دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a method of improved recovery in which alkaline chemicals such as sodium hydroxide are injected during a water flood or combined with polymer flooding. The chemicals react with the natural acid present in certain crude oils to form surfactants within the reservoir. The surfactants enable the water to move additional quantities of oil from the depleted reservoir. Compare chemical flooding, polymer flooding, water flooding.

n: (EOR) 1. the introduction of artificial drive and displacement mechanisms into a reservoir to produce a portion of the oil unrecoverable by primary recovery methods. To restore formation pressure and fluid flow to a substantial portion of a reservoir, fluid or heat is introduced through injection wells located in rock that has fluid communication with production wells. See alkaline (caustic) flooding, gas injection, micellar-polymer flooding, primary recovery, secondary recovery, tertiary recovery, thermal recovery, waterflooding. 2. the use of certain recovery methods that not only restore formation pressure but also improve oil displacement or fluid flow in the reservoir. These methods may include chemical flooding, gas injection, and thermal recovery.

one or more of a variety of processes that seek to improve recovery of hydrocarbon from a reservoir after the primary production phase.

n: a method of improved oil recovery in which chemicals dissolved in water are pumped into a reservoir through injection wells to mobilise oil left behind after primary or secondary recovery and to move it toward production wells. The chemical solution includes surfactants or surfactant-forming chemicals that reduce the interfacial and capillary forces between oil and water. releasing the oil and carrying it out of the pores where it has been trapped. The solution may also contain cosurfactants to match the viscosity of the solution to that of the oil to stabilise the solution and to prevent its adsorption by reservoir rock. An electrolyte is often added to aid in adjusting viscosity. Injection of the chemical solution is followed by a slug of water thickened with a polymer. which pushes the released oil through the reservoir. decreases the effective permeability of established channels so that new channels are opened. and serves as a mobility buffer between the chemical solution and the final injection of water.

n: a method of enhanced recovery in which various hydrocarbon solvents or gases (such as propane, LPG, natural gas, carbon dioxide, or a mixture thereof) are injected into the reservoir to reduce interfacial forces between oil and water in the pore channels and thus displace oil from the reservoir rock. See chemical flooding. gas injection. micellar-polymer flooding.

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: a substance that consists of large rnolecules formed frorn srnaller rnolecules in repeating structural units (rnonomers). In oilfield operations, various types of polymers are used to thicken drilling rnud, frac- turing fluid, acid, water, and other liquids. See micellar-polymer flooding, polymer mud. In petroleum refining, heat and pressure are used to polyrnerize light hydrocarbons into larger rnolecules, such as those that rnake up high-octane gasoline. In petrochernical production, polymer hydrocarbons are used as a feedstock for plastics.

a synthetic or man made gelling agent that increases viscosity and helps control leakoff.

n: a type of miscible drive in which a polyrner is injected into an injection well to allow oil and water to rnix and flow to a producing well. See miscible drive. Corn pare alkaline (caustic) flooding, chemical flooding, waterflooding.

n: a soluble compound that concentrates on the surface boundary between two substances such as oil and water and reduces the surface tension between the substances. The use of surfactants permits the thorough surface contact or mixing of substances that ordinarily remain separate. Surfactants are used in the petroleum industry as additives to drilling mud and to water during chemical flooding. See micellar- polymer flooding, surfactant mud.

n: A chemical that acts as a surface active agent. This term encompasses a multitude of materials that function as emulsifiers, dispersants, oil-wetters, water-wetters, foamers and defoamers. The type of surfactant behavior, whether acting as an emulsifier o

a chemical that is attracted to the surface of a fluid and modifies the properties such as surface tension.