Terms
The volumetric sweep efficiency at any time is the fraction of the total reservoir volume contacted by the injected fluid during the recovery. When using water, consideration of the mobility of the fluids, is an important factor when determining the area and vertical sweep efficiencies. This would help to determine the mobility ratio. If M is less than 1 then oil is capable of travelling at a rate equivalent to the water. An increase in the viscosity of the oil would mean that M would increase and this would lead to the injected fluid moving around the oil. This would also make it harder for the oil to penetrate the pore. To improve this ratio then the viscosity of the water has to be increased. When M is greater than 1 the displacing fluid has greater mobility than the displaced fluid. Also the position of the water injection and the flooding patterns would go a long way to determining the recovery patterns. Also to consider in oil recovery is the position and orientation of the injection wells around the production well. As the mobility ratio increases the sweep efficiency decreases. Once a channel of water exists between the injector and the producer then little additional oil would be recovered.
If permeability varies vertically then an irregular vertical fluid front can develop and this is as a result of the differing permeabilities and the mobility ratio.
Displacement efficiency refers to the fraction of oil that is swept from unit volume of reservoir upon injection. This depends on the mobility ratio, the wettability of the rock and the pore geometry. The wettability is determined by whether or not the grains preferentially absorb oil of water.
Read more about this topic: Enhanced Oil Recovery
Famous quotes containing the word terms:
“They were pipes of pagan mirth,
And the world had found new terms of worth.
He laid him down on the sunburned earth
And raveled a flower and looked away.
Play? Play? What should he play?”
—Robert Frost (1874–1963)
“Before I get through with you, you will have a clear case for divorce and so will my wife. Now, the first thing to do is arrange for a settlement. You take the children, your husband takes the house, Junior burns down the house, you take the insurance and I take you!”
—S.J. Perelman, U.S. screenwriter, Arthur Sheekman, Will Johnstone, and Norman Z. McLeod. Groucho Marx, Monkey Business, terms for a divorce settlement proposed while trying to woo Lucille Briggs (Thelma Todd)
“Suppose you go to war, you cannot fight always; and when, after much loss on both sides, and no gain on either, you cease fighting, the identical old questions, as to terms of intercourse, are again upon you.”
—Abraham Lincoln (1809–1865)