Abstract: In a gas flooding or miscible gas flooding operation, the sweep efficiency of the gas is improved using a mixture of an alkylated diphenyl sulfonate and an alpha-olefin sulfonate as the surfactants in a mobility control fluid or diverter.

Abstract: A gas flooding process for displacing oil within a reservoir is improved by injections of a surfactant having a composition and concentration correlated with those of the brine used to remain substantially within the water phase of the injected fluid at a concentration below the critical micelle concentration of the surfactant.

Abstract: A polymer is disclosed that is useful in increasing the viscosity of carbon dioxide. That polymer comprises a polydialkylsilalkylene polymer; wherein the dialkyl group is preferably dimethyl, methylethyl, or diethyl; and the alkylene group is preferably ethylene or methylene. Preferably, the polymer is polydimethylsilalkylene. That polymer can be used in a method for recovering oil from an underground oil-bearing earth formation penetrated by an injection well and a producing well, in which method carbon dioxide is injected into the formation to displace oil towards the producing well from which oil is produced to the surface. The viscosity of the carbon dioxide injected into the formation is increased at least three-fold by the presence of a sufficient amount of the polydialkylsilalkylene polymer and a sufficient amount of a cosolvent to form a solution of the polymer in the carbon dioxide.

Abstract: A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing reservoir comprising:contacting the reservoir with at least one metal component selected from the group consisting of vanadium components in which vanadium is present in the 5+ oxidation state in an amount effective to promote the chemical modification of at least one component of the hydrocarbons in the reservoir, iron components in which iron is present in the 3+ oxidation state in an amount effective to promote the chemical modification of at least one component of the hydrocarbons is the reservoir, manganese components in which manganese is present in the 3+ oxidation state in an amount effective to promote the chemical modification of at least one component of the hydrocarbons in the reservoir and mixtures thereof, and at least one oxygen transfer agent in an amount effective to do at least one of the following: maintain at least partially the promoting activity of the metal component; produce at least a portion of metal compon

Abstract: The invention discloses a method to enhance flow of oil bearing crude from a stripper well, by sealing the concentric well casing and tubing components together across the annular space between these components, at a level generally above any liquid in the casing, to define a sealed space open via perforations in the casing to the surrounding oil bearing formation; by evacuating gases from the defined sealed space to establish subatmospheric pressure conditions therein that may be reduced only by flow of fluids including the crude through the well casing perforations from the surrounding oil bearing formation; by discontining these conditions and immediately thereafter injecting a fluid into the defined sealed space, to pressurize the defined space to superatmospheric pressure conditions; by repeating both phases of the cycle between the subatmospheric and superatmospheric pressure conditions, sequentially over and over; and by operating a lift pump means in the well tubing, at least part of the time during e

Abstract: An improvement is presented in a process for increasing the yield of production wells in crude oil reservoirs having inhomogenous strata, wherein an aqueous solution of a salt is injected through an injection well into the reservoir, without causing fracturing thereof, and then salt crystals are formed at stratum temperature by removing water from the solution. If desired, the salt crystals can be redissolved and reformed at other parts of the reservoir.

Abstract: The invention is a method of recovering hydrocarbons from an underground vertical hydrocarbon reservoir having a substantial vertical thickness, an oil saturation relatively near residual oil saturation to gas, and at least one injection well and one production well penetrating the reservoir. The method comprises injecting a surfactant slug into the bottom of the reservoir above any water zone or aquifer, and driving the surfactant slug upwards through the reservoir by the use of some driving force. The driving force may be supplied by one or more of a combination of methods comprising producing the gas cap of the reservoir, producing hydrocarbons banked above the surfactant slug, or injecting fluid below the surfactant slug. Hydrocarbons are recovered at one or more production wells.

Abstract: The invention is a method for recovering residual hydrocarbons from a reservoir which has been previously swept by gas. The invention steps comprise drilling and completing at least one horizontal injection well relatively near the top of the reservoir, injecting a miscible solvent through the horizontal injection well to create a curtain of solvent falling through the previously gas swept reservoir, and producing hydrocarbons and other fluids that have been banked below the falling solvent curtain through a vertical or horizontal production well.

Abstract: A process for dissolving surfactants in miscible gaseous drive fluids is discussed. The poor solvent properties of these drive fluids are enhanced by the addition of a cosolvent which facilitates solubilization of the surfactant into the drive solvents. Solubilization of surfactants in the HLB range of 0 to 10 can be facilitated by the addition of less polar cosolvents. Surfactants of HLB range 10 to 20 will show improved solubility with more polar cosolvents. Surfactants with low solubility parameter values and low polarity will require minimal cosolvent addition. A miscible drive phase enriched with surfactant will show improved mobility in a subsurface, oil-bearing, formation due to the foaming action generated with in-place aqueous fluids.

Abstract: All energy resources available from a geopressured geothermal reservoir are used for the production of pipeline quality gas using a high pressure separator/heat exchanger and a membrane separator, and recovering waste gas from both the membrane separator and a low pressure separator in tandem with the high pressure separator for use in enhanced oil recovery, or in powering a gas engine and turbine set. Liquid hydrocarbons are skimmed off the top of geothermal brine in the low pressure separator. High pressure brine from the geothermal well is used to drive a turbine/generator set before recovering waste gas in the first separator. Another turbine/generator set is provided in a supercritical binary power plant that uses propane as a working fluid in a closed cycle, and uses exhaust heat from the combustion engine and geothermal energy of the brine in the separator/heat exchanger to heat the propane.

Abstract: A process for decreasing total fluid flow through a large natural or induced fracture where smaller multiple fractures are created. These multiple fractures each have a smaller aperture than said natural or induced fracture. The combined fluid flow through said multiple fractures is sufficiently less than the total fluid flow through said large fracture, thereby decreasing fluid bypass and improving sweep efficiency.

Abstract: The invention is a method of recovering hydrocarbons from underground hydrcarbon formations by injecting a mixture of carbon dioxide and a polar alcohol or polar glycol additive, said additive having less than about 9 carbon atoms. The mixture of carbon dioxide and additive is injected at a temperature and pressure above the critical temperature and pressure of carbon dioxide. The alcohol or glycol additive comprises about 0.1% to about 10% by weight of the injected mixture. After being injected through an injection well, the mixture is driven through the formation and the hydrocarbons and other fluids are recovered at one or more production wells.

Abstract: A mechanism and flow conduits for introducing and transporting a set of separated fluids and a stream of solid fines through passageway in a rotating metallurgical converter for introducing such fluids and solid fines into a liquid metal contained in the converter.Stationary conduits from flow sources connect to a non rotative sleeve which forms the external portion of a rotary joint able to introduce a set of separated fluids into the rotating converter passageways. Each separated stationary fluid conduit connects to port holes in the fixed sleeve to lead the flow to the interior of the sleeve, and connects a circumferential channel formed in rotating rings located between a rotating shaft affixed to the converter vessel trunnion pin and the static sleeve with a seal between each adjacent ring and corresponding channel. A port hole is located in each rotating channel ring for leading the fluid through internal flow paths inside and along the axis of the shaft body.

Abstract: Hydrocarbons are produced from a subterranean reservoir by maintaining the effective reservoir pressure below the reservoir crushing pressure during a first production period, causing the effective reservoir pressure to exceed the reservoir crushing pressure after such first production period so as to crush the reservoir and reduce the reservoir permeability, and then producing hydrocarbons from the reservoir during a second production period in which hydrocarbon production is enhanced due to better sweep efficiency as a result of the lowered permeability of the reservoir.

Abstract: A water-soluble inorganic non-crosslinking salt is incorporated in an aqueous gel-like solution of a water-soluble uncrosslinked polymer at an initial higher polymer concentration. The salt accelerates the dilution of the polymer solution with an aqueous diluent to an aqueous polymer solution at a predetermined lower polymer concentration. The gel-like polymer solution is diluted without substantially degrading the polymer so that it retains desirable properties for use in a hydrocarbon recovery process.

Abstract: Improved vertical and/or horizontal sweep efficiency in a deep subterranean oil containing formation having a temperature in excess of 250.degree. F. containing relatively high permeability zones and relatively low permeability zones is obtained by injecting an aqueous polysulfide solution into the formation that preferentially enters the relatively high permeability zones and allowing the aqueous polysulfide solution in the relatively high permeability zones to disproportionate under the temperature conditions within the relatively high permeability zones to form a precipitate of elemental sulfur in situ which plugs the relatively high permeability zones in the formation. Thereafter, improved sweep efficiency is realized in displacing oil from the lesser permeable zones.

Abstract: A reservoir is produced by injecting a mixture of carbon dioxide and nitrogen produced by treatment of a Claus plant gaseous effluent stream into the reservoir to enhance production.

Abstract: In a carbonated waterflood oil recovery process the corrosivity of a premixed solution is reduced by dissolving the CO.sub.2 in water containing enough sodium carbonate or bicarbonate to maintain a pH of at least about 4.

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: 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: A hydraulic accumulator-compressor vessel using geothermal brine under pressure as a piston to compress waste (CO.sub.2 rich) gas is used in a system having a plurality of gas separators in tandem to recover pipeline quality gas from geothermal brine. A first high pressure separator feeds gas to a membrance separator which separates low pressure waste gas from high pressure quality gas. A second separator produces low pressure waste gas. Waste gas from both separators is combined and fed into the vessel through a port at the top as the vessel is drained for another compression cycle. High pressure brine is then admitted into the vessel through a port at the bottom of the vessel. Check valves control the flow of low pressure waste gas into the vessel and high pressure waste gas out of the vessel.

Abstract: In a process for completing and operating a well, which process involves passing carbon dioxide through a case, cemented and perforated well, carbon dioxide-induced damage of the cement is avoided by coating the cement tunnel walls so that the carbon dioxide is passed through perforation tunnels which have been internally coated by epoxy resin.

Abstract: Disclosed is a process for preparing relatively low molecular weight, water absorbing, acrylic polymers for use as drilling fluid additives by aqueous polymerization of (A) an acrylic monomer, such as acrylic acid neutralized 0 to 100 mole percent with, for example, ammonia, and/or an alkali such as Na.sub.2 O.sub.3, and/or an amine; with (B) acrylamide in a mole ratio of 70 to 100 mole percent (A) to 30:0 mole percent (B). The molecular weight is limited to 1,000 to 50,000, such as by adding a chain transfer agent to the polymerization mixture, to achieve excellent results as a drilling fluid additive. The monomer, such as partially neutralized acrylic acid, is polymerized in aqueous solution in the presence of a polymerization initiator without external heating while allowing water to evaporate off.

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: A method for diverting CO.sub.2 injection in injection wells by the use of perforation ball sealers composed of polymer compounds covered with a thin coating of elastomer of low enough density to float in the injected fluids, yet able to stand the adverse temperatures of CO.sub.2 injection.

Abstract: A process for recovering hydrocarbons, e.g., crude petroleum, from a formation comprising: (a) injecting carbon dioxide into the formation; (b) shutting off the wells to the formation to allow the carbon dioxide to contact and disperse in the hydrocarbons in the formation; (c) recovering hydrocarbons from the formation; (d) repeating steps (a), (b) and (c) at least once; (e) injecting a carbonated aqueous liquid composition into the formation to drive the hydrocarbons toward the production well or wells and (f) recovering hydrocarbons from the formation.

Abstract: This invention contemplates a method of enhancing oil and/or gas recovery by properly drilling injection and production wells into a reservoir, incorporating flow control valves and sensors in both sets of wells, and connecting these valves and sensors to a surface computer. The computer compares the fluid flow data from the valves and sensors to a theoretical flow model of the reservoir to determine actual fluid flow paths in the reservoir. The computer then determines the optimum fluid flow rates and paths and adjusts the valve open-close patterns and settings accordingly, to force the reservoir fluid flows into those paths. The computer continually performs these operations so as to constantly provide maximum sweep efficiency and therefore optimum reservoir productivity. In conjunction with the above methodology, the densities and viscosities of the injected fluids can be varied so that they can assist with the vertical movement of fluids within the reservoir.

Abstract: A method of recovering oil from an underground accumulation of oil. The method comprises introducing into the top of the accumulation of oil a gas whereby oil is forced from the accumulation to a well. In particular, oil in recesses opening downwardly is forced downwardly by the gas to leave the recess and migrate to the well.

Abstract: A method for simultaneous recovery of crude oil from multiple zones in a reservoir is disclosed wherein multiple wells, each in fluid communication with at least two hydrocarbon zones separated by an impermeable barrier, are used to produce oil in an enhanced recovery process. The end product from recovery in one zone is used to augment the recovery process in another zone.

Abstract: A process is provided in which carbon dioxide is injected into an oil-containing reservoir as an aid in recovering oil from the reservoir. Oil can be produced from at least one production well in the reservoir and carbon dioxide-containing hydrocarbon gas will be produced with the oil. Heavy ends are stripped from the carbon dioxide-containing hydrocarbon gas and substantially all of the carbon dioxide in reinjected into the oil-containing reservoir.

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

Abstract: In a hydrocarbon recovery system including CO.sub.2 pressurization of an underground formation, a sealing cement comprised of Portland cement and Class C fly ash.

Abstract: A method is disclosed of displacing reservoir fluids through a subterranean retrograde or gas-condensate reservoir wherein a displacement fluid is introduced into the reservoir and it is displaced along with the reservoir fluids through the reservoir. The displacement fluid can be inherently miscible with the reservoir fluids at the temperture and pressure of the reservoir and comprises a nonoxidizing gas selected from a group consisting of carbon dioxide, flue gas, nitrogen, residue gas, and mixtures thereof in selected proportions.

Abstract: From 5 to 35%, preferably 10 to 30%, by volume of hydrocarbon gases may be incorporated as a diluent into carbon dioxide-containing gas injected during secondary exploitation of oil reservoirs. The reservoir pressure is maintained at 100 to 120 atm., respectively, up to 250 atm. The preferred range is 120 to 200 atm. The hydrocarbon gases may be added to the carbon dioxide-containing gas prior to injection and/or use may be made of ambient hydrocarbon gases present in the reservoir. The optimum gas injection rate is 40-80 m.sup.3 /day/m of formation.

Abstract: A method for drilling a plurality of wellbores for producing an oil and/or gas field to the maximum extent with the least number of wellbores wherein at least two longitudinally extending drilling zones are established spaced apart and essentially parallel to one another and drilling alternate longitudinally spaced apart curved wellbores from said drilling zones, each curved wellbore extending toward the producing formation and the opposing drilling zone, each curved wellbore being straightened out and thereafter following a predetermined producing formation until the wellbore reaches the vicinity of the opposing drilling zone. A plurality of the alternating longitudinally spaced wellbores are employed along a pair of drilling zones and a plurality of pairs of drilling zones can be employed. The resulting series of wellbores can be employed to carry out an enhanced oil recovery process by using part of said wellbores as injection wells and part of said wellbores as producing wells.

Abstract: Electrical current is caused to flow between an electrode well located in an aquafer above viscous hydrocarbon-bearing formation and an electrode well located in an aquafer below the hydrocarbon-bearing formation. The electrical current thereby tends to spread out in a broad plate-like configuration from each electrode well. This increases the area of the hydrocarbon-bearing formation through which current is flowed, thereby extending the region which is heated by electrical dissapation. The nature of the aquafers and their location eases and resolves much of the adverse vaporization and pressure buildup that occurs in other systems. This also allows water to be readily injected to into or produced from the electrode wells to further control vaporization and pressure buildup without adversely affecting gravity drainage, other drive mechanisms or injection programs operating within the hydrocarbon-bearing formation. In addition, this enables the electrode wells to be used in a more continuous manner.

Abstract: Oil recovery method using injection of non-condensible gas (1) into an oil zone (16) via perforations along the length of an injection well (12) to drive oil through the zone to a production well (14), with the gas injected at a rate no greater than 2,000,000 SCFD per acre and with sufficient velocity to emulsify the oil.

Abstract: An enhanced oil recovery process in which carbon dioxide is injected into the oil-bearing formation under supercritical conditions to act as a solvent for the oil. Mobility of the carbon dioxide is controlled by the use of a dissolved polymer whose solubility is enhanced by the use of an entrainer comprising a polar organic compound such as an alcohol or a glycol.

Abstract: Oil is recovered from a subterranean oil reservoir by injecting foam-forming components through an injection well while preventing fluid outflow from an adjacent production well, so that the pressure is increased in the zone between the wells, then permitting fluid outflow from the production well while continuing the injection, until the rate of the outflow is significantly reduced, and repeating the injecting and outflowing steps until the rate of oil production is significantly reduced.

Abstract: The disclosed invention is a method of conducting a miscible flood with a flooding medium predominantly composed of carbon dioxide or nitrogen in a shorter period of time with acceptable hydrocarbon recovery. The invention is practiced by injecting a predominantly carbon dioxide or nitrogen medium into the underground hydrocarbon reservoir at such a rate as to produce a frontal advance velocity in the reservoir of about 2 to about 15 times the critical velocity of flow for that flooding medium through the instant reservoir. This high flooding velocity, substantially above critical velocity, is maintained until the flooding front has traveled about 60% to about 90% of the distance from the injection to the production systems. At this time, the frontal advance velocity is reduced to a value approximately equal to or less than the critical velocity for the remainder of the miscible flood.

Abstract: The disclosed invention is a method of conducting a miscible carbon dioxide and hydrocarbon solvent flood in a steeply dipping reservoir. A mixture of carbon dioxide and light hydrocarbon solvent is injected in the updip end of the reservoir in such a ratio as to achieve at least multiple contact miscibility between the mixture and the formation hydrocarbons. As the flood front moves downdip with increasing formation pressure, the amount of injected enriching hydrocarbon solvent is decreased while multiple contact miscibility is maintained in the flood front. Hydrocarbons and carbon dioxide are recovered from at least one production well downdip of the injection well.

Abstract: This invention discloses a more efficient and more self supporting method of producing oil from a viscous oil-bearing permeability stratified reservoir. In situ combustion with oxygen is carried out near a first injection well in a manner such that carbon dioxide substantially free of nitrogen is produced. The carbon dioxide substantially free of nitrogen produced by in situ combustion is then injected into a second injection well to swell, reduce the vicosity of in-place oil and displace oil from a separate part of the stratified reservoir. Water with or without other mobility and solubility control agents can be injected in either or both the combustion step and carbon dioxide displacement step. In situ combustion with or without nitrogen may thereafter be initiated adjacent the second injection well to produce the less permeable or more viscous oil-bearing strata to either produce oil left by carbon dioxide injection or to produce more nitrogen-free carbon dioxide.

Abstract: A method is disclosed for the displacing reservoir fluids, such as a rich gas, through a subterranean reservoir, such as a gas-condensate reservoir, wherein a displacement fluid is introduced into a reservoir and it is displaced along with the reservoir fluids through the reservoir. The displacement fluid develops in situ miscibility with the reservoir fluids at the temperature and pressure of the reservoir and comprises a nonoxidizing gas and fluids produced from the reservoir. The nonoxidizing fluid can be selected from a group consisting of carbon dioxide, flue gas, nitrogen, and combinations of these, and the fluids produced from the reservoir are in the form of dry hydrocarbon gas.

Abstract: A method is disclosed for forming a carbon dioxide-containing mixture which is miscible with crude oil. The method comprises maintaining a mixture of crude oil and carbon dioxide in an extraction zone at a temperature and pressure such that multiple phase equilibrium is achieved therebetween. A carbon dioxide-rich phase that includes a mixture of carbon dioxide and hydrocarbons is withdrawn and is miscible with the reservoir crude oil when injected into the reservoir from which the crude oil was produced.

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 relatively closely spaced injection well and production well pair is used as a single electrode and is used in a way that significantly increases the effective radius of an electrode production location. This is achieved by appropriately spacing of the wells and flowing aqueous fluid between wells at a pressure below the pressure driving oil toward the production well. The controlled pressure flowing aqueous fluid forms a highly conductivity flow path for oil flowing toward the production well. The effectiveness of the increased well pair drainage radius is achieved or augmented by injecting aqueous fluid, preferably steam or hot water, into the formation at a pressure great enough to drive oil toward the well pair and using the formation injection well as an electrode for electrically heating the oil. More than one well pair may be used either as a separate or the same electrode. One injection well or one production well may be used to form two or more well pairs.

Abstract: A method for oil, gas and mineral recovery by panel opening drilling including providing spaced injection and recovery drill holes (10, 12) which respectively straddle a deposit bearing underground region (20), each drill hole including a panel shaped opening (18, 19) substantially facing the deposit bearing region (20) and injecting the injection hole (10) with a fluid under sufficient pressure to uniformly sweep the deposits in the underground region to the recovery hole (12) for recovery of the deposits therefrom. An apparatus (50) for creating such panel shaped is also provided.

Abstract: A method of extracting bitumen from a subsurface tar sand bed wherein a shell of frozen earth is formed around the periphery of at least a portion of the tar sand bed, followed by recovering bitumen from such portion of the tar sand bed within the shell of frozen earth by suitable means such as, for example, solvent extraction. Also disclosed is apparatus for freezing the earth surrounding one of a plurality of boreholes drilled in the earth within earth freezing distance of each other around the periphery of such portion of the tar sand bed.

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: A borehole is formed down into the ground and extends towards an underlying pay zone, and then is turned horizontally through the pay zone, and then continues back up towards the surface of the earth; so that the resultant borehole is continuous from an inlet to an outlet, with the inlet and outlet being spaced from one another. When the free end of the drill string arrives at the outlet, one end of a casing string is attached thereto, and the casing string is pulled back through the entire borehole so that the borehole is cased from the outlet to the inlet, or vice versa. The casing is perforated adjacent to the pay zone so that the hydrocarbons may flow from the pay zone into the interior of the casing. Production is achieved through either of the spaced inlet or outlet; or, by using one vertical length of the borehole to force fluid to flow through the entire borehole, thereby forcing the production to the surface.