Terminology Series Y

Working in the Oil and Gas industry will introduce you to a whole new set of industry-specific vocabulary – to help you understand we’ve collated a list of a few terms beginning with the letter "Y" that focus on Production and Drilling.


Can be used as a drilling term to refer to the volume occupied by one bag of dry cement after mixing with water and additives to form a slurry. Or the specified minimum yield strength of steel used in a pipe.

It can also be used when discussing Drilling Fluids to specify the quality of a clay corresponding to the number of barrels of 30-cP viscosity mud that one tonne would produce.

Yield stress

The stress that must be applied to a material to make it begin to flow (or to yield).

Yield point

A geology term used to describe the elastic limit of a material. When the elastic limit is surpassed by an applied stress, permanent distortion occurs.

Or sometimes used as a Drilling Fluids term to describe the parameter of the Bingham plastic model which is a two-parameter rheological model widely used to describe flow traits of muds.


A production term used to describe the part of a gate valve that operates as a spacer between the bonnet and the operator.

Young-Laplace equation

A nonlinear partial differential equation describing the pressure difference across an interface between two fluids at a static, curved interface, used to define the capillary pressure.

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