WO2009049358A1

WO2009049358A1 - Apparatus and process for extracting oil and gas from oil shale and tar sand deposits

Info

Publication number: WO2009049358A1
Application number: PCT/AU2008/001518
Authority: WO
Inventors: Rodolfo Antonio M. Gomez
Original assignee: Gomez Rodolfo Antonio M
Priority date: 2007-10-15
Filing date: 2008-10-15
Publication date: 2009-04-23
Also published as: AU2008314493A1

Abstract

A process and apparatus are described for extracting oil and gas from deep oil shale and tar sand deposits using pulsed electric energy in situ between electrodes placed in wells to preferentially affect kerogen bonds within the oil shale. In a preferred embodiment recycled gases or solvents are used to assist in recovering oil from the oil shale or tar sand wells. In another preferred embodiment oil shale or tar sands are mined, comminuted and exposed to electromagnetic energy in a surface installation for recovery of oil and gas.

Description

APPARATUS AND PROCESS FOR EXTRACTING OIL AND GAS FROM OIL SHALE AND

TAR SAND DEPOSITS

FIELD OF INVENTION This invention relates to a process and apparatus for processing of oil shale for the extraction of oil and gas and also applies to the extraction of bitumen from tar sands in situ.

PRIOR ART

The hydrocarbons in oil shale are still in the form of kerogens that require heat and pressure to convert to oil. In general, the main process used to extract oil from oil shale is retorting to a temperature of at least

450 C. High temperatures tend to produce more gas and carbon instead of crude oil. The richness of an oil shale is measured in its content of oil expressed in litres per tonne as determined by the Fischer assay method where the oil shale is retorted at 450 C and the oil produced is measured.

Tar sands are hydrocarbon deposits where bitumen coats the surface of sands such as those of Alberta, Canada. These deposits may be close to the surface and can be mined economically by open pit methods.

Where the tar sands are deep, generally solution mining is preferred such as practiced in the extraction of

Orinoco crude oil in Venezuela.

Processing Of Deep Oil Shale Deposits And Tar Sands There is no known commercial process for extracting oil and gas from deep oil shale deposits, however, development of such a process has been given impetus by the high crude oil prices and the huge oil shale deposits under the states of Colorado, Utah and Wyoming in the United States for instance. The most well-known process is being developed by the Shell Oil Company which consists of freezing an enclosed wall section of the oil shale and then applying heat. It is claimed that it will take several years before oil will start to flow and can be pumped to the surface.

Considine et al (assigned to Raytheon) is proposing the use of electromagnetic energy to extract oil shale from deep deposits. Their process and apparatus is described in International Patent Application WO 2007/078350. The apparatus consists of a central borehole where electromagnetic energy and a critical fluid consisting of carbon dioxide, nitrogen oxide and oxygen with catalysts are injected. The oil shale is initially heated to about 200 to 250 C and it is claimed that contents of the critical fluid react with the kerogen to raise the temperature to about 450 C thereby converting the kerogens to oil and gas. Pressure of 3,500 - 35,000 Kpa (500 to 5,000 psi) is maintained either at a constant rate or pulsed. Oil, gas and the critical fluid are recovered in auxiliary wells spaced from the central borehole and processed to recover the oil and recycle the critical fluid. The main feature of Considine et al appears to be the use of RF energy initially to heat the oil shale and let the reaction of the critical fluid with the hydrocarbons to provide additional heat to reach the retorting temperature of 450 C in the oil shale to convert the kerogens to oil and gas.

Considine cites US Patent 4, 140, 179 of Raymond Kasevich et al (assigned to Raytheon) where a plurality of electrodes in a borehole was used to apply RF energy to the oil shale but this system did not function because as the formation was heated, the electrical conditions changed and the dipole antennae and elements had to be removed and changed. Considine further cites and adopted into his patent application, US Patent 4,508,169 issued on April 2, 1985 to Vernon L. Heeren and assigned to Raytheon of an RF applicator positioned down a borehole supplied with electromagnetic energy through a coaxial transmission line whose outer conductor terminates in a choking structure comprising an enlarged coaxial stub extending back along the outer conductor. Considine also cites Raymond Kasevich US Patent 5,065,819 issued on November 19, 1991 assigned to KAI Technologies discloses an electromagnetic apparatus for in situ heating of organic materials of sub-surface formations such as oil shale or tar sands consisting of an RF generator operating in either continuous or pulse mode, supplies electromagnetic energy over a coaxial transmission line to a downhole collinear array antennae. A coaxial liquid- dielectric impedance transformer located in the well head couples the antennae to the RF generator.

The main feature of Considine et al appears to be the use of RF energy initially to heat the oil shale and let the reaction of the critical fluid with the hydrocarbons to provide additional heat to reach the retorting temperature of 450 C in the oil shale to convert the kerogens to oil and gas.

I believe the application of RF electromagnetic energy by Considine and other inventors is inefficient because the large amount of energy dispersed by the RF antennae is dispatched to all regions instead of being concentrated in a particular region for the effective treatment of the oil shale. Finding the efficient frequency and the matching antennae characteristics is difficult as the oil shale dielectric changes with temperature and the extent of removal of kerogens.

I also believe the emission of large amounts of RF energy that is powerful enough to process oil shale would present undue radiation damage to humans and animals in the vicinity of the oil shale.

Processing Of OiI Shale On The Surface

Some oil shale deposits are located near the surface and can be mined by conventional open pit methods. The oil shale can then be processed usually by retorting methods in a variety of equipment in batch or continuous mode. The Suncorp method for tar sands processing was tried in Queensland, Australia, operating at a temperature of just over 700 C. The project was abandoned when smelly carbamates were formed and later on, it was discovered that dioxin was also produced in the process.

A promising continuous retorting process is the Paraho process which is a short vertical furnace. Heat is introduced at the bottom and the hot gases with the oil are collected near the top. Favourable results were produced with the supervision of the US Department of Energy. The Paraho process is being considered by one of the major Queensland oil shale developers.

The other surface process for treating oil shale is the wet process such as that proposed by the Rendall process. In this process, the fine oil shale is mixed with a solvent such as toluene and then heated to about 450 C. The toluene has previously been conditioned with hydrogen. It is generally known that some solvents such as telarin and methanol are good hydrogen carriers. In an article in the JAICHE, vol. 34, No. 4, p. 568-668, Treday J. and Smith J using supercritical toluene was shown to be effective for the extraction of kerogen oil and gas from shale. The oil formed and the solvent are then evaporated in a process step called the supercritical solvent extraction. The product gases are distilled to produce the oil and the solvent which is recycled to the toluene hydrogenation step. The Rendall process claims that sulphur is recovered as hydrogen sulphide and metals such as vanadium and molybdenum are also recovered from the residue but Rendall has not given details. It is proposed to apply the Rendall process to an oil shale property in Julia Creek in Queensland, Australia.

It is the object to this invention to provide an improved and safe method and apparatus for the extraction of crude oils from oil shale and tar sands or to at least provide an useful alternative.

DESCRIPTION OF THE INVENTION

In one form the invention comprises a process of extracting oil and gas from a mass of oil shale comprising; selecting a frequency of pulsed electric energy to apply to the mass of oil shale, which frequency preferentially affects kerogen bonds within the oil shale; applying pulsed electric energy at the selected frequency in a wet or dry process to the mass oil shale; and extracting oil and gas from the treated mass of oil shale.

In one preferred embodiment the mass of shale oil is treated in situ.

Preferably the pulsed electric energy comprises direct current or alternating current electric energy and is applied to the oil shale between sets of spaced apart electrodes.

Preferably applying the pulsed electrical energy at the selected frequency comprises applying direct current (DC) electric energy between spaced apart positive and negative electrodes. The pulsed DC electrical energy can be supplied with a square wave and at a voltage as necessary to achieve the desired result.

Preferably the spaced apart electrodes comprise a central electrode in a central well and a plurality of peripheral electrodes in a plurality of peripheral electrodes respectively positioned around the central electrode and the applying electric energy at the selected frequency comprises sequentially or selectively applying the electric energy between the central and peripheral electrodes.

The central and peripheral electrodes can be spaced apart by from 50 to 500 metres.

Preferably the central electrode and a plurality of peripheral electrodes each comprise a plurality of vertically spaced electrode segments and the applying of pulsed electric energy at the selected frequency comprises sequentially or selectively applying the electric energy between respective pairs of the spaced apart electrode segments.

Preferably the process including supplying reagents selected from one or more the group comprising hydrogen, carbon monoxide, and compressed air into the central well to aid in the extraction of the oil from the oil shale.

Preferably the oil and collected in the central well or the peripheral wells of the in situ mass of oil shale and is pumped to a surface processing plant where the oil is separated.

Preferably a hot gas mixture containing one or more of carbon dioxide, hydrogen and carbon monoxide is delivered at high pressure into the central well to provide reducing gases to the kerogens to produce more crude oil and to provide additional low cost heat for the process. A small amount of compressed air can be injected into the central well to react with the hot gases to provide additional low cost heat for the process.

Preferably the process further includes isolating the mass of oil shale by water interception wells or cement and chemical grouting around the periphery thereof.

Preferably the optimum frequency of the electric energy is determined by dielectric measurement of the oil shale and subsequently by experimentation on the maximum oil yield and maximum naphtha and diesel production. In a preferred embodiment the optimum frequency is in the low range of from 1 kilohertz to 10 megahertz to ensure good penetration of the pulsed electric energy waves into the oil shale. In an alternate process according to the invention the mass of shale oil is mined, comminuted to approximately minus 200 microns and mixed with a solvent before being preheated and fed into an electromagnetic reactor and treated as discussed above, therein producing a treated oil shale solvent slurry.

The solvent can be selected from the group comprising gasoline, naphtha, kerosene, diesel, toluene, or any light hydrocarbon fraction.

Preferably hydrogen gas is supplied to the electromagnetic reactor sufficient to meet the hydrogen deficiency of kerogen in the oil shale and to convert it to more crude oil, or to the more valuable light crude oil.

Preferably the electromagnetic energy is applied to the electromagnetic reactor to give a temperature of 275 to 400 C and the hydrogen is supplied at a pressure of 5,500 to 10,000 Kpa (800 to 1500 psi).

In an alternate process according to the invention the mass of shale oil is mined, comminuted and treated in a kiln selected from a vertical kiln or a inclined kiln.

Preferably the where the vertical kiln comprises a preheating zone, a reactor zone and a regenerative zone, respective valves to transfer a charge of the oil shale in the vertical kiln apparatus from the preheating zone to the reactor zone and from the reactor zone to the regenerative zone, and the mass of shale oil is fed into the preheating zone, is preheated by regenerative gases, and then transferred to the reactor zone to be heated to 250 to 400 C with electromagnetic energy and with hot gases produced therein being extracted to a solids separation and condensing system to recover oil and gas therefrom.

In an alternate form the invention comprises an apparatus using pulsed electric energy to extract oil and gas from oil shale in-situ, the apparatus comprising a first electrode assembly and a second electrode assembly, the second electrode assembly being spaced apart from the first electrode assembly thereby enclosing mass of oil shale there between, an electric generator to generate and apply pulsed electric energy between the first electrode assembly and the second electrode assembly at a selected frequency.

The first electrode assembly may be the segmented part of the conductor centre well and the second electrode assembly may be the segmented conductor part of the peripheral wells.

Preferably the first electrode assembly and the second electrode assembly each comprise electrodes extending substantially vertically and preferably each of the first electrode assembly and the second electrode assembly comprise a plurality of vertically spaced electrically independent electrode segments. In operation, switching between electrodes or electrode segments is carried out at as high as 50 kilohertz so that the whole mass of oil shale bounded by the electrodes is acted upon by the pulsed electric energy.

Preferably the electric generator includes a pulse generating device, a coupling, an impedance matching device, a switching device to activate the segments in the respective electrodes, and a switching device that allows the pulsed electric energy to be applied to the pairs of electrodes or their independent segments in a continuous circular pattern.

The apparatus can further include means to supply a hot gas containing carbon dioxide, hydrogen and carbon monoxide at high pressure into the mass of oil shale from the centre electrode well including a small amount of compressed air.

In an alternate form the invention comprises an apparatus using electromagnetic energy to extract oil and gas from oil shale comprising; a comminution apparatus to comminute oil shale, an agitator to mix crushed oil shale with a solvent mixture to produce a slurry, a pre-heater to heat the slurry, an electromagnetic energy application apparatus to apply electromagnetic energy at a selected frequency to provide a treated slurry, means to add hot water to the treated slurry and an extraction arrangement to separate the treated slurry into desired fractions.

Preferably the solvent is selected from one of or a mixture of gasoline, naphtha, kerosene, diesel, toluene or any light hydrocarbon fraction.

The apparatus can further include means to supply hydrogen gas to the electromagnetic reactor sufficient to meet the hydrogen deficiency of the kerogen to convert it to crude oil.

In an alternate form the invention comprises an apparatus using electromagnetic energy to extract oil and gas from oil shale comprising; a vertical kiln apparatus, the vertical kiln apparatus comprising a preheating zone, a reactor zone and a regenerative zone, respective valves to transfer charge in the vertical kiln apparatus from the preheating zone to the reactor zone and from the reactor zone to the regenerative zone, an electromagnetic energy application apparatus to supply electromagnetic energy at a selected frequency to the charge in the reactor zone, a hot gas extraction apparatus to extract hot gas from the reactor zone and a condenser and distillation arrangement to separate gas from the reactor zone into desired fractions.

Kerogen is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic solvents because of the huge molecular weight (upwards of 1,000 Daltons) of its component compounds. The soluble portion is known as bitumen. When heated to the right temperatures in the Earth's crust, some types of kerogen release crude oil or natural gas, collectively known as hydrocarbons. When such kerogens are present in high concentration in rocks such as shale, and have not been heated to a sufficient temperature to release their hydrocarbons, they may form oil shale deposits.

As kerogen is a mixture of organic material, rather than a specific chemical; it cannot be given a chemical formula. Indeed its chemical composition can vary distinctively from sample to sample. Kerogen from the Green River Formation oil shale deposit of western North America for instance contains elements in the proportions C 215 : H 330 : O 12 : N 5 : S 1.

The use of electromagnetic (EM) energy has important advantages over conventional heating. The first is that chemical reactions are achieved at a lower temperature because EM energy vibrates the molecules in addition to heating. The second is that EM energy tends to affect polar molecules rather than non-polar molecules. In oil shales, EM energy will target the polar molecules rather than the non-polar pure hydrocarbon molecules. Conventional heat will affect all molecules so that if high temperature is required to react the polar molecules, the non-polar hydrocarbon molecules are usually converted to gas and carbon.

It will be seen that by this invention there is provided a process of using pulsed electric energy and electromagnetic energy to extract oil and gas from oil shale in various situations including an in situ situation where a mass of oil shale is enclosed between a central antennae and several peripheral antennae subjecting the enclosed mass of oil shale to electromagnetic energy or at the surface where electromagnetic energy is used to extract oil and gas from oil shale.

DESCRIP TION OF THE DRAWINGS This then generally describes the invention but to assist with understanding reference will now be made to preferred embodiments with the assistance of the accompanying drawings.

In the drawings:

Figure 1 shows a first embodiment of an pulsed electric energy process for extracting oil and gas from deep oil sands and oil shale deposits;

Figure 2 shows a layout of wells and electrodes over an oil shale field with the extraction process of the embodiment of Figure 1;

Figure 3 shows an alternative embodiment of an electromagnetic process for extracting oil and gas from oil shale using an electromagnetic reactor; and Figure 4 shows an alternative embodiment of an electromagnetic process for extracting oil and gas from oil shale using a vertical kiln; DESCRIPTION OF PREFERRED EMBODIMENTS

A first embodiment of the invention relates to extracting oil and gas from deep oil shale deposits and is explained with reference to Figure 1.

The most well known deep oil shale deposits are the estimated 1.1 trillion tonnes of oil shale lying about 1,000 feet below the surface of Colorado, Utah, and Wyoming. The price of crude oil above US$100 per barrel has initiated great interest to recover the oil in this oil shale deposit. This invention proposes an pulsed electric energy process to extract oil in situ. The frequency of the pulsed electric (PE) energy is important to the success of the process. As the oil shale deposit is below the water table, it is important that most of the PE energy is applied to the oil shale and not to the water. The optimum frequency is first determined by measuring the dielectric constant of the oil shale and then actual testing be carried out because the optimum frequency changes as the oil shale progresses to complete treatment. The optimum frequency is that which preferentially affects kerogen bonds and less preferentially affects hydrogen oxygen bonds and non-polar bonds of materials within the oil shale.

It is preferable to apply a frequency in the low range, 1 kilohertz to 10 megahertz to ensure good penetration of the PE energy in the oil shale.

The PE generator of the present invention is capable of variable frequency production. First, the electrode of the central borehole is the positive electrode and another set of peripheral receiving negative electrodes are installed around the central borehole antenna at distances ranging from 50 to 500 metres. The outer electrode pattern is arranged to optimise extraction for a particular oil shale. Secondly, it is preferred that the central borehole electrode and the receiving electrodes are constructed in several independent vertically spaced segments that can be activated separately. This construction allows portions of the oil shale to be radiated with concentrated electric energy. The electrode segments may also be made of a range of different lengths to accommodate changes in the optimum frequency required as the oil shale is heated. Thirdly, it is preferred that the electronic controls are arranged so that the peripheral electrodes are activated one after another in a sequential circular pattern. This rotary switching can be done at high speed of up to 50 kilohertz. This arrangement allows the whole of the oil shale enclosed to be acted on by the electric energy rather than just the oil shale directly between the central antennae and the individual peripheral antennae. The circuit is also arranged so that any segment of the central electrode and the peripheral electrodes can be activated and activated in a circular sequential action.

Figure 1 shows a method of extracting oil from oil shale using PE energy and Figure 2 shows a layout of wells and electrodes over an oil shale field with the extraction process of the embodiment of Figure 1.

In Figure 1 an oil shale deposit 27 is overlain by overburden 28 and there may be a water table 29. The system according to one embodiment of the present invention consists of a central borehole or well 1 and a series of peripheral wells 3 located in a pattern away from the central borehole 1. The central borehole 1 is composed of non-conductor parts 8 and 9 and conductor segments 5a of a conductor 5 with a central pipe 4 to extract oil and gas entering the central borehole and another pipe 6 to receive a high pressure composite gas 7 of CO₂, CO, H₂. The central borehole 1 has a conductor casing segment 13 with openings 13a to allow the entry of oil, water and gas 12. The non-conductor 9 electrically isolates conductor segments 5a. The shielded cable 21 is made of several independent wires that connect to independent segments 5a of the conductor 5. The peripheral production wells 3 are constructed similarly of independent segments 11 that can be connected separately to the pulsed electric generator 2. This allows the electric energy to be concentrated in a selected portion of the oil shale such as the region marked 19. The peripheral production well 3 has a section 11 with openings 1 Ia to allow the oil, water, and gas 12 to be collected and pumped 14 to the surface where these streams 16 and 17 are dispatched to processing 26 to recover the crude oil, the gas and the water.

The surface installation include the PE generator 2 which includes pulsed, coupling, impedance matching and the switching circuitry for supplying the electric energy to the segments 13 in the central emitting electrode 5 and the segments 10a of the receiving electrode 10 via shielded cables 21.

A gasification plant 23 is fed with gas 20 and air or oxygen 22 and with the products 7 being carbon dioxide, carbon monoxide and hydrogen, pressurised by compressor 25 and then heated by heater 18 before being fed into the central borehole 1 through inlet pipe 6. A small amount of compressed air 24 is also introduced into the centre borehole 1 to react with the gases 7 and provide additional low cost heat for the process. The pressurised gas is preferably of a high enough pressure to keep water away from the operating region and displace the water from the oil shale.

Figure 2 shows a plan over the oil shale feed showing the centre borehole 1, the PE generator 2, the production wells 3 and the water interception wells 15.

Hence it will be seen that this embodiment consists of a central electrode well and peripheral production wells that collect the oil formed from the oil shale and several electrodes located around the central production electrode as shown on Figure 2. In operation, the PE energy is applied to at least a portion of the volume between the central electrode and the peripheral electrodes in a continuous circular alternating fashion. In addition the central electrode and the peripheral electrodes may be constructed of several electrically isolated portions and the PE energy can be applied to the separate parts sequentially or randomly. As the oil is formed, it percolates through the oil shale to the central collection well and mostly to the peripheral wells and enters the respective casings through the holes in the casing. If necessary, as shown in Figures 1 and 2, some water interception wells may be installed if water in the process becomes a problem. Further water isolation of the volume to be processed can be achieved by cement or chemical grouting in addition to the water interception wells. The advantage of this process is that there is no surface pollution and the energy consumption is low and there is hardly any water consumed.

A further embodiment of the invention comprises a wet electromagnetic method of oil shale processing and is depicted in Figure 3.

Figure 3 depicts a wet electromagnetic energy process for extracting oil and gas from the oil shale in a surface plant according to the present invention. Run of mine ore 31 from open pit or underground operations is delivered to a crusher 32 and the product is sized in screen 33 with the oversize feeding into a crusher 34 and the undersize joining the crushed ore to the intense agitator or rotating scrubber where solvent and heat are added. Alternatively for size reduction, the oil shale may be ground fine by an intense vortex grinder 35 followed by cyclone separators 36 and the fine oil shale delivered to the intense agitator or scrubber 37.

The slurry of oil shale and solvent is heated in pre-heater heat exchanger 39 and heated in heater 40 before being fed into the electromagnetic reactor 42. Hydrogen 41 is added while the oil shale slurry is stirred and electromagnetic energy applied. The slurry is discharged through the pre-heater heat exchanger 39 and then into mixer 43 where water 44 and reagents 45 are added. The water, solvent, oil and spent shale mixture is passed through a cooler 46 before it is discharged into a flash tank 47 to reduce the pressure. Gas and steam from the flash tank 47 is passed into a condenser 50 where water with chemicals 49 is separated. The dry gas is passed to a hydrogen sulphide converter where elemental sulphur 62 is produced and hydrogen gas 56 is recycled to the electromagnetic reactor.

Slurry from the flash tank 47 is passed to a hydrocyclone 48 where strong scrubbing action separates oil from the surface of the spent oil shale particles. The overflow and under flow of hydrocyclone 48 is discharged into the thickener 57 where oil is separated from the water and is fed to a heater 52 then into the distillation column 51 where the crude oil product 59 is recovered and the solvent is collected from the condenser 53 and then sent to solvent storage 38 for recycle and the gas 62 is sent to the hydrogen sulphide processing to recover sulphur and hydrogen gas for recycle. Water and spent oil shale residue from thickener 57 is fed into thickener 58 where the water is recovered for recycle to water storage 44.

The underflow is fed into filter 60 where water recovered is sent to storage 44 and the solid residue is sent to metal extraction 61.

Hence it will be seen in Figure 3 the processing of oil shale using electromagnetic energy. Run of mine oil shale is passed through one or two roll crushers or fine grinding through intense vortex grinder. An intense vortex grinder is shown in US Patent Application Serial Number: 10/482907 entitled "INTENSE VORTEX DRYER, COMMINUTOR AND REACTOR " and the teachings therein are incorporated in their entirety herein by reference. Preferably the grind fineness is about minus 80 microns but will depend on the type of oil shale. A solvent such as kerosene, naphtha, gasoline, and other light fractions is mixed with the oil shale at about 20 to 40 percent solids and then passed through the heat exchanger and heater before being fed into the electromagnetic reactor. EM energy is fed either at the bottom of the reactor or at the top through a window made of quartz or sapphire. The frequency of the electromagnetic energy is initially measured from the dielectric constant of the oil shale. The temperature of the electromagnetic reactor is maintained between 275 and 400 C while the hydrogen pressure is maintained between 5,500 and 10,000 Kpa (800 and 1500 psi). Hydrogen manufactured from the electrolysis of water or by the decomposition of methane is fed continuously at a rate sufficient to meet the hydrogen deficiency of the oil shale. The combination of electromagnetic frequency, temperature, hydrogen pressure and the solvent are optimised during the process to produce not only the maximum amount of crude oil but to produce the maximum amount of valuable components such as naphtha, auto diesel, and jet fuel. This is determined by tests on the oil shale. The spent slurry is passed through a heat exchanger with the incoming feed slurry before it is fed into a mixer where water is added to allow the separation of the oil and solvent from the spent shale residue. Reagents are added to the water beforehand such as pH modifiers, emulsion breakers and wetting agents for better separation of the oil, water and the spent shale residue. The spent slurry is then passed through a cooler before de-pressuring in a flash tank. The gas is passed through a condenser where water with probably ammonia is collected and the rest of the gas consisting of light hydrocarbons, hydrogen and hydrogen sulphide is passed through an electrolytic cell to breakdown the hydrogen sulphide into hydrogen and elemental sulphur. An electrolytic cell as shown in US Patent Number: 6,955,753 entitled "TREATMENT OF CRUDE OILS " and the teachings therein are incorporated in their entirety herein by reference. The cleaned gas is used for heating and electricity generation. The slurry from the flash tank is fed into a hydro-cyclone then to a thickener to separate the oil/solvent, water and the spent shale residue. The oil is recovered and passed on to a heater and a distillation column where crude oil is recovered and sent to further processing for the removal of sulphur and heavy metals using my process described in my US Patent 6,955,753 mentioned above. The gas produced from the distillation column is passed through a cooler to recover the solvent for recycle to the electromagnetic reactor. The gas from this cooler joins the gas from the flash tank condenser for processing to break up the hydrogen sulphide. The water and spent shale from the first thickener is passed to a second thickener where the water is recovered for recycle to the process. The thickener underflow is passed to a filter to recover more of the water before the residue is sent to the metals recovery processing to recovery of potentially valuable metals such as vanadium and molybdenum. This wet method of extracting the oil offers good conditions for the subsequent recovery of any metal values in the oil shale.

Figure 4 is a diagram of a vertical kiln powered by EM energy to extract oil and gas from an oil shale.

The vertical kiln apparatus 69 comprises a feed hopper 71,a preheating zone 74, a reactor zone 77 and a regenerative zone 79,. Valves 72 are used to transfer charge of the oil shale between the zones in the vertical kiln apparatus from the preheating zone to the reactor zone and from the reactor zone to the regenerative zone but prevent hot gases from passing in the opposite direction. An electromagnetic energy application apparatus is used to supply electromagnetic energy at a selected frequency to the electrodes 78 in the reactor zone 77 to heat the charge in the reactor zone. A hot gas extraction apparatus 81 is used to extract hot gas from the reactor zone and a condenser and distillation arrangement is used to separate gas from the reactor zone into desired fractions.

Preheated crushed oil shale 70 of plus 10 mm size is fed into the feed hopper 71 and is fed continuously into the preheat chamber 74 through rotary valve 72. This kiln may be inclined to the horizontal to minimise the load on the oil shale and prevent crushing to allow free passage of hot gases through the oil shale mass in each section. Hot gas 75 from the regeneration chamber 19 enters the bottom of the preheat chamber 74 to preheat the oil shale. The preheated oil shale is transferred to the reactor section 77 where the oil shale is subjected to electromagnetic energy, the frequency of which is optimized by measuring the dielectric constant and by experimentation as discussed earlier. The electrodes 78 are located opposite each other. The hot gases 81 containing the oil and gas from the oil shale are extracted at the top of the reactor chamber 77 and sent to the condenser for recovery of the oil, gas and chemicals such as ammonia. The hot spent oil shale is passed through the rotary valve 72 into the regenerative chamber 79. Cold gas from the preheat zone 74 is blown into the bottom of the regenerative chamber via line 73 and blower 76 to cool down the spent oil shale 82 which has passed from the reactor zone through rotary valve 72.

Hence it will be seen that in the inclined vertical kiln as shown in Figure 4, which can be inclined so that there will be no excessive loading on the oil shale particles during the process to prevent clogging of the furnace and allow free circulation of the hot gases carrying the oil and gas. To ensure good gas circulation, the size of the oil shale feed is preferably no finer than 10 millimetres. Oil shale is fed at the top of the vertical furnace and feed into the pre-heater section which is controlled by a rotary valve or by a bell valve arrangement to control the flow of gases. Oil shale in the pre-heater section is heated by the hot gases coming from the regeneration section. The heated oil shale is fed into the electromagnetic section through another rotary valve. The oil shale is heated to reaction temperature of about 200 to 400 C by electromagnetic waves. Hot gas containing the crude oil is drawn off from this electromagnetic section and sent to cooling and crude oil recovery. The spent hot oil shale is transferred to the regeneration section through another rotary valve. Cool gas from the pre-heater section is passed through the regeneration section to heat the gas and cool the oil shale residue. The spent cool shale residue is discharged through a rotary valve and sent to metal recovery.

EXPERIMENTAL WORK

Large-scale laboratory tests were carried out on a dry process for electromagnetic extraction of the oil and gas from an oil shale and a wet electromagnetic process for treating an oil shale from Estonia. Dry Electromagnetic Process

The apparatus consisted of a 2 litre flask with 1,250 grams of minus 200 micron shale inverted inside a BONN CM-1300T electromagnetic oven fitted with 2 rotating magnetrons. Electromagnetic frequency was 2450 megahertz. A vacuum line operated at 8 to 10 kPa connects the inverted flask to a condenser cooled with water at 60 C from a water bath with the condenser discharging into a 1 litre flask and the vacuum line leading to a water trap before the vacuum pump. The vacuum pump discharges into a caustic column to trap any hydrogen sulphide produced.

The objective of this experiment was to determine if oil and gas can be produced using electromagnetic energy. Using a handheld infrared temperature measuring device, light oil and water were observed to begin filling the 1 litre receptacle after the condenser at 100 C. Dark light and heavy oil was observed to fill the 1 litre receptacle at 200 C. Foul smelling mercaptan gases were observed passing through the caustic absorber. For safety reasons, the experiment was terminated at this point as the test objective has been achieved. It would be difficult to carry out a mass balance because of the amount of tar that is collecting in the circuit of the apparatus.

Wet Electromagnetic Process

The apparatus used was a 4-litre PARJR autoclave fitted with a stirrer and capable of 300 C and 10,000 KPa. Aside from the external electrical heater, this autoclave was fitted with a 2 kilowatt SAIREM electromagnetic generator with variable power controls and an automatic electromagnetic tuner to ensure maximum absorption of the electromagnetic energy in the charge. Frequency of the electromagnetic energy was 2450 megahertz.

Various solvents were tested to see which would dissolve bitumen including low octane and high octane gasoline, auto diesel, toluene, kerosene, white spirits, SHELL Mexicut, turpentine, and others. Dissolution was of varying degree with gasoline and kerosene being the most effective.

The charge consisted of 600 Estonia shale ground in a rod mill to minus 55 microns and on one test, 1,400 grams of toluene. In another test, the charge was also 600 grams of minus 55 micron shale but with 1,400 grams of 98 octane gasoline. One purpose for the addition of the solvent was to produce and oil- solvent mixture that is lighter than water to allow the separation of the oil produced and the oil shale residue.

The tests were carried out for 3 hours at 300 C and 2,000 KPa pressure with hydrogen being fed into the autoclave at 200 mis per minute. It was noted that very little electromagnetic energy (less than 75 watts) was required to maintain the operating conditions. The exit gas was cooled to collect any light hydrocarbon before the gas was discharged into a caustic absorber. It was difficult to carry out a mass balance because there was a significant amount of light hydrocarbon liquid lost in the cooling section of this apparatus.

The charge was cooled overnight and then 500 mis of distilled water was added and then the charge was heated and stirred at 100 degrees Celsius for 1 hour before the charge was cooled to room temperature.

The oil fraction was on top with the water in the middle and the solid residue was at the bottom. The liquids were separated and then the residue was washed twice with 1 litre of boiling water. The first filtrate contained more oil than the second filtrate with the oil floating on the surface.

Visually, there was more oil recovered with the 98 Octane gasoline solvent than with the toluene solvent.

The shale residue was quite clean, ready for the extraction of any valuable metals contained in the oil shale.

Claims

1. A process of extracting oil and gas from a mass of oil shale comprising; selecting a frequency of pulsed electric energy to apply to the mass of oil shale, which frequency preferentially affects kerogen bonds within the oil shale; applying pulsed electric energy at the selected frequency in a wet or dry process to the mass oil shale; and extracting oil and gas from the treated mass of oil shale.

2. A process as in Claim 1 wherein the mass of shale oil is treated in situ.

3. A process as in Claim 2 where pulsed direct current or alternating current electric energy is applied to the oil shale between sets of spaced apart electrodes.

4. A process as in Claim 3 wherein the spaced apart electrodes comprise a central electrode in a central well and a plurality of peripheral electrodes respectively positioned around the central electrode and the applying electric energy at the selected frequency comprises sequentially or selectively applying the pulsed electric energy between the central and peripheral electrodes.

5. A process as in Claim 3 wherein the central electrode and a plurality of peripheral electrodes each comprise a plurality of vertically spaced electrically independent electrode segments and the applying of electric energy at the selected frequency comprises sequentially or selectively applying the pulsed electric energy between respective pairs of the spaced apart electrode segments.

6. A process as in claim 3 wherein oil extracted is collected in the central well or the peripheral wells of the in situ mass of oil shale and is pumped to a surface processing plant where the oil is separated and the solvent or gas is prepared and recycled to the oil shale extraction process.

7. A process as in claim 4 where a hot gas containing one or more gases selected from carbon dioxide, hydrogen and carbon monoxide is delivered at high pressure into the central well with a small amount of compressed air to react with gases to provide additional low cost heat for the process.

8. A process as in Claim 2 further including isolating the mass of oil shale by water interception wells or cement and chemical grouting around the periphery thereof.

9. A process as in claim 1 where the optimum frequency of the electric energy is determined by dielectric measurement of the oil shale and subsequently by experimentation on the maximum oil yield and maximum naphtha and diesel production.

10. A process as in Claim 1 wherein the mass of shale oil is mined, comminuted to approximately minus 200 microns and mixed with a solvent before being preheated and fed into an electromagnetic reactor, and therein producing a treated oil shale solvent slurry .

11. A process as in Claim 10 wherein the solvent is selected from the group comprising gasoline, naphtha, kerosene, diesel, toluene or any light hydrocarbon fraction.

12. A process as in Claim 10 wherein where hydrogen gas is supplied to the electromagnetic reactor sufficient to meet the hydrogen deficiency of kerogen in the oil shale and to convert more kerogen to crude oil.

13. A process as in Claim 12 wherein the electromagnetic energy is applied to the electromagnetic reactor to give a temperature of 300 to 400 C and the hydrogen is supplied at a pressure of 5,500 and 10,000 Kpa (800 and 1500 psi).

14. A process as in Claim 10 where the treated oil shale solvent slurry is mixed with water and modifier to separate the oil-solvent from the spent oil shale residue.

15. A process as in Claim 14 where the oil is separated from the solvent and water and the oil is sent to refining while the solvent and water are recycled to the process and the oil shale residue is sent to metal extraction.

16. A process as in Claim 1 wherein the mass of shale oil is mined and treated in a kiln selected from a vertical kiln or a inclined kiln.

17. A process as in Claim 16 wherein the where the kiln comprises a preheating zone, a reactor zone and a regenerative zone, respective valves to transfer a charge of the oil shale in the kiln apparatus from the preheating zone to the reactor zone and from the reactor zone to the regenerative zone, a product gas extraction arrangement from the reactor zone, a hot gas transfer arrangement to transfer preheating gas from the regenerative zone to the preheating zone and a return gas transfer arrangement to transfer cooled regenerative gas from the preheating zone to the regenerative zone, whereby the mass of shale oil is fed into the preheating zone, is preheated by regenerative gases, and then transferred to the reactor zone to be heated to 250 to 400 C with hot product gases produced therein being extracted via the product gas extraction arrangement to a solids separation and condensing system to recover oil and gas therefrom and the spent shale oil being transferred to the regenerative zone to heat regenerative gases therein.

18. An apparatus using electromagnetic energy to extract oil and gas from a mass of oil shale in-situ, the apparatus comprising a pulsed direct current or alternating current generator to apply electrical energy at a selected frequency, a first electrode assembly connected to the positive of the generator and a second electrode assembly connected to the negative of the generator, the second electrode assembly being spaced apart from the first electrode assembly in the oil shale thereby enclosing the mass of oil shale there between, whereby oil and gas can be extracted from the mass of oil shale.

19. An apparatus as in Claim 18 wherein the first electrode assembly and the second electrode assembly each comprise electrodes extending substantially vertically.

20. An apparatus as in Claim 18 wherein each of the first electrode assembly and the second electrode assembly comprise a plurality of vertically spaced electrode segments.

21. An apparatus as in Claim 18 wherein the electric generator includes a pulsed electrical energy generating device, a coupling device, an impedance matching device and a switching device to activate the segments in the respective antennae, such that the electric energy is applied in a continuous circular pattern.

22. An apparatus as in Claim 18 further including means to supply a hot gas containing carbon dioxide, hydrogen and carbon monoxide at high pressure into the mass of oil shale and a small amount of compressed air into the centre well.

23. An apparatus using electromagnetic energy to extract oil and gas from oil shale comprising; a comminution apparatus to comminute oil shale, an agitator to mix crushed oil shale with a solvent mixture to produce a slurry, a pre-heater to heat the slurry, an electromagnetic energy application apparatus to apply electromagnetic energy at a selected frequency to provide a treated slurry, a means to add water with modifiers to the treated slurry and an extraction arrangement to separate the treated slurry into desired fractions, whereby oil and gas can be extracted from the mass of oil shale.

24. An apparatus as in Claim 23 where the solvent is selected from one of or a mixture of gasoline, naphtha, kerosene, diesel, toluene or any light hydrocarbon fraction.

25. An apparatus as in Claim 23 further including means to supply hydrogen gas to the electromagnetic reactor sufficient to meet the hydrogen deficiency of the kerogen to convert more kerogen to crude oil.

26. An apparatus using electromagnetic energy to extract oil and gas from oil shale comprising an inclined or vertical kiln apparatus, the kiln apparatus comprising a preheating zone, a reactor zone and a regenerative zone, respective valves to transfer a charge of the oil shale in the kiln apparatus from the preheating zone to the reactor zone and from the reactor zone to the regenerative zone, a product gas extraction arrangement from the reactor zone, a hot gas transfer arrangement to transfer preheating gas from the regenerative zone to the preheating zone and a return gas transfer arrangement to transfer cooled regenerative gas from the preheating zone to the regenerative zone, an electromagnetic energy application apparatus to supply electromagnetic energy at a selected frequency to the charge in the reactor zone, and a condenser and distillation arrangement to separate gas extracted by the product gas extraction arrangement into desired fractions, whereby oil and gas can be extracted from the mass of oil shale.