The permanent equipment installed at the surface (or on the seabed for subsea wells) at the top of a well, providing structural support for the casing strings and a pressure-containing connection point for the Christmas tree and production equipment.
The segment of the oil and gas industry concerned with the exploration for and production of crude oil and natural gas. Upstream activities include seismic surveying, exploration drilling, appraisal, development, and production operations. See also Midstream, Downstream.
The temporary cessation of production from a well or field, typically by closing the wellhead valves. Wells may be shut in for maintenance, safety, regulatory compliance, market conditions (low prices), or to manage reservoir pressure.
Natural gas containing significant quantities of heavier hydrocarbons (ethane, propane, butane, pentanes) in addition to methane. Wet gas requires processing at a gas plant to separate the natural gas liquids (NGLs) from the sales-quality dry gas.
Crude oil or natural gas containing a significant concentration of hydrogen sulphide (Hâ‚‚S) 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.
A vessel designed for the bulk transport of liquid cargoes, including crude oil (crude tankers), refined products (product tankers), LNG (LNG carriers), and LPG (LPG carriers). Tanker sizes range from small coastal vessels to Very Large Crude Carriers (VLCCs) and Ultra Large Crude Carriers (ULCCs) capable of carrying over 300,000 deadweight tonnes.