Exploration and drilling are upstream activities in the oil & gas industry used to locate, characterize, access and produce from geological hydrocarbon deposits of petroleum (oil) and natural gas. The upstream sector of the oil & gas industry is also referred to through the synonymous industry term of exploration & production (E&P) or the activities of searching for, recovering, and producing crude oil and natural gas.
In the oil & gas industry chain, E&P companies utilize traditional strategies in exploration geophysics including gravity, magnetic, passive seismic, and seismic reflection surveys of subsurface geologies. Discovered features of subsurface geology suggestive of a hydrocarbon deposit constitute a “lead” that leads to more seismic profiling to identify a “prospect” reservoir. Exploration wells are then drilled to determine the features and extent of the prospect hydrocarbon reservoir. The staged process of upstream exploration activities is indicative of the high costs at each step, with investment in a particular area or field proceeding only when suitable leads and prospects are discovered.
Production drilling follows exploration surveying and drilling when a suitable prospect for oil and gas recovery is conclusively identified. A drill string and drill bit is used to drill an oil or gas well and is controlled from the surface drill rig. The drilled well is then completed in order to optimize the flow of oil or gas into the well casing so that primary production can commence. Future phases of secondary and tertiary or enhanced hydrocarbon recovery (EOR) can be facilitated through the drilling of injection wells.