Abstract: Apparatus for extracting contaminants from a stream comprising a contaminant-containing mixture of liquids and gases which comprises: (a) a contaminant-containing mixture input; (b) a vapor-liquid separator receiving the contaminant-containing mixture from the input and producing a liquid component stream at a first outlet and a gaseous component at a second outlet; (c) an optional first contaminant removal system receiving the liquid component stream from the vapor-liquid separator and producing a contaminant-free liquid stream; (d) a vacuum inducing device in fluid communication with the contaminant-containing mixture input and the vapor-liquid separator and receiving said gaseous component from the vapor-liquid separator; (e) a cooling element receiving the gaseous component at a first temperature from the vacuum inducing device and producing the gaseous component at a second temperature from a first outlet and a condensed liquid component from a second outlet, said second temperature being lower than said

Abstract: Methods for vacuum extraction of contaminants from subsurface media which involves vacuum withdrawal through a conduit, of vaporized contaminant, assisted by a tube for allowing air bubbles to flow through the liquid-phase hydrocarbon zone thereby causing enriched hydrocarbon vapors to be extracted through the vacuum applied to the conduit.

Abstract: A method and apparatus for recovering oil and clarifying waste water from an oil field are disclosed. The method includes the step of treating the waste water with an aqueous de-emulsifying agent comprising wattle tannin, an inorganic coagulant and a synthetic polymer flocculant to destabilize the oil emulsion and rapidly agglomerate the oil particles formed thereby. Efficiency of the present de-emulsifying agent permits use of flotation equipment for rapid clean-up of the waste water and obviates the need for large settling pits.

Abstract: In accordance with the present invention, there is now provided a method for removing asphaltene deposits in a well environment such as the wellbore and near-wellbore regions, comprising the injection of deasphalted oil therein to solubilize the asphaltene deposits obstructing the well environment. More specifically, the method of the invention comprises the injection of deasphalted oil into the wellbore and the near-wellbore formation followed by a soaking period and a production period. The method of the present invention has the great advantage of readily dissolving precipitated asphaltene in a well environment without other costly treatments such as the use of solvents like xylene or toluene. Furthermore, the present method does not require the incorporation of any additives in the deasphalted oil.

Abstract: Geothermal brines are extracted from the earth, flashed and the remaining liquids are injected back into the earth. Although it would be advantageous for resource maintenance to inject the same amount of liquid as extracted, addition of liquid causes massive system upsets that prevent such addition. River or other similar surface waters can now be added to the brine stream created when extracting power from a geothermal source, after adding a crystal structure modifier to the brine stream. In operations where the brine stream is returned to the earth, the weight rate of the brine injected into the earth is brought to at least 90% what it was when extracted from the ground.

Abstract: NORMs are inhibited or prevented from precipitating with scale produced by a hot aqueous solution by adding multiple portions of a crystal structure modifier to the aqueous solution as it cools before and during removal of silicon containing components by precipitation. Preferred crystal structure modifiers include polyacrylate crystal structure modifiers and phosphonomethylated amines.

Abstract: A sparging well borehole has a single pipe extending downwardly in it. The lower end of the pipe terminates in the saturated zone and has orifices for discharging pressurized gas, usually air, which is injected into the saturated zone to liberate volatiles. A layer of impervious material is in the bore hole above the orifices and the hole is filled to the top from above the impervious layer with a porous material. A dome is positioned at the upper end of the borehole with an opening in the dome over the borehole. The dome is connected to a vacuum source to cause the vapor that is produced in the saturated zone and that is induced to migrate through the vadose zone and permeate the porous material in the borehole to be accumulated in the negative pressure interior of the sealed dome and collected for treatment by way of a piping system.

Abstract: In a steam flood enhanced oil recovery operation, vapor and liquid in the casing annulus of the production wells is forwarded through a liquid separator with the thus separated vapor being forwarded to an eductor at the injection well where the vapor is mixed with incoming steam for injection and circulation through the formation.

Abstract: A fluid extraction device to remove fluid contaminants from the vadose zone of unsaturated subsurface area by selectively evacuating liquid and gas therefrom comprising a lower well screen assembly coupled to a vacuum source through an upper fluid conduit structure including a fluid flow control to separately extract liquid and vapor from the vadose zone and a fluid flow indicator to separately monitor the flow of liquid and vapor through the upper fluid conduit structure.

Abstract: A method for recovering connate fluids (e.g. oil) from a low permeability subterranean reservoir (e.g. diatomite) through a single wellbore. Upper and lower intervals are fractured from the wellbore that the fractured intervals only partially overlap, thereby leaving a partial, natural barrier formed of random-spaced, low permeable areas along the interface between the fractured intervals. This partial barrier improves the sweep efficiency of a drive fluid (e.g. water) which is injected into the lower fractured interval by forcing it to spread outward into the reservoir before it is flows through the upper fractured interval. The drive fluid is injected at approximately the same rate as that at which the fluids are produced so that displacement of oil occurs primarily due to imbibition.

Abstract: Oil well production fluid composed of oil and water and containing in excess of 100 ppm water soluble petroleum carboxylates in anionic form dissolved in the water is treated by acidifying the fluid to a pH of 6.0 or lower with a combination of a strong organic acid and a strong mineral acid and then is intimately mixed. The oil and water are separated one from the other. The content of the water soluble organics in the water is thereby substantially transferred to the oil phase. In a second aspect of the invention, water used to extract corrosive compounds to render the oil suitable for fueling gas turbine power plants is acidified to a pH of 6.0 or lower and is thereafter intimately mixed with fuel oil.

Abstract: A process for the treatment or processing and transportation of a natural gas from a gas well to a reception and treatment or processing terminal comprises, in a zone in the producing well, contacting the natural gas and a recycled liquid phase containing water and at least one anti-hydrate additive and/or at least one anti-corrosion additive, both of which being at least partly miscible with water and which vaporize in the pure state or as an azeotrope. The resultant additive-containing gaseous phase is cooled to form an uncondensed and a condensate. The condensate containing substantially all of the additive is separated from the uncondensed gas and is recycled to the contact zone in the producing well.

Abstract: A method and apparatus for disposing of water at gas wells. Water from the water holding tank is collected periodically in a heating vessel. Hot fluid from an auxiliary engine system, such as the oil pump or the water pump for the compressor engine, is pumped through a heat conductive coil around the heating vessel to heat the well water in the heating vessel. The heated well water then is injected into the hot exhaust line from the compressor either between the compressor and the muffler or alternatively is injected directly into the muffler. The heating vessel is pressurized with gas from the well to assist in the evacuation of the heated water from the heating vessel and the injection of the well water into the hot exhaust. A system of valves controls the delivery of water to the heating vessel, ensures that the heating vessel will not be over pressurized and deactivates the apparatus when the gas compressor is not running.

Abstract: The invention provides a method of recovering water from an acid workover, the water including dispersed solids and emulsified oil. According to the method, the water is treated with an effective amount of a dispersion of a water-soluble cationic polymer.

Abstract: Large gas pockets in a crude oil transfer pipeline are detected and separated. As a large gas pocket forms, the liquid level drops (and the hydraulic head declines) in the export riser portion of the transfer pipeline, increasing the pressure required to transfer the fluid. Detection of the lower level and separation decreases the pressure required. Smaller gas pockets, which can be swept down the export riser portion, are not separated. The detecting and separating functions can be combined in a float-type gas vent valve, or separate gas detectors and gas vent valves can be used. The separated gas can be recombined with the crude oil, or used at an import platform, or separately transported to an on-shore facility. If the separated gas requires pressurization, a compressor-expander may be used to compress gas for flow in one direction and recover power from the expanding gas during flow in the other direction.

Abstract: A mobile vapor recovery apparatus (10) efficiently removes materials from the vadose layer of earth soil. The apparatus (10) has a plurality of intake ports (14a-14d) each configured to releasably connect to a well pipe communicating gas having vaporized materials from a well in the soil. The intake ports (14a-14d) communicate the gas to a common manifold (24). A fluid collection tank (26) receives the gas from the manifold (24) and collects fluid entrained in the gas. A blower (32) draws the gas into the intake ports (14a-14d) by forcing the gas from the tank (26) and out of an exhaust port (34). A transportable support frame (12) is configured to support the plurality of intake ports (14a-14d), the fluid collection tank (26), and the blower (32) in a self-contained transportable unit. In addition, the mobile vapor recovery apparatus (10) may be mounted within a trailer unit (82) having a locking mechanism (102).

Abstract: Radioactivity and fluoride ion are inhibited or prevented from precipitating in scale formed from a geothermal brine by adding a scale inhibitor to the cooling brine solution. Preferred scale inhibitors include polyacrylate dispersants and phosphonomethylated amines.

Abstract: A method for dumping carbon dioxide gas into the ground of the sea bottom comprises injecting carbon dioxide gas into the ground of the sea bottom to fix the carbon dioxide gas in the ground of the sea bottom. A method for dumping carbon dioxide gas into the ground of permafrost regions comprises boring a well and injecting carbon dioxide into the ground to fix carbon dioxide in the ground. A method for recovering and consuming natural gas found in the ground of permafrost regions with low pollution comprises exploiting and consuming hydrate of natural gas present in permafrost regions to produce carbon dioxide as a by-product and injecting the carbon dioxide by-product into the ground of permafrost. A method for gathering natural gas by using dumped carbon dioxide gas as a heat generating source comprises injecting carbon dioxide gas or liquefied carbon dioxide gas into layers of hydrate of natural gas present in the ground of the sea bottom or in permafrost regions.

Abstract: Soluble salts are prevented from precipitating from a brine concentrate produced from the flashing a geothermal brine by diluting the brine concentrate with preconditioned condensate. The pH of the condensate is first adjusted to within two pH units of brine concentrate. Then concentration of sulfide ion is reduced by oxidizing sulfide to sulfate by exposure to air for a period of time sufficient to oxidize a substantial portion of the sulfide, but short enough to prevent a substantial concentration of oxygen from dissolving in the condensate. The preconditioned condensate is then mixed with the brine concentrate to form an injection stream. The injection stream is then injected into the earth.

Abstract: In accordance with illustrative embodiments of the present invention, a process for the secondary recovery of oil found in a dolomite formation includes generating in-situ decomposition of the dolomite by heating it to a temperature in the range of from 1,400.degree.-1,750.degree. F. which produces a reaction that has magnesium and calcium oxides and a large quantity of carbon dioxide as products. The carbon dioxide saturates the oil in surrounding formations and makes it more movable toward one or more recovery wells. The heat is convected into the formation by a fluid that is injected into the well from the surface.

Abstract: Device, in particular for regulating and reducing the fluctuations in the composition of a polyphasic flow including at least one liquid phase and one gaseous phase. This device comprises a container for separating said phases and at least one admission opening for the polyphasic mixture, as well as means for extracting the content of the container. The extraction means (3, 7, 40, 41) extend into said container (2, 39, 56) in such a manner that during normal operation, they extend through the liquid-gas interface (6). Said extraction means include extraction openings (4, 16, 19, 50, 51) arranged on both sides of the interface in normal operation; the sum of the throughflow sections of said openings, estimated from a reference position on at least a portion of a vertical axis, varies as a function of the slope, considered on said axis and for said portion, said portion extending during normal operation on both sides of said interface.

Abstract: An oil separation method and apparatus for the continuous separation of acceptable oil from contaminated oil containing solids and liquids withdrawn from an oil well. Three separate settling tanks are partitioned and provided with skimmers, as appropriate, to enable contaminated oil to dwell sufficiently within the tanks. After sufficient dwell time, the skimmers remove separated oil from the top layer and move it to an oil tank. Liquids such as water and emulsified oil are separated into an intermediate layer and moved to further settling tanks to provide sufficient dwell time for oil separation and collection. The first settling tank has a rotating jet spray header for agitating the solids accumulated in the bottom of the first tank and a series of suction headers for withdrawing the solids without interruption of the top oil layer or the separation operation.

Abstract: A method and apparatus for substantially eliminating slug flow and for separating the liquid phase of a liquid/gas mixture from the gas phase thereof is provided. A deceleration table contained within a housing decelerates liquid slugs and causes entrained gas to separate therefrom. The decelerated liquid passes through orifices in the deceleration table and is subsequently discharged from the housing while the separated gas rises above the deceleration table and is separately discharged from the housing. The liquid and gas phases can be recombined or permanently separated.

Abstract: A process for two phase vacuum extraction of contaminants from the ground involves vacuum withdrawal of liquid and gaseous phases as a common stream, separation of the liquid and gaseous phases, and subsequent treatment of the separated liquid and gases to produce clean effluents. Two phase vacuum extraction employs a single vacuum generating device to remove contaminants in both the liquid stream and soil gases through a single well casing.

Abstract: In an oilfield production system, a water driven jet pump is used to evacuate vapors from storage tanks to thereby recover the vapors and prevent emissions from passing to the atmosphere. The jet pump entrains the vapors in process water which is passed to a process separator already in the system. The gas is separated for recovery.

Abstract: Disclosed is a process for removing contaminants from a contaminated area of the ground having a vadose zone and a water table which comprises providing a borehole in the contaminated area; placing in the borehole a perforated riser pipe inside of which is situated a vacuum extraction pipe with an opening situated near, at, or at any point below the water table within the perforated riser pipe; while introducing a gas into the riser pipe, applying a vacuum to the vacuum extraction pipe to draw gases and liquid from the soil into the perforated riser pipe and from the riser pipe into the vacuum extraction pipe and transport both the gases and the liquid to the surface as a common stream; forming from the common stream a stream which is primarily liquid and a stream which is primarily gaseous; and separately treating the separated liquid and gas streams. Also disclosed is an apparatus for carrying out the process.

Abstract: An arrangement is provided for expelling highly volatile impurities from a ground water and a soil through which the ground water flows under the action of vacuum in a well shaft driven into an area of contaminated ground water and by directing a gas below a water level in the well shaft.

Abstract: A solvent stimulation process whereby a viscosity reducing agent is circulated through a horizontal well via a production string. Said agent exits the production string and enters an annulus formed by said string and a liner. Said agent diffuses into the reservoir at a pressure below the reservoir pressure. As said agent diffuses through the reservoir under the influence of a concentration gradient, it reduces the oil's viscosity and makes it mobile. Simultaneously, oil of reduced viscosity migrates into the well under a pressure drawdown influence. A pseudo steady state production rate is achieved when convective movement of the oil of reduced viscosity is exactly counterbalanced by the diffusional rate of the viscosity reducing agent in a stimulated radial zone along said well. This stimulates a large volume of oil through the extensive surface area of the wellbore thus producing increased volumes of hydrocarbonaceous fluids from the reservoir.

Abstract: Environmentally-safe work-over operations are carried out on a well of an offshore platform by transporting an auxiliary oil-and-water separator together with well work-over equipment and installing it temporarily on the platform. The large volumes of oil- or chemical-contaminated fluids generated during a well work-over operation are collected and run through the high-capacity auxiliary oil-and-water separator before being disposed of and without upsetting the performance of the regular platform separator handling the flow of production fluids from other wells on the platform.

Abstract: A multi-phase separating apparatus for fluid containing a gaseous component. The apparatus includes a first tank which receives a stream of the multi-phase fluid which is to be resolved into discrete components. A second or separating tank positioned at a lower elevation than the first tank, receives a stream of substantially gas-free liquid. Said gas-free multi-liquid stream is conducted through a valved conduit. The latter includes a buoyant element which is displaceable by liquid in the lower tank, to form a barrier to avoid backflow or oscillatory fluid response of said liquid. Liquid accumulated in the lower tank thus maintains said tank in a substantially full condition. Liquid monitors in the separating tank monitor liquid levels and control outflow from the unit.

Abstract: A method is disclosed for polishing geothermal brines containing iron-rich silica scale and silica particles suspended therein while removing and recovering copper, silver and other precious metals dissolved therein. The method comprises passing brine having a pH just below about 5.0 through a conduit packed with a metal higher in the electromotive series than silver for a time sufficient for a substantial portion of the copper and silver therein to precipitate onto the packing. Preferably, the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to act as a filter for said suspended particles. Dissolving the packing in a suitable acid will leave a precious metal-rich residue behind for subsequent recovery. When the brine is treated in accordance with this method, the useful life of injection wells used to return cooled brine back to the geothermal field is extended by at least about 3 time as compared to that observed with untreated brine.

Abstract: An enhanced oil recovery process uses a heated organic vapor to reduce the viscosity of a crude oil, especially heavy crude oil. The recovery process is also enhanced because the organic vapor forms a liquid phase miscible with the crude oil, thereby further reducing the viscosity of the crude oil.

Abstract: Asphalt precipitation in the flow path of an oil production well is inhibited by splitting the produced crude oil in a separator train into a light fraction containing gaseous and oil components having a relatively low aromaticity and molar weight and a heavy fraction having a relatively high aromaticity and molar weight and subsequently reinjecting at least part of the heavy fraction to a location in the flow path of the well where asphalt precipitation is expected to occur.

Abstract: A method for generating oxygen-depleted air for injection into a subterranean coal seam for increasing production of methane. Air and produced fluids comprising methane are input into a fuel cell power system; and fuel cell power system exhaust comprising oxygen-depleted air is injected into the coal seam.

Abstract: An apparatus and method for injecting fluid into and producing fluid, including gas, from a subterranean formation via a well in fluid communication with the formation. Fluid is injected into the subterranean formation through a first generally tubular conduit in the well and fluid is produced from formation to the surface through this conduit until fluid flow ceases. Thereafter, fluid is pumped from the formation into the tubular conduit and diverted into the annulus defined between the conduit and the well. The pressure drop created by this diversion causes gas to break out of the produced fluid. The remaining fluid is diverted back into the conduit and pumped to the surface while the gas is produced to the surface via the annulus.

Abstract: Improved water quality of overboard waters discharged from off-shore oil producing rigs is obtained by treating oily produced waters from a crude oil separator, and prior to exposure to air, with an effective coalescing amount of a combination of an iron chelating agent and various polymeric coagulating/coalescing agents. The preferred chelating agent is citric acid, or its salts, EDTA, HEDTA, or mixtures thereof. The polymeric coagulating/coalescing agents may be anionic, cationic, ampohoteric, but are most preferably copolymers of acrylamide with at least one of the monomers chosen from the group consisting of acrylic acid, methacrylic acid, DMAEA, DMAEM, or their acid of quaternary salts, DADMAC, MAPTAC, AMPS, and the like.

Abstract: A method to improve the displacement efficiency of hydrocarbonaceous fluids from a formation where at least two horizontal perforated wellbores are utilized. One horizontal wellbore is placed at a lower level and another is placed at a higher level in said formation. Thereafter, a first displacement liquid immiscible with and having a density greater than hydrocarbonaceous fluids in said formation is injected into said lower horizontal wellbore. Afterwards, a second hydrocarbon immiscible displacement liquid having a density greater than said first liquid is injected into said lower wellbore. The second liquid displaces said first displacement liquid and hydrocarbonaceous fluids to said higher level in the formation. Subsequently, the displacing liquids and hydrocarbonaceous fluids are produced to the surface.

Abstract: A method of heating produced fluid in a wellbore having multiple tubing strings. In the portion of the wellbore above the dual-string packer a portion of hot injection fluid is selectively flowed from the injection tubing string into the casing annulus where the production tubing is heated, and the flowing viscosity of fluids therein is lowered.

Abstract: Pressurized petroleum flows from a well into a turbine. The petroleum undergoes a pressure reduction in the turbine and then enters a separation chamber where it is separated into liquid and gaseous phases. The liquid phase is sent to a pump which serves to transfer the liquid phase to a station remote from the well. Similarly, the gaseous phase is directed to a compressor which functions to transfer the gaseous phase to a station remote from the well. The pump and the compressor are coupled to the turbine which uses the energy liberated by the petroleum during pressure reduction to drive the pump and the compressor.

Abstract: The invention is a method of recovering petroleum hydrocarbons from an underground formation penetrated by at least one injection well and at least one production well, which comprises injecting through an injection well a mixture of carbon dioxide and about 0.1% to about 20% by weight trichloroethane at a temperature and pressure above the bubble point of the mixture, and recovering hydrocarbons and other fluids at a production well.

Abstract: A process and apparatus is disclosed for removing volatile organic contaminants from vadose soil areas. Air is drawn through recovery probes positioned in the soil area being monitored. At intervals a blower is activated to draw gaseous vapors from the contaminated soil area above the underground water level. These gases are gathered within a water separator tank where gases and accidentally gathered liquids are separated. The gases are then passed through a filtration device for cleaning thereof. The device includes a water purifying system for dry cleaning contact water known to be contaminated. An external reservoir is provided for receiving of the contact water and for movement of the contact water into the water separator tank as desired. The level of water within the tank is constantly monitored. An aspiration means may be activated within the water separator tank to bubble through the contaminated liquid for stripping organic contaminants therefrom.

Abstract: An apparatus 10 for removing underground contaminants from a contaminated subsurface area 16 is provided. The apparatus 10 includes a wellbore 12 aligned in the contaminated subsurface area for releasing predetermined substances into selected areas of the contaminated subsurface area so that the substances and contaminates are intermixed and for recovering the intermixture of substances and contaminates from selected areas of the contaminated subsurface area. A driving apparatus 83 is provided for rotating and sliding an inner housing 68 of the wellbore 12 along first and second predetermined paths respectively. An injection system 22 injects the predetermined substances into the wellbore 12 and recovery system 26 applies pressure to the wellbore so that the intermixture of substances and contaminants can be extracted from the contaminated area. The intermixture of substances and contaminates are then collected and stored for subsequent removal in a vacuum tank 28.

Abstract: A method of producing hydrocarbon diluent from heavy crude oil, comprises pre-heating the crude oil to produce a heated crude oil, separating in a separator vessel by flashing the heated crude oil to produce a first vapor fraction and a first liquid fraction, thermally cracking in a cracking unit at least a portion of the first liquid fraction to produce a first liquid effluent, quenching the first liquid effluent, recycling at least a portion of the quenched first liquid effluent into a separator, condensing the first vapor fraction, and separating in a separator vessel the condensed vapor fraction to produce the hydrocarbon diluent and gas.

Abstract: Many petroleum discoveries which have heretofore been regarded as intractable owing to the immobility of the petroleum can be economically recovered by a process involving local visbreaking of the intractable petroleum in order to produce a medium/heavy cracked gas oil which is injected into a subterranean formation of the intractable petroleum in order to recover the petroleum.

Abstract: A process and device for decontamination of contaminated soil wherein contaminated soil is precleansed by a pressurized flushing and cutting jet of a cutting device located in a borehole. The soil is removed from the existing soil structure and flushed so intensely that is largely freed from adhering pollutants. The fine particles of the flushed and precleansed soil, together with the pollutants, are sluiced as a slurry in a return flow through a preventer. For decontamination, they are conveyed to a decontamination plant where the remaining pollutants are extracted. The coarse particles of soil remain in the ground. Finally, the cleansed soil, together with a bonding agent, is flushed back into the borehole where it forms a soil structure capable of bearing loads.

Abstract: A method for providing improved measurement of oil, water, and gas flow rates in producing wells using thru-tubing wireline inflatable and retrievable packers or plugs to systematically isolate producing zones within a wellbore. Surface flow rates are measured before and after zonal isolation, with the zonal production rate determined by the measured difference in flow rate before and after isolation. Surface measurement of individual production zones allows greater accuracy in measuring multiphase flows, while at the same time allowing evaluation of reservoir properties of the lower, isolated zones.

Abstract: A method is disclosed for polishing geothermal brines containing iron-rich silica scale and silica particles suspended therein while removing and recovering copper, silver and other precious metals dissolved therein. The method comprises passing brine having a pH just below about 5.0 through a conduit packed with a metal higher in the electromotive series than silver for a time to sufficient for substantially all of the silver and other precious metals therein to precipitate onto the packing. Preferably, the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to act as a filter for said suspended particles. Dissolving the packing in a suitable acid will leave a precious metal-rich residue behind for subsequent recovery. When the brine is treated this process, the useful life of injection wells used to return cooled brine back to the geothrmal field is extended by at least about 3 times as compared to that observed with untreated brine.

Abstract: Methods and apparatus for vacuum extraction of contaminants from the ground which, in a preferred embodiment, involves vacuum withdrawal of liquid and gaseous phases as a common stream, separation of the liquid and gaseous phases, and subsequent treatment of the separated liquid and gases to produce clean effluent. A primed vacuum extraction employs a single vacuum generating device to remove contaminants in both the liquid stream and soil gases through a single well casing utilizing a priming tube which introduces air or other gas to the liquid collected at the bottom of a well. The present invention permits vacuum extraction of both liquids and gases from the subsurface by way of wells having a liquid layer which is more than thirty feet below the soil surface or in which a screened interval of the extraction pipe is entirely below the liquid surface.

Abstract: A process for in-situ enrichment of gas used in miscible flooding in a subterranean hydrocarbon-bearing reservoir. A drive gas such as methane, lean natural gas, nitrogen, carbon dioxide or mixtures thereof is used to immiscibly displace formation hydrocarbons. After gas breakthrough the produced fluid is separated into oil and gas components. The separated gas, which has been enriched with intermediate hydrocarbon compounds extracted from the formation hydrocarbons, is mixed with the drive gas injected into the reservoir so as to enrich the injected gas sufficiently to cause miscible displacement of the formation hydrocarbons. When the drive gas is carbon dioxide, methane and/or nitrogen may be extracted from the separated gas prior to being mixed with the drive gas.

Abstract: A process for two phase vacuum extraction of contaminants from the ground involves vacuum withdrawal of liquid and gaseous phases as a common stream, separation of the liquid and gaseous phases, and subsequent treatment of the separated liquid and gases to produce clean effluents. Two phase vacuum extraction employs a single vacuum generating device to remove contaminants in both the liquid stream and soil gases through a single well casing.