talisman Energy (now Repsol Oil & Gas Canada). It is composed mostly of bitumen blended with sweet synthetic and condensate diluents and 21 existing streams of both conventional and unconventional Alberta heavy crude oils at the large Husky Midstream General Partnership terminal in Hardisty, Alberta. Western Canadian Select—the benchmark for heavy, acidic (TAN <1.1) crudes—is one of many petroleum products from the Western Canadian Sedimentary Basin oil sands. Calgary-based Husky Energy, now a subsidiary of Cenovus, had joined the initial four founders in 2015.
Western Canadian Select (WCS) is the benchmark price for western Canadian crude blends. The price of other Canadian crude blends produced locally are also based on the price of the benchmark.
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula SO
2. It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of metals refining and the burning of sulfur-bearing hydrocarbon fuels.
Urals oil is a reference oil brand used as a basis for pricing of the Russian export oil mixture. It is a mix of heavy sour oil of the Urals and the Volga region with light oil of Western Siberia. Other reference oils are Brent, West Texas Intermediate and Dubai.
Urals brand oil is supplied through the Baku-Novorossiysk pipeline system and the Druzhba pipeline. Urals oil futures trade on Moscow Exchange. There was also an effort to trade it on NYMEX under the name of REBCO (Russian Export Blend Crude Oil).
Dubai Crude is a medium sour crude oil extracted from Dubai. Dubai Crude is used as a price benchmark or oil marker because it is one of only a few Persian Gulf crude oils available immediately. There are two other main oil markers: Brent Crude and West Texas Intermediate.
Dubai Crude is generally used for pricing Persian Gulf crude oil exports to Asia. The Dubai benchmark is also known as Fateh, used in the United Arab Emirates. Forward trade of Dubai Crude is limited to one or two months.
Tapis crude is a Malaysian crude oil used as a pricing benchmark in Singapore. Tapis is very light, with an API gravity of 43°-45°, and very sweet, with only about 0.04% sulfur. While it is not traded on a market like Brent Crude or West Texas Intermediate (WTI), it is often used as an oil marker or price referencing indicator for Asia and Australia.
The price of Tapis in Singapore is often considerably higher than the price of benchmark crude oils such as Brent or West Texas Intermediate (WTI), the more commonly referenced in market commentaries. This is because its lightness (i.e. higher ° API) allows for greater production of higher-value products, such as petrol, than from Brent or WTI. Its high price is also due to the purity of the blend. Its extremely low sulfur content means it requires less refinery processing than sourer crude oils, and hence a lower processing cost.
Isthmus-34 Light is a sour crude oil produced in Mexico mainly in the Campeche zone, in the Gulf of Mexico along with the extraction centers in Chiapas, Tabasco, and Veracruz. The name derives from the nearby Isthmus of Tehuantepec. Before 2017, the oil was a component of the OPEC Reference Basket (despite Mexico's not being a part of OPEC). It has the following characteristics: