An aromatic hydrocarbon (C₈H₁₀) produced during petroleum refining and petrochemical processing. Xylene exists as three isomers (ortho, meta, and para). Para-xylene is the most commercially valuable, used as a feedstock for PET plastic and polyester fibre production. Xylene is also used as a solvent and in some oilfield chemical applications.
An exploration well drilled in an area with no previous drilling or known production — a frontier location. Wildcat wells carry the highest geological risk but also the highest potential reward if a new discovery is made.
A tax levied on companies that earn unexpectedly high profits due to external circumstances (such as a surge in oil prices) rather than their own actions. The UK’s Energy Profits Levy (EPL), introduced in 2022, is an example of a windfall tax on oil and gas producers operating on the UK Continental Shelf.
A slender cable (single or multi-conductor) used to lower instruments, tools, or devices into a wellbore. Wireline operations include logging (measuring formation properties), perforating (opening holes in casing to allow reservoir fluids to enter), and setting or retrieving downhole equipment.
The primary benchmark for crude oil pricing in North America. WTI is a light, sweet crude oil with approximately 39.6° API gravity and 0.24% sulphur content. WTI futures are traded on NYMEX (New York Mercantile Exchange) and are among the most liquid commodity contracts in the world.
Crude oil or natural gas containing a significant concentration of hydrogen sulphide (H₂S) and/or other sulphur compounds. Sour hydrocarbons require additional processing (sweetening) to remove sulphur before sale or refining. Sour crudes typically trade at a discount to sweet crudes.
The commencement of drilling a new well. The spud date is the date on which the drill bit first penetrates the ground surface (or seabed in offshore operations).
The current market price for immediate purchase and delivery of a commodity. Oil and gas spot prices fluctuate continuously based on supply, demand, geopolitics, weather, and market sentiment. Spot prices are distinguished from forward or futures prices, which reflect expectations for future delivery.
Equipment, infrastructure, or operations located on the seabed. Subsea production systems — including wellheads, trees, manifolds, flowlines, and control systems — enable the production of offshore oil and gas without the need for a surface platform at the well location. Subsea technology has been critical for deepwater development.
Crude oil with a low sulphur content (typically below 0.5%), which is easier and less costly to refine. Sweet crudes generally command a premium over sour crudes. Brent and WTI are both sweet crude benchmarks.