# Temperature Gradient

## Definition - What does Temperature Gradient mean?

Temperature Gradient is the rate of temperature change as the depth of an oil well or a gas well increases. It is a physical quantity denoted by temperature per unit length. The commonly used units to represent Temperature Gradient are Degree Fahrenheit per 100 feet or Degree Celsius per meter. The SI unit for Temperature Gradient is Kelvin per Meter (K/m).

## Petropedia explains Temperature Gradient

As the depth of drilling increases, the temperature and Temperature Gradient of the well also increase. It is also known as geothermal gradient or simply thermal gradient. Average Temperature Gradient ranges from 25 to 30 degree Celsius per km or 15 degree Fahrenheit per 1000 feet. Temperature Gradient can be expressed as dt/dL.

Temperature Gradient is a vector quantity and is given by the formula:

dT = dt/dL

dT = (dt/dx, dt/dy, dt/dz)

L = x, y and z the three coordinates of location of interest under the ground.