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[721 Inventors R9291" L- Mmman , _ 2,841,375 7/195s Salomonsson .............. .. 166/256 X 1432 Wichita Plaza Bldg., Wichita; ‘ " 3,010,707 I I/1961 Craighead et al ........... .. 166/258 X Karl E. Becker, 419 First National Bank 3,145,772 8/ I964 I-luitt .......................... .. I66/259 X Bldg., Wichita, Kans. 67202;‘Henry C. 3,283,814 I ll I966 Schlicht et al. ............. .. l66/259 X gleysslrg I Ellsworth Road’ La‘--chmom’ Primary Examiner—Stephen J . Novosad _  App] No 8é2'617 . . Anorney—John H. Widdowson [221 Filed Sept. s, 1969 ___i__._  Patented Aug 17’ 1971 ABSTRACT: The invention provides a method for recovering **i?"""'— t , hydrocarbons from a geological formation having combustible [ 54] METHOD 0|: REC()vER|N(; HYDROCARBONS BY organic material. A passageway is established from a point in |N Sn-U CQMBUSTION . V " the formation, through same, and to the surface of the ground. 12 Chims, 4 Drawing FigS_ _ The combustible grganic rlnateriallis ignited. Oxygen-containmg gas IS passe into t e resu ting combustion zone by  U.S.,Cl .............................................. .. ...... .. . 166/258, establishing at lower than normal formation prcssure’ 8 pl_eS_  Int Cl 166/zigillbéggz/22 sure drop from the combustion zone to a point outside the for. . ....................................................... .. mation through the passageway The temperature of com_  Field OI SCIITCII ..... ...................... ..- ........... .. I66/251, bustion is conuoned to only paniany vohfilize the organic I 2581259’ 260' 261* 262' 256' 2661267 material. The gases resulting from the partial combustion are 159 ~ 5i“iZ§.‘.".I“§,i;’§§2Z5,212“ZfJ°33.‘Z.T2‘.f..'2?$2f;‘lii.‘Z.'°§°iZ‘;i UNITED STATES PATENTS stratum and/or from an oil sand. In the preferred specific em2,584,605 2/ I952 Merriam et al. ............ .. 166/258 X bodiment, the method isapplied to recovering hydrocarbons 2,695,163 1 1/1954 Pearce et al. .. 166/259 X from a coal stratum and a separate oil sand stratum, separated 2,734,579 2/1956 Elkins .......... .. 166/2,51 by a stratum of kerogen. In the latter heat of combustion is by 2,780,449 2/1957 Fisher et al. 166/259 conduction passed from" the coal stratum to the oil sand 2,788,956 4/I957 Pevere et al. ............... .. 166/259 stratum. p I i O2 CO/vTA//v//vtr GAS’ 72 V i I
METHOD OF RECOVERING HYDROCARBONS BY IN SITUICOMBUSTION ‘
In the prior art, methods are known to recover hydrocarbons and other volatile chemicals from coal by in situ destructive distillation of the coal, the heat for such being supplied by partial combustion of the coal. Also, it is known to mine hydrocarbons from a stratum of oil sand in a similar manner, that is, partial combustion of the petroleum in situ with heat, and resulting combustion gases being used to enrich a gaseous fluid for recovery of hydrocarbons therefrom in a surface operation, and with heat resulting from combustion being used to. aid in the recovery of a liquid portion of the petroleum. Also, it is known in the art to completely burn coal in situ in a stratum of same to produce heat, and pass the resulting heat by conduction into an oil sand overlying or underlying same to lower petroleum-viscosity and aid in the recovery thereof from the oil sand by normal means of elevating the liquid fluids to the surface, and treating resulting gaseous fluid at the surface to recover the desired hydrocarbon constituents therefrom. The known processes of the prior art have not been successful. Until the invention hereof no procedure existed to optimumly partially burn the coal (normally bituminous) in a coal stratum to result in destructive distillation of the coal, recovering the off gases produced .and utilizing the heat of combustion by conduction and convection to mine and recover hydrocarbons from petroleum in an oil sand overlying and/or underlying the coal stratum and separated therefrom by ia kerogen strata, under controlled conditions of coal combustion, that is, temperature of combustion regulated by the available oxygen in an oxygen controlled and containing gas (principally air), regulated by the amount of oxygen in the gas and/or by the volume of the oxygen-containing gas, or the water vapor content thereof, such being passed into the coal stratum from the surface of the ground. The prior art has attempted complete combustion of the coal, anticipating condensation of the coal volatiles in the oil sand strata as a hindrance to petroleum recovery. We have found the opposite to be true, and such is an important consideration in the process of our invention.
‘This invention utilizes thermo, chemical, and thermochemi
cal processing of combustible organic material in situ and is normally directed at processing bituminous coal in a stratum above or below petroleum in an oil sand stratum, with the two being separated by a kerogen stratum. Other combustible materials found in geological formations to which the invention appliesare for example, sulfur, anthracite coal,_peat, lignite and the like. It is an important feature of the invention that the oxygen-containing gas’ passed into the combustion zone in the combustible material stratum is done so by creating a vacuum (pressure below atmospheric) at the surface of the ground in the outlet end portion of a passageway established into the combustion zone, through the stratum of combustible organic material (bituminous coal), through the oil sand, and to the surface of the ground. This results we have found, in being able to control combustion, especially the temperature thereof, to provide for optimum mining of the coal and recovery of the petroleum in the oil sand. By in effect pulling the oxygen-containing gas down into the combustion zone. the volume thereof is completely controllable, and thus the amount of oxygen available for the partial combustion of the coal in situ. And we have found this makes the process completely controllable, because inert gases can be introduced to lower the percentage of oxygen in the air passed into the combustion zone, or oxygen-rich gas can be introduced into the air to increase combustion and temperature, or the water vapor content of the oxygen-containing gas can be easily controlled by introducing steam to control combustion and the temperature thereof. The gases resulting from combustion of the coal are passed through the coal stratum where they are enriched, as a result of heat of convention and evaporation of coal volatiles thereinto, and thence through the oil sand where they are further enriched in gaseous hydrocar
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bon constituents, and then to the surface where by condensation and/or absorption,-desired recoverable hydrocarbons and other chemicals are removed, with the remainder being available as a fuel gas. Volatiles from combustion gases condensed in the coal stratum and/or oil sand stratum become enriched, collected and pumped to the surface and conveniently from the same passageways or wells used for introducing oxygencontaining as and withdrawing production gases, or the condensates lower the viscosity of the petroleum so that it is more easily recovered by collecting and pumping methods, and a greater percentage of such is ultimately recovered from the oil sand. We have found that important benefits of the invention are that it practicallyand economically increases reserves of recoverable naturally occurring materials in geological formations, and offers a method to recover such from formations that up to now were considered too small, too thin, too deep, too steeply pitched, or others which are considered not amendable to economic exploitation by the conventional methods of recovery. » '
Spaced wells are established by conventional methods and means into the geological formation from which the combustible organic material is recovered by the new method of the invention. A passageway through the fonnation or stratum between the wells is established by conventional methods and means. For example, the passageways_or channels through the seam ofstratum of coal can be made by drilling, shooting and/or preferably by fracturing, utilizing the usual high-pressure oil methods. This is desirably done from the -input well (oxygen-containing gas input), to the chimney well (the outlet from the coal stratum). At the surface, at the outlet of the established passageway, gaseous fluid-pumping means is used to establish a pressure drop from the oxygen-containing gas-inlet, through the coal seam or oil sand to the surface, and in operation as a result of this pressure drop oxygen-containing gas is passed to a point of combustion where the organic material in the seam has been ignited to supply the oxygen for combustion. Complete controllability of the process results. lt is easy to control volume, oxygen, richness, and water vapor of the gas to result in combustion controlled as to temperature and as to the recoverable volatiles produced therefrom as a result of- the destructive distillation of the organic material, coal and/or petroleum.
It is an object of this invention to provide a new method for recoveringhydrocarbons from geological formations.
Another object of this invention is to provide a new method for recovering stratified combustible organic material in geological formations.
It is another object of this invention to provide a new method of mining bituminous coal and petroleum from geological formations.
A further object of this invention is to provide a new method of thermally, and thermochemically recovering and mining coal. from a seam or stratum of same, and petroleum from an oil sand stratum containing such, by controlled partial volatilization of the coal by partially burning same, with resulting heat of conduction and heat of convection in the resulting heated gases being utilized in recovering the petroleum hydrocarbons from the oil sand.
Another object of this invention is to provide a new vacuum operating procedure to recover hydrocarbons and other chemicals from geological formations having combustible organic material therein, especially bituminous coal and petroleum in an oil sand, wherein a pressure lower than atmospheric is established in the outlet of the chimney well into the formation, and as a result passing oxygen-containing gas into the input well and into the combustion zone in the coal stratum, such resulting in a pressure drop through the organic material stratum at pressure lower than normal formation pressure.
Yet another object of the invention is to provide a new completely controllable thermal and thermochemical method of mining coal and/or petroleum which is economical and simple to operate and which results in optimum recovery.