Abstract: A process to recover oil is provided wherein an oil containing subterranean formation is heated by conductive heat transfer from heat injectors operating at temperatures above 900.degree. C. The high temperature levels of this process result in high recoveries of initial oil in place, and recovery of the oil within a short time period. This process is particularly applicable to diatomite formations that have low permeabilities.

Abstract: A method which combines fluid drive and gravity drainage to produce hydrocarbons from a subterranean formation comprises injecting a fluid through at least two upper horizontal wells out into the formation for moving hydrocarbons from the formation into at least one lower horizontal well through which the hydrocarbons are produced, wherein each lower horizontal well is spaced laterally and vertically below and between two respective upper horizontal wells; and producing hydrocarbons through the at least one lower horizontal well at a cumulative rate faster than the cumulative rate of the fluid injected into the upper horizontal wells. The method further comprises injecting a fluid and producing hydrocarbons as just described but with additional upper and lower horizontal wells longitudinally spaced from the first-mentioned upper and lower horizontal wells so that each of the lower horizontal wells operates as a discrete production well.

Abstract: A method of staggered scheduling of injection and/or production into and from alternate rows of injection and/or production wells in hydrocarbon formations penetrated by multiple 5-spot, inverted 5-spot, 7-spot or 9-spot well patterns.

Abstract: A method and apparatus for the improved recovery of oil from porous sub-surface deposits such as tar sands comprising mining and drilling a well with upper and lower horizontal rectangular grids extending outward into the deposit and applying steam heat or super heated crude oil vapor through the lower grid and hot pressurized flue gas through the upper grid. The flue gas and steam or super heated crude oil vapor are produced in a generation facility that provides electricity for the installation from turbine generators, the crude oil for super heating being provided by an initial production from the deposit following flue gas injection. Steam condensate is recycled from the recovered oil to the generation facility thereby reducing the water requirements and environmental pollution, and, where super heated crude oil vapor is used, a portion of the produced crude is used for this purpose.

Abstract: A horizontal production well is located in the lower portion of a heavy viscous oil-bearing reservoir. A vertical injection well is located in the upper portion of the reservoir. Oxygen-enriched gas is injected down the injector well and ignited in the upper portion of the reservoir to create a combustion zone that reduces viscosity of oil in the reservoir as the combustion zone advances downwardly toward the horizontal production well, the reduced-viscosity oil draining into the horizontal production well under force of gravity.

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: Disclosed is an invention for optimizing recovery of petroleum from a subterranean, petroleum containing formation by improving the efficiency of a steam drive through a linear heat reduction schedule and a partial shut-in of the producing well after steam breakthrough. The linear heat reduction schedule and the partial shut-in to compensate for steam override results in maximized discounted net oil recovery with optimal utilization of steam generation capacity.

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: A method of recovering methane from a solid carbonaceous subterranean formation includes injecting a gas that desorbs methane through an injection well into a subterranean formation and recovering methane from a first and a second production wells, or from a first and a second layer. Areal and/or vertical sweep efficiency of the injected desorbing gas can be increased by selectively restricting the flow of recovered fluids from the first or the second production well with the highest monitored ratio of injected desorbing gas. The restriction of flow forces the desorbing gas into higher permeability areas of the subterranean formation.

Abstract: The present method of drilling, completing and fracturing enhances the production from any reservoir where artificial lift devices are required. However, this method is most suitable for a low pressure, partially depleted subterranean reservoir (50) where secondary recovery methods have proven unsuccessful, or where virgin drainage and pressure has been depleted. The method comprises drilling a substantially horizontal wellbore (20) which penetrates a subterranean reservoir (50) at a degree sufficient to provide drainage through the total vertical section of the reservoir. The horizontal wellbore (20) intersects a vertical wellbore (10) at the lowest vertical depth reached. Fracture stimulation may be applied from either the vertical wellbore, the horizontal wellbore, or both. Moreover, several horizontal well bores (20) can be drilled from a single surface (a) location to intersect other vertically drilled wells (10) or existing producing wells in a reservoir.

Abstract: The invention is a method of producing hydrocarbons from a region bounded by two vertical wells and a horizontal well, which comprises injecting a gas through a first vertical well, concurrently performing a cyclic injection, soak and production of gas through a horizontal well, converting the first well to production after the gas injected from the first well reaches the area affected by gas from the horizontal well, and injecting gas through a second vertical well.

Abstract: An apparatus and method are disclosed for producing thick tar sand deposits by preheating of thin, relatively highly conductive layers which are a small fraction of the total thickness of a tar sand deposit, with horizontal electrodes and steam stimulation. The preheating is continued until the viscosity of the tar in a thin preheated zone adjacent to the highly conductive layers is reduced sufficiently to allow steam injection into the tar sand deposit. The entire deposit is then produced by steam flooding.

Abstract: An apparatus and method are disclosed for producing thick tar sand deposits by preheating of thin, relatively conductive layers which are a small fraction of the total thickness of a tar sand deposit, with horizontal electrodes. The preheating is continued until the viscosity of the tar in a thin preheated zone adjacent to the conductive layers is reduced sufficiently to allow steam injection into the tar sand deposit. The entire deposit is then produced by steam flooding.

Abstract: The invention relates to a production simulation process by pilot test in a deposit (1) of hydrocarbons contained ina reservoir (2) with the aid of injection wells (3b, 5b; 7b) and producing wells (4b, 6b, 8b) with horizontal drains, said drains forming, at least in part, a polygonal geometric shape in one plane of the reservoir.By the simulation process:a first state is triggered either by injection or by production for the drains located at the periphery of said geometric shape,a second state, opposite said first state, is triggered either by injection or by production for the drains located inside said geometric shape.the volumetric flowrates of liquid injected and produced are regulated such that the sum of the flowrates of the injection drains is substantially equal to the sum of the flowrates of the production drains.

Abstract: In a fluid flood process for enhancing the secondary recovery of hydrocarbons from a hydrocarbon permeable and hydrocarbon bearing reservoir using plural recovery wells, each adjacent at least one injection well. Each well has a well bore. A horizontal injection fracture extends substantially horizontally from the well bore of each of selected injection well bores. A horizontal recovery fracture extends substantially horizontally from the well bore of each of selected recovery wells and is vertically displaced from and overlapping with one or more of the injection fractures of the adjacent injection wells. A pair of overlapping injection and recovery fractures, that would overlap with a low permeable layer in the reservoir, is selectively positioned vertically at one side of such layer in the reservoir.

Abstract: A process for the assisted recovery of heavy hydrocarbons from an underground formation having a plurality of superimposed reservoirs for the hydrocarbons involves arranging horizontal sections of a plurality of wells so that a first well of a first series of wells extend into a reservoir and is located essentially vertically below a horizontal section of a second well located in an immediately adjacent reservoir, with the first well being used as a steam injection well and the second well being used as a hydrocarbon-producing well.

Abstract: The present invention provides a system and method for producing an effluent contained in a geological formation forming a reservoir for said effluent or producing formation, including a central well, at least one subhorizontal drain as well as a displacing or displacement agent, the displacement agent being injected into the formation either from the central well or from the subhorizontal drain and the displacement agent causes migration of the effluent to be produced.

Abstract: A method for stimulating production of hydrocarbons from multilayered heavy oil formations starts with injecting high quality steam through a first group of wells into the lower most level. Hydrocarbon product generated by the steamflooding are extracted by a second group of wells while the steamflooding preheats the bottom of the second lowermost layer. The second group of wells are then used to inject steam into the second layer and a portion of the first group of wells are used for production from this level. The function of the groups of wells continues to alternate with each successive level while the number of wells used in each group decreases thereby increasing the areal sweep.

Abstract: A method of producing methane by injecting inert gas, such as nitrogen, through an injection well into a solid carbonaceous subterranean formation (e.g., coal) and recovering methane from a production well(s). Methane desorption is achieved by reduction in methane partial pressure rather than by reduction in total pressure alone.

Abstract: A method for the in situ removal of mobilizable contaminants, including volatile and semi-volatile organic compounds, from a contaminated unsaturated zone of primarily porous layers of soil, comprising pulsatilely injecting heated pressurized steam into a first location in the zone in order to heat the soil in the zone, and withdrawing the contaminants under subatmospheric pressure from the soil at a second location in the zone. In specific application, the pulsatile injection of steam is used to heat the soil without directly recovering injected steam for a significant period of time until the targeted soil in the zone is uniformly heated to steam temperature. The pulsatile injection directs the heat in particular directions and to particular areas in the soil zone as desired.

Abstract: A method for intermittent steam injection which comprises completing wells in more than one zone and selecting a number of wells as steam injectors. As interwell communication (temperature breakthrough) develops, producers are shut-in to allow for the reservoir pressure to build up and heat to propagate from the channel of communication (e.g., fractures) to the reservoir matrix. The injection phase is followed by blowdown. Thereafter, shut in producers and, in certain other cases, injectors are put on production.

Abstract: A process for increasing the production of hydrocarbonaceous fluids in a reservoir where foam is injected into a gravity override zone. Foam is injected into the override zone via a well placed in the zone. This foam injection wall is positioned between an injector and a producer well. During a steam-flooding or carbon-dioxide flooding, foam is injected into the override area via the foam injection wall thereby blocking the override area and causing flooding fluids to be directed into an oil rich overridden area. Foam utilized herein can be formed in-situ or ex-situ by a noncondensible gas and a surfactant.

Abstract: A method is disclosed for producing thick tar sand deposits by preheating of thin, relatively conductive layers which are a small fraction of the total thickness of a tar sand deposit. The thin conductive layers serve to confine the heating within the tar sands to a thin zone adjacent to the conductive layers even for large distances between rows of electrodes. The preheating is continued until the viscosity of the tar in a thin preheated zone adjacent to the conductive layers is reduced sufficiently to allow steam injection into the tar sand deposit. The entire deposit is then produced by steam flooding.

Abstract: A process for enhanced recovery of hydrocarbons, such as oil from a geological reservoir through an injection well bore and a plurality of production well bores which extend into the geological reservoir. Flooding is performed through at least one injection well bore into a lower portion of the geological reservoir, to thereby form a substantially horizontal injection fracture which may have an upward vertical component. The vertical component is elongated along an azimuth. The vertical components of any significance size are not always formed on horizontal fractures. However, to avoid intersecting horizontal production fractures into the vertical components, certain procedures must be followed. To this end, the azimuth of the elongation of the vertical component is determined. The producing well bores are then disposed, substantially parallel with the azimuth of the elongation of the vertical component and along a line displaced from the injection well bore.

Abstract: Shale oil is produced from a subterranean interval of oil shale, where the interval is initially substantially impermeable and contains a specified grade and thickness of oil shale. Said interval is conductively heated from borehole interiors which are kept hotter than about 600.degree. C. and are heated at a rate such that kerogen pyrolysis products formed within the oil shale create and flow through horizontal fractures which subsequently extend into fluid-producing wells that are positioned in specified locations.

Abstract: A method of producing coalbed methane by injecting inert gas, such as nitrogen, through an injection well into the coal seam and recovering coalbed methane from a production well(s). Methane desorption from coal is achieved by reduction in methane partial pressure rather than by reduction in total pressure alone.

Abstract: The invention is a method of recovering hydrocarbons from an underground hydrocarbon formation which comprises drilling and completing at least three substantially parallel horizontal wells to form a substantially triangular well pattern within a hydrocarbon formation. The first well is placed relatively near the top of a hydrocarbon interval and the second and third wells are placed near the bottom of the interval on each side of the first well. A recovery fluid is injected into the formation through the second and third wells and hydrocarbons and other fluids are recovered through the first well.

Abstract: A method is provided for recovering oily waste from oily waste accumulations underground comprising sweeping the oily waste accumulation with hot water to recover said oily waste, wherein said area treated is isolated from surrounding groundwater hydraulically. The hot water may be reinjected after the hot-water displacement or may be treated to conform to any discharge requirements.

Abstract: Nahcolite solution mining process comprising drilling at least one well into a Nahcolite bed, circulating hot barren aqueous liquor in a cavity in said Nahcolite bed for a time sufficient to produce a pregnant liquor having an increase in the concentration of NaHCO.sub.3 in the range of from about 3 to about 20% while maintaining Na.sub.2 CO.sub.3 concentration in the range of about 0.25-4%, preferably less than 2.5%, withdrawing said pregnant liquor, cooling said pregnant liquor to preferentially precipitate NaHCO.sub.3 therefrom and to produce a barren liquor, recovering said NaHCO.sub.3, and reheating and re-injecting said barren liquor in said well. The cavity temperature is maintained below about 250.degree. F. and preferably below about 200.degree. F. The barren liquor is injected at a pressure of below about 150 psig. The pregnant liquor is extracted at a temperature in the range of from about 85.degree. F. to about 200.degree. F., and the cystallization occurs at a temperature of about 25.degree.-120.

Abstract: Disclosed herein is a method of degasification, wherein gas and water production from a coal field are maintained at high rates regardless of temporary changes in market demand. While all the produced water is disposed, surplus gas is reinjected in coal by converting some of the producers to injectors. When the demand for gas improves, the injection wells are put back on production. Recovery of gas from wells used as injectors is rapid because of increased reservoir pressure and high gas relative permeability near the wellbore.

Abstract: A process for establishing well-to-well flow communication between a plurality of wells penetrating a subsurface formation is provided. A common fracture network is created by initiating a fracture from a first well, and then propagating that fracture from the first well to a second well. When the fracture has reached the second well, fracturing fluid is injected into the second well and thereby further propagates the fracture to a third well, and so on, so that the fracture is successively propagated to all of the wells. Such a fracture can be located adjacent either a lower or an upper boundary of a tilted subsurface formation, as desired. Techniques are also provided for reducing uneven areal distribution of injection fluids which are injected into fractures.

Abstract: In a CO.sub.2 miscible displacement enhanced oil recovery process, produced CO.sub.2 -hydrocarbon gas containing from more than the maximum CO.sub.2 content tolerable in a fuel gas up to about 70 volume percent CO.sub.2 is reinjected into a small portion of the well pattern volume and produced CO.sub.2 -hydrocarbon gas containing more than 70 volume percent CO.sub.2 is reinjected into a larger portion of the well pattern volume. The method provides a more effective utilization of CO.sub.2 in a CO.sub.2 miscible enhanced oil recovery process while maintaining most of the oil-containing formation under miscible conditions.

Abstract: An oil recovery process employing a well pattern having a horizontal well located along each of the four sides of a substantially rectangular well pattern, a vertical injection well located at the center of the well pattern, and four vertical infill wells located midway between the central injection well and the four corners of the rectangular well pattern. Steam is initially injected through the central injection well and production taken at the four infill walls. After the injection of about 0.5 to about 1.0 pore volumes of steam through the central injection well, central injection is converted to water, the infill production wells are converted to steam injection, and production is taken from the horizontal wells.

Abstract: The invention is a well pattern containing at least one substantially horizontal production well approximately located on and parallel to an axis running between two substantially vertical production wells with the horizontal well having a length equal to about 30% to about 60% of the distance between the two vertical production wells.

Abstract: Heavy oil is recovered from deep reservoirs by injection of a gaseous mixture containing hydrogen, steam and in some cases oil soluble gases and/or vapors. This mixture is produced by a reversible exothermic catalytic reaction in a down-hole reactor and injected into a well drilled, preferably horizontally, into the reservoir. The reactor feed streams are prepared in surface facilities with low air pollution, using as feedstocks water, air and inexpensive fuels, such as natural gas, coke or residual fuel oil.The heavy oil contacted by the injected gaseous mixture is formed into a mobile oil bank of reduced viscosity, which is produced to the surface by means of production wells or by alternatively using the injection well in a production mode. The process is of particular interest for reservoirs deeper than 1,000 feet, located in the vicinity of natural gas fields, oil refineries or coal mines.

Abstract: The invention is a method of recovering hydrocarbons from an underground formation by employing a modified 5 spot or 9 spot well pattern which contains a substantially vertical central well and four substantially horizontal wells, each having one end located relatively near the center of a substantially rectangular well pattern and the other ends located relatively near each of the corners of the well pattern. Preferably, the well pattern will also contain four substantially vertical corner wells located approximately at the four corners of the substantially rectangular modified 5 spot or 9 spot well pattern.

Abstract: The disclosed invention is a method of recovering hydrocarbons through parallel horizontal wells by use of steam and water injection. Steam is injected into two parallel horizontal wells to stimulate the formation and then the second horizontal well is converted to a production well. About the time of steam breakthrough at the second well, the steam injection at the first well is converted to water injection, production is suspended from the second well, and steam is injected through the second and third wells. After a suitable period of stimulation time, the third well is converted to a producing well, steam injection is continued through the second well, and water injection is continued through the first well.

Abstract: The present invention is an improvement on the method of recovering viscous petroleum from a petroleum-containing formation by providing a steam injection well from the earth's surface through the formation, extending at least one lateral hole from the vicinity of the steam injection well through at least a portion of the formation, forming a flow path in the hole isolated from the formation for flow of fluid through the formation, circulating a hot fluid through the flow path to reduce the viscosity of the viscous petroleum in the formation adjacent the outside of the flow path to form a communication path for flow of petroleum in the formation outside of the flow path, and injecting a driving fluid into the formation through the steam injection well and the communication path to promote flow of petroleum in the formation to production wells penetrating the petroleum-containing formation for recovery from the formation.

Abstract: Oxygen is injected into a petroleum bearing subsurface formation penetrated by production well and the petroleum in the formation is subjected to in-situ combustion to heat the formation in a zone surrounding the production well. After heating by the in-situ combustion, heated hydrogen is injected into the heated formation zone by way of the production well. By way of another well penetrating the petroleum bearing subsurface formation and spaced from the production well, fluid is injected into the formation to drive petroleum in the formation between the two wells to the production well for recovery. Hydrogenation of the petroleum occurs in the heated zone in the presence of hydrogen therein.

Abstract: A method to enhance oil production from producing formations using a pressure differential created by evacuating a recovery hole cased through the overburden into the producing formation, and directionally injecting under pressure, into an injection hole in communication with the producing formation, a heated hydrocarbon solvent with surfactant added a distance from the recovery hole. The heat, solvent, pressure differential and surfactant will increase the flow of crude into the recovery hole.

Abstract: The invention is a method of recovering hydrocarbons from an underground formation by employing modified 7 spot well patterns which contain six substantially vertical corner wells forming a substantially hexagonal well pattern and six substantially horizontal wells located within the hexagonal well pattern running between each of the vertical corner wells and the center of the well pattern. Preferably, the modified 7 spot pattern will also contain a substantially vertical central well located relatively near the center of the substantially hexagonal well pattern. Another embodiment contains six substantially vertical corner wells forming a substantially hexagonal well pattern, a substantially vertical central well and six sets of three horizontal wells, each set of three horizontal wells forming a substantially Y-shaped pattern.

Abstract: The effective permeability of subterranean hydrocarbon bearing formations with respect to surfactant and drive fluid injection processes is enhanced by preceding the surfactant fluid injection step with creation of multiple formation fractures using tailored pressure pulses produced by gas generating propellant canisters disposed in the injection well. Fluid injectivity rates are increased by subsequent fracture extensions provided by repeated steps of generating high pressure gas pulses at selected intervals.

Abstract: A method of converting coal and other solid carbonaceous material to gaseous and liquid products by heating the coal in the presence of the gaseous effluent to a sufficient temperature for pyrolyzing the coal to produce liquid and gaseous products. Thereafter, further gasifying the coal to produce a gaseous effluent to be used in subsequent steps to produce liquid and gaseous products.

Abstract: The disclosed invention is a pattern for recovering hydrocarbons by employing modified inverted 5 spot, modified inverted 9 spot and modified inverted 13 spot well patterns which contain pairs of horizontal wells substituted for the vertical wells drilled at the four corners of the well patterns.

Abstract: A process for establishing well-to-well flow communication between a plurality of wells penetrating a subsurface formation is provided. A common fracture network is created by initiating a fracture from a first well, and then propagating that fracture from the first well to a second well. When the fracture has reached the second well, fracturing fluid is injected into the second well and thereby further propagates the fracture to a third well, and so on, so that the fracture is successively propagated to all of the wells. Such a fracture can be located adjacent either a lower or an upper boundary of a tilted subsurface formation, as desired. Techniques are also provided for reducing uneven areal distribution of injection fluids which are injected into fractures.

Abstract: Method and apparatus for enhancing liquid hydrocarbon production through a single traditional producing borehole recognizing traditional producing well spacing from a slowly producing formation by use of non-uniform heating through interrelated electrode arrays surrounding the borehole. Heating the formation around the borehole through an interrelated electrode array designed for the formations geometry and geophysics favorably redistributes the pressure gradient throughout the formation for a substantial distance beyond the borehole permitting net energy effective production. One optimum electrode array may consist of ring electrodes or electrode segments so disposed as to electrically approximate a ring. Electrically conductive well bore casing in the formation may be used as an electrode. A return electrode of low impedance disposed close to the surface of the earth may be utilized.

Abstract: A method of controlling subterranean placement of underground fluids, such as liquids, includes(a) positioning a tubing joint longitudinally in a borehole in the earth to locate the split and gun at selected depth,(b) rotating the tubing to orient the split azimuthally so that a gun in the tubing is aimed in a desired direction laterally,(c) discharging the gun to cause its projectile to travel in said desired direction in the formation, thereby opening up a lateral shot hole in the formation,(d) and pumping fluid under pressure down the borehole to discharge into the shot hole into a selected zone laterally spaced from the tubing.

Abstract: A method and apparatus for enhancing the production of a hydrocarbonaceous fluid from a subterranean geologic reservoir containing same using electrical heating by employing at least three electrodes between the injection wellbore and production wellbore and passing electricity only between the three electrodes.

Abstract: The disclosed invention is a method of recovering hydrocarbons by employing a modified 9 spot well pattern which contains a vertical central well, four vertical corner injection wells and four horizontal wells as the side wells in the pattern. The horizontal side wells are aligned on axes perpendicular to the substantially rectangular boundaries of the modified 9 spot well pattern or aligned on the axes between the four corner injection wells.

Abstract: The disclosed invention is a method of recovering hydrocarbons by employing a seven well pattern comprising five horizontal production wells and two vertical injection wells. Four of the horizontal wells form the four sides of a substantially rectangular pattern with the fifth horizontal well aligned on a diagonal running between two opposite corners of the substantially rectangular pattern formed by the first four horizontal wells. Two vertical injection wells are approximately located near the center of the two substantially triangular patterns formed by the five horizontal wells.