초록 ▼

Enhanced recovery of oil from subterranean sedimentary formations by an in-situ combustion method employing a pattern of an injection well and several production wells, spaced-apart by a treatment zone. Combustion is controlled by placing at least one fluid conduit in a treatment zone and introducin

Enhanced recovery of oil from subterranean sedimentary formations by an in-situ combustion method employing a pattern of an injection well and several production wells, spaced-apart by a treatment zone. Combustion is controlled by placing at least one fluid conduit in a treatment zone and introducing a control fluid through it to modify the flame front. Oxygen may be introduced to take over from combustion air initially introduced through the injection well, to sustain combustion and advance the flame front. Water may be injected through the injection well, alternating with the oxygen through the control conduit to continue a wet combustion method started with air. The strategic placing of control conduits and the introduction of appropriate fluids may be employed to improve the sweep geometry by advancing the flame front or retarding it, or invading areas behind it. Safety means is provided for introducing the oxygen at a velocity greater than the maximum flame velocity encountered in the flame front.

대표청구항 ▼

1. In an in-situ forward combustion method for the recovery of oil from a subterranean sedimentary formation constituting an oil reservoir, in which air is injected through an injection well extending from the surface through the overburden into the oil reservoir at an injection zone under condition

1. In an in-situ forward combustion method for the recovery of oil from a subterranean sedimentary formation constituting an oil reservoir, in which air is injected through an injection well extending from the surface through the overburden into the oil reservoir at an injection zone under conditions to create a flame front moving away from the injection well to burn a portion of said oil and to cause fluids including oil to flow forward through a treatment zone towards at least one production well equipped for withdrawing oil and gases spaced from the injection well, the improvement in which, air is introduced into the treatment zone through the injection well to advance the flame front to a certain point, then the injection of air is discontinued, and molecular oxygen is introduced directly into the treatment zone at a velocity greater than that of the flame front through a separate conduit specially equipped for the injection of molecular oxygen extending from the surface through the overburden into the oil reservoir in proximity to, but spaced from the injection well and between it and the production well to continue the advance of the flame front towards the production well. 2. An in-situ forward combustion method, as defined in claim 1, in which the oxygen is introduced through at least one restricted passage from the conduit to increase the velocity of its delivery into the treatment zone. 3. In an in-situ forward combustion method for the recovery of oil from a subterranean sedimentary formation constituting an oil reservoir, in which air is injected through an injection well extending from the surface through the overburden into the oil reservoir at an injection zone under conditions to create a flame front moving away from the injection well to burn a portion of said oil and to cause fluids including oil to flow forward through a treatment zone towards at least one production well equipped for withdrawal of oil and gases spaced from the injection well, the improvement in which, air and water are introduced through the injection well to advance the flame front to a certain point, then the introduction of air through the injection well is discontinued, and, molecular oxygen is introduced directly into the treatment zone at a velocity greater than that of the flame front through a separate conduit specially equipped for the injection of molecular oxygen extending from the surface through the overburden into the oil reservoir in proximity to, but spaced from the injection well and between it and the production well to advance the flame front towards the production well. 4. A method, as defined in claim 1 or 3, in which the progress of the flame front through the treatment zone is controlled by the positioning of additional oxygen conduits within the treatment zone and supplying oxygen through them at a velocity greater than that of the flame front to increase the volumetric sweep in the direction of the production well. 5. In an in-situ forward combustion method for the recovery of oil from a subterranean sedimentary formation in which there is introduced, through an injection well, a fluid selected from the group consisting of combustion-containing gas, water and a mixture of combustion-containing gas and water under conditions to create a flame front to burn a portion of the oil and to cause fluid, including oil to flow towards at least one production well spaced from the input well by a treatment zone, and equipped for withdrawing oil and gases, comprising, conveying molecular oxygen through a separate conduit specially equipped for injecting molecular oxygen separated from said injection well leading from the surface through the overburden to the formation whereby the molecular oxygen is introduced directly into the formation at a velocity greater than that of the flame front separately from the water to sustain combustion and continue the advance of the flame front towards the production well. 6. A method, as defined in claim 1, 3 or 5, in which the oxygen is injected from the separate oxygen conduit at a velocity greater than the maximum flame velocity encountered in close proximity to the oxygen conduit. 7. An in-situ forward combustion method for the recovery of oil from subterraneous sedimentary formations containing an oil reservoir, in which there is introduced through an injection well extending from the surface through the overburden into the oil reservoir, in an injection zone, air under conditions to burn a portion of the oil to form a flame front and to cause fluids including oil to flow outwards towards a plurality of production wells each equipped to withdraw oil and gases and spaced from the injection well to form a pattern and from which fluids are withdrawn, in which, combustion of the oil in the reservoir is initiated and continued by injecting air through the injection well to produce a flame front and to cause the flame front to advance towards the production wells through a part of the treatment zone, then, the injection of air is discontinued and molecular oxygen is introduced at a velocity greater than that of the flame front through at least one separate conduit extending from the surface through the overburden into the oil reservoir within the treatment zone in proximity to the injection well between it and the production wells and such injection of molecular oxygen is continued to cause the flame front to advance through a further part of the treatment zone. 8. In an in-situ combustion method for the recovery of oil, as defined in claim 7, in which water is introduced alternately to the air as the flame front advances through said part of the treatment zone, and then the injection of air through the injection well is discontinued and water is injected through the injection well alternately with the introduction of oxygen through the oxygen conduit. 9. An in-situ forward combustion method for the recovery of oil from a subterranean sedimentary formation constituting an oil reservoir, in which oxygen-containing gas and water are injected into an injection zone in the oil reservoir, under conditions to burn a portion of said oil to form a flame front and to cause said flame front and fluids including oil to flow through a treatment zone towards at least one production well equipped for withdrawal of oil and gases and spaced from the injection well, in which, the water is injected through an injection well and the oxygen-containing gas is molecular oxygen and is introduced at a velocity greater than that of the flame front through a conduit separated by part of said sedimentary formation from the injection well and extending from the surface through the overburden into the oil reservoir within the treatment zone. 10. A method, as defined in claim 9, in which the oxygen is introduced through the separate conduit at a level below that at which the water is injected through the injection well. 11. A method, as defined in claim 9, in which the oxygen is injected through several separate conduits at respectively different levels below the level at which the water is injected through the injection well. 12. An in-situ forward combustion method for the recovery of oil from a subterranean sedimentary formation containing an oil reservoir, in which air is injected through an injection well extending from the surface through the overburden into the oil reservoir in an injection zone under conditions to burn a portion of the oil to form a flame front and to cause fluids including oil to flow towards a plurality of production wells equipped for withdrawing oil and gases and forming with the injection well and from which fluids are withdrawn spaced from the injection well to form a pattern, in which, combustion of the oil in the reservoir is initiated and continued by injecting air through the injection well to produce the flame front and then air and water are injected through the injection well to cause the flame front to advance through a section of the treatment zone to the point where the aereal sweep of the flame front becomes distorted by drag of the flame front in a particular part of the treatment zone, the improvement in which, molecular oxygen is introduced at a velocity greater than that of the flame front through an oxygen conduit extending from the surface through the overburden into said particular part to cause advance of the flame front to improve the geometry of the flame front. 13. An in-situ forward combustion method for the recovery of oil from a subterranean sedimentary formation constituting an oil reservoir, in which there is introduced through an injection well extending from the surface through the overburden into the oil reservoir at an injection zone, air under conditions to burn a portion of said oil and to cause fluids including oil to flow through a treatment zone towards at least one production well equipped to withdraw oil and gases and spaced from the injection well, in which, combustion of oil in the reservoir is initiated and continued by injecting air through the injection well to produce a flame front and causing the flame front to advance through a section of the treatment zone towards the at least one production well, then, the air is discontinued and molecular oxygen is introduced at a velocity greater than that of the flame front through a separate conduit extending from the surface through the overburden into the oil reservoir within the treatment zone in proximity to the injection well, and such injection of molecular oxygen is continued to cause the flame front to advance through a further section of the treatment zone. 14. A forward combustion method for the recovery of oil, as defined in claim 13, in which water is introduced alternately to the air to cause the flame front to advance through the first section of the treatment zone, then, moleclar oxygen is introduced at a velocity greater than that of the flame front through a separate conduit extending from the surface through the overburden into the oil reservoir within the treatment zone in proximity to the injection well, and water is introduced through the injection well alternately with the oxygen through the oxygen conduit. 15. An installation for the in-situ recovery of oil from subterraneous sedimentary formations containing an oil reservoir, comprising, an injection well extending from the surface through the overburden into the oil reservoir in an injection zone and equipped for injecting air and water to create a flame front moving away from the injection well, a plurality of production wells each equipped to withdraw oil and gases in a production zone each spaced from the injection zone by a treatment zone, each of the production wells being equipped for withdrawing fluids from the formation, at least one fluid conduit extending from the surface through the overburden into the treatment zone at a position close to but spaced from the injection well and equipped for introducing molecular oxygen into the formation at a velocity greater than that of the flame front, to sustain the flame front. 16. An in-situ forward combustion method for the recovery of oil from a subterranean sedimentary formation constituting an oil reservoir, in which air is injected through an injection well extending from the surface through the overburden into the oil reservoir at an injection zone under conditions to create a flame front moving away from the injection well to burn a portion of said oil and to cause fluids including oil to flow forward through a treatment zone towards at least one production well equipped for withdrawal of oil and gases and spaced from the injection well, the improvement in which, a flame front is caused to advance towards the production well to a certain point in the treatment zone, then a separate conduit is introduced behind the flame front, after its passage, and molecular oxygen is introduced directly into the treatment zone at a velocity greater than that of the flame front through a separate injection conduit whereby the oxygen reaches the burned out zone, depleted in hydrocarbon, to support combustion of the coke thereby to provide an additional source of heat behind the flame front.