Abstract: A method for recovering oil from a subterranean, viscous oil-containing formation employing a cyclical injection-production program in which first a mixture of steam and solvent are injected after which fluids including oil are produced until the water cut of the produced fluids reaches 95 percent. Thereafter, the sequence of injection of a solvent/steam mixture and production of fluids including oil is repeated for a plurality of cycles. The ratio of solvent to steam is 2 to 10 volume percent. The mixture of solvent and steam is injected into the lower portion of the formation in which adequate fluid communication exists or in which a communication path is first established. In another embodiment, after the initial solvent/steam injection-production cycle, steam or hot water is injected into the formation followed by production and drawdown of the formation.

Abstract: Oil may be recovered from viscous oil-containing formations including tar sand deposits by providing at least one injection well and at least one spaced-apart production well which extend downwardly from the surface and which extend to, and generally horizontally through, the bottom of the oil-containing formation with fluid communication of the horizontally extending portions of each well with the oil-containing formation. A predetermined amount of solvent, preferably 0.05 to 0.30 pore volume is injected into the bottom of the formation via the injection well and fluids including oil are recovered from the formation via the production well. After the desired amount of solvent has been injected into the formation, production is terminated and both the injection well and production well are shut-in to allow the formation to undergo a soak period for a variable time, preferably for a time between 2 to 20 days per foot of vertical thickness of the oil-containing formation.

Abstract: An enhanced oil recovery method which employs a pressurized gas injection process for the miscible displacement of oil from a subterranean geologic formation wherein the gas is injected into the formation so that the pressure in the formation increases above the miscibility pressure for the gas and oil in the formation and such injection is continued until the pressure in the formation approaches but does not exceed the fracture pressure of the formation, terminating gas injection before the formation is fractured, holding the injected gas in the formation to allow it to expand on its own into the formation thereby lowering the pressure in the formation, and injecting additional gas into the formation when the formation pressure has reached a point where it approaches but does not go below said miscibility pressure. The foregoing sequence of steps are repeated as many times as desired.

Abstract: A subterranean, viscous oil-containing formation not greater than 2500 feet in depth is penetrated by at least one injection well extending into the lower portion thereof. A horizontal fracture is formed in the lower portion of the formation through the injection well. At least one spaced-apart production well penetrates the formation in fluid communication with the upper two-thirds or less of the formation. A slug of steam, about 0.35 to 0.45 pore volume, is injected into the injection well and fluids including oil are recovered from the formation via the production well. The injection well is shut-in for a predetermined period of time while continuing production of oil. Thereafter, a predetermined amount, about 0.03 to 0.10 pore volume, of hot water or low quality steam is injected into the injection well and production is continued until there is an unfavorable amount of water or steam in the fluids recovered.

Abstract: A method for the underground gasification of coal or browncoal, using two boreholes extending through a coal layer with the slope of said layer, for supplying oxygen to a combustion and gasification front in said layer and discharging combustion gases respectively, a filler material being intermittently supplied through one of said boreholes for filling the cavity produced by burning away the coal layer. According to the invention, said filling is started at a moment before the combustion front has reached the discharge borehole, and in particular before the overlying formations will collapse to such a degree that an inadmissible subsidence at the ground level would develop. Thereafter the combustion and gasification is restarted in the same or the opposite sense as may be required for adjusting the orientation of the gasification front in the desired direction.

Abstract: A method is disclosed for recovering hydrocarbons from heavy oil and tar sand formations by a series of sequenced steps, wherein the production wells are initially steam stimulated. Thereafter, about 0.6 to about 1.2 pore volumes of steam of a relatively high steam quality are injected into the formation through the injection wells. An additional quantity of steam is then injected wherein the steam quality is decreased to a relatively low quality. Water injection and wet in situ combustion conclude the method.

Abstract: A method for the recovery of viscous oil from a subterranean, viscous oil-containing formation in which nitrogen is injected into the oil-containing formation following a steam flood.

Abstract: A method of electromagnetic heating in situ recovers liquid hydrocarbons from an earth formation containing viscous hydrocarbonaceous liquid and water in an inorganic matrix where the formation is substantially impermeable to fluids under native conditions. A block of the earth formation is substantially uniformly heated with electromagnetic power to a temperature at which the viscous hydrocarbonaceous liquid is relatively fluid and a portion of the water vaporizes to water vapor at a pressure sufficient to overcome the capillary pressure of the liquid in the matrix. Water vapor thereupon escaping from the block under such pressure is recovered with hydrocarbonaceous liquid driven thereby. The magnitude of the electromagnetic power is controlled to limit the current recovery ratio of water vapor to hydrocarbonaceous liquid below a predetermined limit assuring substantial recovery of the hydrocarbonaceous liquid prior to the driving off of substantially all the water.

Abstract: A method of electromagnetic heating in situ recovers liquid hydrocarbons from an oil shale formation containing kerogen in an inorganic matrix where the formation is substantially impermeable to fluids under native conditions. A block of the oil shale formation is substantially uniformly heated in situ with electromagnetic power to a temperature of about 275.degree. C. where there is pyrolysis of a portion of the kerogen to gas and shale oil at a pressure sufficient to overcome the capillary pressure of the shale oil in the matrix, thereby providing substantial fluid permeability to the formation. The gas thereupon escaping from said block and the shale oil driven thereby are recovered, thereby further increasing the permeability of the formation.

Abstract: This invention provides in the production of heavy oil from a shallow subterranean tar sand bed penetrated by spaced injection and recovery systems, the method comprising:(a) forming a plurality of horizontal fractures spanning the distance between said injection system and said recovery system, said fractures being spaced apart in a vertical direction with respect to each other throughout the depth of the tar sand bed;(b) injecting a solvent for heavy oil and/or steam into said fractures,(c) shutting in the injection and recovery systems for a predetermined period of time to form a heavy oil/solvent mixture by gravity-driven convective mixing, and(d) recovering said heavy oil/solvent mixture in said recovery system by conventional recovery techniques.

Abstract: After a linkage channel is established through an underground coal seam connecting two vertical wells, a tubing bender/straightener is positioned in a first well aligned with the linkage channel. Oxidizer injection tubing is inserted from the wellhead into the tubing bender/straightener. The tubing is forced through the tubing bender/straightener and on into the linkage channel. The coal is ignited and the fire sustained by continuous injection of oxidizer through the tubing, creating a reaction zone separated from the first well with products of reaction recovered through the second well.

Abstract: This invention relates to a method of enhancing oil recovery from an underground reservoir containing oil. A gas which is miscible with oil at the temperature and pressure of injection is injected into the reservoir to displace oil. Injection is carried out in such a way as to make sure that a mixing zone is formed in the reservoir such that each fluid introduced is miscible with the fluid immediately preceding it and the fluid immediately following it. This is done by injecting small slugs of fluid miscible with, but different in composition from, the fluid adjacent to the perforated zone of the well. The injection of each slug is followed by a shut-in period to permit a mixing zone to establish itself.

Abstract: A method for recovering hydrocarbons from a subterranean hydrocarbon bearing formation comprises the steps of providing a production well penetrating in the formation and a plurality of injection wells surrounding the production well. Water is injected into the formation through the injection wells to produce a water flood barrier ringing the production well. A mixture of nitrogen and carbon dioxide gas is injected through the production well and into the formation with the water barrier acting to inhibit the escape of the gas from the portion of the formation surrounding the production well. Gas is injected through the production well into the formation until the formation is pressurized and then gas injection is ceased and the mixture of hydrocarbons and injection gas flowed from the formation through the production well.

Abstract: A method is disclosed for producing viscous petroleum from subsurface deposits. The method employs a vertical well and a horizontal well through the petroleum deposit. A combination of injection procedures through the horizontal and vertical well heat the viscous petroleum in the annulus around the horizontal well. Successive completion intervals are installed in the horizontal well to produce the heated petroleum. The petroleum is driven by a drive fluid passing through previously produced intervals.

Abstract: The disclosed invention is a method for efficiently recovering viscous petroleum from hydrocarbon formations, particularly consolidated tar sand formations. A superheated paraffinic solvent under elevated pressure and temperature is injected into the formation. Thereafter, the formation is rapidly produced until pressure is depleted. The injection and production depletion cycle is then repeated.

Abstract: In a thermal method for the recovery of oil from a subterranean, viscous oil-containing formation, steam in an amount ranging from 0.3 to 0.5 pore volume and an injection rate within the range of 4.0 to 7.0 bbl/day/ac.-ft. is injected into the formation via an injection well completed in the lower 50% or less of the formation and fluids including oil are recovered via a spaced-apart production well completed in the upper 50% or less of the formation. The injection well is then shut-in for a variable time and thereafter a predetermined amount of hot water or low quality steam is injected into the formation via the injection well in an amount ranging from 0.03 to 0.10 pore volume and at an injection rate of 1 to 2.0 bbl/day/ac.-ft. The method is applied to viscous oil-containing formation in which either naturally occurring or induced communication exists between the injection well and the production well in the bottom zone of the formation.

Abstract: Disclosed is a method for recovering oil from a dipping subterranean, viscous oil-containing reservoir having an underlying body of water. An in situ combustion operation is initiated using an oxidizing gas injected through an injection well in fluid communication with the lower portion of the reservoir near the oil/water interface. Fluids including oil and effluent gas are recovered from the reservoir through a production well in fluid communication with a shallower portion of the reservoir. After a predetermined amount of time, injection of the oxidizing gas is terminated and the reservoir is allowed to undergo a soaking period for a predetermined amount of time. Thereafter, a water drive is initiated by injecting water into the injection well and fluids including oil are recovered from the reservoir through the production well.

Abstract: A method for the in situ conversion and recovery of heavy hydrocarbonaceous crude oil containing indigenous trace metal from two adjacent non-communicating hydrocarbon reservoirs which are alternately pressured and recovered which method comprises: (a) heating the heavy hydrocarbonaceous crude oil in a first reservoir to a hydrocarbon conversion temperature; (b) contacting the first reservoir with elemental essentially-anhydrous hydrogen at a pressure from about 200 to about 10,000 psig; (c) heating the heavy hydrocarbonaceous crude oil in a second reservoir to a hydrocarbon conversion temperature; (d) depressuring the first reservoir to yield an effluent comprising hydrocarbonaceous crude oil and unreacted elemental hydrogen; (e) separating the effluent from the first reservoir to recover a hydrocarbonaceous crude oil and a gaseous component comprising elemental hydrogen; (f) contacting the second reservoir with elemental essentially-anhydrous hydrogen, a portion of which is recovered in step (e), at a press

Abstract: Coal is reduced to ash in place by gasification using in situ production techniques, resulting in significant void space underground, which in turn causes roof fall and subsidence. Overburden collapse is stabilized by backfilling with foaming mud cement that hardens into an expanded solid, which quenches and fills the production module and seals residual ash. Rubble volumes and subsidence cracks are sealed against water incursions and contaminated water excursions. Surface facilities above barrier pillars are protected from destructive forces of subsidence draw.

Abstract: The vertical conformance of a steam drive process is improved by conducting the steam flood process in two stages. In the first stage, steam is injected into the lower portion of the formation via an injection well and oil is recovered from the upper portion of the formation via a spaced apart production well. Once there is a breakthrough of steam at the production well, injection of steam and production are terminated. In the second stage, the roles of the injection well and production well are reversed. A thermal recovery fluid comprising steam or hot water is injected into the lower portion of the formation via the production well and oil is recovered from the lower portion of the formation via the injection well until the oil recovered contains an unfavorable amount of steam or water.

Abstract: Oil is recovered from an oil-bearing reservoir in a process employing an in-situ combustion process utilizing a combustion-supporting gas containing at least 75% by volume pure oxygen, and preferably substantially pure oxygen, and a sequence in which the production well or wells are cyclically throttled. In place of using an in-situ combustion process, mixtures of steam and carbon dioxide or mixtures of steam and low molecular weight C.sub.3 -C.sub.8 hydrocarbons are injected into the reservoir and the production well is cyclically throttled. The production well flow rate is restricted until the bottom-hole pressure of the well has increased to an amount of about 30% to about 90% of the fluid injection pressure at the injection well. Thereafter, the production well is opened and oil is recovered therefrom as the bottom-hole pressure declines. The throttled production cycle may be repeated at appropriate intervals during the process.

Abstract: Oil is recovered from an oil-bearing reservoir in a process employing an in-situ combustion process utilizing a combustion-supporting gas containing at least 75% by volume pure oxygen, and preferably substantially pure oxygen, and a sequence in which the production well or wells are cyclically throttled. In place of using an in-situ combustion process, mixtures of steam and carbon dioxide or mixtures of steam and low molecular weight C.sub.3 -C.sub.8 hydrocarbons are injected into the reservoir and the production well is cyclically throttled. The production well flow rate is restricted until the bottom-hole pressure of the well has increased to an amount of about 30% to about 90% of the fluid injection pressure at the injection well. Thereafter, the production well is opened and oil is recovered therefrom as the bottom-hole pressure declines. The throttled production cycle may be repeated at appropriate intervals during the process.

Abstract: Oil is recovered from an oil-bearing reservoir in a process employing an in-situ combustion process utilizing a combustion-supporting gas containing at least 75% by volume pure oxygen, and preferably substantially pure oxygen, and a sequence in which the production well or wells are cyclically throttled. In place of using an in-situ combustion process, mixtures of steam and carbon dioxide or mixtures of steam and low molecular weight C.sub.3 -C.sub.8 hydrocarbons are injected into the reservoir and the production well is cyclically throttled. The production well flow rate is restricted until the bottom-hole pressure of the well has increased to an amount of about 30% to about 90% of the fluid injection pressure at the injection well. Thereafter, the production well is opened and oil is recovered therefrom as the bottom-hole pressure declines. The throttled production cycle may be repeated at appropriate intervals during the process.

Abstract: Improved methods and apparatus are provided for recovering high viscosity oils from sub-surface earth formations. In particular, a large diameter shaft hole is employed and a plurality of substantially horizontal drill holes extend radially from the shaft hole into the formation. It is a feature of this invention to provide vertically spaced drill holes oriented to improve the recovery of the oil. Methods are provided for further enhancing oil recovery by coordinating the injected fluid with the location of injection within the formation.

Abstract: A method of oil recovery from subterranean formations, and especially water wet sand formation, comprising the steps of sequentially establishing a rate of oil production for the formation as a function of formation characteristics, such as perosity, permeability, depth of formation and past production from the formation. Second, injecting into the formation a bank of chilled water solution containing carbon dioxide gas and citric acid and phosphoric acid. Third, driving the bank of water solution from the injection well by any suitable means to the production well and withdrawing oil from the production well at the established rate of oil production. The method is especially adapted as a tertiary oil recovery method and effectively provides a 70% horizontal and vertical sweep of the formation.

Abstract: This invention relates to a method where the soak time, required for solvent and crude oil mixing in the gravity assisted solvent flooding process, is significantly reduced. This is accomplished by inducing vertical flow of solvent into the heavy crude oil part of the reservoir through the use of intermediate wells drilled between injection and production wells and completed in the top of the oil reservoir. Steam or gas may be used prior to the introduction of the solvent to reduce the resistance to subsequent solvent flow.

Abstract: A method for the enhanced recovery of both natural gas and liquid petroleum from hydrocarbon-containing subterranean formations, particularly dipping subterranean formations, by the consecutive steps of introducing a gaseous displacement fluid to recover natural gas and thereafter introducing an oil-miscible displacement fluid to recover undrained oil and/or other liquid petroleum.

Abstract: Gas production wells, which no longer produce gas utilizing conventional primary and secondary means of recovery, can be returned to production by treatment comprising addition of an aqueous solution of certain phosphate ester surfactants followed by successive treatment with water. Increased production also can be obtained in low-producing gas wells by similar treatment with certain phosphate ester surfactants. Subsequent to treatment of a producer well, said phosphate ester surfactant aqueous solution is forced into the formation utilizing water and said surfactant and water mixture is allowed to remain in the producing well, for an effective period of time ranging from not less than 24 hours to one month. Thereafter, conventional fluid drive means are then utilized to recover gas from the subterranean gas formation.

Abstract: A process for the underground gasification of coal and carbonaceous materials in makes the customary lengthy preliminary task of establishing an underground interconnection between wells and cavities unnecessary. Instead, according to the invention, the circulation of gasifying agents and product gases is between one or more wells and the boundary of an underground generator (i.e. cavity system) through a reaction zone in the generator.

Abstract: The vertical conformance of a steam drive process is improved and steam override reduced by utilizing a solvent push-pull process in the lower portion of the formation adjacent the production well. Steam is injected into the injection well with production of fluids from the production well. The production well contains two flow paths from the surface, the first being in fluid communication with the upper portion of the formation. Production is continued until there is a water breakthrough from the formation via the first flow path in the production well. After production via the production well is terminated, a predetermined amount of solvent is injected into the lower portion of the formation via the second flow path in the production well while continuing to inject steam into the injection well.

Abstract: Oil may be recovered from viscous oil-containing formations including tar sand deposits by providing at least one injection well and at least one spaced-apart production well which extend downwardly from the surfaces and which extend to, and generally horizontally through, the bottom of the oil-containing formation with fluid communication of the horizontally extending portions of each well with the oil-containing formation. Solvent is injected into the injection well and fluids including oil are recovered from the production well until the fluid recovered contains an unfavorable amount of solvent, preferably at least 90 percent. After injection of the solvent is terminated, both the injection well and the production well are shut-in and the formation is allowed to undergo a soak period for a predetermined time, preferably for a time of between 2 to 20 days per foot of formation thickness.

Abstract: Oil may be recovered from viscous oil-containing formations including tar sand deposits by first establishing a fluid communication path in the lower portion of the formation intermediate at least one injection well and a production well. A hydrocarbon solvent having a density less than oil contained in the formation and a viscosity not greater than 1/100 the viscosity of the oil contained in the formation under formation conditions is injected into the communication path and fluids including oil are recovered from the production well until the fluid recovered contains an unfavorable ratio of oil to solvent. The production well is shut-in and an additional quantity of the hydrocarbon solvent is injected into the fluid communication path, preferably until a total amount of between 0.05 to 0.30 pore volume.

Abstract: Oil may be recovered from viscous oil-containing formations including tar sand deposits by first establishing a fluid communication path in the lower portion of the formation intermediate at least one injection well and a production well. At least one additional interior production well in fluid communication with the upper portion of the formation is drilled within the formation defined by the injection well and production well. A hydrocarbon solvent having a density less than oil contained in the formation under formation conditions is injected into the fluid communication path via an injection well and fluids including oil are recovered from the production well until solvent is detected in the fluid recovered.

Abstract: A method for recovering oil from a tilted oil-bearing reservoir having a water zone in fluid communication with and directly below an oil zone wherein a large amount of solvent is injected along the water-oil interface so that a part of the solvent fingers into the oil, lowering its viscosity and making the oil more mobile for production. The remainder of the solvent is driven through the reservoir by a water flood wherein the rate is controlled slow enough that gravity minimizes fingering of the water into the oil layer, sweeping oil toward the production well. Solvent stimulation of the producing well provides additional incremental recovery and encourages the flooded oil toward the production well.

Abstract: An enhanced petroleum oil recovery method for increasing the quantity of oil recoverable from an underground deposit thereof is provided which involves injecting into a first point in such deposit a liquid mixture of low molecular weight, light hydrocarbons; alternately reducing and raising the back pressure exerted on said deposit so as to alternately induce boiling and condensation of said light hydrocarbon mixture; recovering from a second point in said deposit under controlled back pressure a mixture of said light hydrocarbons and oil; separating the light hydrocarbons from the extracted petroleum oil by distillation; and then recycling the light hydrocarbons to the injection step. Another aspect of the invention involves utilizing the essential features thereof for the recovery of oil from oil-bearing sands, e.g. tar sands, which are mined and brought to the surface.

Abstract: The vertical or both vertical and horizontal conformance of a stem drive process is improved by employing one or more infill wells between the injection well and production well, the infill well being in fluid communication with the bottom half or less of the formation. In the first step, petroleum is recovered from the infill well after oil production at the production well has proceeded to a predetermined point. After water cut of fluids being produced from the infill well reaches a predetermined value, the production well is converted from a production well to an injection well and steam is injected into the converted well while continuing recovering fluids from the infill well. When one infill well is employed in a more or less aligned arrangment between injection and production wells, the vertical conformance is improved. When one or more infill wells are utilized in a pattern comprising one or more injectors and one or more producers, both horizontal and vertical conformance is improved.

Abstract: The recovery of petroleum produced from an oil reservoir is enhanced by injecting water such as from a geopressured aquifer having a natural gas content at or near saturation at a temperature above 300.degree. F. into the oil reservoir at a flow rate sufficient to develop a back-pressure in the oil reservoir equal to between about 80% of its fracture pressure and a pressure below its fracture pressure and producing oil from the oil reservoir when the injection of water necessary to maintain the back-pressure below the oil reservoir fracture pressure drops below a predetermined level. The recovery of petroleum also is enhanced by using sand screening means to complete a portion of the well bore penetrating into the oil reservoir and a straddle packer assembly means which can be raised and lowered relative to the screening means.

Abstract: An in situ coal gasification process adapted for large scale commercial projects is provided. Techniques are provided to insure establishment of a gasification front over the full seam thickness as each successive injection well in the array is brought on line. This is accomplished by controlling the oxidant introduction in a prescribed manner during the early stages of injection after pneumatic communication between well pairs has been established. Also provided are techniques and standards for avoiding or controlling subsidence and for conducting gasification operations in free water laden seams and in coal seams subject to spontaneous combustion.

Abstract: Disclosed are systems for removing hydrocarbons from subterranean deposits thereof. A fluid-impervious barrier screen is formed to isolate parts of the deposit or to isolate the deposit from adjacent fluid-permeable earth formations. The barrier screens are formed by fracturing a vertical zone in the formation by micropercussive fracturing or detonation of microexplosive charges in a series of closely-spaced bore-holes to form a vertically extending fractured plane. The fractured plane is sealed with a sealing medium to form a fluid-impervious screen.Hydrocarbons trapped in the enclosed deposit zone are flushed from the formation by recirculating a fluid medium such as superheated brine and/or hot gases through the enclosed deposit zone under sufficient pressure to cause turbulent flow through the pore formations and to relieve the overburden pressure. The flushing medium may be injected in a series of pressure pulses to force the fluid through the pores by hydraulic ramming.

Abstract: Disclosed is a method for conducting an enhanced oil recovery process comprising injecting an oil displacing fluid into an injection well and recovering petroleum displaced by the fluid from one or more spaced-apart production wells, by an improved method in which the sweep efficiency or horizontal conformance of the displacement process is increased. A fluid is injected into the producing well, which fluid has a viscosity not substantially greater than the viscosity of water at the conditions of injection, but which reacts with oil present in the formation, forming a viscous emulsion which restricts the flow of fluids through the portion of the formation contacted by the emulsion-forming fluid. As a result of this treatment, there is a reduction in tendency for the displaced and injected fluids to form cusps as they approach the production well, thereby failing to sweep substantial portions of the formation.

Abstract: Crude oil and gas production wells, which no longer produce oil or gas utilizing conventional primary and secondary means of recovery, can be returned to production by treatment comprising addition of an aqueous solution of certain phosphate ester surfactants followed by successive treatment with a hydrocarbon. Increased production also can be obtained in low-producing oil and gas wells by similar treatment with certain phosphate ester surfactants. Subsequent to treatment of a producer well, the phosphate ester surfactant is forced into the formation utilizing a hydrocarbon and said surfactant and hydrocarbon mixture is allowed to remain in the producing well, for an effective period of time ranging from not less than 24 hours to one month. Thereafter, pumping and/or conventional fluid drive means are then utilized to recover oil or gas from the subterranean oil or gas formation.

Abstract: A process is provided for the recovery of hydrocarbons from a reservoir of heavy oil containing sands. An injection stream comprising steam, hydrocarbon diluent, and a gas which is gaseous at formation temperature and pressure and soluable in the formation fluids at injection pressure is injected into the reservoir to mobilize the heavy oil, producing a flow of formation fluids which is subsequently produced from the reservoir. Suitable gases include carbon dioxide and oxygen. Naphtha is a preferred diluent. The provision of both diluent and gaseous additives in the steam injection stream is shown to improve conformance within the reservoir to enhance ultimate recovery of hydrocarbons from the reservoir.

Abstract: In a dipping underground petroleum reservoir devoid of a natural gas cap, a mixture of gases soluble in petroleum is injected into a well positioned in an up dip location. Gases in the mixture are selected for their diverse solubility and diffusion characteristics. Gas injection is terminated followed by attic oil production wherein the gases accompanying the produced oil are separated and measured. The separated gases are then compared quantitatively with gases injected and the solubility capabilities of the produced oil. Results are used to estimate the size of the attic portion of the reservoir. Alternating cycles of gas injection and attic oil production are continued until the well is engulfed by the expanding artificial gas cap.

Abstract: A zone of increased heat and enhanced fluid mobility is established between an injection well and a production well vertically traversing a heavy oil (bitumen, tar) reservoir by (a) first horizontally hydraulically fracturing between the wells, and (b) then injecting hot water and/or steam into the injection well at a very high rate, at a sufficient pressure, and for a sufficient time (holding sufficient back pressure on the production well if needed) to float the formation along the fracture system between the wells, to effect channel flow of fluids through the floated fracture system (with production from the production well), and to effect effective and uniform heating of substantial reservoir volume perpendicular to the channel flow. Thereupon, other thermal methods such as matrix flow steam flooding can be employed to recover additional oil.

Abstract: A method for steam stimulating a heavy oil reservoir which realizes significant energy savings is disclosed. Steam is injected into the reservoir via one well, permitted to soak and then produced back directly into the reservoir via a second well. This flowback steam production is terminated when wellhead pressures equalize, or when more than trace amounts of hydrocarbons are produced. Additional steam is injected into the reservoir via the second well, permitted to soak, and heated heavy oil is produced via both wells.

Abstract: This invention relates to methods and systems for recovering high viscosity oils, petroleum substances and other minerals from subsurface earth formations. In particular, one or more large diameter shaft holes are provided which preferably terminate in an enlarged subterranean chamber. A plurality of drill holes are provided, with perforated piping which extend radially from the chamber into the formation, and from which oil and the like may be recovered. It is a particular feature of this invention to provide means and methods for injecting a mixture of steam and a noncondensable gas into the drill holes, whereby the driving mechanism of the formation may be selectively maintained or enhanced at the same time the viscosity of the oil in the formation is reduced.

Abstract: High viscosity petroleum, such as heavy oils and tar, is recovered by first drilling a number of production wells in a conventional pattern, then drilling a plurality directionally drilled injection wells extending radially inward toward each producing well, such that the surface location of each injection well is not less than the normal spacing between production wells, and the bottom hole location approaches the production well closely enough that fluid communication between the two wells can be established by the injection of heated fluids into the injection well. The petroleum is then recovered from the producing well by conventional thermal means.

Abstract: Hydrogen is injected into an underground petroleum reservoir that is devoid of natural gas. Due to its high rate of diffusion, hydrogen disperses rapidly throughout the reservoir, including the tight portions that are relatively impermeable to the injection of water. Pressure is lowered in the reservoir when the crude oil is substantially saturated with hydrogen. Hydrogen then migrates from the tight portions of the reservoir, sweeping petroleum into the more permeable portions. Expanding hydrogen experiences a temperature rise which in turn heats the crude oil and further reduces the viscosity for added mobility. A water sweep displaces the oil to production wells. In an alternate embodiment hydrogen is injected into an underground petroleum reservoir as a prelude to fire flood techniques. The absorbed hydrogen dilutes the crude in place and provides a fuel with much wider flammability limits to sustain the underground fire.

Abstract: A process for enhanced recovery of petroleum from subterranean formations wherein a vapor mixture of steam and a petroleum fraction containing naturally occurring phenolic and carboxylic compounds is injected via an injection well, and a mixture of steam condensate and petroleum is produced via a production well.

Abstract: When processing a fragmented permeable mass of particles containing oil shale for recovering liquid and gaseous values, a portion of the oil shale is thermally metamorphosed. However, a zone of non-thermally metamorphosed particles can be left in the fragmented mass after completion of processing. To inhibit leaching by water of water-soluble constituents of such non-thermally metamorphosed particles, a heating fluid, such as a mixture of fuel and an oxygen-containing gas, is introduced to the fragmented mass containing non-thermally metamorphosed particles for heating at least a portion of the non-metamorphosed particles to a sufficiently high temperature for forming water-insoluble metamorphic minerals at at least the surfaces of such particles.