US3194311A

US3194311A - Control of combustion in in situ treatments of carbonaceous deposits

Info

Publication number: US3194311A
Application number: US162211A
Authority: US
Inventors: Walter C Sheldon
Original assignee: Marathon Oil Co
Current assignee: Marathon Oil Co
Priority date: 1961-12-26
Filing date: 1961-12-26
Publication date: 1965-07-13
Anticipated expiration: 1982-07-13

Description

y 1965 w. c. SHELDON 3,194,311

CONTROL OF COMBUSTION IN IN SITU TREATMENTS OF United States Patent 3,194,311 CONTROL OF COMBUSTION IN IN SITU TREAT- MENTS 0F CARBONACEOUS DEPOSITS Walter C. Sheldon, Englewood, Colo., assignor to Marathon Oil Company, a corporation of Ohio Filed Dec. 26, 1961, Ser. No. 162,211 Claims. (Cl. 166-11) This invention relates to a treatment of underground reservoirs and more particularly relates to methods of preparing underground carbonaceous deposits for subsequent in situ combustion recovery treatments.

In situ combustion techniques for recovery of petroleurn values from carbonaceous deposits are well known in the art. They are frequently used for secondary recovery treatment of oil reservoirs when such reservoirs can no longer be economically worked by conventional pumping methods. Such methods also are used for initial treatment of other types of petroleum deposits when the viscosity of the material in a reservoir is too high for economical pumping operations. Such deposits may include tar sands and other reservoirs containing viscous petroleum liquids.

These latter deposits frequently occur in relatively thick formations. For purposes of this invention a relatively thick formation may be defined as one that exceeds thirty feet in thickness; When treating such relatively thick formations or deposits by in situ combustion operations, the upper portion of the deposit tends to burn or burns much more rapidly than its lower portions. This apparently is the result of difierences in density between the injected air and the hydrocarbons (oil) in place which causes a propagated flame front to spread upwardly and outwardly, while downward movement is retarded; and undesirable overburning of limited areas of the reservoir above the point of initial flame propagation occurs, resulting in loss of valuable petroleum material which otherwise might have been recovered.

It is an object of this invention to provide a simple, efiicient and economical method of treating relatively thick underground reservoirs in order to condition or prepare them for controlled in situ combustion recovery operations.

It is another object of the invention to provide a simple,

effiicient and economical method of preparatory treatment for a lower portion of combustion zones in a carbonaceous deposit for providing balanced or controlled in situ combustion throughout the upper and lower portions thereof.

It is still another object of the invention to provide a simple, economical and efficient method of controlling the direction and rate of advance of the combustion front in in situ combustion operations performed in relatively thick petroleum reservoirs.

When using the method of controlling in situ combusion in carbonaceous deposits according to this invention, for formation to be treated is penetrated by a plurality of wells, and in the usual practice these wells will'include an injection'well and one or more production wells. The production wells may be located in any of the conventional'or other spacing pattern employed in recovery of crude oil by other secondary methods. One such pattern is the inverted five-spot pattern in which a substantially centrally located injection well has four production wells spaced at substantially even intervals thereabout.

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As shown in the accompanying drawing, the injection well 1 and a plurality of production Wells 2a and 2b should be drilled downward through substantially the entire depth of the formation 3 to be treated. A packer 4 is set in injection well 1 to separate the deposit 3 into two parts. Preferably, packer 4 is located in relation to the permeability of the structure and in some instances two packers may be used at vertically spaced points in the well.

Casing 5 may be placed in injection well 1 to any desired depth, and

casing

6a and 6b preferably are provided for wells 2a and 2b, respectively. Preferably the casings are capped at the surface, and support one or a plurality of conduits. Conduits '7 and 7a are supported in casing 5 to deliver fiuid (solution or air) to selected depths in injection Well 1 and conduit 8a in casing 6a and conduit 8b in causing 6b deliver the production material to the surface. In preparing for operation, an aqueous solution of a suitable combustion catalyst or an oil soluble catalyst is injected through the injection well below the packer or packers and introduced into the lower zones or portions of the deposit to be treated. A catalyst is employed to serve one or both of two functions, i.e., to promote or control combustion and/or initiate combustion by spontaneous combustion. The catalyst is introduced through the well as a solution so as to distribute it through the portions of the formation where combustion is to be controlled. After combustion is initiated, the combustion front movement is controlled by the relative distribution of air or other oxygen-containing gas.

In one procedure utilizing my invention, the catalyst system is comprised of an aqeous solution of a suitable metal salt which is initially injected into the deposit through the injection well below the packer, and between packers if a plurality of packers is used, and thence into the surrounding formation. The pyrophoric material is then formed in place from the injected solution by suitable treatment, such as the introduction of hydrogen sufide to form a pyrophoric metallic sulfide when a pyrophoric material is desired. Under some circumstances, a pyrophoric material will not be desired, in which case an aqueous solution of a suitable catalyst such as a metallic salt is injected without further treatment. Thereafter, air is injected into the treated area. If pyrophoric ma terial has been utilized, spontaneous combustion results from the air introduction. Where a non-pyrophoric catalyst is employed, conventional ignition practices will be required.

As an example of utilizing a pyrophoric material, an

through an injection well, followed by the injection of a quantity of hydrogen sulfide gas or hydrogen sulfide in natural gas. The FeCl and the hydrogen sulfide react to form FeS and hydrogen chloride. When this reaction is essentially complete, a quantity of dry air is injected, which causes spontaneous ignition of the FeS and thus propagation of a combustion front in the lower portion of the deposit. The quantity of hydrogen sulfide which is injected is preferably in a stoichiometric excess of that required for complete reaction of the iron chloride, or in excess of that required to completely react the FeCl solution above described.

The air injection is an important factor of the foregoing method of initiating the combustions front action. Since the catalyst used is initially in an aqueous solution, the air flow must be continued until such time as it is substantially dry in order for it to spontaneously ignite.

a i Once combustion-has been initiated thequantity of air injected is determined by desired temperatures and'jrates of flame front movement. Further, by-use of suitable temperature sensitive probes or'thermocouples, together flow paths to the formation to be treated. Otherwise, multiple strings of tubing may be used. By useof suita-'; ble packers and selective perforation of the outer casing;

it is possible to initiate afiame front atany. of a plurality in an aqueous solution is passed" downwardly through the appropriate passage to the desired portions of the forma-.

tion. Next, hydrogen sulfide or hydrogen sulfide I in natural gas, if such is required, is passed downwardly through the same passage asthe catalyst. air or other oxygen enriched gas is passed down through the fiow paths in quantities appropriate to maintain temperature and/or rate of frontal advance. a

In either of the foregoing described procedures, it is I sometimes desirable'to leave the packer or packers in place since .it'yiel'ds a greater degree of'control over, the oper-.

Subsequently,

' may beavailed of within the spirit and scope 'of the invention as definedinth hereunto. appendedlclaims.

I claim:

1. YA method for controlling combustion'permeable undergroundcarbonaceous deposits, Whichcomprisesjm troducing a combustion catalyst through an injection well into ,a selectedlevel throughout a permeable portion of such a depositbetwen said injection well and a production I well, directing oxygen-containing gas through saidiinjecof levels, In such an arrangement, the: catalytic material V well. p o a v 2.,1A method for controlling combustion in permeable underground carbonaceousdeposits, which i comprisesuina troducing a combustion catalystrthrough an'injection welli 1 tion Well into the portion of said deposit containing the.

combustion catalyst in a quantity .su'fficient to initiate zones of spontaneous combustiontherein, propagating a. combustion front movement fromthe spontaneousycombusion zones by 1 continued introduction of oxygen-con raining gas into the selected level'of thepermeable portion, introducing oxygen containinga gas through a separated passage ins-aid injection well into vanjadjoining level- V 'of the permeable :deposit'after. a predetermined interval for initiatinga combustion front movementims aid adwjoining level. substantially,.simultaneously withthe first I combustion front movement, and removing evolved prodmovements through thesproduction':

ucts of both frontal into {a selected level throughouta.permeable-portionof 'ation relative to the rates of air injection to the'fla'me;

front.- Fromthe foregoing, it will beapparent that at least-some permeability :is requiredin the deposit in whichjthein situ combustion operation is to be .con-

ducted after preparation for treatment according to this invention It is to be understood that in lesspermeable formations, When necessary, sand fracturing. oro hydrofracturing techniques may be utilized 'as'a preliminary step in the treatment;

With processes according'to this invention; it is possible'for an operator to treat relatively thick formations 'as defined hereinbefore andto obtain balanced or selective control of heat front movement. and beneficiation through the entire thickness of such formation. This may be done "by initiating a .combustion frontadjacent the bottom of the formation and allowing the gravity dif ference between injected air or oxygen-enriched gases and thereservoir fluids to exert the characteristic property of causing flame or combustion frontpropagation upwardly and outwardly from the point of ignition. Alternatively,

it is possible. to initiate in situ combustion simultaneously at a plurality of levels in the same formation, and by conunderground carbonaceous deposits, which comprises 'in'-;

troclucing' a combustion catalyst through an injectiouiwell, into a selected.levelithroughout-apermeable portion of i such a deposit :between said injection well and a;produc-, tionwell, directing oxygen-containing gas throughsaid 1 injection .well into .the portion of said deposit. containing 1 trolof'the' air or oxygen input to plurality of flame or,

combustion fronts, to obtain'a controlled ?or balancedv from the formation; a

7 When combustion takes place concurrently in both combustion zones, uniform rate of advance isnot' required, and one. advance may be rapid and the-other quite new; Also, it is not necessary to maintain constant -temperatures'througha given zone, or uniform tempera-.

tur'e'sin the plurality of zones. Frontal movement is slow'when oxygen supply is low andincreases as more oxygen is-supplied Thus, control of oxygen input may be regulated to establish'any desired condition in the operation.

be used will include dimethyl zinc, cacodyl and hydrides; of phosphorus, boron and silicon. Another type of 'jspon-- taneous'reaction which may be availed of is the reaction of chlorine onv finely divided antimony. V Changes. and modifications: of materials and procedures When spontaneous "heating. and eduction of variable petroleum constituents such a deposit between said injection well and a production well, directing oxygen-containing gas throughsaid injec- =tion, introducinggoxygen-containing gas; through} a sepa-; combustioncatalystina quantity, sufficient,to'initiateizones' of the permeable deposit after a predetermined period of .bustion front movement from thespontaneous' combustion zones by continued introduction ;of oxygen-containing; gas

into the selected level of the 'permeable portion, introduce; ingoxygen-containing gas through a separated passage in said injection Welljintoan adjoining overlaying level of:

the permeable depositafter a predetermined periodof combustionfront propagation at the selected level for initiating a combustion front movement insaid iadjoin-y ing level substantially simultaneously with thefirstcom; bustion front movement'andat adifferent;ratea-than' in said selected level, and. removing evolved products of both.

frontal movements through'th'e, production well.

3. A method for controlling" combustion in permeable the combustion catalyst ina :quantity suliicie'ntgto initiate zones. of spontaneouszcomb'ustiontherein, propagating a" combustion front movementfroimthe spontaneous com-"'- -;bustion zones by continued introduction 'of ;oxygen=eontaining gas: into the: selectedlevel of the permeable Per-: tion', introducing oxygen-containing; gasthronghalseparatedpassage in said injection well into. an adjoining level; of the permeable deposit after a predeterminedperiod of combustion front propagation .atr'the. isele'ected- :level; for initiating a combustion front movement in I said adjoining +7 level substantially simultaneonslywitlrthe 1first combus tion-front movement, controlling the rate ofcbmbustion ,frontpropagation at aselectedratefin therespective levels by introducing,- different quantitiesrof simultaneous-oxy--= gen-containing. gas thereto, andremoving'evolved products of both. frontalrnovements through thejproduction ;well..

zones of spontaneous combustion therein, propagating a combustion front movement from the spontaneous combustion zones by continued introduction of oxygen-containing gas into the selected level of the permeable portion, introducing oxygen-containing gas into an adjoining overlaying level of the permeable deposit after a predetermined period of combustion front propagation at the selected level for initiating a combustion front movement in said adjoining level substantially simultaneously with the first combustion front movement, maintaining substantially uniform rate of simultaneous combustion propagation at the respective levels by introducing more oXygen containing gas into the lower level than is introduced into the upper level, and removing evolved products of both frontal movements through the production well.

5. A method for controlling in situ combustion in relatively thick underground carbonaceous deposits, which comprises penetrating a permeable portion of such a deposit With at least one injection well and at least one production well at horizontally distant locations, disposing a packer in one of said injection wells intermediate the top and bottom of the deposit, introducing a combustion catalyst through said injection well into the permeable portion below the packer level, directing oxygen-containing gas through said injection well into the portion of the deposit containing the combustion catalyst in a quantity suflicient to initiate spontaneous combustion therein, introducing oxygen-containing gas through a separated passage in said injection well into the permeable portion above the packer at a predetermined time interval after initiating combustion in the underlying portion thereof while continuing introduction of oxygen-containing gas into the underlying portion, and removing evolved products of the combustion in both levels through the production well.

6. A method for controlling in situ combustion in relatively thick underground carbonaceous deposits, which comprises penetrating a permeable portion of such a deposit with at least one injection well and at least one production well at horizontally distant locations, disposing a packer in one of said injection wells intermediate the top and bottom of the deposit, distributing an aqueous solution of pyrophoric forming metal throughout the permeable portion below the packer level between the injection well and the production well, next introducing hydrogen sulfide gas into the permeable portion containing the pyrophoric metal, directing oxygen-containing gas into the permeable portion containing the pyrophoric metal and hydrogen sulfide gas in a quantity sufficient to initiate spontaneous combustion in the material previously introduced and establish a frontal advance therein, introducing oxygen-containing gas into the permeable portion above the packer at a predetermined time interval after initiating combustion in the underlying portion thereof, so as to initiate a frontal advance in said upper level, and removing evolved products of the combustion in both levels through the production well.

7. A method for controlling in situ combustion in relatively thick underground carbonaceous deposits, which comprises penetrating a permeable portion of such a deposit with at least one injection Well and at least one production well at horizontally distant locations, disposing a packer in one of said injection wells intermediate the top and bottom of the deposit, distributing an aqueous solution of FeCl throughout the permeable portion below the packer level between the injection well and the production well, next introducing hydrogen sulfide gas into the permeable portion containing the FeCl directing oxygen-containing gas into the permeable portion containing the -FeCl and hydrogen sulfide in a quantity sufficient to initiate spontaneous combustion in the material previously introduced and establish a frontal advance therein, introducing oxygen-containing gas into the permeable portion above the packer at a predetermined time interval after initiating combustion in the underlying portion thereof, so as to initiate a frontal advance in said.

upper level, and removing evolved products of the combustion in both levels through the production well.

8. The method for controlling in situ combustion in relatively thick underground carbonaceous deposits, which comprises penetrating substantially the entire depth of a permeable portion of such a deposit with at least one injection well and at least one production well at horizontally distant locations, disposing a packer in one of said injection Wells intermediate the top and bottom of the permeable portion, distributing an aqueous solution of FeCl;,, throughout the per-meable portion below the packer level between the injection well and the production well, next introducing hydrogen sulfide in natural gas into the permeable portion containing the FeCI directing dry air into the permeable portion containing the 'FeCl and hydrogen sulfide in a quantity in a stoichiometric excess of that required to completely react the FeCl solution thereby initiating spontaneous combustion and establishing a frontal advance in the permeable portion below the packer level, introducing oxygen-containing gas through a separated passage into the permeable portion above the packer at a predetermined time interval after initiating combustion in the underlying portion so as to initiate and maintain a simultaneous frontal advance in the upper level, and removing evolved products of both frontal movements through the production well.

9. A method for controlling in situ combustion in relatively thick underground carbonaceous deposits, which comprises penetrating a permeable portion of such a deposit with at least one injection well and at least one production well at horizontally distant locations, disposing a packer in one of said injection Wells intermediate the top and bottom of the deposit, introducing a combustion catalyst through said injection well and throughout the permeable portion below the packer level, directing oxygen-containing gas through said injection well into the portion of the deposit containing the combustion catalyst in a quantity suflicient to initiate spontaneous combustion therein, introducing oxygen-containing gas through a separated passage into the permeable portion above the packer at a predetermined time interval after initiating combustion in the underlying portion thereof so as to initiate a frontal advance in the upper level substantially simultaneously with the first combustion front movement, and removing evolved products of both frontal movements through the production well.

10. A method for controlling in situ combustion in relatively thick underground carbonaceous deposits, which comprises penetrating a permeable portion of such a deposit with at least one injection well and at least one production well at horizontally distant locations, disposing a packer in one of said injection Wells intermediate the top and bottom of the deposit, introducing a combustion catalyst through said injection well and throughout the permeable portion below the packer level, directing oxygen-containing gas through said injection well into the portion of the deposit containing the combustion catalyst in a quantity sufiicient to initiate spontaneous combustion therein, introducing oxygen-containing gas through a separated passage into the permeable portion above the packer at a predetermined time interval after initiating combustion in the underlying portion thereof so as to initiate a frontal advance in the upper level substantially simultaneously with the first combustion front movement, determining the combustion front temperatures in the overlaying and underlying portions under treatment, varying the combustion front tempera- 61F. and rate of advance in each said portion by changing the input of oxygen-containing gas thereto, and removing evolved products of both frontal movements through the production well.

(References on following page)

Claims

1. A METHOD FOR CONTROLLING COMBUSTION IN PERMEABLE UNDERGROUND CARBONACEOUS DEPOSITS, WHICH COMPRISES INTRODUCING A COMBUSTION CATALYST THROUGH AN INJECTION WELL INTO A SELECTED LEVEL THROUGHOUT A PERMEABLE PORTION OF SUCH A DEPOSIT BETWEEN SAID INJECTION WELL AND PRODUCTION WELL, DIRECTING OXYGEN-CONTAINING GAS THROUGH SAID INJECTION WELL INTO THE PORTION OF SAID DEPOSIT CONTAINING THE COMBUSTION CATALYST IN A QUANTITY SUFFICIENT TO INITIATE ZONES OF SPONTANEOUS COMBUSTION THEREIN, PROPAGATING A COMBUSTION FRONT MOVEMENT FROM THE SPONTANEOUS COMBUSION ZONES BY CONTINUED INTRODUCTION OF OXYGEN-CONTAINING GAS INTO THE SELECTED LEVEL OF THE PERMEABLE PORTION, INTRODUCING OXYGEN-CONTAINING GAS THROUGH A SEPARATED PASSAGE IN SAID INJECTION WELL INTO AN ADJOINING LEVEL OF THE PERMEABLE DEPOSIT AFTER A PREDETERMINED INTERVAL FOR INITIATING A COMBUSTION FRONT MOVEMENT IN SAID ADJOINING LEVEL SUBSTANTIALLY SIMULTANEOUSLY WITH THE FIRST COMBUSTION FRONT MOVEMENT, AND REMOVING EVOLVED PRODUCTS OF BOTH FRONTAL MOVEMENTS THROUGH THE PRODUCTION WELL.