Process and system for above ground extraction of crude oil

Abstract

Processes and systems for the above ground extraction of crude oil from a mud-water slurry well bore mined from oil rich diatomite formations. The slurry is separated into liquid and solid factions, the liquid faction having oil, water and small sized solids, and the solid faction having larger chunks of solids. The solids faction is processed to form a slurry mixture which is cooked to disassociate oil therefrom and is centrifuged to yield an oil/solvent faction, a water faction, and a lowered oil content solids faction. The oil/solvent faction is further processed to separate the oil and solvent. Alternately, the mud-water slurry is treated to form an emulsion having a neutral pH, with solids being removed and the remaining emulsion processed to break the emulsion by removal of water as a vapor to recovery crude oil, with remaining crude oil in the solids being further processed.

Claims

1. A process for extracting crude oil above ground from a solid, oil bearing material, comprising the following steps: (a) obtaining a solid, oil-laden material and adding water to the solid, oil-laden material to form a water and oil-laden material slurry; (b) processing the water and oil-laden material slurry above ground by passing it over a shaker screen to separate the oil-laden material into a liquid faction and a shaker separated solid faction, the liquid faction having oil, water and some small sized solids, and the shaker separated solid faction having larger sized chunks of solids; (c) collecting the shaker separated solid faction and processing any overly large sized solid chunks therein into smaller sized chunks of solids; (d) passing the liquid faction thorough a centrifuge to collect a centrifuged oil faction, a water faction, which water faction is available for reuse in the process, and a centrifuged solids faction; (e) taking the centrifuged solids faction and the shaker separated solid faction and further processing same in a solids processing plant; (f) in the solids processing plant processing the shaker separated solid fraction by dry grinding, and/or augering, and/or wet grinding with water and a solvent to form ground solids; (g) in the solids processing plant directing the centrifuged solids faction and the ground solids into a slurry tank/heated reactor, and adding water and a solvent to form a slurry mixture, and heating the slurry mixture for a time period to further disassociate oil from the solids' faction in the slurry mixture; (h) taking the heated slurry mixture from the slurry tank/heated reactor and passing it though a centrifuge to yield an oil/solvent faction, a water faction, and a lowered oil content solids faction; and (i) taking the lowered oil content solids faction and subjecting same to thermal desorption and collecting solvent and water therefrom to yield thermally desorbed solids.

2. The process for extracting crude oil above ground from a solid, oil bearing material of claim 1, wherein step (a) of obtaining a solid, oil-laden material and adding water to it to form a water and oil-laden material slurry is carried out by well bore mining.

3. The process for extracting crude oil above ground from a solid, oil bearing material of claim 1, wherein the solid, oil bearing material comprises oil bearing diatomaceous earth.

4. The process for extracting crude oil above ground from a solid, oil bearing material of claim 1, wherein step (c) of processing any overly large sized solid chunks into a smaller sized chunks of solids is accomplished using a hammer mill to reduce the solids into solid chunks sized between about 0.125 and 2, after which the smaller sized solid chunks are passed over the shaker screen in step (b).

5. The process for extracting crude oil above ground from a solid, oil bearing material of claim 1, wherein in steps (f) and (g) at least one solvent is used selected from the group consisting of light naphtha, naphtha, heavy naphtha, aromatics consisting of benzene, trichlorobenzene, 1,2,3 trichlorobenzene, and cumene, biodiesel methyl ester, alcohols consisting of methanol, butanol, ethanol, and isopropanol, wide cut aromatics, toluene, and turpentine or di limonene compounds.

6. The process for extracting crude oil above ground from a solid, oil bearing material of claim 1, wherein in step (g) the slurry mixture is heated at about 120 F. to about 200 F. for about 1 hour to 4 hours.

7. The process for extracting crude oil above ground from a solid, oil bearing material of claim 1, wherein in step (f) the centrifuge comprises a three phase decanter centrifuge.

8. The process for extracting crude oil above ground from a solid, oil bearing material of claim 1, wherein in step (h) the solvent collected from thermal desorption of the solid will be reused in the process.

9. The process for extracting crude oil above ground from a solid, oil bearing material of claim 1, wherein in step (i) the thermally desorbed solids can be used for backfill at a site from which the solid, oil bearing material was removed.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIGS. 1A-1C are diagrammatic flow charts showing the various steps and equipment used in an exemplary embodiment of the invention using solvents in the oil extraction.

(2) FIG. 2. is a diagrammatic flow chart showing the various steps of an embodiment of the invention using solvent in the oil extraction.

(3) FIG. 3 is a diagrammatic flow chart showing the various steps of an embodiment of the invention using emulsification in the oil extraction.

DETAILED DESCRIPTION

(4) The inventors have invented environmentally benign processes and systems for the above ground recovering of crude oils from a deposit initially located in subterranean formation. The processes involve the recovery of crude from oil rich materials, such as diatomite formations that bear high percentages of oil. These diatomite formations are sometimes above ground and therefore such formations can be easily mined with known methods. More commonly, however, they are found below ground. When mined above ground, the diatomite can be ground up and mixed with water to form muds that are subsequently processed using the process of the invention. Likewise, underground formations can be readily mined, for example, by using water jet technology. Water jets can cut into formations as large as 30 in diameter and typically at depths from 100 to 2000 below the surface. The resulting diatomite mud is pumped to the surface for oil extraction. Typically, the maximum size of mud rock is 3 inches to still enable it to be pumped to the surface. Pressure and abrasion reduce particle size. Further sieving, crushing or blending may be necessary to achieve uniform muds. In addition to oil rich diatomite formations, there are other oil rich formations that can be accessed for their oil, including shale, sandstone, and limestone formations.

(5) The Applicant has found that using the processes and systems of the invention, the recovery of oil from oil bearing material can be advantageously carried out above ground to thereby avoid introducing any deleterious chemicals back into the earth.

(6) Turning first to a solvent based process, the basic steps for crude recovery after the solid matrix is brought to surface as a mud is as follows, and is described with reference to FIGS. 1A, 1B, and 1C.

(7) Turning first to FIG. 1A, the well bore mining (WBM) operation 10 produces oil-laden solids in a water slurry, with the water slurry containing some free crude oil. The water content of the mud will generally be in a range of about 1:1 to 4:1 water: solids, and as adjusted as required. The mud is blended at the surface to generate a smooth and uniform slurry. The viscosity of this mud is a function of how much water is used to cut into the formation and how much fresh water is used versus recycled water. By recycling some of the muds, the total water content can be precisely controlled. The higher the recycle the higher the solids content of the mud. The ratio of water to solids is important in extracting crude. If there is too little water the solids cannot be distributed in solution and there is not enough solvent (water as solvent) to start to extract crude. If there is too much water the solution becomes unnecessarily dilute and the volume of water needing to be process becomes unnecessarily high. The ratio of 1:1 water:solids is the minimum, and 4:1 water:solids is the maximum. After about 4:1 water:solids, too much water is being handled.

(8) Next, the oil-laden material is separated by a shaker 12 equipped with ideally at least two shaker screens. This divides the materials into a liquid faction 14 and a solid faction 16. The liquid faction 14 is the faction that passes through a lower shaker screen with a smaller mesh size. The liquid faction 14 will contain water and free crude oil plus any solids that pass through the smaller openings in the screen with the smaller mesh size of the shaker unit. In one embodiment of the invention, the screen with the smaller mesh size of the shaker unit has openings about 3 mm (0.125) in size which allow passage therethrough of particles having a diameter smaller than 3 mm (0.125). The solid faction 16 will consist of solid particles between about 3 mm to 51 mm (0.125 to 2) in size. Particles larger than 51 cm (2) will be separated out, e.g., by being captured above an upper shaker screen with 51 cm (2) openings which upper screen is located above the shaker screen with the smaller mesh size. Those particles sized between 3 mm (0.125) and 51 mm (2) will pass through the upper shaker screen but not through the lower screen with a smaller mesh size and will be further processed in a solids process plant 24, which is further described in FIG. 1B. Particles that are above 51 mm (2) in diameter will not pass through the upper screen and will be diverted to a crusher or hammer mill 13 where the particles will be reduced in size below 2, and then passed through the shaker unit 12 again for separation as described above, ideally with all particles passing through the upper screen and some particles also passing through the lower screen. Once the liquid faction is obtained, it is subjected to centrifugation 18, e.g., preferentially by a 3-phase plant to separate the liquid faction into and oil faction, water, and solids. Optionally, the liquid faction can be subjected to centrifugation by a 2-phase plant (not shown) to separate the liquid faction into liquids and solids, with the liquids being further processed later. In the case of processing by a 3-phase plant, there will be three outputs from the centrifuge 18, namely oil, which can be collection in a crude oil production tank 20, water which can be collected and reused for well bore mining (WBM) 22, and solids that will be processed in a solids process plant 24. The solids will in most cases still retain some oil and will be directed to a solids processing plant 24. The solids 26 from the solid faction coming off of the shaker 12. (e.g., solid particles sized between about 3 mm to 51 mm (0.125 to 2) in size) will likewise be collected for further processing at the solids processing plant 24.

(9) The solids processing plant 24 is now described, in reference to FIG. 1B. The solids processing plant 24 can be incorporated together with the first part of the system of FIG. 1A, or can be located at a different site and can be a completely different system. In the solids processing plant 24, solids from a centrifuge 28 are directed to a slurry tank/heated reactor 30, where one or more non-water solvents 32 and water 34 (if necessary) are added to the slurry tank/heated reactor 30. Hereinafter use of the term solvent refers to non-water solvents. The contents of the slurry tank/heated reactor 30 can preferably be heated to about 120 F. to about 200 F. for about 1 to 4 hours. If desired, a blanket of inert gas, such as nitrogen, can be introduced into the top of the slurry tank/heated reactor 30 for enhanced safety. In the process, the solvents can be one or more solvents selected from the group consisting of light naphtha, naphtha, heavy naphtha, aromatics including benzene, trichlorobenzene, 1,2,3 trichlorobenzene, cumene, biodiesel methyl ester, alcohols (methanol, butanol, ethanol, isopropanol), wide cut aromatics, toluene and turpentine or di limonene compounds. The solvents can be selected based on the nature of the oil captured in the formation, e.g., light oil versus heavy oil may require different solvents. Some preferred solvents include light naphtha and alcohols such as methanol and ethanol, with methanol being particularly useful since it is zeotropic and can be easily removed from water by distillation. Acetone is also an attractive optional solvent because it is zeotropic. The inventors have found that adding between about 0.5% to about 70% weight percent of methanol to the water will greatly aid in the oil extraction process of the invention as methanol will help mobilize the crude oil from the diatomaceous earth. Moreover, recover of the methanol can be easily and reliably accomplished during the phase of driving the water off, including by distillation.

(10) Solids from a shaker 40 are further processed with larger particles being subjected to dry grinding 42 and augering 44, and with solvents 46 and water 48 added to form a wet grind 50. The thusly processed shaker solids are directed to the slurry tank/heated reactor 30. The contents of the slurry tank/heated reactor 30 are preferably subjected to 3 phase decanter centrifugation 60, with the outputs being an oil/solvent mixture 62, water 64, and solids having a lower oil content with some residual solvent 66. The oil/solvent 62 can be further processed to remove the solvent from the oil, e.g., but filtration and/or thermal desorption, with the now pure oil be collected, and the solvent be made available for reuse. The water 64 will be likewise made available for reuse in well bore mining or otherwise. As for the solids having a lower oil content with some residual solvent 66, these solids will be tested to determine their oil contents and solvent content. If the oil content and residual solvent content are sufficiently low and pass all regulatory requirement without further processing, the solids may be used, e.g., to be reintroduced into the well bore mining site to reclaim the mining site to its previously unmined condition, or an even better condition.

(11) Turning lastly to FIG. 1C, this shows processing of the solids produced by the solids processing plant with the solids having a lower oil content with some residual solvent 66. Thermal desorption equipment 68 can be used to remove solvent and water from the low oil content solid faction, which solvent and water can be reused in the system, forming a virtually solvent-free low oil content solid which can be used for backfill purposes. The solids are subjected to thermal desorption, preferably at about (e.g., at about 250 F. to 450 F. (about 121 C. to 232 C.) to as high as about 950 F. to 1100 F. (about 510 C. to 595 C.). This drives off solvent+water (possibly with some small traces of oil) 70 and solids with some residual water 72. The solvent plus water 70 is processed to collect the solvent which will be recycled for reuse. In the process of the invention, some preferred solvents include light naphtha and alcohols such as methanol and ethanol, with methanol being particularly useful since it is zeotropic and can be easily removed from water by distillation. The now clean solids, free of any solvents or brought down to a very low level of solvent, can be used, for example by being reintroduced into the well bore mining site to reclaim the mining site to its previously unmined condition or even better.

(12) In another embodiment the present invention is an above ground process for extracting crude oil from diatomaceous/clay soil 100 comprising the following steps, and is described with reference to FIG. 2: (a) Obtaining diatomaceous/clay soils 110, or other materials high in oil and adding water to form an oil laden solids/water slurry, for example by well bore mining using high pressure water; (b) Separating the oil laden water slurry by a shaker into a liquid faction (having oil, water, and solids) and a solid faction having mostly oil laden solids 112; (c) Processing the liquid faction by centrifugation to separate it into oil, water, and solid factions 114, wherein the oil faction will be collected, for example in a tank 116, the water will be collected and made available for reuse, and the solids will be collected for further processing to remove any remaining oil; (d) Processing the solid factions from the centrifuge by adding additional solvent and water is necessary to form a slurry 118, which slurry will be stored in a slurry tank 120; (e) Processing the solids from the shaker by dry grinding the solids and adding water and solvents 122 and moving the newly formed slurry to the slurry tank 120; (f) Subjecting the slurry from the slurry tank to three phase decanter centrifugation to separate the slurry into an oil/solvent faction, a water faction, and a solid faction with a low level of solvent/oil content 124; (g) Subjecting the oil/solvent faction to distillation or filtration to remove the solvent from the oil for reuse, and test the solids for oil content and if oil content is still high, reintroduce the solids to the slurry tank 126 in step (f) for further processing. Once the processed solids have a low enough oil content with residual solvent, in step (h) the solids will be further processed by thermal desorption 128 (e.g., at about 250 F. to 450 F. (about 121 C. to 232 C.) to as high as about 950 F. to 1100 F. (about 510 C. to 595 C.) to separate out solvent+water and solids+water 130. The solvent will be extracted from the water so that the water and solvent can be reused, and the now clean solids+water can be used for WBM backfill 132, optionally with additives such as solidifying agents such as Pozzlin (a silica cement additive) or other cementitious binders.

(13) The process of the invention allows a good recovery yield of the oils to be obtained, i.e., an oil recovery yield higher than or equal to 90%, such yield being calculated with respect to the total quantity of the oils present in the solid matrix by weight. The process of the invention allows this good recovery yield to he obtained all while operating with a lower energy requirement than prior art systems. Furthermore, the process of the invention results in a final solid residue to be obtained, i.e., a crude deficient solid matrix, with characteristics that allow it to he replaced in situ without the necessity for further treatments. If a petroleum solvent is added during the processing in a sufficiently large enough quantity, it may be necessary to recover the solvent from the solids before placing the solids back in the ground. This solvent recovery can he for economic reason (e.g., to allow collection and reuse of the solvent), for regulatory reasons, and/or for safety reasons.

(14) The process and system of the invention achieves high rates of crude oil removal using relatively less water, less energy, and more environmentally benignly than using prior art methods. Moreover, the resulting solids will have relatively low levels of remaining petroleum products or added chemicals, and can be reused (e.g., when mixed with Portland cement or Pozzlin, a cementitious binder) to refill the extraction site to restore the site to lessen the chance for ground subsiding from occurring.

(15) The above solvent-based system and process relies on the use of solvents to help extract the oil for the solids and liquid factions. Applicant has also found that the recovery of crude oils from a diatomaceous formation be also be carried out by creating an oil-in-water emulsion, wherein the formations of the oil in water emulsion is a key aspect of the method by which the extraction of the crude from the solids is accomplished. The emulsion process extracts the crude from the solids as the crude preferentially enters the water phase. This emulsion can be formed by utilizing the clays contained in the solids as dispersion agents and adjusting the pH accordingly to form the emulsion, or by adding surfactants as needed to form the emulsion. While forming the emulsion, additional detergents can be added or small amounts of solvents to aid in the crude extraction process.

(16) Process and System of Oil Recover using Emulsion Formation. There are several ways in which emulsions of these types are formed. Emulsions can be formed that are stabilized by dispersed solid particles and in our case, with clay as the stabilizing dispersed solid particle.

(17) Emulsions stabilized by solid particles are known as Pickering emulsions. A Pickering emulsion is an emulsion that is stabilized by solid particles (for example colloidal silica) which adsorb onto the interface between the two phases. This type of emulsion was named after S.U. Pickering, who described the phenomenon in 1907, although the effect was first recognized by Walter Ramsden in 1903.

(18) If oil and water are mixed and small oil droplets are formed and dispersed throughout the water, eventually the droplets will coalesce to decrease the amount of energy in the system. However, if solid particles are added to the mixture, they will bind to the surface of the interface and prevent the droplets from coalescing, thus causing the emulsion to be more stable.

(19) Properties such as hydrophobicity, shape, and size of the particle can have an effect on the stability of the emulsion. The particle's contact angle to the surface of the droplet is a characteristic of the hydrophobicity. If the contact angle of the particle to the interface is low, the particle will be mostly wetted by the droplet and therefore will not be likely to prevent coalescence of the droplets. Particles that are partially hydrophobic (i.e., contact angle of approximately 90) are better stabilizers because they are partially wettable by both liquids and therefore bind better to the surface of the droplets.

(20) When the contact angle is approximately 90, the energy required to stabilize the system is at its minimum. Generally, the phase that preferentially wets the particle will be the continuous phase in the emulsion system.

(21) Additionally, it has been demonstrated that the stability of the Pickering emulsions can be improved by the use of amphiphilic Janus particles, due to the higher adsorption energy of the particles at the liquid-liquid interface. In the case of the instant invention, surfactants such as amines, amphoteric or other can optionally be added to improve the interface.

(22) Other adjustments will be made to change the clay's behavior. Clays can be water loving or oil loving. In oil sands froth treatment, an undesirable intermediate layer often accumulates during the separation of water-oil emulsions. The layer referred to as rag layer is a complex mixture of water, oil, solids and interfacially active components. The presence of a rag layer has a detrimental impact on the separation of water and fine solids from diluted bitumen. In the Applicant's system, Applicant has noted a tendency toward oil loving, which is noted by layer below crude floating on the surface of the water as the emulsion is broken. Some of this behavior is caused by components in the crude, mainly naphthenic acids. These acids can make the clay more oil loving. The clay's charge on the surface is most likely positive, which is attracted to the negative charge of carboxylate (naphthenate). This can be changed by adjusting the pH, adding a particular solvent that is non polar in small amounts or by adding certain surfactants. All of these additions can adjust the clay's behavior and the emulsion stability and the emulsions ability to extract crude from the soil particle.

(23) As noted, the process involves the recovery of crude from starting oil bearing material such as a diatomite formation. These diatomite formations can be above ground and therefore easily mined with known methods, or more commonly are found underground as is described above to form muds that are subsequently processed using the processes of the invention.

(24) The basic steps for crude recovery using emulsion formation after the solid matrix is brought to surface as a mud is as follows: 1) Adjust the water content of the mud as required (1:1 to 4:1 water: solids). The mud is blended at the surface to generate a smooth and uniform slurry. The viscosity of this mud is a function of how much water is used to cut into the rock and how much fresh water is used versus recycled water. By recycling some of the muds, the total water content can be precisely controlled. The higher the recycle the higher the solids content of the mud. The ratio, water to solids is important to both forming the emulsion and extracting crude. Too little water, and an emulsion will not form, as solids cannot be distributes in solution. Too little water and then there is not enough solvent (water as solvent) to extract crude and provide the continuous phase for the crude to emulsify into. The ratio of 1:1 is the minimum, and 4:1 is the maximum. After 4:1, too much water is being handled. 2) Either use the clays present in the solids as the dispersion agent or add additional surfactants and at same time and adjust the mixture to a pH of between about 12 and 14. Sodium hydroxide, for example, can be effectively used to change the pH. The above process procedure is also used with the addition of specific surfactants that act as detergents. In this case, the pH is adjusted to between 2 and 5, or 7 to 9. The detergent aids in removing the crude oil from the diatomaceous/clay soils, while the surfactant will be a nonylphenol with 5 or 6 moles of ethylene oxide. The goal is to emulsify only crude in water, allowing all solids to fall out of solution. Additional surfactants if needed are determined during the laboratory phase prior to the project starting. While forming the emulsion, additional detergents or small amounts of solvents can be added to aid in the crude extraction process. These too will be determined during laboratory phase prior to project start. Additives range from 0.5% to 2.0% by weight of the water phase. The detergents can be a surfactant or a particular solvent. Good optional solvents include ethanol and particularly methanol (which is zeotrophic, meaning that the water and methanol can be efficiently separated from each other by distillation). The optional solvent can be added until the solvent comprises about 0.5% to about 70% weight percent of the liquid. (3) If no optional solvent is added, heat the mixture while mixing to a minimum of 73 C. but below about 95 C. to avoid boiling. If an optional solvent has been added, heat the mixture while mixing to an elevated temperature that is below the boiling temperature of the optional solvent. For example, methanol has a boiling point=64.7 C.) and ethanol has a boiling point 78.24 C., so if methanol is the added solvent, heat the mixture to below about 60 C. and if ethanol is added heat the mixture to below about 73 C. (4) Subject the heated mixture to high shear blending which will reduce the size of the solids and simultaneously form the emulsion. The high shear mill blending will reduce the diatomaceous silica size to less than 5 mm. During this stage, extraction of crude is accomplished by the effects of the pH, temperature and energy from shearing. The emulsion is then formed from the conditions of the shear, pH temperature and clay content and clay type. (5) Recirculate the mixture through the high shear mill for approximately 30 minutes to extract the crude oil from the solid material and to enter the water phase. At this point, the mixture should be two phases, stable oil in water emulsion and solids substantially free of crude oil. (6) Separate the solids from the stable oil in water emulsion. These solids will gravity separate or more efficiently, can be removed by subjecting the two phases to centrifugation (such as a decanter), or gravity settling. A decanter centrifuge is a centrifuge with the bowl and scroll in a horizontal configuration as opposed to a vertical disk stack. The machine is specifically designed to separate liquids and solids in industrial settings at high volumes. (7) Recover the crude oil. The emulsion, now minus the solids, is subjected to thermal desorption or an emulsion breaker (chemical to destabilize the emulsion) to remove most of the water (which is recovered for reuse) and break the emulsion, thereby yielding the crude oil which is collected. Thermal desorption involves feeding the crude water mixture into a heated barrel and screw, sometimes under vacuum. The screw moves one phase along, the phase that does not turn to vapor, the vapor phase is removed at the top end of the barrel and cooled back to a liquid in a condenser. The solids removed can be treated as per above several additional times to achieve the crude oil recovery desired. Yield can be determined in the field by use of a field Retort test, a small distillation unit that can extract liquids from solids, or in a proper lab using a Soxhlet Extraction method, which is a repeated solvent wash extraction of liquids from solids. If an optional solvent was added, utilize distillation to separate the solvent from the water so that the solvent can be reused in the process.

(25) In the above process, the optional solvent (if used) can be selected form chemicals including light naphtha, naphtha, heavy naphtha, aromatics including benzene, trichlorobenzene, 1,2,3 trichlorobenzene, cumene, biodiesel methyl ester, alcohols (methanol (boiling point=64.7 C., 148.5 F.), butanol, ethanol (boiling point 78.24 C., 172.83 F.) isopropanol), wide cut aromatics, toluene and turpentine or di limonene compounds. Some preferred solvents include light naphtha and alcohols such as methanol and ethanol, with methanol being particularly useful since it is zeotropic and can be easily removed from water by distillation. Acetone is also an attractive optional solvent because it is zeotropic. The inventors have found that adding between about 0.5% to about 70% weight percent of methanol to the water phase will greatly aid in the oil extraction process of the invention as methanol will help mobilize the crude oil from the diatomaceous earth. Moreover, recover of the methanol can be easily and reliably accomplished during the phase of driving the water off, including by distillation.

(26) The process of the invention allows a good recovery yield of the oils to be obtained, i.e., an oil recovery yield higher than or equal to 90%, such yield being calculated with respect to the total quantity of the oils present in the solid matrix by weight. The process of the invention allows this good recovery yield to be obtained all while operating with a lower energy requirement than prior art systems. Furthermore, the process of the invention results in a final solid residue to be obtained, i.e., a crude deficient solid matrix, with characteristics that allow it to be replaced in situ without the necessity for further treatments. If a petroleum solvent is added during the processing in a sufficiently large enough quantity, it may be necessary to recover the solvent from the solids before placing the solids back in the ground. This solvent recovery can be for economic reason (e.g., to allow collection and reuse of the solvent), for regulatory reasons, and/or for safety reasons.

(27) The emulsion formation process of the invention achieves high rates of crude oil removal using relatively less water, less energy, and more environmentally benignly than using prior art methods. Moreover, the resulting solids will have relatively low levels of remaining petroleum products or added chemicals, and can be reused (e.g., when mixed with Portland cement) to refill the extraction site to restore the site to lessen the chance for ground subsiding from occurring.

(28) Turning to FIG. 3 there is shown a diagrammatic flow chart showing the various steps of an emulsion formation process for above ground oil recovery embodiment of the invention 200. In a first step (210 in the figure), first obtain diatomaceous/clay soils solids and add water to form a mud. Next, adjust the water content of the mud to a desired ratio of water and solids to form solid/water mixture (212). Then, use clays in diatomaceous/clay soil solids as a dispersion agent or add surfactants & adjust mixture to pH of 12 to 14 (214). This step can also be modified with the addition of specific surfactants that act as detergents. In this case, the pH is adjusted to between 2 and 5, or 7 to 9. The detergent aids in removing the crude oil from the diatomaceous/clay soils, while the surfactant will be a nonylphenol with 5 or 6 moles of ethylene oxide. The goal is to emulsify only crude in water, allowing all solids to fall out of solution. If an optional solvent will be added, add it at this step (216). After that, heat the mixture while mixing to 73 C. to 95 C. (temperatures at atmospheric pressure), or less if a lower boiling point optional solvent was added (218). Keeping the temperature below 95 C. will help prevent boiling with water only, and for example, under 60 C. if methanol was added. Next, subject the heated mixture to high shear blending to reduce the size of the solids and simultaneously form the emulsion (220). After that, recirculate the mixture through the high shear mill to extract the crude oil from the solid material and to enter the water phase, at which point, the mixture will be in two phases, namely a stable oil in water emulsion phases, and a solid phase substantially free of crude oil (222). Then, separate the solids from the stable oil in water emulsion (224). Following this, recover the crude oil from the stable oil in water emulsion (226). Lastly, if an optional solvent was used, remove and separate the solvent from the water for reuse, such as by distillation (228).

EXAMPLE

(29) In a 1,000 ml beaker, add 500 ml of oil field process water (oil field process water is the recovered water from operations, and new incoming water is also used). Add 5 grams of sodium hydroxide flakes and dissolve to raise the pH to the range of about 12 to 14 pH. Optionally add a solvent such as methanol at about 0.5% to about 70% weight percent of the water. Heat this mixture to about 73 C. and maintain at this temperature. Add 200 grams of passing 5 mesh diatomaceous/clay soil containing 18.2% crude by weight (determined by solvent extraction) to the hot mixture. High shear (Silverson L4R mixer) this mixture to both reduce particle size of soil while extracting crude from soil during shearing. During this extraction phase, the crude oil emulsion is formed using clay as the dispersed stabilizing agent. The mixture will turn very black as crude is extracted and emulsified. After about 30 minutes of shear time, turn off mixer, allow solids to fall to bottom of beaker. The liquid phase is separated in a separate beaker. The emulsion pH is adjusted to neutral (pH 7) and placed in an oven at 65 C. to evaporate the water and the optional methanol, leaving the crude behind. The crude recovery was determined to be 91% of the 18.2% crude available in the diatomaceous/clay soil.

(30) The preferred embodiments of this invention have been disclosed, however, so that one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention.