US 3766982 A
In-situ treatment of oil shale or other hydrocarbonaceous material by an inexpensive hot gaseous fluid, such as air or flue gas, as a heat transfer agent to volatilize kerogen or other hydrocarbonaceous matter and preferably also as a carrier of sufficient heat to crack and fissure the material to make it permeable to gas flow therethrough. Recovery of the volatilized hydrocarbonaceous material is through one or more bore holes remote from the location of hot gas introduction and aided by at least, but preferably, partial hydrogenation within a localized zone between location or locations of hot gas introduction and the one or more bore holes, preferably adjoining the latter.
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Description (OCR text may contain errors)
United States Patent [191 J ustheim [4 1 Oct. 23, 1973  Inventor: Clarence l. Justheim, Salt Lake City, Utah  Assignee: Justheim Petroleum Company, Salt Lake City, Utah  Filed: Dec. 27, 1971  Appl. No.: 212,659
 US. Cl 166/261, 166/272, 166/247  Int. Cl E21b 43/24  Field of Search 166/303, 256, 259, 166/260, 261, 272, 247
 References Cited UNITED STATES PATENTS 3,692,110 9/1972 Grady 166/259 2,595,979 5/1952 Pevere et al.... 166/303 3,285,335 11/1966 Reistle, Jr. 166/303 X- 2,969,226 1/1961 Huntington 166/261 X 3,040,809 6/1962 Pelzer 1'66/303 3,051,235 8/1962 Banks 166/261 3,084,919 4/1963 Slater 166/261 X 3,102,588 9/1963 Fisher 166/261 3,521,709 7/1970 Needham... 166/259 X 3,598,182 8/1971 .lustheim [66/247 3,237,689 3/1966 Justheim 166/247 Primary ExaminerStephen J. Novosad Attorney-Philip A. Mallinckrodt et a1.
 ABSTRACT ln-situ treatment of oil shale or other hydrocarbonaceous material by an inexpensive hot gaseous fluid, such as air or flue gas, as a heat transfer agent to volatilize kerogen or other hydrocarbonaceous matter and preferably also as a carrier of sufficient heat to crack 7 and fissure the material to make it permeable to gas flow therethrough. Recovery of the volatilized hydrocarbonaceous material is through one or more bore holes remote from the location of hot gas introduction and aided by at least, but preferably, partial hydrogenation within a localized zone between location or 10- cations of hot gas introduction and the one or more bore holes, preferably adjoining the latter.
7 Claims, No Drawings METHOD FOR THE IN-SITU TREATMENT OF HYDROCARBONACEOUS MATERIALS BACKGROUND OF THE INVENTION 1. Field This invention is in the well-developed field of in-situ treatment of hydrocarbonaceous materials, especially oil'shales, for the recovery of the hydrocarbonaceous material contained therein.
2. State of the Art The distillation of oil shale has received much attention for many years and has been carried out commercially to limited extents in various parts of the world. ln-situ distillation has been recognized as practical and perhaps the most economical approach to the recovery of the great quantities of hydrocarbonaceous reserves known to exist in the form of oil shale, much of which is represented by rich oil shale deposits in areas of Colorado, Utah, and Wyoming of the United States of America. Insitu distillation has either been carried out commercially or proposed by various methods of applying heat to the shale in its natural underground location. For example, electric heaters have been lowered into the bore holes and hydrocarbonaceous vapors drawn off through other bore holes, sometimes with the aid of suction exerted through such other bore holes. In practically all instances, however, the well recognized lack of permeability of oil shale and of most underground deposits thereof has severely limited commercial operations. A variety of proposals have been made for fissuring and cracking oil shale deposit, e.g., by the use of explosives, the application of heat of exceptionally high temperature, and the solvent action of injected natural gas, so fluid heat exchange media can be circulated through the underground deposit and kerogen vapors recovered. It is also known to inject heated pure hydrogen gas into an underground deposit of oil shale for heat exchange and permeabilitizing purposes, depending upon the temperature employed, the hydrogen gas also effecting hydrogenation of the kerogen as and when released in vapor form, see my recently issued U.S. Pat. No. 3,598,182 and my earlier U.S. Pat. No. 3,237,689, as well as several U. S. and foreign patents cited therein.
SUMMARY OF THE INVENTIO In accordance with the present invention, a relatively cheap source of heat is utilized for diffusion throughout the area of an underground deposit of oil shale to be treated at any given time, such source including a gaseous fluid heat transfer agent (such as air or an inert gas) that is relatively inexpensive as compared to pure hydrogen, thereby minimizing need for precautions that might otherwise be deemed advisable against possible circulation losses of such fluid in the deposit due to unanticipated crevices and the like of major extent. Combined with the admittedlyold use of such a relatively inexpensive fluid heat transfer medium is the injection of hydrogen gas into a localized zone in the path of flow of such heat transfer medium and associated vapors from the location or locations of introduction of the heat transfer medium to one or more vaporrecovery bore holes provided for recovery of the volatilized kerogen. Preferably a single extraction bore hole is utilized, with the hydrogen injection zone adjoining such bore hole. In this way, the volatilized kerogen is at least partially hydrogenated before extraction from the ground, to ecological and anti-pollution advantage as well as facilitating delivery of such volatilized kerogen values to the surface by reason of the chemical changes taking place due to the hydrogenation. Injection of the hydrogen gas can be effected in any suitable manner, e.g., by one or more special bore holes extending downwardly into the deposit from the surface or laterally from any underground workroom that may be provided as part of the in-situ workings. If desired a special hydrogenation room may be provided adjacent to or adjoining the vapor recovery bore hole into which the hydrogen is introduced and through which the kerogen vapors are passed before being sent to the surface. Heating of the heat-transfer gas to desired temperatqres for kerogen distillation alone, or for that and the cracking and fissuring of the normally impervious oil shale, can be effected in any suitable manner, e.g., by a nuclear reactor, a pebble heater, or some other source of heat at the required temperature.
DETAILED DESCRIPTION OF BEST MODE PRESENTLY CONTEMPLATED It is believed unnecessary to illustrate any specific system for carrying out the invention, since the use of bore holes, underground rooms, etc. in the in-situ treatment of oil shale for the volatilization and recovery of its kerogen content are well detailed in the prior art and any particular deposit will require its own specific arrangement of these workings.
The best mode presently contemplated of carrying out the invention is the heating of the air or other relatively inexpensive heat-exchange gas to requisite temperature, either above or below ground in a nuclear reactor, pebble heater, or other suitable heating device, and the injection and circulation thereof through an underground deposit of oil shale, with recovery of the kerogen vapors, in essentially the manner shown in my previously referred to U.S. Pat. Nos. 3,237,689 and 3,598,182. Combined with this is the injection, into the vicinity of the recovery bore hole or holes and in the path of flow of the vaporized kerogen to be recovered, of hydrogen gas so as to effect at least partial hydrogenation of the vapors and a lightening thereof by reason of the chemical reaction with respect to their oxygen, nitrogen, and sulfur constituency prior to rising of such vapors through the recovery bore holes, either because of their natural tendency to rise or because of suction applied to such recovery bore holes. As previously indicated, it is presently contemplated that a single recovery bore hole will be utilized, so as to concentrate the hydrogen into a relatively small zone adjoining such bore hole. By utilizing one or more sets of paired heat injection and recovery bore h'oles, cost of hydrogenation is kept to a minimum and permeability induced by use of ultra high temperature (2,000F.) beating medium is kept to a maximum.
In addition to the ecological and anti-pollution advantages of carrying out at least partial hydrogenation of the kerogen vapors underground, rather than at the surface, are the advantages derived by the character of the vaporized kerogen product with respect to the facilitating of its removal from the underground location.
Optimum temperature to be maintained in the hydrogenation zone is between about 1,050F. and l,250"F., the higher temperatures between 1,200F. and 1,250F. favoring hydrogasification of the surrounding shale to yield greater mobility to the kerogen vapor product.
The hydrogen utilized can come from any source, including so-ca'lled synthesis gas" derived from the oil shale itself, In the use of air as the heat exchange gas, it is advantageous to utilize hydrogen in quantity such that it constitutes less than 4 percent or more than 74 percent of any resulting air-hydrogen mixture, to avoid danger of accidental explosions and the need for special precautions to avoid conditions leading to ignition of the mixture. I z I Although special emphasis has been placed herein on the treatment of oil shale by the disclosed method, it should be realized that the method'is also applicable to deposits of other hydrocarbonaceous materials, such as bituminous sands, coal, etc.
The present method has the advantage of considerable economy in the in-situ treatment of an underground deposit by the use of only partial hydrogenation for the purpose of facilitating recovery of the distillation vapors.
Whereas this invention is here illustrated and described with respect to certain preferred procedures thereof, it is to be understood that many variations are possible without departing from the inventive concepts particularly pointed out in the claims.
I claim: y
l. A method for the in-situ recovery of the hydrocarbonaceous content of hydrocarbonaceous materials, comprising heating to at least distilling temperature for the hydrocarbonaceous material concerned a heatexchange gas that is relatively inexpensive in comparison to substantially pure hydrogen; injecting the soheated gas into an initial zone of an underground depositof hydrocarbonaceous material to be distilled; flowing said gas through said underground deposit from said initial zone to a product-withdrawal zone for vaporizing hydrocarbonaceous matter in said deposit; in-
jecting hydrogen gas into a localized hydrogenation zone disposed in the path of heat-exchange gas and vapor flow toward said product-withdrawal zone and in close adjacency-to the product-withdrawal zone, and maintaining the temperature in the.hydrogenation zone between l,050 F. and l,250 F., said hydrogen gas being injected in an amount s'ufficientfor at least partial hydrogenation of hydrocarbonaceous vapors .to be withdrawn; and withdrawing from said productwithdrawal zone, at least partially hydrogenated hydrocarbonaceous vapors.
2. A method in accordance with claim 1, wherein the deposit of hydrocarbonaceous material is oil shale.
3. A method in accordance with claim 2, wherein the oil shale in the distillation area of the deposit is rendered permeable to the flow of gas and vapors therethrough by heating the heat-exchange gas to substanquantity of hydrogen gas injected into the hydrogena-' tion zone is such that the mixture of air and hydrogen gas contains less than 4 percent or more than 74 percent hydrogen.
7. A method in accordance with claim 1, wherein at least one set of paired injection and vapor recovery bore holes are utilized for heat-exchange gas injection and hydrogenated vapor withdrawal, respectively.