دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: the area near the wellbore where invading mud filtrate forces out the movable formation fluids. Often abbreviated Rxo

part of the rock that has been flushed with a sweep fluid. The area may have little hydrocarbons remaining.

n: a polymer-water solution used in micellar-polymer flooding as a zone of viscosity transition between the initial injection of surfactant-water solution and the final injection of drive water. The lead edge of the polymer solution has a mobility equal to or less than that of the surfactant solution. and the trailing edge has a mobility close to that of water. This buffer zone prevents the drive water from fingering past the surfactant solution and thus reducing sweep efficiency. See micellar-polymer flooding.

n: the ratio of the mobility of a driving fluid (water or a chemical solution at residual oil saturation to the mobility of the driven fluid (oil) at connate water saturation. The mobility ratio affects the sweep efficiency of an improved recovery project.

a comparison of the ability of a fluid to move through another fluid or to displace the fluid.

n: a gelled viscous fluid placed at a specific depth in the well. usually to overcome or minimise a problem at that depth. For example. a special bentonite pill may be spotted (placed) at or near a formation to which drilling fluid is being lost. The pill may seal the formation and reduce or stop the lost circulation problem.

n: a relatively small volumn of specially prepared fluid placed or circulated in the wellbore. Fluid pills are commonly preparedfora variety of special functions, such as a sweep pill prepared at high viscosity to circulate around the wellbore lost-circulati

a volume of gelled fluid mixed for a specific purpose. A fluid loss pill for example.

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.

n: a device that varies a frequency at a constant rate and incorporates an oscillator that can be programmed to provide an output over a specified frequency range.

a displacement. In the reservoir a sweep is displacement of a hydrocarbon fluid from a reservoir rock by a flooding fluid. In the wellbore, a sweep is a viscous pill circulated around to help clear the wellbore of cuttings or debris.

n: the efficiency with which water displaces oil or gas in a water drive oil or gas field. Water flowing in from the aquifer does not displace the oil or gas uniformly but channels past certain areas due to variations in porosity and permeability.

the percentage of original oil in place displaced from a formation by a flooding fluid.

a spacer designed to pick up and transport particles from the well.

the part of a field that has the best production characteristics (permeability, porosity, hydrocarbon saturation, pressure, etc.).