Abstract:
Following completion of a secondary recovery operation at breakthrough of the driving flood at the production wells, additional injection wells are located where the oil saturation in the formation is usually higher, usually adjacent production wells with the new injection wells being located between production wells.
Abstract:
The interface between driving and driven fluids in a secondary recovery operation is reshaped after a cusp has developed by injection of a fluid via wells controlling the flow gradients, and the arrival of the injected driving fluid into the vicinity of a production well is delayed by the imposition of a dynamic gradient barrier of produced formation fluids.
Abstract:
At the conclusion of a secondary recovery operation after breakthrough of the driving fluid at the production wells in a direct line drive, injection wells in alternate series are shut in and the production wells in the adjacent series are converted to injection wells, for tertiary recovery via the remainder of the production wells by the imposition of a new set of flow gradients.
Abstract:
WHERE Vrx and Vry are the X and Y components, respectively, of the velocity of flow in the reservoir at a point r, Q is the rate of a forcing fluid entering the reservoir, i is the total current in the electrolytic solution, Phi is the effective porosity of the medium containing the reservoirs, Sv and Sh are the vertical and horizontal scale factors, respectively, of the reservoir to the model and ARE VOLTAGE GRADIENTS IN THE X and Y directions, respectively, at a point in the model corresponding to the point r in the reservoir. the velocities are used to compute the interface positions of the petroleum or gas and the fluid in the reservoir by determining each incremental change in distance Delta s for a point, commonly referred to as a trace point of the interface between the fluid and the petroleum or gas, in accordance with the following equation: An insulated grid, having four electrode probes at each intersection, overlays an analog model, using an electrolytic solution, of a petroleum or gas reservoir so that some or all of the probes are immersed in the electrolytic solution. Electrodes representing an injection well and a withdrawal well in the reservoir introduce an alternating current in the electrolytic solution corresponding to the injection rate of a fluid in the injection well. Alternating current voltages present at the probes, resulting from the alternating current in the electrolytic solution, are processed to provide digital signals. The digital signals are applied to a digital computer which determines the fluid velocity at a point r of the reservoir in accordance with the following vector equations: