US3512584A - Apparatus for obtaining bitumens from underground deposits - Google Patents

Description

H. I ANGE Original Filed Aug. 4, 1967 INVENTOR ATTORNEYS APPARATUS FOR OBTAINING BI'IUNVIENS FROM UNDERGROUND DEPOSITS May 19, 197.0

H4 Ns' A/var uw e, 201% States Patent O 3,512,584 APPARATUS FOR OBTAINING BITUMENS FROM UNDERGROUND DlEPOSlTS Hans Lange, Wietze, Germany, assignor to Deutsche Erdol-Aktiengesellschaft, Hamburg, Germany Original application Aug. 4, 1967, Ser. No. 658,522. Divided and this application Jan. 6, 1969, Ser. No. 810,057 Claims priority, application Germany, Aug. 12, 1966, 50 8 U.S. Cl. 166-57 1 Claim ABSTRACT OF THE DISCLOSURE An apparatus for recovering bitumens from underground deposits having a casing for insertion in a borehole, a packer positioned in the casing intermediate the ends, a tubing having a footing extending through the packer, a ball check valve in the footing maintained in closed position by a compression spring, a cage lled with coarse particulate material positioned in the lower end of the casing below the footing, a vessel positioned in the cage having means for igniting, and a second tubing extending through the packer into the cage which permits the introduction of a pressure gauge.

CROSS-REFERENCES TO RELATED APPLICATIONS Applicant claims priority under 35 U.S.C. 119 for German application, Ser. No. D 50,833 Vla/5a, tiled Aug. l2, 1966.

The present application is a division of application Ser. No. 658,522 tiled Aug. 4, 1967.

Incorporated by reference herein is the disclosure of applicants copending U.S. patent application, Ser. No. 440,852, led Mar. 18, 1965, now U.S. Pat. 3,344,856, dated Oct. 3, 1967 which in turn is a continu'ation-in-part of U.S. patent application Ser. No. 349,589, filed Mar. 5, 1964, now U.S. Pat. 3,360,044, dated Dec. 26, 1967.

The title of the copending application is Process for the Extraction of Liquid and Solid Bitumens from Underground Deposits, and the lapplication relates to a continuous method of extracting liquid and solid bitumens from underground deposits where injection and production borings are inserted into an underground stratum of the bitumens, combustion gases are fed to the underground deposit and ignited, the bitumens are brought to the surface in liquid and gaseous phases, a portion of the bitumens are recovered, another portion of the bitumens is recirculated into the stratum to be burned by the heat in the reaction zone and a continuous process is provided.

BACKGROUND OF THE INVENTION The iield of the invention is processes for supplying input and output to wells wherein the input includes heating. A particular tield of the invention is processes for heating wells which includes the introduction of heated iluid.

The process of U.S. Pat. No. 3,344,856, supra, has for an object the production of bitumens from deposits containing liquid bitumens by in situ combustion wherein the in situ combustion is effected in a specially prepared burning zone. According to this invention, incorporated herein by reference, the in situ combustion is effected with a cornpressed oxygen gaseous mixture containing carbon dioxide and steam. This mixture contains 80-'95% oxygen. When such a gaseous mixture, composed mainly of oxygen, is brought into contact with mineral oil components in the injection or treatment boring, the apparatus elements contained in the borings or the areas in the immediate neighborhood of the borings, a highly explosive mixture is 3,512,584 Patented May 19, 1970 formed. This mixture causes explosions in the neighborhood of the boring or leads to a series of explosive blasts in the deposit.

According to this prior disclosure the process for the extensive recovery of liquid and solid bitumens from underground deposits comprises the steps of:

(a) Locating at least one relatively deep flooding boring, at least one relatively shallo-w production boring, at least one treatment boring and at least one leading boring, said treatment and leading borings located between said ilooding boring and said production boring and spaced a predetermined direction apart from one another in the stratum of underground deposit of bitumens;

(b) Introducing into said treatment boring an activated gas combustion comprising oxygen and hot modied gas of combustion comprising steam and carbon dioxide;

(c) Developing a hot reaction zone between at least one of said treatment -borings and at least one of said leading borings having a given temperature range by the sensible heat of said gas of combustion and a reaction of a portion of said bitumens and oxygen and producing additional modiiied gases of combustion;

(d) Conducting further into said stratum ahead of said reaction zone said additional modified gases of combustion from (c), where they condense and dissolve to form a liquid phase of the contents of the stratum; and

(e) Advancing said reaction zone and displacing ahead of it the stratum contents with condensed and dissolved gas of combustion in the direction of the production boring by the introduction of water through said ooding boring, and removing the advanced stratum contents through the production boring,

For initiating the in situ combustion in the burning zone, precautions are necessary in order to permit the introduction and ignition of the gases without danger of explosions.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to avoid explosions associated with the process for obtaining bitumens from underground deposits.

Another object of the present invention is to provide a preliminary preparation of a treatment boring prior to the commencement of an in situ combustion.

Still another object of the present invention is an improved apparatus for insertion in the treatment boring of a process for obtaining bitumens from underground deposits.

Upon further study of the specification, drawings and claims other objects and advantages of the present invention will become apparent.

According to the present invention, the production of bitumens from deposits containing liquid bitumens by the in situ combustion process disclosed in U. S. Pat. No. 3,344,856, supra, is improved by a process and apparatus for the preliminary preparation of the treatment boring and the commencement of the in situ combustion. The present process and apparatus is characterized in that when the space above the packer located above the injection or treatment borings contains traces of oil, the space is tilled with water or gaseous nitrogen under high pressure and through this treatment boring the gaseous mixture consisting mainly of carbon dioxide and steam is injected. The gaseous mixture is heated to above 200 C., `depending on the pressure and saturation temperature of the steam. The gaseous mixture is gradually enriched with oxygen from 0% at the beginning to 21% by volume. This gaseous mixture is injected into the restricted space in the boring below the packer and into the immediate neighborhood thereof, to displace and oxidize whatever oil may be present. The temperature of the oxygen containing gaseous mixture is gradually increased and ignition is effected by contacting t-he gaseous mixture containing oxygen with catalysts or readily oxidizable substances located in the bottom of the treatment boring.

It is important in the present process to provide for the effective removal of any and all oil components which may be present in the boring or in the apparatus contained therein so as to prevent explosions in the transitional regions between the parts of the apparatus that have been freed from oil and the surrounding oil-containing deposits. In the present invention this is accomplished by dividing the transitional region into the smallest possible separate spaces and by filling these spaces with sand and gravel so that the propagation of explosion waves will be impeded and promptly stopped in the same manner as in the porous parts of the deposit. The introduction of gaseous mixtures with increasing oxygen contents at temperatures not over 205 C. will also drive out and oxidize any residual oil from the immediate neighborhood of the boring.

BRIEF DESCRIPTION OF THE DRAWINGS The apparatus for carrying out the improved process is shown in the annexed drawings wherein:

FIG. l shows in cross section a treatment or injection boring inserted into an underground bituminous deposit from the surface of the ground; and

FIG. 2 shows a modified embodiment of FIG. 1.

With particular reference to FIG. 1, the treatment or injection boring is shown having a casing 1 provided with a perforated liner 20a that extends into the oil bearing sand 26. The casing is held firmly in place in the surrounding rock 3 by cement 2. A cage 15 is positioned in the casing 1 at the level of the perforated liner 20a adjacent the oil bearing sand. The cage is in the form of a tubular structure with outer and inner jackets of perforated non-corrosive iron. The space between the outer `and inner jackets is completely lled with coarse sand while the space inside the inner jacket is partly filled therewith. A vessel 16 with a fusible bottom 17 is positioned upon the sand in the inner jacket. The vessel is lled to level 19 with a covering liquid such as water containing pieces of the substance such as phosphorus which ignites in the presence of oxygen.

A packer 7 with a peripheral seal 9 is set in the casing 1 above the liner 20a in cage 15. The packer is initially tightly sealed with closure caps 5 and 8 to a horizontal position. A tubing 4 is shown lowered through the pivoted closure caps 5 and 8 and central opening 14 of the packer down to almost the level of the cage 15. Ihe lowermost section of the tube 4 contains an upwardly floating check valve in the form of a ball valve 10, a sealing member 11 and a valve closing spring 12. The tubing 4 carries elastic or resilient centering devices 6 at about 10 meter intervals. Besides their centering function, the devices 6 also divide the space above the packer into separate cornpartments 27 to provide better heat insulation for the tube 4.

The free space above the packer 7 between the casing 1 and tubing 4 is filled with nitrogen under pressure or with water, introduced through valve 24.

As shown in FIG. 2, the packer 7' is shown through which is passed a second tubing 28 with a valve 24 at its upper end. This second tubing 28 permits the 'introduction of hydrocarbons for combustion and the insertion of a pressure gauge 29 which is lowered by a supporting cable 30 into the cage 15.

A plurality of packers 21 are shown located in the liner a for the purpose of controlling the fluids intro-A duced into the oil bearing sand 26.

Casing 1 is closed at the top by a cover 23 which is equipped with a Valve 24. Tubings 4 and 28 carry valves and 24 at their upper ends. In the mineral oil industry it is sometimes common practice to provide perforated liners of smaller diameters than casing 1. Such a smaller perforated liner is shown at 20h.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The process of the present invention is carried out in the apparatus shown in the drawing by first lowering a tubing temporarily into the casing 1 above the packer 7 while the closure caps 5 and 8 maintain the packer secure. Through this tubing an oil solvent or an emulsion thereof in fwater is introduced in order to remove the residual oil from the casing. Suitable solvents are: gasoline, a mixture of water with alcohols or a mixture of surface active chemical solvents in water or chlorinated hydrocarbons.

The solvent or emulsion is circulated until the casing has been thoroughly cleaned. This temporary tubing is then removed and substituted by the permanent tubing 4 which is lowered into the casing 1 through the central opening 14 of the packer by pivoting the closure caps 5 and 8 to their vertical positions. The permanent tubing 4 is lowered to almost the level of the cage 15.

Nitrogen under a pressure of about 5-10 atmospheres above deposit pressure or water is introduced through the valve 24 into the free space above the packer 7 between the casing 1 and the tubing 4. Heated modified gases of combustion at a temperature of about ZOO-295 C. are now forced through the tubing 4 and through the boring into the oil deposit. After about 48 hours the gases of combustion are gradually enriched with oxygen. This enrichment is continued `for another 48 hours until the oxygen content is increased to 21% for the purpose of oxidizing the oil or bituminous residues.

After the deposited oil has been thoroughly removed from the parts of the apparatus and from the immediate neighborhood of the boring so that the porous explosion retarding regions in the deposit can be activated, the temperature of the activated gases of combustion is slowly increased to about 275 to 475 C. These activated gases of the combustion consist of carbon dioxide, oxygen and steam. With this increased temperature the readily fusible bottom 17, formed for example from tin having a melting point of about 232 C., so that the bottom 17 of vessel 116 melts so as to lose the protective liquid therein and the pieces of phosphorus 18 are ignited by the oxygen.

In an alternative form vessel 16 also contains a catalytic agent such as platinum to initiate in situ combustion with the formation of a burning front between two specially prepared borings.

As particularly shown in FIG. 2, the second tubing 28 facilitates the introduction of hydrocarbons for combustion until the oil content of the burning space is sufficiently high to support combustion.

When the second tubing 28 is no longer needed for the introduction of fuel, a pressure gauge 29 is lowered by the supporting cable 30 into the cage 15. Fluid pressure readings are transmitted by the cable to above ground. The flow resistance encountered by gas and steam, e.g., by the activated gases of combustion, in the regions of combustion is usually very slight. This flow resistance has to be kept practically constant in the regions between the treatment and leading borings. Increased o'w resistance can result, for example, from the penetration of flooding water into the path of combustion. In a particular embodiment an increased pressure reading on the pressure gauge activates an increase in the amount of oxygen that is added to the gases of combustion so as to increase the underground permeability to gases.

According to another embodiment, when activated gases of combustion of different compositions are introduced at different levels of the deposit, the cage or basket 15 is perforated only below the level of the uppermost packer 21. The activated gases of combustion having different compositions are introduced separately from above ground through tubing 28 to the upper strata and through tubing 4 to the lower strata.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiment is, therefore, to be construed as fairly illustrative and not limitative of the remainder of the specification and claims in any way whatsoever.

EXAMPLE Before the in situ combustion is started, 500; cu. meters per hour of modified gas of combustion at normal conditions is introduced during a period of 48 hours through the `apparatus shown in FIG. 1. This modied gas of combustion comprises 55i20% steam, 41.51 15% CO,l and 3.5i% nitrogen. Under a gauge pressure of 85 atmospheres in the deposit, the condensaion temperature is about 295 C. so that at the foot of the boring this temperature builds up with the displacement of large amounts of mineral oil. The fusible bottom 17 of vessel 16 now releases the ignition material. During the next 48 hours the modified gas of combustion is changed by continually increasing the oxygen content to 21% from its initial composition of 53i20% steam, 39il5% CO2, 3.2i10% N2 and 3i10% O2 so that a weakly activated gas of combustion of the composition 40.2i20% steam, 35i- CO2, 3.08i10% N2 and 2l.0;l l0% O2 is present. With this weakly activated gas of combustion the in situ combustion in the boring and in its immediate neighborhood proceeds at a lower temperature.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Consequently, such changes and modifications are properly, equitably and intended to be, Within the full range of equivalance of the following claims.

What is claimed is:

1. An apparatus for the extensive recovery of liquid and solid bitumens from underground deposits comprising:

.(a) a casing (1) having an upper end and a lower end adapted for insertion in a borehole;

(b) a packer (7) positioned in said casing intermediate said ends;

(c) a tubing (4) having a footing (13) extending through said packer;

,(d) a ball check Valve (10) in said footing maintained in closed position by a compression spring (12), said footing retaining said spring;

(e) a cage (15) filled with coarse particulate material positioned in said lower end of the casing below said footing;

(f) a vessel (16) positioned within said cage having means .(18) therein for igniting; and

(g) a second tubing (28) extending through said packer into said cage adapted to permit the introduction of pressure gauge (29).

References Cited UNITED STATES PATENTS 2,895,555 7/1959 De Priester 166-59 2,913,050 11/1959 Crawford 166-59 X 3,072,188 1/1963 Morse 166-59 X 3,087,545 4/1963 OBrien 166-59 X 3,109,482 11/1963 OBrien 166-59 X 3,298,439 l/l967 Rees 166-59 STEPHEN J. NOVOSAD, Primary Examiner

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