Abstract: In an inverted nine-spot pattern in an areally homogeneous reservoir, oil recovery is enhanced when the completion of the sidewells is restricted to the lower 20% of the reservoir. An inverted nine-spot pattern has a steam injection well at the center of the pattern and production wells at each of the four corners of the pattern and at the center of each side of the pattern. Steam is injected at the center well, and oil is produced from sidewells and corner wells.

Abstract: A two-phase fluid is metered by injecting a surfactant into the two-phase fluid, homogenizing the fluid and surfactant with either a porous medium or an orifice plate to form a pseudo-single phase fluid, and metering the pseudo-single phase fluid. In one embodiment, both the injection of surfactant and the homogenization with either a porous medium or an orifice plate occur within one foot of where the pseudo-single phase fluid is metered. In another embodiment, the surfactant is injected at a wellhead and the metering occurs downhole.

Abstract: Steam is injected in a multi-spot pattern in a dipping reservoir. The injection point of that steam is downdip and is offset from the pattern center by at least one-fifth the distance from the pattern center to the downdip producer row of that pattern. Preferably, the amount of offset is between two-fifths and three-fifths the distance from the pattern center to the downdip producer row.

Abstract: The present invention is a method and apparatus for injecting compressible fluids into multiple zones of a hydrocarbon bearing formation, in particular injecting compressible fluid at a predetermined, constant rate into multiple zones through a single tubing string. Producing zones are packed off and limited entry outlets are installed on the injection tubing string at each producing zone. Injection pressure is maintained and limited entry outlets are designed and sized such that the compressible fluid reaches sonic flow through the outlets so that the flow rate no longer responds to changes in downstream pressures.

Abstract: A method for thermal fluid injection into a plurality of strata wherein a well is packed off to establish a first and a second zone. A first tubing string is introduced and is terminated in the first zone. The first tubing string is paralleled by a second tubing string. The first and second tubing strings are physically separated. A first fluid at a first temperature is injected into the first tubing string while a second fluid at a second temperature is simultaneously injected into the second tubing string. The first fluid at the first temperature is applied to the first zone while the second fluid at the second temperature is applied to the second zone.