Sequentially injected separate fluids (e.g., slugs):
(under subclass 268) A process in distinct, separate wells in which gas or liquid quantities are introduced into the pores of the earth through an input well or wells, the quantities being separately identifiable at the point of introduction into the earth, each fluid quantity consisting of a solution, mixture, compound, or element.
(1) Note. The separate identity of the fluid quantities is established by introduction into the earth at different time intervals or in spaced locations. A single fluid quantity may be one whose composition gradually changes in proportions so that there is no distinct break in the time-composition curve. Any distinct break in such a curve is considered to result in separately identifiable quantities. A broad reference to introduction from a plurality of wells or introduction from a single group of perforations is not enough to qualify a quantity as introduced from "spaced locations."
(2) Note. One of the fluid quantities may be a final displacing or driving fluid. The injection of such a fluid is sometimes indicated only by a phrase such as, "driving (the previously placed fluid) toward the output well." The meaning of such a phrase should be construed in the light of the specification. If the specification indicates that the drive is accomplished by a separately identifiable displacing fluid, then the displacing fluid is one of the fluid quantities. If the specification indicates that the drive is merely the continued introduction of a previous fluid or pump pressure, then the drive fluid is not a separately identifiable fluid quantity.
(3) Note. A single compound forming part of a mixture is not a fluid quantity under this definition. Thus, a mixture of three compounds is a single fluid quantity rather than three fluid quantities.
SEE OR SEARCH THIS CLASS, SUBCLASS:
260, for a process involving in situ combustion and injecting specific fuel or catalyst for burning into formation.
261, for a process involving injecting specific material other than oxygen into formation.
269, for processes involving input and output wells and fluid introduced into the formation from vertically spaced locations in an input well.
270+, for a process involving input and output wells including selective plugging or a surfactant.
271, for processes involving input and output wells and a separate fluid for fracturing or attacking the formation.
