دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

unit weight of the solute per million unit weights of the solution. A small correction factor is needed to convert to mg/liter.

the surface weight measurement when pulling a pipe string or wireline out of the hole. Includes both string weight and frictional drag.

n: a cylindrical or spherical device that is affixed to the end of a wireline just above the hook to keep the line straight and to provide weight. v: to soak metal pieces in a chemical solution to remove dirt and scale from the metals surface.

a chemical treatment of the tubulars to remove pipe dope, mill scale and mud or cement residue.

n: in roller chain, the plate into which the pin link pins ends are immovably fixed. The pins are riveted to the link plate on one side and either riveted or fixed with cotters to the other pin link plate. pin packer n: a packer in which the packing element is held in position by brass or steel pins. When weight is put on the packer, two metal sleeves telescope, shearing the pins and allowing the element to fold and pack off.

a hydraulic workover/snubbing tubing running term – when the weight of the pipe is sufficient to pull the pipe into a well against the surface pressure.

hydraulic workover/snubbing tubing running term – when the weight of the pipe is not sufficient to pull the pipe into a well against the surface pressure and additional force (snubbing) is required.

n: a braking device used on a lay barge to control the descent rate of the pipe. Tensioners also support the entire submerged weight of the pipe as it approaches the bottom.

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 pi: 1. value that indicates hook load or force, read from a weight indicator;1 point = 1,000 pounds, or 500 decanewtons. 2. in mud density measurement, the portion of the muds weight expressed in decimal points. For example, a mud that weighs 12.2 pounds per gallon (1,461.8 kilograms per cubic metre) weighs two points more than 12 pounds ( 1,438 kilograms). Also, if a 12.2 potmd-per-gallon muds density is increased to 12.5 pounds per gallon (1,497.8 kilograms per cubic metre),the density has been raised by 3 points.

n: a polymer whose basic repeating unit, or rnonorner, is a cornbination of carbon, hydrogen, oxygen, and nitrogen. Polyacrylarnides are used to adjust the viscosity of water slugs during chernical flooding operations. They can also adhere to the walls of rock pores, decreasing the effective permeability of established channels, forcing the injection fluid into new channels, and thus irnproving sweep efficiency.

n: polymer with a high molecular weight. The basic repeating unit or monomer of polyacrylamide is a combination of carbon, hydrogen, oxygen and nitrogen. Polyacrylamides increase the viscosity of the water slug that precedes the final water injection. Polyac

a polymer with a very stable carbon chain. A good friction reducer in small amounts, but the polymer may cause formation damage. Can be used to gel acid, but the polymer will not break.