Petroleum engineering may be a field of engineering concerned with the activities associated with the assembly of hydrocarbons, which may be either petroleum or gas . Exploration and production are deemed to fall within the upstream sector of the oil and gas industry. Exploration, by earth scientists, and petroleum engineering are the oil and gas industry's two main subsurface disciplines, which specialise in maximizing economic recovery of hydrocarbons from subsurface reservoirs. economic geology and geophysics specialise in provision of a static description of the hydrocarbon reservoir rock, while petroleum engineering focuses on estimation of the recoverable volume of this resource employing a detailed understanding of the physical behavior of oil, water and gas within porous rock at very high .

The combined efforts of geologists and petroleum engineers throughout the lifetime of a hydrocarbon accumulation determine the way during which a reservoir is developed and depleted, and typically they need the very best impact on field economics. Petroleum engineering requires an honest knowledge of the many other related disciplines, like geophysics, economic geology, formation evaluation (well logging), drilling, economics, reservoir simulation, reservoir engineering, well engineering, artificial lift systems, completions and petroleum production engineering.