CA1122518A - Recovery of bitumen from tar sand material - Google Patents

Abstract

ABSTRACT

The invention relates to a method for recovering bitumen from tar sand material by contacting the tar sand material with a heated aqueous fluid characterized in that said heated aqueous fluid contains an amine having the formula:

wherein R1 and R2, which may be the same or different, are each hydrogen or C1 to C6 alkyl, and R3 is C3 to C20 alkyl or a group of the formula -R4NH2 wherein R4 is C2 to C18 alkylene, the total number of carbon atoms in R1, R2 and R3 being from 3 to 20.
Various embodiments of the invention are described including a thermal recovery process, a hydraulic mining process, and the treatment of mined tar sand.

Description

~22~

RECOVERY OF BITUMEN FROM TAR SAND MATERIAL

This invention relates to an improved method for the recovery of bitumen from tar sand material. More particularly, it relates to a process involving contacting the tar sand materlal with a heated aqueous fluid containing certain amines.
One embodiment of the invention provides a thermal recovery process involving injection of steam and the amine into a tar sand formation. Another embodiment provides a hydraulic mining process involving passing high velocity jets of the heatea aqueous fluid into a cavit~ of the formation and recovering bitumen and sand with the aqueous fluid from the cavity. A further embodimen~ provides a method involving contacting mined tar sand material with the heated aqueous fluid.
There are many subterranean petroleum-containing formations from which petroleum cannot be recovered because the petroleum viscosity is so high that it will not flow or cannot be pumped to the surface of the earth without first applying a treatment to reduce the petroleum viscosity.
The most extreme example of viscous petroleum-containing formations are the so-called tar sand or bituminous sand deposits. The largest and most famous deposit of tar sand is the Athabasca tar sand deposit of Alberta, Canada.
Although this deposit contains in excess of 700 billion barrels of petroleum, essentially no recovery of petroleum has ~een af~ected by commercial means from these deposits because of the very high viscosity o~ the oil. Other viscous oil formations are found in the United States and in various other countries throughout the world.
Thermal recovery techniques have been used success-fully for recovering viscous petroleum from subterranean forma'ions in many applications~ although they have been unsuccessful on a commercial basis in other deposits for a variety of reasons. The most successful thermal recovery technique involves introducing sLeam into the formation to raise the temperature of the viscous petroleum, thereby .

~l~Z~

decreasing its viscosity sufficiently for it to flow or be displaced to a well, which may be the same well as ~Jas used for steam injection or a spaced-apart production well.
Although most viscous oil formations can be stimulated to produce some oil by steam injection, the cost effectiveness is such that steam flooding can be applied to viscous oil formations on a profitable basis in only a limited number of instances. The principal cost factor in steam flooding operations is the cost of fuel re~uired to generate the steam for injecting into the formation. Obviously, the amount of oil recovered per unit of fuel required to generate steam used in the recovery of oil is a critical factor, and is the principal reason that many viscous oil formations cannot be successfully exploited by steam stimulated recovery.
Various additives have been proposed in the prior art for improving the effectiveness of steam flooding oil recovery processes. Various solvents have been injected or mixed with steam, and generally result in some improvement in the oil recovery, although it has often been found that the amount of additional oil recovered is not sufficient to justify the cost of the solvents introduced into the forma-tion in combination with steam. The use of liquid, gaseous, and combinations of liquid and gaseous hydrocarbon solvents with steam are disclosed in many prior art references.
U.S. Patent No. 3,822,749 discloses the use of a pretreatment comprising a gaseous phase aliphatic polyamine injected into a formation containing water sensitive clays before injecting steam thereinto, the polyamine being utilized to reduce the water sensitivity of water sensitive clays.
Methods for the recovery o~ bitumen from tar sand deposits can be generally classified as strip mining or in situ separation. Strip mining requires removal of the overburden by mechanical means and the mixture of bitumen and sand that constitutes the tar sand deposit is then similarly removed by mechanical means and transported to a surface processing plant for separation of bitumen and sand. In situ separation processes make use of techniques . . .

- :
: . - : , - . . , : : : . ~ :: . , - - :. :,: : .
, .:

2~

for separating the bitumenfrom the s~d within the tar sand deposit itself, so the bï~u~enin sOme modified form may be transported to the surface with at least a major portion of the sand left in the tar sand deposit. Techniques proposed in the prior art for in situ separation may be classified as thermal or emulsification processes. The thermal techniques include in situ combustion, (fire flooding), and steam flooding. Emulsification processes may also involve the use of steam in addition to an additional chemical to promote emulsification o~ the high viscosity bitumen so that it may be transported to thesurface where the emulsion is resolved into bitumen and water. Although many in situ separation techniques have been proposed in the prior art, none have been both economically and technically successful.
Most known in situ processes involve injection of fluid under fairly high pressures. Injection of high pressure fluid can be conducted safely only if the formation overburden thickness is sufficiently great to contain the high pressure fluids injected thereinto without rupturing.
Strip mining of a tar sand deposit is economically feasible only if the ratio of overburden thickness to tar sand deposit thickness is around 1:1 or less. Even when the tar sand deposit is fairly shallow, strip mining is still very expensive; the cost of removing overburden and tar sand material represents from 50-60 percent of the total cost of producing a pipeline-acceptab}e product. Many deposits have overburden which is too thick to permit exploitation by strip mininy, and not great enough to contain high pressure fluids for in situ separation processes.
In view of the foregoing it can be appreciated that there is a substantial, unfulfilled need for a method ,for recovery of bituminous material from tar sand deposits, particularly those intermediate depth deposits which are not suitable for strip mining or for in situ recovery processes in~7Olving injecticn OI a high pressure fluid.
U.~. Patents No. 3,951,457 and 3,B58,654 describe hydraulic mining processes for recovering heavy oil from oil sand deposits.

22~

~ ethods taught in the prior art for processing tar sands recovered from open pit mines or strip mines include direct coking, anhydrous solvent extraction, cold water separation techniques which make use of a wetting agent, and several hot water techniques, some of which also employ wetting agents or other chemicals in combination with hot water.
The fuel costs for the direct coking technique are presently prohibitive, and the solvent cost for the anhydrous solvent technique is excessive, even with solvent recovery processes.
The hot or cold water separation techniques appear to hold great promise for processing mined tar sand. Several problems have been encountered, however. Emulsion formation is almost spontaneous when bituminous petroleum contacts hot water containing an alkalinity agent such as sodium hydroxide. ~hile formation of a stable oil-in-water emulsion is useful in some in situ recovery processes, emulsions of both the oil-in-water and water-in-oil type are frequently formed as a by product of cold or hot water separation processes. In either case, the emulsion must be broken or resolved into its individual phases. Resolving emulsions involving bituminous petroleum is usually difficult for several reasons. Asphaltic substances are very effective emulsifying agents and form very stable emulsions.
Furthermorerthespecific gravity of bitumen is almost exactly equal to that of water, which means there will be no gravity-related forces due to density differences to aid in phase separation, even if surface forces responsible for emulsification can be neutralized. The bituminous petroleum has a very great affinity for sand grain surfaces, and many hot water processes do not effectively strip the bituminous petroleum from the sand grains.
Another very serious problem, which has been encoun-tered in commercial separation projects, is formation of astable froth. The air- or other gas-entrained froth is very stable, and quite often huge, unmanageable volumes of tne froth are produced.
In view of the foregoing, it can be appreciated : ':: ' ' ' :: :'.
: , .

~ ~2S~

that there is a substantial, unfulfilled need for a surface processing method for separating bitumen or bituminous petroleum recovered from surface or subterranean tar sand deposits by mechanical means such as strip mining, which does not result in formation of an emulsion or froth.
U.S~ Patent No. 3,846,276 describes a separation process employing hot water and a polyphosphatewetting agent.
In its broadest aspect, the present invention comprises a method for recovering bit~en from tar sand 10 material by contacting the tar sand material with a heated aqueous fluid containing an amine having the formula:

wherein Rl and R2, which may be the same or different, are each hydrogen or a Cl to C6, and preferably a C2 to C4, alkyl, linear or branched, R3 is a C3 to C20 and preferably C4 to C12 alkyl, linear or branched, or -R4NH2 wherein R4 i5 C2 to C18, and preferably C3 to Cll alkylene, linear or branched, and the sum of the number of carbon atoms in Rl, R2 and R3 is rom 3 to 20, and preferably 7 to 13.
One example of a material which is within ~he scope of the above formula, which has been tested and found to effectively dislodge bitumen from sand grains is diethylaminopropylamine (C2H5)2NC3~6NH2. This material is a water-white substance with a typical amine odor, having a boiling point of 159C and a freezing point of -100C.
The specific gravity is 0.82 (20/20C) and the flash point is 145 C. It is known for use as a curing agent for epoxy resins, and as a chemical intermediate for other manufacturing and processes.
Another example of a preferred amine within the above formula, which has been examined and found to improve greatly the oil recovery effectiveness of steam flooding, is a C10-Cl3 sec alkyl primary amine. This compound is available commercially ~rom Texaco Petrochemical Sales under the designation PT-9108, ana has a boiling point of 259c, and is only slightly soluble in water.

- 5(a) -In the drawings which accompany this specification and form a part thereof, Figure 1 shows a tar sand deposit in which a combination injection-production well has been drilled, in accordance with one embodiment of the present invention. Figure 2 shows in a semischematic form the separation of bitumen from mined tar sand material by hot aqueous fluid containing amine.
- In one embodiment, the amine is introduced into a tar sand formation by mixing the amine with steam and injecting it into the formation, or the amine may be introduced

3~

- 5(a) -- . :~ . - ...... . .
, " . :- .
- ' ~

- ~r2~1 B

separately in the form of one or more slu~s of amine, followed by steam to accomplish mixing ln the formation.
From 0.1 to 30, and preferably from 2 to 10, pore volume percent of amine should be utilized, the amount o amine being nearer the upper end of the preferred range with formations containing very viscous petroleumr i.e., the amount of amine required increases roughly in proportion to the viscosity of petroleum present in the formation. The amine effectively reduces the attraction between the viscous lo oil and the surface of the sand grains or other îormation mineral matrix, thereby greatly increasing the amount of oil recovered from the zone thro-ughwhich the steam passes.
This embodiment of the present invention concerns an improved thermal oil recovery method, introducing steam into the formation fox the purpose of heating viscous oil contained therein, therehy reducing the viscosity of the oil so it may be displaced to a well. Conventional steam flooding is applied commercially in two somewhat different ways, one being a steam drive process in which steam is injected into the formation by one or more injection wells to pass through the formation, displacing and mobilizing petroleum, the petroleum being displaced to a spaced-apart production well from which it can be recovered to the surface of the earth. The other commonly used method is the steam push-pull, or huff-and-puff, method, in which steam is injected into a formation, allowed to remain in the formation for a period of time sufficient to transfer thermal energy to the viscous petroleum, and then fluids including petroleum are recovered from the formation by the same well as was used for introduction of steam into the formation. Both methods are successful for recovering viscous oil, to varying degr,ees depending on the viscosity of the oil, the attractive ~orces between the oil and the formation mineral surfaces, as well as many other factors.
Steam drive is thepreferred method in most applications, since it achieves oil recovery at greater distances from the wells, and its thermal efficiency is greater than that of push-pull steam methods.

:

f~

In applying the process of this invention to a subterranean, viscous oil-containing formation, the preferred method comprises introducing the steam and amine into the formation by one or more injection wells, and recovering oil mobilized and displaced by the steam and amine from the formation from one or more production wells, which are spaced apart from the injection wells. This involves the commonly known steam-drive oil recovery process, and effects recovery at much greater depths in the formation from the well than is possible with the push-pull steam flooding me-thod.
In applying the process of the invention, either saturated or superheated steam may be utilized. The most practical method involves the use of saturated steam, and the preferred steam quality ranges from 20 to 100~, and preferably from 60 to 80~.
If it is desired to mix the amine described above with steam, then the concentration of amine should be from 0.5 to 25, and preferably from 2 to 10, percent by weight.
The steam and amine mixture may be injected into the formation in the early phase of the steam flooding operation, until the total amount of amine introduced into the formation is in the range of from 0.1 to 30, and preferably 2 to 10, pore volume percent, based on the pore volume of the recovery zone being treated. After this amount of amine has been injected, steam (without amine ) may be injected for a period of time sufficient to displace the previously injected fluids as well as mobilize oil through the formation. It is more efficient to introduce the ~ amine into the formation during the early stages of steam injection, rather than injecting steam for any prolonged period of time and then injecting amine mixed with or sequentially with additional steam.
Another method of applying the process of the invention involves injecting one or more discrete slugs of the amine irto the formation, before or interspersed with periods of injecting substantially pure steam into the formation. Since some of the preferred species are only - ~ ~

12~

slightly soluble in water, this is an effective means of accomplishing intimate contact between the amine and steam with bitumen present in the formation.
Another embodiment of the invention involves the recovery of bitumen, by a hydraulic mining technique, wherein the tar sand is contacted by a fluid comprising hot water or steam and the amine. In one embodiment, an injection string capable of both rotation and axial (vertical) movement, equipped near its lower end with jet nozzles which direct the aqueous hydraulic mining fluid as one or more jet streams against the face of the iar sand deposit, s employed. A separate communication path to the surface o~ the earth facilitates movement of the injected hydraulic mining fluid, with bitumen dispersed therein, to the suxface for further processing. The injection strin~
is constructed so as to permit simultaneous rotation and vertical movement as the aqueous hydraulic mining fluid is injected down the injection string and out through the jet nozzles, so that a stream of fluid sweeps the tar sand deposits.
This embodiment can best be understood by referring to Fig. 1 of the attached Drawings, in which a tar sand deposit 1 is located at a depth which is too great for economical strip mining and not deep enough to permit using an in situ recovery technique requiring injection of a high pressure fluid. A combination injection-production well 2 is drilled to the bottom of the tar sand deposit, and casing 3 is set to the top of the formation. A separate injection string 4 is run inside the casing 3j to the top of the tar sand deposit. The injection string 4 is equipped with nozzles 5 near the bottom thereof, and the completion equipment on the surface includes means r such as kelly drive bushing 7, fo~ rotating the injection string ana lifting hook 6 for raising and lowering the string as fluid is pumped down the string. A swivel 8 provides an essentially leak-proof seal between the non-rotating upper portion and the rotating lower portion of inJection string 4. P~p 9 pumps the aqueous hydraulic mining fluid down the injection string 4 with sufficient pressure to form high velocity je~s , : --' ~

~z~

10, and ensure that jets 10 contact the tar sand with considerable impact velocity to dislodge bitumen and sand.
The rotatable, vertically moveable injection string

4 contains an interior flow path 11 for pumping the aqueous hydraulic mining fluid down the string, where a portion of it passes out through jets 5 to form jet streams 10, which impinge against the walls 12 of the cavity which has been formed in tar sand deposit 1. Some means for pumping the dislodged hitumen from the lower portion of the cavity must be provided, e.g. jet pump 13. The fluid for operating the jet pump is the aqueous hydraulic mining fluid in this embodiment, although a separate hydraulic fluid may be used.
A portion of the aqueous hydraulic mining fluid passes to the jet pump _ via flow line 14, where it exits through nozzle 15, and then through venturi 16. The passage o~
fluid through the venturi creates a zone of reduced pressure in the venturi, which draws bitumen and other material from the bottom of the cavity and forces it upward toward the surface via return flow path 17. The fluid including bitumen passes out through flexible fluid discharge line 18 into settling tan~ 19. More than one tank in series may be utili~ed, although only one is shown for simplicity.
The fluid separates into oil or bitumen and water, with the sand separating to the bottom of settling tank. The water is recycled through holding tank 20 via line 21. The water is heated in heat exchanger 22 and pumped via 1uid inlet line 24 into the top of injection flow path 11, where it passes back to jets S as described above.
A noncondensible gas such as nitrogen, air, methane, carbon dioxide, etc., or a mixture of one or m~ore of the gases, is used in the embodiment shown in the Drawing.
The gas is supplied from compressor or vessel 23, to mix with the aqueous hydraulic fluid and pass via flexible input line ?4 to injection flcw path 11. The use of gas in this process is very desir~ble since it aids in supporting the overburden, improves pumping efrectiveness, and by maintaining the cavity gas filled, allcws the jets of hydraulic mining fluid to penetrate deeper into the ~ormation.

-:
, :~ :

- ~: - , '~

The top of the injection string contains a high pressure swivel assembly 25 into which fluid injection and discharge lines connect. A loop 26 is also provided for engaging lifting hook 6 connected to the drawworks (not shown). This arrangement allows theentire assembly to be lowered into the well and moved up and down as needed to allow the jet streams 10 to sweep the entire vertical thickness of the formation. The hydraulic mining string is rotated by a convenient means such as a drilling rig kelly ~not shown), engaging the kelly drive bushing 7 The surface apparatus should also include a sealing element 27 so that no blow-by occurs between the hydraulic mining injection string assembly 4 and casing 3. This allows maintenance of positive fluid pressure within cavity 12, for purposes to be described below.
On the very bottom of ~he assembly of this illus-trative embodiment is a conventional drill bit 28, which permits drilling the well through the tar sand interval with the same equipment asis used for the hydraulic mining operation. The drill bit is also useful ~or breaking up clumps of tar sand material, which are dislodged and accumulate in the bottom of the cavity in the tar sand deposit.
The overall equipment as embodied in the attached Drawing is known in the art of hydraulic mining. For e~amplç, an axticle titled "Subsurface Hydraulic Mining Through Small Diameter Boreholes": pages 24-27, Mining and Minerals Engineer ng, November, 1969 describes an essentially identical apparatus used in drilled consolidated formations such as limestone with an abrasive laden fluid pumped by an explosion type pumping system..
The particularly rotating in~ection string shown in the Drawing is not an essential fea~ure of the invention, although it is the preferred method for obtaining the desired jetting action. A non-rotating string with a plurality of horizonially displayed nozzles could also ~e used.
In operation, the aqueous hydraulic mining fluid is pumped from supply tank 20. The fluid injection pressure `:

need not be as high at the start of the operation as will be required later in the process, since the hydraulic mining fluid jet will only have to tra~el a relatively short distance before contacting the face of the cavity in the tar sand deposit. If a noncondensible gas such as air, nitrogen, carbon dioxiae, methane or natural gas is used, it is mixed with the aqueous hydrualic mining fluid, and a two phase mixture is pumped down string 11 and out jets 5. The presence of a noncondensible gas is a highly desirable embodiment of the process of the in~ention for several reasons. The cavity in the tar sand deposit should be filled with gas rather than liquid, especially after application of the process for a sufficient period to create a large cavity, to increase the distance that the jets travel away from the hydraulic mining apparatus. Also, maintaining a positive gas pressure in the cavity helps support ~he overburden and assists in the pumping action in the bottom of the cavity.
As the bitumen and some sand are removed from the tar sand deposit, a cavity is created adjacent to the nozzles on injection string 4, and the size of this cavity increases with time. As the cavity size increases, it is necessary to increase the hydraulic mining fluid injection pressur~, so that fluid jet stream 10 will reach to the cavity walls with sufficient velocity to dislodge bitumen and sand.
Throughout the process o the invention, a mixture of bitumen and aqueous hydraulic mining fluid, with sand suspended therein, flows back of the surface of the earth via the return flow path 17. The bitumen/hydraulic mining fluid mixture passes via flow line 18 into separation tank 19.
Sand settles to the bottom and may be removed mechanically.
Bitumen separates into one phase, and is removed by line 29 and then to surface processing equipment. Aqueous hydraulic mining fluid constitutes the other liquid phase, passing via line 21 back to tank 20, where it can be reheated and recycled into the injection string 11.
The temperature of the aqueous hydraulic ~luid may be from 80 to lQ5 C (180 to 220F3 or above. In one :-, , -.. . . .
- . ~ ~ : . ,: , .

31.~ 8 preferred embodiment, the temperature of the bitumen-aqueous fluid pulp being produced is monitored, and the temperature is adjusted to yield a pu~p temperature in the range of from 70 to 95 C (160F to 200F) and preferably as near 82 C (180 F) as possible.
The bitumen-hot water mixture more closely resembles the pulp of the hot water surface processes used in separating bitumen from tar sand material obtained by strip mining, than it does any of the produced fluids obtained from known tar sand in situ separation techniques.
The effectiveness of the fluid for separating oil and sand increases with temperature. It is highly preferred that the fluid be in the liquid phase at the temperature and pressure in the extraction zone of the formation, since greater penetration is achieved with liquid jets than with vapor phase jets. The fluid temperature may, however, be such that the fluid is at least partially in the vapor phase at atmospheric pressure; The preferred temperature is greater than 65 C tlS0F) and preferably greater than 82C
(180F), and below the boiling point of the fluid at the pressure in the cavity or treatment zone of the formation.
In a slightly different embodiment, a smalI but effective amount of a solvent for bitumen is included in the hydraulic mining fluid. Monocyclic aromatic solvents, such as benzene, toluene or xylene, as well as saturated hydrocarbon solvents having from four to eight carbon atoms, naphtha, or mixtures thereof, may be injected with the hot aqueous fluid.
The presence o~ a small amount of solvent increases the effectiveness of the process substantially. The preferred ratio of solvent to aqueous hydraulic mining fluid is from about 0.01 to about 0.50.
The amine described above is mixed with hot water or steam in a concentration of from 0.5 to 25, and preferably from 2 to 10, percent by weight.
Noncondensible gas is, in a preferred embodiment, injected into the formation simultaneously with the hydraulic mining ~luid. The use of a noncondensible gas in this process improves its operation considerably and in several ways. Maintenance of a positive pressure aids in supporting the overburden and helps the pumping action. By keeping the cavity formed in the formation by this process filled with gas rather than with liquid, the jets of fluid travel ~urther away from the injection string. Also, some gas is dissol~ed and/or entrained in the pulp of bitumen and aqueous fluid, and this gas forms small bubbles during the surface separation to aid in separating bitumen and aqueous fluid.
Any readily available substance, at least a 10 substantial portion of which remains gaseous at the temperature and pressure of the formation, and which is unreactive with the fluid injected and with petroleum may be used. Air is a suitable material when hot water is used, but steam and air should not be used together, because of the likelihood of initiating an oxidative reaction. Nitrogen may be used safely with steam, as well as with hot or cold water.
Carbon dioxide may also be used with any of the hydraulic mining fluids described above. Hydrocarbons such as methane or ethane may also be used. Dependiny on the temperature and 20 pressure of the tar sand formation, propane may sometimes be used. Mixtures of any two or more of the foregoing materials may also be used. The volume ratio of noncondensible gas to aqueous hydraulic mining fluid may be from about 1/10 to about 10. The noncondensible gas may be introduced simultan-eously as a mixture using the same injection string, orsimultaneously using separate injection strings, or slugs of aqueous hydraulic mining fluid may be alternated with slugs of non-condensible gas.
According to another embodiment, bitumen may be separated from mined tar sand materials by a technique wherein the tar sand is contacted by the hot aqueOus fluid containing the amine. The tar sand is fed continually into a mixing vat where contact with the hot water-amine treating fluid occurs. The mi~ture is fed to a settling tank for separation into sand, bitumen and an aqueous phase having a minor amount of bituminous material contained therein.
The mixture may be contacted with a hydrocarbon treating fluid which solubilizes the bitumen and facilitates separation thereof, if needed.
This embodiment of the invention can best be under-stood by referring to Fig. 2 of the attached Drawings, in which tar sand material which has been dug from an open pit mine and transported by mechanical means, is dumped into container 101. Screw conveyor 102 conveys tar sand at a steady rate into mixing vessel 103, which is equipped with a stirring device 104. An aqueous treating fluid comprising water and from 0.05 to 25, and preferably from 2 to 10, percent by weight of an amine, is prepared in container 105, from which the solution is pumped by pump 106 through heat exchanger 107 wherein the fluid is heated to a temperature in excess of 37C (100F) and preferably between 37 and 99 C
(100F and 210F). The heated aqueous fluid mixes with tar sand in tank 103, where the mixture is agitated by mixer 104 and them pumped by pump 108 into separation tank 109.
For a continuous process, a series of separation tanks may be used in parallel, with sequential routing of the fluid to the several tanks, so the mixture can remain quiescent for a period of time sufficient to facilitate settling of sand 110 in the bottom of the tank. Most of the bitumen a~cumulates in a zone immediately above the sand layer.
An aqueous layer forms on top, which is comprised of the aqueous, amine-containing fluid having a small amount of bitumen dispersed therein. Sand is removed from the lower zone in tank 109 continuously or intermittently, by some means such as the screw conveyor 113.
A hydrocarbon fluid from tank 114 is metered by pump 115 into the separation tank 109 at a predetermined flow rate. The aqueous treating fluid and hydrocarbon are mixed in separation tank 109 by stirrer 116. Bituminous material from the lower layer, as well as from the a~ueous suspension, dissolves in the hydrocarbon and forms layer 117. The hydrocarbon with bitumen dissolved therein is transported via line 118 to a refinery. Presence of hydrocarbon in the bitumen aids pumping to the refinery process unit. Separation an2 recovery of hydrocarbon treating fluid may be accomplished in the refinery unit.

,. . . .

- . :
I

22~

Of course, hydrocarbon recovery may be accomplished immediately after leaving separation unit 109 if desired.
The hot aqueous treating fluid 119 is pumped via line 120 and pump 121 through filter 122 to tank 5 for recycling through the separation process equipment.
The amine is generally mixed with hot water in a concentration of from 0.5 to 25, and preferably from 2 to 10, percent by weight.
Although concentrations greater than this may be used, there is no particular advantage in using larger concentra-tions, and while the cost of the material is low, ecomomics of the process are optimized by using the lowest concentration of amine which is effective for separating bitumen and sand.
Sufficient alkalinity agent should be added to the solution to bring the pH thereof to a value above 7, and preferably above 9.
Heating the aqueOus fluid to a temperature in excess of 37 C (100F) will increase the effectiveness of this 2Q separation technique. The preferred operating temperature is from about 37 to 99C (100F to about 210F) and the especially preferred range is from 65 to 99 C (150 F to 210F) One attractive ~eature of the process of the invention is the fact that bitumen is not emulsified and no froth is formed on contact with the hot aqueous amine-containing fluid. Bitumen is removed effectively frcm the sand, but remains in a separate phase, which will orm a discretè
layer distinct from the aqueous fluid if agitation is stopped. The bitumen may be pumped to the refining process unit, the water-amine fluid being recycled through the separation equipment.

~ ~ ' " ` :

EXAI~ LE

A pilot field project is undertaken utiliz:ing an inverted five-spot pattern with one injection well in the

5 center of a square grid and a producing well on each of the four corners of the square. The distance of each side of the square is 200 feet (60.96 m.). The wells are cornpleted in a viscous oil formation containing 11 API crude, which is too viscous to flow or be displaced by ordinary primary 10 or secondary recovery techniques. The porosity is 39 percent and the permeability is 1200 millidarcies. The oil saturation is 61 percent. The formation thickness is 45 feet (13.71 m.).
The total pore volume of each grid unit is 0.39 x 200 x 15 200 x 45 = 702,000 cubic feet (0.39 x 60.96 ~ 60.96 x 13.71 -19,880 cubic meters). Since the horizontal sweep efficiency of such a pattern is 70 percent and the vertical conformance is ~0 percent, only 42 percent or 294,840 cubic feet (8350 cubic meters) will be contacted by steam. The 20 process applied to this pilot involves the use of a 5 percent pore volu~ne treatment of a dodecyl amine. Five percent amounts to 14,740 cubic feet (994 cubic meters), which requires about 340 tonnes of the dodecyl primary amine.
In applying the process, 80 percent quality steam 25 is injected into the injection well for two days to preheat the portions of the formation immediately around the injection well, to facilitate injection of the amine into the formation. The total amine treatment is applied in four discrete slugs, each involving injecting 190,000 pounds 30 (86.26 tonnes) of amine into the formation followed by injection of steam for 60 days. Steam and amine comingle in the formation with one another and with the formation petroleum, effecting viscosity reduction of the petroleum and also effectively reducing the retentive forces between 35 the viscous petroleum and the formation sand grains. After the last treatment of amine is completed, steam injection is continued in the formation until a total of two pore volumes of steam (based as water) have been injected into the formation. This requires approximately 90 weeks of injection.

, , , - 17 ~
As a result of the above described process, the residual oil saturation is reduced from 51 percent to 12 percent, within the zone contacted by the injected fluids, which is considered as excellent for this particular reservoir.

EXAMP~E 2 Laboratory tests were conducted utilizing samples of tar sand material. The samples were mixed at room temper-ature with diethylaminopropylamine as a solvent, and it was observed that under static conditions at ambient temperature, essentially all of the viscous tar sand materials were dislodged and removed from the mineral surfaces of the tar sand sample, thus indicating the effectiveness of this material for removing viscous petroleum from sand grains~
Tar sand materials are bituminous in character and there is a great affinity between the hydrocarbon portion and the sand grains which is a major cause of the great dif~iculty that has been encountered in obtaining recovery of petroleum from tar sand deposits. Accordingly, the above-described observation is quite significant ~or application to bituminous, viscous petroleum ~ormation as well as other `
viscous oil formations.
A series of displacement tests were conducted in small, seven-inch cells which were packed with 10.5 API crude oil, sand and water to give an initial oil saturation of about 0.55 and a permeability of about 0.36 darcies. The first cell was steam ~looded at a 120 gram per hour steam rate at an injection pressure of 2~0 PSI (16.33 atmospheres) while maintaining 200 PSI (13.6 atmospheres) backpressure~
The second cell was treated first with 10 percent pore volume amine additive before injecting the same quality steam at the same steam injection rate. The amine used in this test was a C10-Cl3 (secondary alkyl) primary amine available commercially from Texaco Petrochemicals ~epartment under the desingation PT-9108.- A11 of the amine was injected in a single 10 percent pore volume slug be~ore injecting steam into the core. The ~irst steam flood succeeded in reducing the oil saturation to 0.195 which -: ~ ' . . ' - -. :

. : ,: . :

is equivalent~to 63.6 percent recovery. In the second flood, employing the amine, the oil saturaticn was reduced from the same 0.55 initial level to 0.051, for 90.7 percent recovery, which is 40 percent greater than the base steam S run. This is considered to be an excellent recovery for such viscous crude, and readily illustrates the effectiveness of the process of the invention for recovering viscous petroleum.
To illustratethe comparative effectiveness of the steam amine oil recovery method of the invention, the following is a tabulation of the residual oil saturation of laboratory steam displacement tests with steam or mixtures of steam and various additives.

15 Oil Recovery Fluid Residùal Oil Saturation Steam alone (average of several runs) 25 Steam plus ethanol 24.4%
Steam plus carbon dioxide 21.6%
Steam plus propane and ethanol 19.4 Steam plus condensate 17.4 Steam plus t-butyl alcohol +
pentane 17.0 Steam plus BZ Raffinate 16.4 Steam plus aromatic solvent 16.2 25 Steam plus heavy CR gasoline 14.0 Steam plus benzene 13.0 Steam plus light SR gasoline 11.1~
Steam plus Udex Extract 9~3Q
Steam plus Amine 5.1~
The above data clearly indicate the surprising superiority of the use of steam plus a~ine as compared to steam or mixtures of steam and other additives.

EX~LE 3 A tar sand deposit is to be exploited and it is determined that the thickness of the tar sand deposit is 65 feet (19.8 m) and the thickness of the overburden is 275 feet (83.8 m). Since the ratio of overburden thickness to tar sand deposi~ thickness is considerably greater than 111, . ' : ~ -:
: , :
- ~, ,:

~! 2~

strip mining is not economic. Moreover, the overburden thickness is not thick enough to make high pressure gas injection safe.
A well is drilled to the bottom of the deposit and a casing is set to the top portion of the tar sand deposit and cemented. A hydraulic mining apparatus similar to that shown in the Drawing is used. The lower portion of the assembly is equipped with four horizontally oriented jet nozzles so that fluids pumped into the assembly will exit through these nozzles in a generally horizontal direction with considerable velocity. The surface equipment includes means for rotating the assembly ~y an electric motor, and sealing devices to establish a liquid tight seal between the rotating and non-rotating members are also provided. The hydraulic mining fluid chosen for this field trial is initially water at 93C (200F) containing 5.0~ by weight of dodecylamine. Methane is injected with the hot fluid to insure a gas-filled cavity and to provide support for the overburden. The volume ratio of methane to hydraulic mining fluid is about 2:10. Initially the injection pressure is approximately 6.8 atmospheres (100 pounds per square inch~, since the jet of aqueous hydraulic mining fluid emerging from the nozzles must flow only a short distance before it impinges against the tar sand deposits. The mixture of bitumen from the tar sand and the hot aqueous hydraulic mining fluid is pumped by a jet pump in the bottom of the hydraulic mining assembly, and flows to the surface through a return flow path integral to the hydraulic mining assembly. The fluid produced at the surface contains "free" bitumen (not emulsified), hydraulic mining fluid, gas and sand separation is accomplished in two gravity settling tanks in series. Bitumen is sent to processing facilities and the aqueous rluid is recycled.
The pH and temperature of the fluid mixture ~pulp) being produced are monitored continually. The ~emperature of the hydraulic mining fluid being injected is adjusted to maintain the pulp temperature at 82 C (180 F)~
The hydraulic mining assembly is positioned so the jets ..

, .

are initially adjacent the top of the tar sand deposit.
The assembly is rotated at 4 rpm and slowly lowered. The rate of lowering is initially about 30 cm (one ~oot) per minute. As the bottom of the assembly reaches the bottom of the tar sand deposit, the direction is reversed and the assembly is raised at about 30 cm. (one foot) per minute, while rotating and injecting hydraulic mining fluid.
As the cavity diameter increases, the aqueous hydraulic mining fluid jet streams from the nozzles must travel ~urther away from the injection point before contacting the wall of the cavity in the tar sand deposit, and so the injection pressure must be increased. The need for an increase in injection pressure is deter~ined by monitoring the ratio of bitumen and sand to aqueous fluid in the pulp being produced to the surface of the earth. A decrease in the concentration of bitumen and sand in the produced pulp indicates that the jets of aqueous hydraulic mining fluid are not moving sufficiently far away from the nozzles to contact virgin tar sandr and so the injection pressure must be increased. By increasing the injection pressure in small increments, e~g., 5 or 10 psi (0.3 or 0.6 atmospheres) at a time, the injected aqueous hydraulic mining fluid stream may be made to continually contact the outer cavity walls within the tar sand deposit. The static gas pressure in the cavity is maintained constant since- it is not desired to create a fracture between the pressurized tar sand formation and the surface of the earth, which would establish an undesired return communication path through the overburden to the surface. While the static pressure in the cavity expressed in pounds per square inch must not exceed the overburden thic~ness expressed in feet, the injection pressure may go much higher, up to 70 atmospheres (1000 pounds~ or more. This process is continued until a substantial decrease in bitumen sand content of the produced bitumen sand water slurry is observed, and an increase in injection pressure up to 102 atmospheres (1500 psi) fails t~ cause a corresponding increase in the bitumen sana content of the produced fluid pulp. This indicates that .. : ..- ~ :
, - , . .

The maximum range of the hydraulic mining fluid jet within the cavity has been reached and no additional bitumen can be recovered by this technique from the cavity.
After it has been determined that the hydraulic mining process has been extended as far into the tar sand deposit as possible, the hydraulic mining fluid remaining within the cavity may be recovered by pumping to the surface for reuse in adjacent areas of the deposit.

i0 EXAMPLE 4 A tar sand deposit having an overburden varying ~rom 3 to 12 meters (10 to 40 feet) in thickness, said deposit having an average thickness of 19.8 m. (65 feet~ is exploited by means of open pit strip mining. After stripping away lS the overburden, tar sand is dug from the deposit using scrapers and transported by truck to the separation process equipment. The equipment is theoretically capable of removing the tar sand at a rate of 1500 tonnes per hour, although actual production rate is 1000 tonnes per hour. The bitumen 20 content of the tar sand is 14 percent by weight.
Separation is accomplished by using a number of units, each with a capacity of 200 tonnes per hour. The tar sand is fed by screw conveyor into a 15750 liter ~5000 gallon) mixing tank. An aqueous ~luid comprising water and 10 25 percent by volume dodecylamine is formulated in a 3150 liter ~1000 gallon) tank and fed into the 15750 liter (5000 gallon) tank at a rate of 3150 liters (1000 gallons) per hour. The water-amine is heated to a temperature of 96C (205F3 by passinq through a gas ~ired heater prlor to being added to 30 the 15750 liter (5000 gallon) tank.
Two separation tanks are provided for each mixing tank, so the mixing tank output is passed first to one separation tank and then to the other. Each separation tank has a volume of 9450 liters (3000 gallons). A screw conveyor 35 removes sand from the bottom of tne separation tanX. Bituminous petroleum accumulates in a layer immediately above the sand layer, and an aqueous layer having a small amount of bitumen dispersed therein accumulates on top. Diesel oil is added to ~2~
~ 22 -the separation tank and mixed. Bitumen from the layerimmediately above the sand as well as that dispersed in the aqueous phase, dissolves in the diesel oil. After mixing is stopped, a layer of diesel oil and bitumen forms on top, which is decanted and sent to the refinery.
The hot aqueous amine-containing fluid is passed through a sand pack filter and then back to the treating fluid make up tank for recycling through the unit.
Sand from the setting tank is placed in excavations lo formed in earlier stagès of strip mining operations.
The separation technique effectively removes approximately 90 percent of the bitumen from the tar sand.

Claims (19)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A method for recovering bitumen from tar sand material by contacting the tar sand material with a heated aqueous fluid characterized in that said heated aqueous fluid contains an amine having the formula:

wherein R 1 and R2, which may be the same or different, are each hydrogen or C1 to C6 alkyl, and R3 is C3 to C20 alkyl or a group of the formula -R4NH2 wherein R4 is C2 to C18 alkylene, the total number of carbon atoms in R1, R2 and R3 being from 3 to 20.

2. A method according to Claim 1 characterized in that R1 and R2 are C2 to C4 alkyl.

3. A method according to Claim 1 or 2 characterized in that R3 is C4 to C12 alkyl, or R4NH2 wherein R4 is C3 to C11 alkylene.

4. A method according to Claim 1 or 2 characterized in that the amine is diethylaminopropylamine or a C10 to C13 alkyl primary amine.

5. A method according to Claim 1 characterized in that said bitumen is recovered from a subterranean, permeable formation penetrated by at least one well by introducing steam containing said amine into said well as said heated aqueous fluid to contact bitumen, thereby increasing the mobility thereof and reducing the attraction between the bitumen and the formation mineral surface.

6. A method according to Claim 5 characterized in that the formation is penetrated by at least one injection well and by at least one production well, and the steam and amine are injected into the formation by means of the injection well to mobilize and displace bitumen through the formation to the production well from which it is recovered.

7. A method according to Claim 5 or 6 characterized in that the amine is introduced into the formation in one or more slugs followed by injection of substantially pure steam into the formation.

8. A method according to Claim 5 or 6 characterized in that the amine is comingled with steam, with the concentration of amine being from 0.5 to 25 percent by weight.

9. A method according to Claim 5 or 6 characterized in that the total amount of amine introduced into the formation is from 0.1 to 30 percent of the pore volume of the formation.

10. A method according to Claim 1 characterized in that bitumen from a subterranean, tar sand deposit, penetrated by at least one well, comprising:
(a) introducing a mixture of hot water or steam and the amine as said aqueous fluid, into the formation via the well in the form of a high velocity jet which rotates within the formation, said jet contacting the formation with sufficient energy to dislodge bitumen and unconsolidated minerals; and (b) recovering a fluid pulp comprised of bitumen, unconsolidated minerals, and aqueous fluid from the formation.

11. A method according to Claim 10 characterized in that a noncondensible gas is introduced into the formation simultan-eously with the aqueous fluid.

12. A method according to Claim 10 or 11 characterized in that the high velocity jet of aqueous fluid is moved in vertical direction within the formation.

13. A method according to Claim 10 characterized in that the aqueous fluid is heated to a temperature of greater than 65°C before being introduced into the formation.

14. A method according to Claim 13 characterized in that the temperature is below the boiling point of the fluid at the pressure within the cavity in the formation.

15. A method according to Claim 10, 11 or 13 characterized in that the temperature of the fluid being introduced is adjusted to yield a produced pulp temperature of from 70 to 95°C.

16. A method according to Claim 1 characterized in that the tar sand material has been recovered from subterranean deposits by mining.

17. A method according to Claim 16 characterized in that the temperature of the aqueous fluid is from 37 to 99°C.

18. A method according to Claim 16 or 17 characterized in that the concentration of amine is from 0.5 to 25.0 percent by weight.

19. A method according to Claim 16 or 17 character-ized by the additional step of contacting the hot aqueous fluid with a hydrocarbon fluid to promote separation of residual bitumen from the aqueous fluid.