دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

a fracture created with little or no plastic deformation.

n: plastic deformation of metal at a temperature low enough to insure or cause permanent strain.

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.

n: under theexternal load, the rock presents obviously plastic deformation bbefor the it cracked,

n: some rock under load until it broken, plastic property deformation is not only lattice slip inner mineral grains, but also the loss of organization structure. When the procedure of broken,the shuting of pore also mingles plastic deformation.

n: the naturalform that a section of coiled tubing string will take if spooled from the reel and to rest without any residual bend results from the plastic deformation imparted as the string is spooled around the radius of the reel and guide arch.

n: see plastic deformation.

The stress on a material at which the first significant permanent or plastic deformation occurs without an increase in stress (NACE).