دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: temporary changes in dimensions caused by stress. The material returns to the original dimensions after removal of the stress.

n: the deformation of caused by the effect of overlying-strata pressure which is standed by the rock in the range of elastic limit

deformation of a body in the elastic range, i.e., recovery to the initial shape is possible when the stress or load is removed.

n: the point at which a material permanently deforms when stressed.

n: the maximum stress standed by material keeping elastic deformation without perpetual deformation

the upper range of elasticity, just before the body is permanently deformed.

n: this states that for an elastic material, stress is proportional to strain. In practical terms if a load is doubled then the stretch in the material duo to that load is also doubled, as long as the elastic limit of the material is not exceeded. Thus as th

n: a phenomenon in which a decrease in the diameter of the borehole occurs because a plastic substance, such as salt, is being drilled. Since the temperature of the salt is higher than normal for a given depth (high temperature causes the salt to expand) and since mud weight is usually decreased when drilling such formations to maintain high penetration rates (thus decreasing the hydrostatic pressure exerted on the salt),the section of borehole in the salt zone can expand and possibly stick the drill stem. Also called salt squeeze.

n: Permanent mechanical or physical alteration that does not include rupture. Plastic deformation of rocks typically occurs at high temperatures and pressures, conditions under which rocks become relatively viscous.

a stress level, beyond the elastic limit, that produces yielding in tubulars.