Oil and Gas Terms Beginning with “Y”

YP is the standard oilfield abbreviation for Yield Point, the minimum shear stress (in lb/100 ft² or Pa) required to initiate flow in a Bingham plastic drilling fluid, calculated from Fann VG meter readings using the… Read more →

Young's modulus is a fundamental elastic constant that describes a rock's stiffness, defined as the ratio of longitudinal stress to longitudinal strain under uniaxial loading conditions. Named after British physicist… Read more →

The Young-Laplace equation describes the pressure difference that exists across a static, curved interface between two immiscible fluids, and in petroleum engineering it is the physical foundation of capillary pressure,… Read more →

Yield in petroleum geomechanics refers to the point at which a rock, formation, or material transitions from elastic (recoverable) deformation to plastic (permanent, irreversible) deformation — the stress state at which… Read more →

Yield point (YP) is the minimum shear stress required to initiate and sustain flow in a Bingham plastic drilling fluid, calculated from Fann VG meter readings as YP = theta300 minus plastic viscosity (PV), expressed in… Read more →

Yield stress is the minimum shear stress that must be applied to a material before it stops behaving like an elastic solid and begins to flow, and in drilling-fluid engineering it is the true threshold below which a mud… Read more →