In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors.

Possible reserves are reserves which analysis of geological and engineering data suggests are less likely to be recoverable than probable reserves.

Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%.

A positive-displacement pump makes a fluid move by trapping a fixed amount and forcing (displacing) that trapped volume into the discharge pipe.

Pondage refers to the comparably small water storage behind the weir of a run-of-the-river hydroelectric power plant.

The PONA number is an index for oil components.

In physics, the restoring force is a force which acts to bring a body to its equilibrium position.

A type of electric power converter that contains a network of inductors and capacitors called a "resonant tank", tuned to resonate at a specific frequency.

A measure of how strongly a material resists electrical current.

Electrical resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms, symbolized by the Greek letter omega (Ω).

A ground fault circuit interrupter (GFCI), or Residual Current Device (RCD) is a type of circuit breaker which shuts off electric power when it senses an imbalance between the outgoing and incoming current.

Fluids in an oil or gas reservoir are called reservoir fluids.

Is an enlarged natural or artificial lake created using a dam to store water.

The amount of additional generating capacity that can be provided by generators that are already connected to the power grid.

Oil and gas reserves are the main asset of an oil company.

Research reactors are nuclear reactors that serve primarily as a neutron source.

Research and development (R&D, R+D), known in Europe as research and technological development (RTD), is the set of innovative activities undertaken by corporations or governments in developing new services or products and improving existing ones.

Requirements engineering is the process of defining, documenting, and maintaining requirements in the engineering design process.

A request for quotation (RfQ) is a business process in which a company or public entity requests a quote from a supplier for the purchase of specific products or services.

Reproducibility is a major principle of the scientific method.