SR
`
`XR
`
`United States Patent [ 19]
`Allen
`
`[54] CARRIER GAS VAPORIZED SOLVENT OIL
`RECOVERY METHOD
`Inventor: Joseph C. Allen, Bellaire, Tex.
`[75]
`[73] Assignee: Texaco Inc., New York, N.Y.
`[22] Filed:
`July 11, 1975
`[21] Appl. No.: 594,983
`
`Related U.S. Application Data
`[63] Continuation of Ser. No. 449,136, March 7, 1974,
`abandoned.
`[52] U.S. CI ................................ 166/266; 166/267;
`166/272; 166/274
`[51]
`Int. CI.2 ...•.•.•••.•••••••• E21B 43/22; E21B 43/24
`[58] Field of Search .......... 166/266, 267,272,274,
`166/305, 306, 75
`
`[ 5 6]
`
`2,862,558
`2,880,801
`3,157,230
`3,240,272
`3,354,953
`3,442,332
`3,459,265
`3,459,265
`3,675,715
`3,811,506
`
`References Cited
`UNITED ST ATES PATENTS
`Dixon ................................ 166/272
`12/1958
`Crump ........................... 166/266 X
`4/1959
`Connally, Jr. et al. ............ 166/274
`11/1964
`Orkiszewski ....................... 166/274
`3/1966
`Morse ................................ 166/274
`11/1967
`Keith ...................... ........... 166/266
`5/1969
`Buxton et al. ................. 166/272 X
`8/1969
`Buxton et al. .......... ....... 166/272 X
`8/1969
`Speller, Jr ..................... 166/266 X
`7/1972
`Carlin ................................ 166/274
`5/1974
`
`[ 11]
`
`[45]
`
`4,008,764
`Feb. 22, 1977
`
`7/1974
`3,823,777
`9/1974
`3,837,399
`3,845,820 11/1974
`
`Allen et al. ........................ 166/266
`Allen et al. ........ ................ 166/266
`Allen et al. ........................ 166/266
`
`Primary Examiner-Stephen 1. Novosad
`Assistant Examiner-George A. Suchfield
`Attorney, Agent, or Firm-T. H. Whaley; C. G. Ries;
`Jack H. Park
`
`ABSTRACT
`[57]
`Viscous petroleum may be recovered from viscous
`petroleum-containing formations including tar sand
`deposits by injecting into the formation a gaseous mix(cid:173)
`ture of a carrier gas and a solvent which is liquid at
`reservoir conditions, such as pentane, hexane, heptane,
`octane, carbon disulfide, etc., and mixtures thereof.
`The gaseous mixture is formed by contacting a nor(cid:173)
`mally liquid solvent with a carrier gas such as nitrogen
`and introducing the carrier gas having solvent vapor(cid:173)
`ized therein into the formation. Recovery of petroleum
`and solvent may be from the same well as is used for
`injection or from a remotely located well. The carrier
`gas and/or solvent may be heated prior to injection to
`increase solvency rate and vapor pressure. In through(cid:173)
`put operations, the gaseous solvent mixture may be
`followed by water, hot water or steam to displace the
`residual solvent from the formation.
`
`21 Claims, 1 Drawing Figure
`
`SOL VENT MAKE UP
`
`(SOLVENT)
`
`SOLVENT
`.OIST/LlATION
`t/NIT
`
`OIL ,. SOL VENT
`
`/j
`
`P
`
`OIL
`
`GAS
`STRIPPER
`t/NIT
`
`12
`
`SOLVENT SAT(cid:173)
`t/RATE.O
`r;:::;::=:::::::::;i
`
`.MAKE - UP
`CARRIER GAS
`
`L/Qt/1.0
`SOLVENT
`
`,I
`
`7
`
`CARRIER GA.I
`
`2
`
`\.L'.· ... :·.-.. ;.· .. ·.· ..
`] J_'---i'
`] J_
`LJ
`
`f
`
`IJIL + SOL VENT
`+ GAS
`
`lfEAT
`
`.J
`
`Page 1 of 7
`
`ULI EXHIBIT 1004
`
`

`

`U.S. Patent
`
`Feb. 22, 1977
`
`4,008,764
`
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`Page 2 of 7
`
`ULI EXHIBIT 1004
`
`

`

`1
`
`4,008,764
`
`CARRIER GAS VAPORIZED SOL VENT OIL
`RECOVERY METHOD
`This is a continuation, of application Ser.
`449,136 filed Mar. 7, 1974 now abandoned.
`
`No.
`
`5
`
`2
`men or bituminous petroleum is separated from the
`sand by some means and recovered therefrom through
`a well or other production means drilled into the tar
`sand deposit.
`In situ separation processes described in the litera(cid:173)
`ture include thermal techniques, such as fire flooding
`(or in situ combustion) and steam flooding, and emulsi(cid:173)
`fication drive processes. To be successful, an in situ
`separation process must accomplish two functions: the
`viscosity of the crude oil must be reduced and some
`form of oil displacement or driving mechanism must be
`supplied to the formation. Emulsification processes
`frequently also employ steam, plus a basic material
`such as sodium hydroxide which induces formation of
`15 an oil-in-water emulsion having a viscosity substantially
`lower than the viscosity of the formation petroleum.
`Thermal processes are restricted to formations having
`sufficient overburden thickness to tolerate injection of
`high pressure fluids. Many tar sand deposits exist in
`which the overburden thickness is too thin for thermal
`flooding and too thick for strip mining.
`One other possible process for recovering bitumen
`from tar sand deposits by in situ separation which does
`not require the presence of sufficient overburden thick(cid:173)
`ness to contain high pressures, is solvent flooding. Sol(cid:173)
`vent flooding involves injection of a solvent into the tar
`sand deposit, which solvent dilutes and reduces the
`viscosity of the bituminous petroleum to render it mo(cid:173)
`bile and recoverable by means of a well as is normally
`employed in conventional oil recovery operations. Al(cid:173)
`though many solvents including aromatic hydrocarbons
`such as benzene, toluene and xylene, as well as carbon
`tetrachloride and carbon disulfide, readily dissolve
`bituminous petroleum, these materials are expensive
`and since huge quantities are required, solvent flooding
`has not been considered to be economically feasible.
`Paraffinic hydrocarbons such as ethane, propane, bu(cid:173)
`tane, pentane, etc. are more readily available and less
`expensive than those solvents described above, but it
`has always been uniformly assumed by persons skilled
`in the art that paraffinic hydrocarbon solvents could
`not be used in bituminous petroleum because of the
`danger of precipitating asphaltenes, which would cause
`formation plugging. Indeed, the asphaltic constituents
`of crude oil are frequently defined as pentane insoluble
`materials. Asphalt removal from oil by contacting the
`crude with propane is a well known refinery process.
`Furthermore, the cost of solvent flooding has always
`been considered prohibitive because of the vast quanti(cid:173)
`ties required to saturate the formation.
`It can be seen from the foregoing that there is a sub(cid:173)
`stantial need for a method for recovering viscous petro(cid:173)
`leum such as bitumen or bituminous petroleum from
`tar sand formations by use of moderate quantities of
`readily available, inexpensive solvents in a relatively
`low pressure procedure that can be used in intermedi-
`ate depth deposits as well as in deep deposits.
`
`BACKGROUND OF THE INVENTION
`I. Field of the Invention
`This invention is concerned with a method for recov(cid:173)
`ering viscous petroleum including bitumen from vis- 10
`cous petroleum-containing formations including tar
`sand deposits, and more particularly is concerned with
`an improved carrier gas vaporized solvent flooding
`method especially useful in viscous petroleum-contain(cid:173)
`ing formations including tar sand deposits.
`II. Description of the Prior Art
`There are many subterranean petroleum-containing
`formations in various parts of the world from which
`petroleum cannot be recovered by conventional means
`because the petroleum is too viscous to flow or be 20
`pumped. The most extreme example of viscous pe(cid:173)
`troleum-containing formations are the so-called tar
`sand or bituminous sand deposits. The largest and most
`famous such formation is the Athabasca Tar Sand De(cid:173)
`posit in the northeastern part of the Province of Al- 25
`berta, Canada, which contains over 700 billion barrels
`of petroleum. Other extensive deposits are known to
`exist in the western United States and in Venezuela,
`and smaller deposits exist in Europe and Asia.
`Tar sands are defined as sand saturated with a highly 30
`viscous crude petroleum material not recoverable in its
`natural state through a well by ordinary production
`methods. The petroleum constituent of tar sand depos-
`its are highly bituminous in character and very viscous.
`The sand present in tar sand deposits is generally fine 35
`quartz sand coated with a layer of water, with the bitu(cid:173)
`minous petroleum material occupying most of the void
`space around the water wetted sand grains. The bal(cid:173)
`ance of the void space is filled with connate water, and
`some deposits contain small volumes of gas such as air 40
`or methane. The sand grains are packed to a void vol(cid:173)
`ume of about 35 percent, which corresponds to 83
`percent by weight sand. The balance of the material is
`bitumen and water, and the sum of bitumen and water
`is fairly consistently 17 percent by weight, with the 45
`bitumen portion thereof varying from about 2 percent
`to about 16 percent. One of the characteristics of tar
`sand deposits which differs considerably from conven(cid:173)
`tional petroleum-containing formations is the absence
`of a consolidated material matrix within the formation. 50
`The sand grains are generally in contact although
`mostly uncemented and the bitumen occupies most of
`the void space. The API gravity of the bitumen ranges
`from about 6 to about 8, and the specific gravity at 60°
`F. is from about 1.006 to about 1.027 and the viscosity 55
`is in the millions of centipoise range at formation tem(cid:173)
`perature.
`The methods for recovering bituminous petroleum
`from tar sand deposits are classified as strip mining and
`in situ separation processes. Most of the recovery to 60
`date has been by means of strip mining, although this
`method is economically feasible at the present time
`only when the ratio of overburden thickness to tar sand
`deposit thickness is around I or less. Vast quantities of
`petroleum are known to exist in the form of tar sand 65
`deposits which are not within a range which is econom(cid:173)
`ically suitable for strip mining, and so there is a serious
`need for some form of in situ process wherein the bitu-
`
`SUMMARY OF THE INVENTION
`I have discovered, and this constitutes my invention,
`that viscous petroleum including bitumen may be re(cid:173)
`covered from viscous petroleum-containing formations
`including tar sand deposits by injecting into the forma(cid:173)
`tion a gaseous mixture of a carrier gas and a hydrocar(cid:173)
`bon solvent which is liquid at reservoir conditions.
`Suitable materials for the solvent include paraffinic
`hydrocarbons having from five to ten carbon atoms
`such as pentane, hexane, etc., as well as naphtha, natu-
`
`Page 3 of 7
`
`ULI EXHIBIT 1004
`
`

`

`4,008,764
`
`3
`ral gasoline, carbon disulfide, and mixtures thereof.
`Suitable carrier gases include nitrogen, carbon dioxide,
`methane, ethane, propane, butane, hydrogen, anhy(cid:173)
`drous ammonia, hydrogen sulfide, ethylene or propyl(cid:173)
`ene. For example, nitrogen may be passed through a 5
`vaporizer to vaporize pentane, and then the gaseous
`mixture injected into a subsurface tar sand deposit.
`Viscous petroleum or bitumen absorbs the liquid sol(cid:173)
`vent from the gaseous phase until sufficient solvent is
`absorbed to make the petroleum sufficiently mobile Io
`that it will flow into the production well. Production
`may be taken from a remotely located well or from the
`same well as was used for injecting the gas.solvent
`mixture. Surprisingly, the use of paraffinic hydrocar(cid:173)
`bons such as pentane or hexane in application of this 15
`process to tar sand materials does not result in plugging
`of formation flow channels caused by precipitation of
`asphaltic materials. The carrier gas and/or the solvent
`may be heated prior to injection into the formation to
`increase the solvency rate and vapor pressure of the 20
`solvent. The solvent may be displaced by injecting
`water, hot water or steam into the formation.
`
`4
`the carrier gas through a vessel partly filled with the
`liquid solvent. Baffles in the vessel improve the effi(cid:173)
`ciency of the vaporization step, .and many other types
`of commercially available devices such as multi-tray
`vaporizers, moving film contactors, etc. may be used.
`The process is best understood by referring to the
`illustrative embodiment in the attached drawing, in
`which viscous petroleum-containing formation I
`is
`penetrated by injection well 2 and production well 3.
`Perforations 4 and 5 establish fluid communication
`between the wells and the formation 1. On the surface,
`vaporizer 6 is fed by carrier gas via line 7 and by liquid
`solvent through line 8. Initially, all of the liquid solvent
`and carrier gas will be supplied from. external makeup
`sources, although recycling of both produced solvent
`and carrier gas reduces inventory of these .fluids. Sol-
`vent is thereafter added to vaporizer 6 only as needed
`to maintain the level up to a preselected level. Carrier
`gas is bubbled into the liquid solvent via nozzles 9, so
`that a uniform distribution of gas bubbles in the liquid
`is achieved to insure maximum gas-liquid solvent
`contact. The gaseous phase is saturated with solvent
`vapors, and only gaseous materials are allowed to exit
`through line 10. Baffles 11 aid. in achieving efficient
`25 mixing and prevent liquid solvent from exiting the va(cid:173)
`porizer.
`The gaseous effluent from vaporizer 6, comprising
`carrier gas and vaporized solvent, passes via line 10 and
`is pumped by compressor 14 into injection well 2. The
`30 gaseous mixture of carrier gas and solvent enter the
`formation and flows through the flow channels in the
`formation. Solvent is absorbed directly into the viscous
`petroleum from the gaseous phase. The carrier gas
`serves the essential additional purpose of maintaining
`transmissibility by maintaining the formation flow
`channels open.
`As the viscous petroleum gaseous solvent, the viscos(cid:173)
`ity thereof decreases until flow. of petroleum is initi(cid:173)
`ated. Contact between solvent and viscous petroleum is
`40 achieved in a very uniform manner throughout the
`formation between the injection well and the produc(cid:173)
`tion well, as contrasted to liquid solvent injection
`where maximum solvent-petroleum mixing occurs near
`the injection well, with much of the petroleum between
`the contact point and the production well being essen(cid:173)
`tially uncontacted by solvent.
`The petroleum-solvent mixture flows toward produc-
`tion well 3 being driven by the injected gas. The fluid
`enters well 3 via perforations 5, and is pumped to the
`surface. Some carrier gas is produced simultaneously
`with petroleum and solvent. It is usually desirable to
`separate the gas and petroleum by means such as gas
`stripper 12. The stripped gas is recycled through vapor(cid:173)
`izer 6. The produced fluid then passes through a sol(cid:173)
`vent separator unit. Thermal distillation unit 13 accom(cid:173)
`plishes the separation in this embodiment .. Solvent re-
`cycling is desirable for economic reasons. If a central
`surface processing plant is to be used, as will be the
`case for tar sand operations, for example, the separa(cid:173)
`tion of solvent from the petroleum may be accom(cid:173)
`plished in the central processing plant.
`After the process described above has proceeded for
`a period of time, gas-solvent injection can be termi(cid:173)
`nated and a drive fluid such as wa~er, hot water or
`steam may be injected to displace the residual petro(cid:173)
`leum and solvent. toward the production well.
`In a slightly different embodiment, the carrier gas
`and/or the liquid solvent is heated, so that the gaseous
`
`BRIEF DESCRIPTION OF THE DRAWING
`The attached drawing shows a tar sand formation
`being subjected to the process of my invention with
`provisions on the surface for recycling solvent and
`carrier gas produced along with the crude petroleum.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`I. The Process
`The process of my invention comprises non-aqueous
`gaseous fluid injection operation necessitating at least
`one well drilled into and in fluid communication with 35
`the petroleum formation. A carrier gas such as nitrogen
`is brought in contact with and vaporizes an effective
`solvent which is normally liquid at reservoir conditions
`and the gaseous mixture is injected via the injection
`well into the formation.
`The reasons for using a carrier gas to vaporize the
`normally liquid solvent are many fold. By using this
`procedure, the advantages of gaseous solvents and of
`liquid solvents can be combined. Higher molecular
`weight, liquid solvents are more effective solvents for 45
`high molecular weight, hydrocarbon components of
`viscous petroleum than lower molecular weight process
`gaseous solvents. Also, troubles sometimes encoun(cid:173)
`tered in using liquid solvents such as rapid loss of sol(cid:173)
`vent injectivity due to creation of a viscous bank of the 50
`solvent-petroleum mixture which eventually becomes
`immobile is avoided. Injection of a permanent (non(cid:173)
`condensible) gas with the solvent increases and main(cid:173)
`tains a high pressure which increases oil production
`rate and recovery. The diffusivity of gases is much 55
`higher than liquids, which speeds up the penetration
`rate throughout the formation and increases overall
`conformance. Finally, the total inventory of solvent in
`the formation is reduced materially when gaseous sol(cid:173)
`vent mixture is used as compared to liquid solvent. This 60
`inventory reduction is especially significant in the pro(cid:173)
`cess of my invention, since only a portion of the gas
`injected into the formation is solvent, the major portion
`thereof being the less expensive carrier gas.
`The preferred method for practicing the process of 65
`my invention involves the use of a contactor vessel such
`as a vaporizer, in which the carrier gas can contact
`liquid solvent. This can be accomplished by bubbling
`
`Page 4 of 7
`
`ULI EXHIBIT 1004
`
`

`

`4,008,764
`
`5
`mixture of carrier gas and solvent enter the formation
`at a temperature above ambient temperature. If de(cid:173)
`sired, the temperature may be higher than the tempera(cid:173)
`ture of the petroleum-containing formation so as to
`achieve a limited amount of thermal petroleum viscos- 5
`ity reduction.
`After completion of the oil operation, residual sol(cid:173)
`vent may be recovered from the formation by any of
`several means. If a water, hot water or steam injection
`drive step is used as described above, usually no addi(cid:173)
`tional step is required to recover residual solvent. If no
`such aqueous drive fluid injection step is used, how(cid:173)
`ever, solvent may be recovered by injecting a gaseous
`material, either the same gas used as a carrier gas or
`any other available non-condensable gas, into the for(cid:173)
`mation to scavenge by veporization the residual solvent
`from the formation.
`The process of my invention may also be used in a
`push-pull, single well recovery process, wherein the
`gaseous mixture of carrier gas and solvent are injected
`into the formation for a period of time, until the gase(cid:173)
`ous mixture has penetrated for some distance into the
`formation, and the injection pressure has begun in(cid:173)
`creasing, followed by reduction of pressure and termi-
`. nation of injection of gas so petroleum and absorbed
`solvent can flow into the well bore.
`II. The Liquid Solvent
`Any material which is essentially all liquid at the
`temperature and pressure in the petroleum formation,
`and (2) which is absorbed by the formation petroleum
`from the gaseous phase, and (3) as a result of such
`absorption the viscosity of the petroleum is reduced,
`may be used in the process of my invention. Surpris(cid:173)
`ingly, I have found that paraffinic hydrocarbons are the
`preferred solvents. Any paraffinic hydrocarbon having
`from about five to about ten carbon atoms or more may
`be used. Linear or branched chain species may be used,
`and mixtures of numerous types are satisfactory sol(cid:173)
`vents. Commercial blends such as naphtha or natural
`gasoline may be used. Carbon disulfide, CS 2, alone or
`mixed with paraffinic hydrocarbon solvents are also
`effective. Aromatic hydrocarbons such as benzene
`have not been found to be satisfactory. This is an espe(cid:173)
`cially unexpected result since such materials are nor(cid:173)
`mally considered to be preferred solvents especially for
`asphaltic petroleum such as is found in tar sands.
`III. The Carrier Gas
`Any material which is essentially all gaseous at for(cid:173)
`mation temperature and pressure, and which is unreac(cid:173)
`tive with the liquid solvent being used, may be used as
`the carrier gas. Nitrogen is very suitable for use as the
`carrier gas in my process. Air may also be used, but
`precautions must be taken when using a flammable
`liquid solvent to avoid fire or explosion dangers. Gase(cid:173)
`ous paraffinic materials such as methane, ethane or
`propane, as well as gaseous, olefinic hydrocarbons such
`as ethylene or propylene may also be used. Carbon
`dioxide is another preferred carrier gas. Hydrogen sul(cid:173)
`fide may also be used if precautions are taken to pre(cid:173)
`vent escape of the material into the atmosphere· at the
`production well. Hydrogen or anhydrous ammonia may
`also be used. Crude materials such as natural gas, flue
`gas, exhaust gas, etc. may also be used, although some
`processing step to remove particulate matter and cor(cid:173)
`rosive materials is advised. Mixtures of any two or more
`of the foregoing materials may also be used.
`Ordinarily, there is no need to regulate the ratio of
`carrier gas and solvent. Generally,
`the preferred
`
`6
`method of operating comprises saturating or essentially
`saturating the carrier gas with solvent at the operating
`conditions.
`IV. Field Example
`In order to better understand the process of my in(cid:173)
`vention the following pilot field example is offered as
`an illustrative embodiment ofmy invention; however, it
`is not meant to be !imitative or restrictive thereof.
`A tar sand deposit is located at a depth of 200 feet
`10 and the thickness of the deposit is 70 feet. Since the
`ratio of overburden thickness to tar sand deposit thick(cid:173)
`ness is greater than one, the deposit is not economically
`suitable for strip mining. It is determined that the most
`attractive method of exploiting this particular reservoir
`15 is by means of carrier gas vaporized solvent flooding.
`A commercial grade natural gasoline is available at
`an attractive price in the area, the composition of this
`material being 90 percent C6 through C9 • This material
`is essentially all liquid at reservoir pressure and temper-
`20 ature, so it is quite suitable for use as the liquid solvent.
`Flue gas available from a steam generator operating
`nearby in the field is passed through a filter and a
`scrubber to remove particulate matter and corrosive
`materials, and the scrubbed flue gas, which is approxi-
`25 mately 86 percent nitrogen and 14 percent carbon
`dioxide, is used as the carrier gas.
`A multiple baffle gas vaporizer unit capable of han(cid:173)
`dling 50,000 standard cubic feet of gas per hour is
`installed near the injection well and connecting lines
`30 are added so that carrier gas and liquid solvent may be
`introduced into the vaporizer and gaseous effluent
`pumped to the injection well. The nitrogen-carbon
`dioxide carrier gas and the solvent are both heated to a
`temperature of 120° F. prior to introduction thereof
`35 into the vaporizer. The gaseous effluent is compressed
`to a pressure of 150 pounds per square inch and in(cid:173)
`jected into the formation. Production of carrier gas is
`obtained within 20 days from the production well,
`which is located 100 feet from the injection well. Oil
`40 production begins 10 days after the carrier gas first
`appeared. Produced gas comprising the injected carrier
`gas and a small amount of methane is stripped from the
`produced fluid and recycled through the vaporizer unit.
`Solvent is removed from the produced fluid by distilla-
`45 tion for recycling through the vaporizer.
`After production has continued for 12 months, the
`gas-oil ratio begins to rise. Gas analysis indicates that
`the solvent content thereof is beginning to increase,
`indicating absorption of solvent by formation petro-
`50 Ieum has reached an equilibrium. Gaseous fluid injec(cid:173)
`tion is terminated and hot water is injected into the
`injection well to displace additional petroleum and
`solvent. The petroleum production rate increases rap(cid:173)
`idly and remains high for several months, and then
`55 decreases as the injected hot water begins to break
`through. The injection of hot water is stopped after the
`water-oil ratio rises above about 50.
`V. Experimental Section
`In order to demonstrate the operability of the process
`60 of my invention, and further to determine the magni(cid:173)
`tude of oil recovery resulting from the application of
`several specific embodiments thereof, the following
`laboratory experimental work was performed.
`A glass tube measuring approximately % inch in di-
`65 ameter and two feet in length was filled with loosely
`packed tar sand material obtained from a strip mining
`operation in the Athabasca Tar Sand Deposit. The tube
`containing the tar sand material was mounted at a 45°
`
`Page 5 of 7
`
`ULI EXHIBIT 1004
`
`

`

`Table I
`
`Oil Recovery Using Carrier
`Gas Vaporized Solvents
`Liquid Solvent
`
`o/r Recovery
`
`Benzene ( C,.H,;)
`Carbon Disulfide (CS,)
`Light Naphtha (equiv. to C,H,0 )
`Hexane (C,;H,)
`
`0
`25
`28
`71
`
`Run
`
`A
`B
`C
`D
`
`7
`angle. The liquid solvents to be evaluated were placed
`in an efficient contactor and nitrogen was bubbled
`through the liquid solvents at atmospheric pressure.
`The nitrogen carrier gas was thereby saturated with the
`solvent being evaluated, and the gaseous mixture was
`then passed through the tube packed with tar sand
`material. The gaseous mixture entered the tube at a
`pressure only slightly above atmospheric pressure. No
`back pressure or restriction was applied to the outlet
`end of the tube. The data obtained are summarized in 10
`Table I below.
`
`8
`2. A method as recited in claim 1 wherein the solvent
`is selected from the group consisting of paraffinic hy(cid:173)
`drocarbons having from five to ten carbon atoms, car(cid:173)
`bon disulfide, naphtha, natural gasoline, and mixtures
`thereof.
`3. A method as recited in. claim 2 wherein the solvent
`is pentane.
`4. A method as recited in claim 2 wherein the solvent
`is heptane.
`5. A method as recited in claim 2 wherein the solvent
`is naphtha.
`6. A method as recited in claim 2 wherein the solvent
`is natural gasoline.
`7. A method as recited in claim 2 wherein the solvent
`15 is carbon disulfide.
`8. A method as recited in claim 1 wherein the solvent
`is hexane.
`9. A method as recited in claim 1 wherein the carrier
`gas is selected from the group consisting of nitrogen,
`20 air, methane, natural gas, ethane, propane, butane,
`ethylene, propylene, carbon dioxide, flue gas, exhaust
`It can be seen from the data contained in Table I
`gas, hydrogen sulfide, hydrogen, anhydrous ammonia,
`and mixtures thereof.
`above that benzene ( Run A) was ineffective for recov(cid:173)
`10. A method as recited in claim 9 wherein the car-
`ering bituminous petroleum from a tar sand material
`using this process. This is somewhat surprising since 25 rier gas is nitrogen.
`11. A method as recited in claim 9 wherein the car-
`benzene is normally considered to be a preferred sol-
`rier gas is methane.
`vent for bitumen. Carbon disulfide was effective. The
`12. A method as recited in claim 9 wherein the car-
`light naphtha was superior to carbon disulfide, which is
`rier gas is carbon dioxide.
`unexpected. Hexane is the most effective solvent of
`13. A method as recited in claim 9 wherein the car-
`those tested, which is quite surprising. No plugging due 30
`rier gas is ethane.
`to asphaltic material precipitation was apparent during
`14. A method as recited in claim 9 wherein the car(cid:173)
`any of these tests. In the case of using carrier gas vapor(cid:173)
`rier gas is flue gas.
`ized carbon disulfide, naphtha and hexane, the pe(cid:173)
`15. A method as recited in claim 1 wherein the mix-
`troleum-solvent extract flowed out of the tube by grav-
`ture of carrier gas and solvent is introduced into the
`ity drainage alone.
`formation at a temperature greater than surface am bi(cid:173)
`While my invention has been described in terms of a
`ent temperature.
`number of specific illustrative embodiments, it is not so
`16. A m'ethod as recited in claim 1 wherein the mix(cid:173)
`limited, since many variations thereof will be apparent
`ture of carrier gas and solvent is introduced into the
`to persons skilled in the related art without departing
`formation at a temperature at least equal to the forma(cid:173)
`from the true spirit and scope of my invention. Simi- 40
`tion temperature.
`larly, while a mechanism has been proposed to explain
`17. A method as recited in claim 1 comprising the
`the benefits derived from application of the process of
`additional step of introducing a drive fluid selected
`my invention, it is not hereby asserted that this is the
`from the group consisting of water, hot water and
`only mechanism responsible therefor. It is my intention
`steam into the formation after termination of introduc-
`that my invention be limited and restricted only by such
`tion of the mixture of solvent and carrier gas.
`limitations and restrictions as appear in the appended
`18. A method as recited in claim 1 comprising the
`claims.
`additional step of introducing a non-condensable gase(cid:173)
`I claim:
`ous fluid into the formation to recover solvent retained
`1. A method for recovering viscous petroleum in- 50
`by the formation.
`eluding bitumen
`from
`subterranean, viscous pe(cid:173)
`19. A method as recited in claim 1 comprising the
`troleum-containing formations including tar sand de(cid:173)
`additional step of separating the carrier gas from the
`posits, the formation being penetrated by at least one
`produced fluid.
`production well and by at least one injection well, both
`20. A method as recited in claim 1 comprising the
`wells being in fluid communication with the formation, 55
`additional step of separating the solvent from the pro(cid:173)
`comprising:
`duced fluid.
`a. passing an inert carrier gas which is gaseous at
`21. A method for recovering viscous petroleum in(cid:173)
`formation temperature and pressure through a
`cluding bitumen from a subterranean, viscous pe(cid:173)
`solvent for petroleum which is liquid at formation
`troleum-containing formation including a tar sand de(cid:173)
`temperature and pressure to vaporize the solvent 60
`posit, the formation being penetrated by at least one
`thereby forming a gaseous mixture of the solvent
`production well and by at least one injection well, both
`and carrier gas;
`wells being in fluid communication with the formation,
`b. introducing the gaseous mixture of carrier gas and
`comprising:
`solvent into the formation via the injection well;
`a. passing an inert carrier gas which is gaseous at
`and
`formation temperature and pressure selected from
`c. recovering a produced fluid comprising formation
`the group consisting of hydrogen, anhydrous am(cid:173)
`monia and mixtures thereof, through a solvent for
`petroleum, having solvent absorbed therein and the
`petroleum which is liquid at formation temperature
`carrier gas from the production well.
`
`4,008,764
`
`5
`
`35
`
`45
`
`65
`
`Page 6 of 7
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`ULI EXHIBIT 1004
`
`

`

`9
`
`4,008,764
`
`10
`solvent into the formation via the injection well;
`and
`c. recovering a produced fluid comprising formation
`petroleum having solvent absorbed therein, and the
`carrier gas from the production well.
`* * * * *
`
`and pressure to vaporize the solvent thereby form(cid:173)
`
`ing a gaseous mixture of the solvent and carrier gas;
`
`b. introducing the gaseous mixture of carrier gas and
`
`s
`
`10
`
`IS
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`so
`
`55
`
`60
`
`65
`
`Page 7 of 7
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`ULI EXHIBIT 1004
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`