Petroleum engineering is a field of engineering concerned with the activities related to the production of Hydrocarbons, which can be either crude oil or natural gas.

A gas evolved from petroleum. The main components of petroleum gases are hydrocarbons, but they may also contain other substances, such as hydrogen sulphide or lead alkyls as minor constituents.

A petroleum geologist is an earth scientist who works in the field of petroleum geology, which involves all aspects of oil discovery and production.

Petroleum geology is the study of origin, occurrence, movement, accumulation, and exploration of hydrocarbon fuels.

The petroleum industry, also known as the oil industry or the oil patch, includes the global processes of exploration, extraction, refining, transporting (often by oil tankers and pipelines), and marketing of petroleum products.

Petroleum licensing or exploration license is the act of giving licenses (geographical areas at land or sea) to a company or a joint venture allowing them to search for commercially feasible deposits for the extraction of petroleum.

In geology, a petroleum play, or simply a play, is a group of oil fields or prospects in the same region that are controlled by the same set of geological circumstances.

Petroleum products are materials derived from crude oil (petroleum) as it is processed in oil refineries.

Petroleum oils are characterised as either black or white (clean). Black oils include crude oil, furnace oil, fuel oil, tar and asphalt. White oils include benzene, kerosene, and gasoline.

An industrial process plant where crude oil is transformed and refined into useful products such as petroleum naphtha, gasoline, diesel fuel, asphalt base, heating oil, kerosene, liquefied petroleum gas, jet fuel and fuel oils.

A petroleum reservoir or oil and gas reservoir is a subsurface pool of hydrocarbons contained in porous or fractured rock formations.

A petroleum seep is a place where natural liquid or gaseous hydrocarbons escape to the earth's atmosphere and surface, normally under low pressure or flow.

Petroleum transport is the transportation of petroleum and derivatives such as gasoline (petrol). Petroleum is transported via rail cars, trucks, tanker vessels, and through pipelines.

In petroleum geology, a trap is a geological structure affecting the reservoir rock and caprock of a petroleum system allowing the accumulation of hydrocarbons in a reservoir.

Petrology is the branch of geology that studies rocks and the conditions under which they form.

In the physical sciences, a phase is a region of space (a thermodynamic system), throughout which all physical properties of a material are essentially uniform.

Phase change materials, commonly referred to as PCMs, are a technology that is used to store sensible and latent heat within a building structure at a higher storage capacity than standard building materials.

In chemistry and thermodynamics phase transitions (or phase changes) are the physical processes of transition between the basic states of matter of solids, liquids, and gasses.

A phasor measurement unit is a device used to estimate the magnitude and phase angle of an electrical phasor quantity (such as voltage or current) in the electricity grid using a common time source for synchronization.

A photodiode is a semiconductor p-n junction device that converts light into an electrical current.