US 3191679 A
Description (OCR text may contain errors)
June 29, 1965 w. s. MILLER 3,191,679
MELTING PROCESS FOR RECOVERING BITUMENS FROM THE EARTH 9 34 Q9 30 23 25 N I I I3 2 H I 20 l i I '26 l I 32 I i -|s I l I l l4 9 i=1 Znl Original Filed April 13. 1961 way/ W )Wf INVENTOR. mNDELL 5. MILLER United States Patent C) 3,191,579 MELTING PROCESS 1 6R RECQVERING EITUMENS FROM THE EARTH Wendell S. Miller, 1341 (lornstoclr Ave., Los Angeies 24, Calif.
Original application Apr. 13, 1961, Ser. No. 113,577, new Patent No. 3,131,914, dated May 5, 1964. Divided and this application Apr. 20, 1964, Ser. No. 360,961
2 Claims. (Cl. 166-39) This application is a division of my co-pending application Serial No. 113,577, filed Apr. 13, 1961, now Patent No. 3,131,914.
This invention relates to an improved process for recovering from the earth certain meltable and combustible bitumens of the character of Gilsonite, grahamite, tar and the like.
As is well known, there are numerous deposits of Gilsonite and grahamite at various points in the earth, which are actually relatively rich in these substances, but which are in some Ways so positioned in the earth as to render it impossible to mine these deposits by conven tional methods. In many instances, these bitumens are found in very narrow or thin vertically extending veins, which may extend downwardly into the earth to a very substantial depth, but which are too narrow to dig out utilizing conventional mining equipment. The general object of the present invention is to provide a process which is capable of recovering from the earth the above discussed substances, which heretofore could not be mined efiectively. As will appear, the present process may be utilized with a minimum of expense to bring bitumens to the surface of the earth in a form essentially ree of other substances.
In performing the process of the invention, the bitumen is converted to a condition in which it is easily recoverable from a location deep within the earth, with the conversion being effected very uniquely by actually burning a portion of the material in the earth. This burning of some of the substances itself produces heat in the earth, which acts to melt additional portions of the surrounding-bitumen, so that this material may then be easily withdrawn upwardly to the surface of the earth in molten freefiowing condition. In the simplest variation of the invention, the molten material is pumped upwardly by the pressure of the gases of combustion produced by the burning operation itself.
The above and other features and objects of the present invention will be better understood from the following detailed description of the typical embodiments illustrated in the accompanying drawings in which:
FIG. 1 is a vertical section through a first type of apparatus for recovering an earth substance in molten form;
FIG. 2 shows an arrangement similar to FIG. 1, but in which the apparatus extends downwardly to the production zone at an inclination and through an adjacent formation of less readily meltable material than is being produced from the mine.
In FIG. 1, I have represented at 19 a body or a layer of materials spaced beneath the surface 11 of the earth, and containing a substance to be recovered. This body 10 may typically consist of Gilsonite, grahamite or other similar bitumens. Above the body 19, there is illustrated in FIG. 1 an over-burden or upper strata 12. This layer 12 may in most instances be formed of a material or materials having a melting temperature well above the melting temperature of the substance to be recovered from layer 19.
In recovering the material from body 1% by the apparatus of FIG. 1, the first step is to drill into the earth a hole or bore 13, which may initially be of a uniform diameter through the entire vertical distance from the surface of the earth 11 down to the bottom 14 of the hole. In FIG. 1, the lower portion of this bore as originally drilled is represented in broken lines at 15. After bore 13 has been drilled into the earth, there are installed in this bore two desirably concentric pipes 16 and 17, with the former being disposed about the latter to provide an annular vertically extending passage 18 between the pipes. As will be understood, each of these pipes 1d and 17 will in most cases be formed of a series of separate sections or stands, threadedly joined together in an end-to-end series to form overall pipe assemblies of proper lengths to reach the producing formation. The inner pipe 17 extends downwardly to a location 19 spaced but a short distance above the bottom 14 of the bore. The outer pipe 16, on the other hand, terminates at a point 20, spaced well above the lower end 19 of pipe 17. The upper end of annular passage 18 about pipe 17 is suitably sealed or closed by conventional well head apparatus of any desirable type, as represented by the seal diagrammatically represented at 21 in FIG. 1. A gas containing oxygen is fed into the upper end of annular space 18 through a titting represented at 22, and from a source of such gas under pressure indicated at 23. This gas coming from source 23 may in some instances be pure oxygen, and in other instances be air or another mixture of gases containing oxygen and capable of supporting combustion. Source 23 preferably maintains a continuous flow of such combustion supporting gas downwardly through passage 18, to emit continuously from the lower end 20 of pipe 16. This rate of oxygen feed to the production zone may be great enough to support combustion of the material in body 10 continuously. Molten production fluid flows upwardly through inner pipe 17, and discharges from the upper end of that pipe through a line 2-4 leading to an accumulation tank 25.
In conjunction with the apparatus thus far described, there is also provided some means for initiating combustion of the production substance near the lower end of pipe 16. This means for starting the combustion may be simply a mass of burning Thermit or other material injected into the upper end of annular space 18 to fall downwardly there through to the production zone, or may be any other convenient type of igniting system. In FIG. 1, I have typically represented an arrangement in which there is provided about inner pipe 17 at a location directly below the lower end 2% of pipe 16, an annular mass 26 of highly combustible material, typically Thermite, which is ignited electrically by current fed to body 26 through wires 27 extending upwardly to the surface of the earth. These wires connect at the surface of the earth to a power source 23, through a switch 29 whose closure fires the combustible charge 26.
Assuming that the bore 13 has been drilled downwardly to location 14 (with the bore being of a uniform diameter for its entire length), and assuming that all of the apparatus illustrated in FIG. 1 is in position as shown, the first step in placing the apparatus in operation may be to actuate the air or oxygen source 23 to commence a flow of air or oxygen downwardly through passage 18, and then upwardly through pipe 17 and to tank 25. This tank 25 may have an upper vent 31 through which air or gases or combustion in the upper portion of the tank may escape to the atmosphere, leaving any production liquid which comes upwardly through pipe 17 in the tank. After the air or oxygen flow has been commenced, the operator closes switch 29 to fire combustible charge 2%. This charge is designed to raise the temperature of the portion of body 10 which is disposed directly adjacent the lower end of pipe 1 5 to a value causing the combustible Gilsonite, grahamite, or the like to burn. The rate of oxygen delivery through passage 18 is maintained at a value such as to continue this burning even arouses after charge 26 is gone, and as long as it is desired to continue the production from zone 1! The heat of combustion is high enough to melt a large amount of the G-ilsonite, grahamite, or the like forming the wall of bore 13, so that this molten material falls downwardly to the bottom of bore 13, as represented at 31. The burning action progressively enlarges the lower portion of the bore to form a cavity 32 considerably larger in diameter than the upper portion of bore 13. Preferably, most of the burning takes place in the upper portion of cavity 32.
The molten material 31 which falls to the bottom of the cavity is forced upwardly through pipe 17 by the pres.- sure of the gases of combustion resulting from burning operation. This molten material flows into tank 25, and any air and other gases mixed with the molten material is vented off to the atmosphere through vent 30. If the pumping action reaches a point where all of the liquid 31 has been removed from the bottom of the cavity, then the gases of combustion flow upwardly through pipe 17 and to the atmosphere without intermixed liquid until additional molten material accumulates in the bottom of the cavity, at which time the liquid pumping action recommences automatically. It is also noted that the pressure of upper stratum 12 above lower body 10 effectively prevents the upward advancement of the burning or melting action beyond the interface 33 between the two strata, since it is assumed that layer 12 is not readily combustible or meltable.
There may be provided in the line leading from oxygen or air source 23 to passage 18 a variable passage throttle valve 34, which is capable of regulatingthe rate of air or oxygen delivery, andthereby varying the temperature maintained in the cavity 32. This temperature is maintained at a value sufficiently above the melting temperature of the substance being produced to assure arrival of the substance in molten readily flowable conditionin tank 25. For this purpose, the temperature may be regulated either by reference to a reading produced at the surface of the earth by a temperature responsive element located within cavity 32, or by merely noting the condition of the produced substance as it reaches tank 25.
FIG. 2 shows an arrangement which may be considered identical with that of FIG. 1, except that the bore 52 through which pipes 53 and 54 extend downwardly is disposed at an angle such that it first passes througha relatively non-inflammable and non-meltable formation 55, and then enters the combustible and meltable formation 56 (typically of Gilsonite or grahamite) at a location spaced beneath the surface of the earth. Air or oxygen is fed to the burning zone from a source 57 and through the outer passage between pipes 53 and 54, while the production fluid is pumped upwardly through the inner pipe by the pressure of the gases of combustion. The arrangement of FIG. 2 is particularly useful where the formation 56 takes the form of a very thin or narrow vertical vein of Gilsonite or the like, extending upwardly to the surface of the earth, so that if the pipes extended vertically through that vein to the surface, the heat of the pipes might cause melting of the material about the pipes, and the resultant formation of a leakage space about the pipes. Since the pipes of FIG. 2 pass through formation 55 which is essentially incombustible, and which melts at a higher temperature than material 56, there is no danger of melting the material about pipe 54 by the heat of that pipe, so that the discussed leakage gap cannot be developed.
1. The process for removing from the earth a combustible and meltable solid bitumen emplaced in a formation in which a bituminous stratum communicates with the surface of the earth and adjoins a second noncombustible and infusible formation, comprising the steps of producing in said second formation a bore hole communication with said bituminous formation at a point remote from the surface of the earth and sufficiently remote from the said bituminous formation near the surface of the earth to provide thermal isolation of said formation from said bore hole, inserting in said bore hole conduit means communicating with said bituminous formation at a point remote from the surface of the earth, supplying oxidizing gas to said formation at a point remote from the surface of the earth, igniting bitumen in said bituminous formation into in situ combustion with said oxidizing gas, melting portions of said bitumen by means of the heat produced by said in situ combustion, removing said melted bitumen through said conduit by means of the gases produced by said combustion.
2. The process for removing a combustible and meltable solid bitumen from a nearly vertically standing formation of said bitumen adjacent an incombustible and infusible solid formation, comprising the steps of slant drilling a bore hole through said incombustible formation into communication with said bituminous formation at a point remote from the upper end thereof, supplying oxidizing gas to said bituminous formation through said bore hole, igniting said bitumen into com bustion with said oxidizing gas in situ, melting portions of said bitumen by means of the heat of said in situ combustion removing said melting porions of bitumen by a path sufficiently remote and thermally isolated from said bituminous formation near the upper end thereof to prevent the direct communication of said in situ combustion with the surface of the earth along said path.
References Cited by the Examiner UNITED STATES PATENTS 531,787 1/95 Dubbs.
BENJAMIN HERSH, Primary Examiner.