CA1173356A - In situ recovery of viscous materials - Google Patents
In situ recovery of viscous materialsInfo
- Publication number
- CA1173356A CA1173356A CA000394280A CA394280A CA1173356A CA 1173356 A CA1173356 A CA 1173356A CA 000394280 A CA000394280 A CA 000394280A CA 394280 A CA394280 A CA 394280A CA 1173356 A CA1173356 A CA 1173356A
- Authority
- CA
- Canada
- Prior art keywords
- boreholes
- injection
- steam
- formation
- borehole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000011345 viscous material Substances 0.000 title claims abstract description 16
- 238000011084 recovery Methods 0.000 title claims description 12
- 238000011065 in-situ storage Methods 0.000 title claims description 9
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 98
- 239000000463 material Substances 0.000 claims abstract description 24
- 238000005553 drilling Methods 0.000 claims abstract description 12
- 238000002347 injection Methods 0.000 claims description 57
- 239000007924 injection Substances 0.000 claims description 57
- 238000000034 method Methods 0.000 claims description 44
- 238000004519 manufacturing process Methods 0.000 claims description 28
- 229930195733 hydrocarbon Natural products 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 150000002430 hydrocarbons Chemical class 0.000 claims description 13
- 239000004215 Carbon black (E152) Substances 0.000 claims description 12
- 238000010795 Steam Flooding Methods 0.000 claims description 8
- 238000010793 Steam injection (oil industry) Methods 0.000 claims description 8
- 208000036366 Sensation of pressure Diseases 0.000 claims description 5
- 230000000977 initiatory effect Effects 0.000 claims description 5
- 239000000839 emulsion Substances 0.000 claims description 3
- 239000002904 solvent Substances 0.000 claims description 3
- 208000010392 Bone Fractures Diseases 0.000 claims 10
- 206010017076 Fracture Diseases 0.000 claims 10
- 238000005755 formation reaction Methods 0.000 abstract description 53
- 239000010426 asphalt Substances 0.000 abstract description 6
- 238000007630 basic procedure Methods 0.000 abstract 1
- 229940090044 injection Drugs 0.000 description 14
- 239000003921 oil Substances 0.000 description 8
- 230000008569 process Effects 0.000 description 7
- 230000000638 stimulation Effects 0.000 description 6
- 239000011269 tar Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- 230000007246 mechanism Effects 0.000 description 4
- 239000011275 tar sand Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000002791 soaking Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 125000001183 hydrocarbyl group Chemical group 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000012056 semi-solid material Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/18—Repressuring or vacuum methods
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/30—Specific pattern of wells, e.g. optimising the spacing of wells
- E21B43/305—Specific pattern of wells, e.g. optimising the spacing of wells comprising at least one inclined or horizontal well
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
Case 5562 CLR/nlh/ejl ABSTRACT OF THE INVENTION
Viscous materials, such as bitumen, can be recovered from subsurface earth formations such as tar sands, by forming a shaft, or first borehole, to the base of the desired subsurface formation, extending the shaft into the underburden, forming a tunnel in the underburden outwardly from the shaft, and drilling second boreholes outwardly and upwardly from the tunnel into the subsurface formation.
Steam is injected into these second boreholes unit the viscosity of the material is reduced, and the liberated material is collected. Variations of this basic procedure are discussed.
Viscous materials, such as bitumen, can be recovered from subsurface earth formations such as tar sands, by forming a shaft, or first borehole, to the base of the desired subsurface formation, extending the shaft into the underburden, forming a tunnel in the underburden outwardly from the shaft, and drilling second boreholes outwardly and upwardly from the tunnel into the subsurface formation.
Steam is injected into these second boreholes unit the viscosity of the material is reduced, and the liberated material is collected. Variations of this basic procedure are discussed.
Description
Case 5562 GLR/nlh/ejl ~ 3 ~ 10/14/81 BACKGROUND OF THE INV~:NTION
This invention relates to a method for the recovery of materials such as minerals and viscous hydrocarbons from subsurface earth formations. In a particular application of the invention, the method relates to the in situ recov-ery of bitumen from -tar sands or oil sands.
Various techniques have been considered for recovering bitumen from tar sand formations that are too deep for surface miningO These techniques typically involve raising the temperature of the formation to reduce the viscosity of the bitumen, to assist in the separation of the bitumen from the sand matrix, and to promote movement of the liberated bitumen. The temperature can be raised by variows means, such as electrical heating, fire flooding, steam flooding, etc. Dwe to the high expenses and low recovery rates, these techniques typically have not been too successful.
There are ~lso various types of mining techniques frequently used in the prior art to reach and process these
This invention relates to a method for the recovery of materials such as minerals and viscous hydrocarbons from subsurface earth formations. In a particular application of the invention, the method relates to the in situ recov-ery of bitumen from -tar sands or oil sands.
Various techniques have been considered for recovering bitumen from tar sand formations that are too deep for surface miningO These techniques typically involve raising the temperature of the formation to reduce the viscosity of the bitumen, to assist in the separation of the bitumen from the sand matrix, and to promote movement of the liberated bitumen. The temperature can be raised by variows means, such as electrical heating, fire flooding, steam flooding, etc. Dwe to the high expenses and low recovery rates, these techniques typically have not been too successful.
There are ~lso various types of mining techniques frequently used in the prior art to reach and process these
2~ deep tar sands. Some of the techniques used involve drilling or excavating one or more vertical shafts into the tar sand formation and then extending lateral horizontal tunnels from the shaft. U.S. 4,160,481 discwsses some of -these techniques.
The inherent and expressed disadvantages of the prior art are overcome with the present invention.
.
Case 5562 GLR/nlh/ejl ri~ ~ :L o/l4/sl S~MMA~Y OF THE INVENTION
_ There are several embodiments involved in the present invention, and -these generally involve different methods of entering and then thermally treating the tar sand forma-tion. All o-f the embodiments involve a first step of drill ing or excavating a borehole or shaft to the base of the subsurface formation to be exploited. Typically this for-mation is a tar sands or oil sands formation, but the tech-nique can be used in other subsurface formations that com-prise solid and semi-solid and viscous materials such as kerogen, high viscosity hydrocarbon materials such as heavy oils, inorganic ores, and the like.
The next step involves extension of the borehole or sha-ft below the base of the formation. This involves :15 drilling or excavating into the stratum immediately below .;the formation to be exploited. This terminal end of the shaft or borehole, in the stratum below the desired forma-tion, is then, optionally, enlarged to form an operating chamber below the base of the desired formation.
The next step involves the excavating of one or more tunnels extending laterally from this operating chamber in the stratum below the base of the formation.
The next step concerns the drilling of a plurality of ~ second boreholes extending substantially upwardly and out-: 25 ward into the desired formation from these tunnels.
'The above-listed steps are common to the first phase of the invention. Various embodiments of the invention are practiced by altering the succeeding steps.
For example, in one embodimen-t, steam is conducted down the first borehole or shaf~ and along the -tunnel and . .
Case 5562 &LR/nlh/ejl ~ 10/14/81 thence injected into the plurality of second boreholes drilled from the t~mnel. Or steam can be generated in the chamber and then injected via the tunnel into the plurality of boreholes. It is a :Eeatwre of this embodiment that the steam used is at a pressure above the fracture pressure of the formation to be exploited. It is a characteristic of oil sands or similar hydrocarbon deposits that any flow channels in the formation matrix are effectively plugged with the solid or semisolid hydrocarbon material. The rate of injection for steam or any other heating medium at . subfracture pressures would be -too low to achieve the rate of heat input necessary to recover economically the hydro-carbon. S-team pressures above fracture pressure will per-mit high rates of injection. The injection of this steam is maintained for a time period resulting in an increase of the temperature o-f that portion of the formation surround-ing the boreholes and the chamber. A "soaking" cycle can follow, for a discrete time period. When the pressure of the steam on the system is released, any liberated material of reduced viscosity can move, by gravity, and by means of the increased pressure due to the steam injection, to the lower portions of the second boreholes and thence via the t~mnel to the lower portion of the chamber found in the stratum below the desired formation. The injection/produc-tion cycle is repeated until insufficient additional hydro-carbon is produced to warrant further cycles. The recovered viscous material can be moved to the surface, by means well-known in the art, for further processing.
Case 5562 ~ 3 ~ GL~/0lh/ei8l ; The above-mentioned injec-tion/production cycle is one of several methods for recovering heavy hydrocarbons from underground formations. In this invention, two recovery mechanisms are described ~-md used.
One mechanism involves a stimulation process, such as by steam. This process involves a single well and is well-known in the art as "huff and puff," since steam is in-jected into a reservoir optionally remaining for a finite soaking period, and then allowed to vent back through the entrance. Hydrocarbon production through the entrcmce is then noted. Several stimulation cycles may be needed for an appreciable outflow of desired ma-terial. The injection well and the production well are the same well, depending on the time during the stimulation process.
;~ 15 The other mechanism is called a "drive," and at least two wells are used. ~ere, for example, s-team can be in-jected into one well, and, after a finite time, production is noted from a production well.
; Pressure cycling, with variations in the s-team pres-sure, can be used for either mechanism.
In another embodiment, steam, at a pressure above the fracture pressure of the for~ation to be exploited, is in-jected into the boreholes, as in the above-described embodiment, continuing the injection/ production cycles until the viscous material between the wells is made mobile, stopping the steam flow into the injector wells, completing selected second boreholes as producer wells, initiating a flooding procedure, exemplified by a fire flood, water flood, steam flood, emulsion flood, or solvent flood, flowing from injector wells to production wells, and Case 5562 GI.R/nlh/ejl 10/1~/81 ~ ~ 73 3 ~d~
collecting the liberated ma-terial of reduced viscosity as before.
In another embodiment, after the second boreholes are extended subs-tantially upward and outward into the desired formation from the t~mnels, some of these second boreholes are completed as injector wells, and the remainder of the second boreholes are completed as producer wells. Then steam, at or above fracturing pressure, is injected into the second boreholes completed as injector wells. A nu~ber 10 of injection/production cycles are carr:ied out so as -to in ` crease the temperature of that portion of the formation surrounding the boreholes. The steam flow into -the bore-holes designated as injector wells is -then stoppecl, and a ~` flooding procedure is lnitiated, using the same or a dif-ferent procedure from the choices noted above, such that the flooding material flows from injector wells to producer wells. The liberated material of reduced viscosity is then collected as before.
In a further embodiment of the invention, steam, at a pressure above fracturing pressure of the desired forma-tion, is injected into the second boreholes, as the begin-ning of a stimulation phase. The injection/production cycles of steam stimulation are continued for some time so as to increase the temperature of the surrounding formation.
Selected second boreholes are completed as producer wells, and a steam flood is then initiated, with the variation that the steam pressure is cylically varied.
Following steps in the procedure are as previously described.
' -Case 5562 GLR/nlh/ejl 10/1~/81 ~ 3 ~
Tn another embodimenk, after the second boreholes are drilled from the chamber into the desired forma-tion, some of these second boreholes are completed as injector wells and the remainder are completed as producer wells. Then steam, at a pressure above the fracturing pressure, is injected into the boreholes comprising the injector wells.
The previously-described injection/production cycles are carried out, resulting in a -temperature increase of the surrounding formation. A steam flood is then initiated, with the modification that the steam pressure is cyclically varied during the flooding. The steam pressure can be varied from about atmospheric to the operating pressure.
Liberated hydrocarbon material i5 then treated as discussed above.
15The embodiments discussed above have one or more of the advantages discussed below.
A central shaft, with associated tunnels and bore-holes, has the advantages over wells drilled from the surface of:
20~a) reduced drilling costs, (b) horizontal wells or boreholes are easier to drill, (c) there is less heat loss be-tween the surface and the tar sands or oil sands, formation, 25or reservoir, and (d) the movement of recovered oil from the for-mation to the surface is more efficient than when wells are drilled from the surface.
The advantages of continuing the shaft or borehole into the zone below the formation or reservoir include:
:`~
:
Case 5562 GLR/nlh/ejl ;~5~q 10/14/81 (a~ increased safety, since an operating chamber and the tunnels are formed in the zone below -the formation, (b) wells can be cemented in the zone below the 5or~ation, while there is great difficulty in cementing wells in an oil sands or tar sands formation, and (c) it is easier and safer to complete wells that have their beginning or terminus in the 10tunnels below the formation.
~; The advantage of using -tunnels from the central shaft as the starting point for the boreholes, rather than drilling the boreholes radially outward from the shaft, is that the boreholes can be drilled parallel to one another;
giving a more uniform coverage of the reservoir. The rectangular Iayout with tunnels is also more amenable to a repeated pattern.
Using a steam pressure greater than the fracturing ~ pressure of the formation allows injection of the steam - 20 into the formation or reservoir at a sufficient rate to recover the hydrocarbon product economically. The greater pressure also allows a higher percentage of the formation or reservoir to be con-tacted, and this gives a higher usage efficiency for the injected steam. This greater pressure also allows a greater percentage of the formation to be processed.
Cyclical operation involving varying the steam pres-sure improves the recovery of the product and offers an improved oil/steam ratio. The "cycles" can vary in time - 30 from about 10 to about 50 hours, from peak to peak.
Case 5562 GLR/nlh/ejl ~ 3~3,~ 10/1~/81 Other advantages of the embodiments of the process will be noted by those who are skilled in the arts involved in this process.
', DESCRIPTION OF THE DRAWIN&S
5Figure 1 shows a side view of the first borehole ex-tending below the base of the formation and into the under-burden, with a tunnel extending normal to the borehole and secondary boreholes extending normal to the tunnel and up-wardly into the desired formation.
10Figure 2 shows a top view of the first borehole,the tunnel, and the secondary boreholes.
DETAILED DESCRIPTION OF THE INVENTION
The described process for the in situ recovery of viscous materials can be used where the desired formation or reservoir is greater than about 30 meters from the surface. For example, the invention is operable where the formation or reservoir is from about 90 to about 900 meters below the surface.
The thickness of the subsurface formation can`vary, such as from about 1 m to about 300 m, depending on the geology at that location. Formations thicker than about 5 m. are more economical to work.
In order to reduce the viscosity of, for example, the tar sands or oil sands found in the formation an operating temperature of about 40C or higher is desirable. The tem-;'perature of sa-turated steam at the injection pressure in ~ 9 .
';
Case 5562 ~ ~,,3 ~ ~ GLR/nlh/ejl the formation will give a gradient of operating tempera-tures, being highest near the injection nozzle and becoming lower as the distance from the injection nozzle increases.
The quality o~ the steam used for in~jection can vary .~ 5 from about 50% to abou~ 100%. The injection pressure used should be of the order of about 17 ~Pa/m or more, prefer-ably from about 22 to about 44 ~Pa per meter of depth. The steam injection rate should be about the water equivalent ~of 15 m3/d/well or more, preferably from about 80 to about :: 10 350 m3/d/well.
The number of ver-tical shafts penetrating the over-burden, and the material underlying the formation will depend on -the size of the deposit and the desired produc-tion rate. The minimum number is 1, while a preferred or working n~ber can vary between about 4 and about 25.
: The number of tunnels starting from each shaft can vary from 1 to 9 depending on the desired layout. The pre-ferred number is 1 or 2. The length of each tunnel will : normally be established by ventilation requirements.
` 20 Figure 1 illustrates a simplified cross-section view of an in situ operation. A shaft, or first borehole 2, is sunk through overburden l into the desired formation 3.
~; The borehole is continued below the base of formation 3, .~ in-to the underburden 4. Tunnel 5 is formed at the base of, and normal to, the first borehole 2. From this tunnel, .. ~ second boreholes 6 are drilled upwardly and radially out-. wardly, to penetrate formation 3. Casing 7 is used to . reduce the probability of collapse of borehole 6. One embodiment of production tubing (borehole 6 completed as a ~. 30 producing well) is shown as 8. Some known method of moving ,: .
`~ 10 :
Case 5562 GLR/nlh/ejl 10/l~/81 ~ 3 ~ ~
: material liberated from the borehole to the surface, such as a pump, is not shown.
Figure 2 shows how tunnel 2 is formed relative to the first borehole 1. Second boreholes 3 are typically ormed ; 5 normal to tunnel 2.
The stimulation injection time should be 5 days or more, such as from about lO to about :L00 days. The stimu-la-tion cycles are 1 or more, such as from about 5 to about 25.
The number of second boreholes, varying in number from about 2 to about 200 and extending upwardly and outwardly from the tunnels into the hydrocarbon-bearing formation, can vary with the length of the -tunnels, with spacing of about 5 to about 300 m, pre~erably from about 8 -to about ~00 m. The length of these second boreholes can vary from a few meters, ~uch as about 3, to a length that will allow :~ connection with another, distant well, after the tempera-ture of the intervening formation has been raised to allow movement of the desired material, such as a viscous hydro-carbon. This latter distance may vary from about 50 m to : about 600 m.
' ,`'~ 11 - .
'` .
The inherent and expressed disadvantages of the prior art are overcome with the present invention.
.
Case 5562 GLR/nlh/ejl ri~ ~ :L o/l4/sl S~MMA~Y OF THE INVENTION
_ There are several embodiments involved in the present invention, and -these generally involve different methods of entering and then thermally treating the tar sand forma-tion. All o-f the embodiments involve a first step of drill ing or excavating a borehole or shaft to the base of the subsurface formation to be exploited. Typically this for-mation is a tar sands or oil sands formation, but the tech-nique can be used in other subsurface formations that com-prise solid and semi-solid and viscous materials such as kerogen, high viscosity hydrocarbon materials such as heavy oils, inorganic ores, and the like.
The next step involves extension of the borehole or sha-ft below the base of the formation. This involves :15 drilling or excavating into the stratum immediately below .;the formation to be exploited. This terminal end of the shaft or borehole, in the stratum below the desired forma-tion, is then, optionally, enlarged to form an operating chamber below the base of the desired formation.
The next step involves the excavating of one or more tunnels extending laterally from this operating chamber in the stratum below the base of the formation.
The next step concerns the drilling of a plurality of ~ second boreholes extending substantially upwardly and out-: 25 ward into the desired formation from these tunnels.
'The above-listed steps are common to the first phase of the invention. Various embodiments of the invention are practiced by altering the succeeding steps.
For example, in one embodimen-t, steam is conducted down the first borehole or shaf~ and along the -tunnel and . .
Case 5562 &LR/nlh/ejl ~ 10/14/81 thence injected into the plurality of second boreholes drilled from the t~mnel. Or steam can be generated in the chamber and then injected via the tunnel into the plurality of boreholes. It is a :Eeatwre of this embodiment that the steam used is at a pressure above the fracture pressure of the formation to be exploited. It is a characteristic of oil sands or similar hydrocarbon deposits that any flow channels in the formation matrix are effectively plugged with the solid or semisolid hydrocarbon material. The rate of injection for steam or any other heating medium at . subfracture pressures would be -too low to achieve the rate of heat input necessary to recover economically the hydro-carbon. S-team pressures above fracture pressure will per-mit high rates of injection. The injection of this steam is maintained for a time period resulting in an increase of the temperature o-f that portion of the formation surround-ing the boreholes and the chamber. A "soaking" cycle can follow, for a discrete time period. When the pressure of the steam on the system is released, any liberated material of reduced viscosity can move, by gravity, and by means of the increased pressure due to the steam injection, to the lower portions of the second boreholes and thence via the t~mnel to the lower portion of the chamber found in the stratum below the desired formation. The injection/produc-tion cycle is repeated until insufficient additional hydro-carbon is produced to warrant further cycles. The recovered viscous material can be moved to the surface, by means well-known in the art, for further processing.
Case 5562 ~ 3 ~ GL~/0lh/ei8l ; The above-mentioned injec-tion/production cycle is one of several methods for recovering heavy hydrocarbons from underground formations. In this invention, two recovery mechanisms are described ~-md used.
One mechanism involves a stimulation process, such as by steam. This process involves a single well and is well-known in the art as "huff and puff," since steam is in-jected into a reservoir optionally remaining for a finite soaking period, and then allowed to vent back through the entrance. Hydrocarbon production through the entrcmce is then noted. Several stimulation cycles may be needed for an appreciable outflow of desired ma-terial. The injection well and the production well are the same well, depending on the time during the stimulation process.
;~ 15 The other mechanism is called a "drive," and at least two wells are used. ~ere, for example, s-team can be in-jected into one well, and, after a finite time, production is noted from a production well.
; Pressure cycling, with variations in the s-team pres-sure, can be used for either mechanism.
In another embodiment, steam, at a pressure above the fracture pressure of the for~ation to be exploited, is in-jected into the boreholes, as in the above-described embodiment, continuing the injection/ production cycles until the viscous material between the wells is made mobile, stopping the steam flow into the injector wells, completing selected second boreholes as producer wells, initiating a flooding procedure, exemplified by a fire flood, water flood, steam flood, emulsion flood, or solvent flood, flowing from injector wells to production wells, and Case 5562 GI.R/nlh/ejl 10/1~/81 ~ ~ 73 3 ~d~
collecting the liberated ma-terial of reduced viscosity as before.
In another embodiment, after the second boreholes are extended subs-tantially upward and outward into the desired formation from the t~mnels, some of these second boreholes are completed as injector wells, and the remainder of the second boreholes are completed as producer wells. Then steam, at or above fracturing pressure, is injected into the second boreholes completed as injector wells. A nu~ber 10 of injection/production cycles are carr:ied out so as -to in ` crease the temperature of that portion of the formation surrounding the boreholes. The steam flow into -the bore-holes designated as injector wells is -then stoppecl, and a ~` flooding procedure is lnitiated, using the same or a dif-ferent procedure from the choices noted above, such that the flooding material flows from injector wells to producer wells. The liberated material of reduced viscosity is then collected as before.
In a further embodiment of the invention, steam, at a pressure above fracturing pressure of the desired forma-tion, is injected into the second boreholes, as the begin-ning of a stimulation phase. The injection/production cycles of steam stimulation are continued for some time so as to increase the temperature of the surrounding formation.
Selected second boreholes are completed as producer wells, and a steam flood is then initiated, with the variation that the steam pressure is cylically varied.
Following steps in the procedure are as previously described.
' -Case 5562 GLR/nlh/ejl 10/1~/81 ~ 3 ~
Tn another embodimenk, after the second boreholes are drilled from the chamber into the desired forma-tion, some of these second boreholes are completed as injector wells and the remainder are completed as producer wells. Then steam, at a pressure above the fracturing pressure, is injected into the boreholes comprising the injector wells.
The previously-described injection/production cycles are carried out, resulting in a -temperature increase of the surrounding formation. A steam flood is then initiated, with the modification that the steam pressure is cyclically varied during the flooding. The steam pressure can be varied from about atmospheric to the operating pressure.
Liberated hydrocarbon material i5 then treated as discussed above.
15The embodiments discussed above have one or more of the advantages discussed below.
A central shaft, with associated tunnels and bore-holes, has the advantages over wells drilled from the surface of:
20~a) reduced drilling costs, (b) horizontal wells or boreholes are easier to drill, (c) there is less heat loss be-tween the surface and the tar sands or oil sands, formation, 25or reservoir, and (d) the movement of recovered oil from the for-mation to the surface is more efficient than when wells are drilled from the surface.
The advantages of continuing the shaft or borehole into the zone below the formation or reservoir include:
:`~
:
Case 5562 GLR/nlh/ejl ;~5~q 10/14/81 (a~ increased safety, since an operating chamber and the tunnels are formed in the zone below -the formation, (b) wells can be cemented in the zone below the 5or~ation, while there is great difficulty in cementing wells in an oil sands or tar sands formation, and (c) it is easier and safer to complete wells that have their beginning or terminus in the 10tunnels below the formation.
~; The advantage of using -tunnels from the central shaft as the starting point for the boreholes, rather than drilling the boreholes radially outward from the shaft, is that the boreholes can be drilled parallel to one another;
giving a more uniform coverage of the reservoir. The rectangular Iayout with tunnels is also more amenable to a repeated pattern.
Using a steam pressure greater than the fracturing ~ pressure of the formation allows injection of the steam - 20 into the formation or reservoir at a sufficient rate to recover the hydrocarbon product economically. The greater pressure also allows a higher percentage of the formation or reservoir to be con-tacted, and this gives a higher usage efficiency for the injected steam. This greater pressure also allows a greater percentage of the formation to be processed.
Cyclical operation involving varying the steam pres-sure improves the recovery of the product and offers an improved oil/steam ratio. The "cycles" can vary in time - 30 from about 10 to about 50 hours, from peak to peak.
Case 5562 GLR/nlh/ejl ~ 3~3,~ 10/1~/81 Other advantages of the embodiments of the process will be noted by those who are skilled in the arts involved in this process.
', DESCRIPTION OF THE DRAWIN&S
5Figure 1 shows a side view of the first borehole ex-tending below the base of the formation and into the under-burden, with a tunnel extending normal to the borehole and secondary boreholes extending normal to the tunnel and up-wardly into the desired formation.
10Figure 2 shows a top view of the first borehole,the tunnel, and the secondary boreholes.
DETAILED DESCRIPTION OF THE INVENTION
The described process for the in situ recovery of viscous materials can be used where the desired formation or reservoir is greater than about 30 meters from the surface. For example, the invention is operable where the formation or reservoir is from about 90 to about 900 meters below the surface.
The thickness of the subsurface formation can`vary, such as from about 1 m to about 300 m, depending on the geology at that location. Formations thicker than about 5 m. are more economical to work.
In order to reduce the viscosity of, for example, the tar sands or oil sands found in the formation an operating temperature of about 40C or higher is desirable. The tem-;'perature of sa-turated steam at the injection pressure in ~ 9 .
';
Case 5562 ~ ~,,3 ~ ~ GLR/nlh/ejl the formation will give a gradient of operating tempera-tures, being highest near the injection nozzle and becoming lower as the distance from the injection nozzle increases.
The quality o~ the steam used for in~jection can vary .~ 5 from about 50% to abou~ 100%. The injection pressure used should be of the order of about 17 ~Pa/m or more, prefer-ably from about 22 to about 44 ~Pa per meter of depth. The steam injection rate should be about the water equivalent ~of 15 m3/d/well or more, preferably from about 80 to about :: 10 350 m3/d/well.
The number of ver-tical shafts penetrating the over-burden, and the material underlying the formation will depend on -the size of the deposit and the desired produc-tion rate. The minimum number is 1, while a preferred or working n~ber can vary between about 4 and about 25.
: The number of tunnels starting from each shaft can vary from 1 to 9 depending on the desired layout. The pre-ferred number is 1 or 2. The length of each tunnel will : normally be established by ventilation requirements.
` 20 Figure 1 illustrates a simplified cross-section view of an in situ operation. A shaft, or first borehole 2, is sunk through overburden l into the desired formation 3.
~; The borehole is continued below the base of formation 3, .~ in-to the underburden 4. Tunnel 5 is formed at the base of, and normal to, the first borehole 2. From this tunnel, .. ~ second boreholes 6 are drilled upwardly and radially out-. wardly, to penetrate formation 3. Casing 7 is used to . reduce the probability of collapse of borehole 6. One embodiment of production tubing (borehole 6 completed as a ~. 30 producing well) is shown as 8. Some known method of moving ,: .
`~ 10 :
Case 5562 GLR/nlh/ejl 10/l~/81 ~ 3 ~ ~
: material liberated from the borehole to the surface, such as a pump, is not shown.
Figure 2 shows how tunnel 2 is formed relative to the first borehole 1. Second boreholes 3 are typically ormed ; 5 normal to tunnel 2.
The stimulation injection time should be 5 days or more, such as from about lO to about :L00 days. The stimu-la-tion cycles are 1 or more, such as from about 5 to about 25.
The number of second boreholes, varying in number from about 2 to about 200 and extending upwardly and outwardly from the tunnels into the hydrocarbon-bearing formation, can vary with the length of the -tunnels, with spacing of about 5 to about 300 m, pre~erably from about 8 -to about ~00 m. The length of these second boreholes can vary from a few meters, ~uch as about 3, to a length that will allow :~ connection with another, distant well, after the tempera-ture of the intervening formation has been raised to allow movement of the desired material, such as a viscous hydro-carbon. This latter distance may vary from about 50 m to : about 600 m.
' ,`'~ 11 - .
'` .
Claims (15)
1. A method for the in-situ recovery of viscous materials from a subsurface formation, comprising:
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one or more tunnels from the lower end of the borehole of step (b) into the underburden below the base of the desired formation.
d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tun-nel(s) of step (b), e) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface formation, f) maintaining the injection of step (e) for a time period so as to increase the tempera-ture of that portion of the formation sur-rounding said second boreholes and any frac-ture fissures formed by the injection, g) releasing the pressure on the system of sec-ond boreholes, thus allowing any liberated material of reduced viscosity to move to the lower portions of said second boreholes and Case 5562 GLR/nlh/ejl thence to the lower portion of the first borehole, h) collecting the liberated material, and i) repeating the injection/production cycle of steps (e)-(h).
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one or more tunnels from the lower end of the borehole of step (b) into the underburden below the base of the desired formation.
d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tun-nel(s) of step (b), e) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface formation, f) maintaining the injection of step (e) for a time period so as to increase the tempera-ture of that portion of the formation sur-rounding said second boreholes and any frac-ture fissures formed by the injection, g) releasing the pressure on the system of sec-ond boreholes, thus allowing any liberated material of reduced viscosity to move to the lower portions of said second boreholes and Case 5562 GLR/nlh/ejl thence to the lower portion of the first borehole, h) collecting the liberated material, and i) repeating the injection/production cycle of steps (e)-(h).
2. The method of claim 1 wherein:
a) the subsurface formation containing viscous materials is approximately 30m or more below the surface, b) the lower portion of the borehole or shaft is enlarged to form an operating chamber below the base of the formation, c) the number of tunnels varies from 1 to about 9, d) the spacing of the second boreholes varies from about 5 to about 300 m, e) the injection stream has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per meter of depth from the surface, and a steam in-jection rate at a water equivalent of greater than 15 m3/d/well, f) the injection time period of step (d) is at least 5 days, and g) the repeated injection/production cycles of step (h) number at least two.
a) the subsurface formation containing viscous materials is approximately 30m or more below the surface, b) the lower portion of the borehole or shaft is enlarged to form an operating chamber below the base of the formation, c) the number of tunnels varies from 1 to about 9, d) the spacing of the second boreholes varies from about 5 to about 300 m, e) the injection stream has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per meter of depth from the surface, and a steam in-jection rate at a water equivalent of greater than 15 m3/d/well, f) the injection time period of step (d) is at least 5 days, and g) the repeated injection/production cycles of step (h) number at least two.
3. The method of claim 2, wherein:
Case 5562 GLR/nlh/ejl a) the number of second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/d/
well, c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can number from about 2 to about 25.
Case 5562 GLR/nlh/ejl a) the number of second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/d/
well, c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can number from about 2 to about 25.
4. A method for the in situ recovery of viscous materials from a subsurface formation, comprising:
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one or more tunnels horizontally outwardly from the borehole of step (b), be-low the base of the formation, d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tun-nel(s) of step (c), e) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface formation, f) maintaining the injection of step (e) for a time period so as to increase the tempera-ture of that portion of the formation Case 5562 GIR/nlh/ejl surrounding said second boreholes and any fracture fissures formed by the injection, g) releasing the pressure on the system of boreholes, thus allowing any liberated material of reduced viscosity to move to the lower portion of the second boreholes and thence to the lower portion of the first borehole, h) collecting the liberated material, i) repeating the injection/production cycle until the viscous material between at least some of the second boreholes is made mobile, j) stopping the steam flow into the second boreholes, k) completing selected second boreholes as producer wells, l) initiating a flooding procedure, selected from the procedures consisting of fire flood, water flood, steam flood, emulsion flood, and solvent flood, flowing from at least one injector well to at least one producing well, and m) collecting the liberated material.
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one or more tunnels horizontally outwardly from the borehole of step (b), be-low the base of the formation, d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tun-nel(s) of step (c), e) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface formation, f) maintaining the injection of step (e) for a time period so as to increase the tempera-ture of that portion of the formation Case 5562 GIR/nlh/ejl surrounding said second boreholes and any fracture fissures formed by the injection, g) releasing the pressure on the system of boreholes, thus allowing any liberated material of reduced viscosity to move to the lower portion of the second boreholes and thence to the lower portion of the first borehole, h) collecting the liberated material, i) repeating the injection/production cycle until the viscous material between at least some of the second boreholes is made mobile, j) stopping the steam flow into the second boreholes, k) completing selected second boreholes as producer wells, l) initiating a flooding procedure, selected from the procedures consisting of fire flood, water flood, steam flood, emulsion flood, and solvent flood, flowing from at least one injector well to at least one producing well, and m) collecting the liberated material.
5. The method of claim 4, wherein:
a) the subsurface formation containing viscous materials is approximately 30 meters or more below the surface, Case 5562 GLR/nlh/ejl b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation, c) the number of tunnels varies from 1 to about 9, d) the spacing of second boreholes varies from about 5 to about 300 m, e) the injection stream has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per foot of depth from the surface, and a steam in-jection rate at a water equivalent of greater than 15 m3/d/well, f) the injection time period of step (f) is at least 5 days, and g) the repeated injection/production cycles of step (i) number at least two.
a) the subsurface formation containing viscous materials is approximately 30 meters or more below the surface, Case 5562 GLR/nlh/ejl b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation, c) the number of tunnels varies from 1 to about 9, d) the spacing of second boreholes varies from about 5 to about 300 m, e) the injection stream has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per foot of depth from the surface, and a steam in-jection rate at a water equivalent of greater than 15 m3/d/well, f) the injection time period of step (f) is at least 5 days, and g) the repeated injection/production cycles of step (i) number at least two.
6. The method of claim 5, wherein:
a) the number of the second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/day/
well, c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can number from about 2 to about 25.
Case 5562 GLR/nlh/eil
a) the number of the second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/day/
well, c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can number from about 2 to about 25.
Case 5562 GLR/nlh/eil
7. A method for the in-situ recovery of viscous materials from a subsurface formation, comprising:
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one of more tunnels horizontally outwardly from the borehole of step (b), below the base of the formation, d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tum-nel(s) of step(c), e) completing at least one of said second bore-holes as an injector well, while completing the remainder of said second boreholes as producer wells, f) injecting steam into said second boreholes completed as injector wells, with the pres-sure of the steam above the fracture pres-sure of the subsurface formation, g) maintaining the injection of step (e) for a time period so as to increase the tempera-ture of that portion of the formation sur-rounding said second boreholes and any fracture fissures formed by the injection, h) releasing the pressure on the system of in-jector boreholes, thus allowing any liber-ated material of reduced viscosity to move to the lower portion of the first borehole, Case 5562 GLR/nlh/ejl i) repeating the injection/production cycle of steps (f)-(h) until hydrocarbon between at least some of said second boreholes is mobilized, j) stopping the steam flow to the injector well, k) initiating a flood procedure, selected from the procedures consisting of fire flood, water flood, steam flood, emulsion flood, solvent flood, flowing from an injector well to a producer well, and l) collecting the liberated material.
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one of more tunnels horizontally outwardly from the borehole of step (b), below the base of the formation, d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tum-nel(s) of step(c), e) completing at least one of said second bore-holes as an injector well, while completing the remainder of said second boreholes as producer wells, f) injecting steam into said second boreholes completed as injector wells, with the pres-sure of the steam above the fracture pres-sure of the subsurface formation, g) maintaining the injection of step (e) for a time period so as to increase the tempera-ture of that portion of the formation sur-rounding said second boreholes and any fracture fissures formed by the injection, h) releasing the pressure on the system of in-jector boreholes, thus allowing any liber-ated material of reduced viscosity to move to the lower portion of the first borehole, Case 5562 GLR/nlh/ejl i) repeating the injection/production cycle of steps (f)-(h) until hydrocarbon between at least some of said second boreholes is mobilized, j) stopping the steam flow to the injector well, k) initiating a flood procedure, selected from the procedures consisting of fire flood, water flood, steam flood, emulsion flood, solvent flood, flowing from an injector well to a producer well, and l) collecting the liberated material.
8. The method of claim 7, wherein:
a) the subsurface formation containing viscous materials is approximately 30 meters or more below the surface, b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation, c) the number of tunnels varies from 1 to about 9, d) the spacing of the second boreholes varies from about 5 to about 300 m, e) the injection stream has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per meter of depth from the surface, and a steam in-jection rate at a water equivalent of greater than 15 m3/d/well, Case 5562 GLR/nlh/ejl f) the injection time period of step (g) is at least 5 days, and g) the repeated injection/production cycles of step (h) number at least two.
a) the subsurface formation containing viscous materials is approximately 30 meters or more below the surface, b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation, c) the number of tunnels varies from 1 to about 9, d) the spacing of the second boreholes varies from about 5 to about 300 m, e) the injection stream has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per meter of depth from the surface, and a steam in-jection rate at a water equivalent of greater than 15 m3/d/well, Case 5562 GLR/nlh/ejl f) the injection time period of step (g) is at least 5 days, and g) the repeated injection/production cycles of step (h) number at least two.
9. The method of claim 8, wherein:
a) the number of second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/d/
well, c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can member from about 2 to about 25.
a) the number of second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/d/
well, c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can member from about 2 to about 25.
10. A method for the in situ recovery of viscous ma-terials from a subsurface formation, comprising:
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one or more tunnels horizontally outwardly from the borehole of step (b), below the base of the formation, d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tun-nel(s) of step (c), Case 5562 GLR/nlh/ejl e) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface formation, f) maintaining the injection of step (e) for a time period 50 as to increase the tempera-ture of that portion of the formation sur-rounding said second boreholes and any fracture fissures formed by the injection, g) releasing the pressure on the system of second boreholes, thus allowing any liber-ated material of reduced viscosity to move to the lower portion of said second bore-holes and thence to the lower portion of the first borehole.
h) collecting the liberated material, i) repeating the injection/production cycle until the viscous material between at least some of the second boreholes is mobilized, j) stopping the steam flow, k) completing selected second boreholes as producer wells, l) initiating a steam flooding procedure, m) cyclically varying the steam pressure during the operation of step (1), and n) collecting the liberated material.
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one or more tunnels horizontally outwardly from the borehole of step (b), below the base of the formation, d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tun-nel(s) of step (c), Case 5562 GLR/nlh/ejl e) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface formation, f) maintaining the injection of step (e) for a time period 50 as to increase the tempera-ture of that portion of the formation sur-rounding said second boreholes and any fracture fissures formed by the injection, g) releasing the pressure on the system of second boreholes, thus allowing any liber-ated material of reduced viscosity to move to the lower portion of said second bore-holes and thence to the lower portion of the first borehole.
h) collecting the liberated material, i) repeating the injection/production cycle until the viscous material between at least some of the second boreholes is mobilized, j) stopping the steam flow, k) completing selected second boreholes as producer wells, l) initiating a steam flooding procedure, m) cyclically varying the steam pressure during the operation of step (1), and n) collecting the liberated material.
11. The method of claim 10, wherein:
Case 5562 GLR/nlh/ejl a) the subsurface formation containing viscous materials is approximately 30 meters or more below the surface, b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation.
c) the number of tunnels varies from 1 to about 9, d) the spacing of the second boreholes varies from about 5 to about 300 m, e) the injection stream has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per foot of depth from the surface, and a steam injection rate at a water equivalent of greater than 15 m3/day/well, f) the pressure of step (m) varies from about atmospheric to the operating pressure, g) the injection time period of step (f) is at least 5 days, and h) the repeated injection/production cycles of step (i) number at least two.
Case 5562 GLR/nlh/ejl a) the subsurface formation containing viscous materials is approximately 30 meters or more below the surface, b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation.
c) the number of tunnels varies from 1 to about 9, d) the spacing of the second boreholes varies from about 5 to about 300 m, e) the injection stream has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per foot of depth from the surface, and a steam injection rate at a water equivalent of greater than 15 m3/day/well, f) the pressure of step (m) varies from about atmospheric to the operating pressure, g) the injection time period of step (f) is at least 5 days, and h) the repeated injection/production cycles of step (i) number at least two.
12. The method of claim 11, wherein a) the number of the second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/d/
well, Case 5562 GLR/nlh/ejl c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can number from about 2 to about 25.
well, Case 5562 GLR/nlh/ejl c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can number from about 2 to about 25.
13. A method for the in situ recovery of viscous ma-terials from a subsurface formation, comprising:
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one or more tunnels horizontally outwardly from the borehole of step (b), be-low the base of the formation, d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tun-nel(s) of step (c), e) completing at least one of said second bore holes as an injector well, while completing the remainder of said second boreholes as producer wells, f) injecting steam into said second boreholes designated injector wells, with the steam having a pressure above the fracture pres-sure of the subsurface formation, g) maintaining the injection of step (f) for a time period so as to increase the tem-perature of that portion of the formation Case 5562 GLR/nlh/ejl surrounding said second boreholes and any fracture fissures formed by the injection, b) releasing the pressure on the boreholes, thus allowing any liberated material of reduced viscosity to move to the lower por-tion of the first borehole, i) repeating the injection/production cycle until hydrocarbon between at least some of said second boreholes is mobilized, j) initiating a steam flooding procedure, k) cyclically varying the steam pressure during the operation of step (i), and l) collecting the liberated material.
a) forming a first borehole to the base of the subsurface formation to be exploited, b) extending the borehole below the base of the formation, c) extending one or more tunnels horizontally outwardly from the borehole of step (b), be-low the base of the formation, d) drilling a plurality of second boreholes extending substantially upwardly and out-wardly into said formation from the tun-nel(s) of step (c), e) completing at least one of said second bore holes as an injector well, while completing the remainder of said second boreholes as producer wells, f) injecting steam into said second boreholes designated injector wells, with the steam having a pressure above the fracture pres-sure of the subsurface formation, g) maintaining the injection of step (f) for a time period so as to increase the tem-perature of that portion of the formation Case 5562 GLR/nlh/ejl surrounding said second boreholes and any fracture fissures formed by the injection, b) releasing the pressure on the boreholes, thus allowing any liberated material of reduced viscosity to move to the lower por-tion of the first borehole, i) repeating the injection/production cycle until hydrocarbon between at least some of said second boreholes is mobilized, j) initiating a steam flooding procedure, k) cyclically varying the steam pressure during the operation of step (i), and l) collecting the liberated material.
14. The method of claim 13, wherein:
a) the subsurface formation containing viscous materials is approximately 30 meters or more below the surface, b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation, c) the number of tunnels varies from 1 to about 9, d) the spacing of the second boreholes varies from about 5 to about 300 m, e) the injection steam has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per meter of depth from the surface, and a steam Case 5562 GLR/nlh/ejl injection rate at a water equivalent of greater than 15 m3/d/well, f) the steam pressure of step (k) varies from about atmospheric to the operating pressure, g) the injection time period of step (g) is at least 5 days, and h) the repeated injection/production cycles of step (h) number at least two.
a) the subsurface formation containing viscous materials is approximately 30 meters or more below the surface, b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation, c) the number of tunnels varies from 1 to about 9, d) the spacing of the second boreholes varies from about 5 to about 300 m, e) the injection steam has a steam quality of from about 50% to about 100%, a pressure of from about 17 kPa to about 44 kPa, per meter of depth from the surface, and a steam Case 5562 GLR/nlh/ejl injection rate at a water equivalent of greater than 15 m3/d/well, f) the steam pressure of step (k) varies from about atmospheric to the operating pressure, g) the injection time period of step (g) is at least 5 days, and h) the repeated injection/production cycles of step (h) number at least two.
15. The method of claim 14, wherein:
a) the number of the second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/d/
well, c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can number from about 2 to about 25.
a) the number of the second boreholes varies from about 2 to about 200, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/d/
well, c) the injection time period can vary from about 10 to about 100 days, and d) the repeated injection/production cycles can number from about 2 to about 25.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000394280A CA1173356A (en) | 1982-01-15 | 1982-01-15 | In situ recovery of viscous materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000394280A CA1173356A (en) | 1982-01-15 | 1982-01-15 | In situ recovery of viscous materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1173356A true CA1173356A (en) | 1984-08-28 |
Family
ID=4121838
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000394280A Expired CA1173356A (en) | 1982-01-15 | 1982-01-15 | In situ recovery of viscous materials |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1173356A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0251881A1 (en) * | 1986-06-26 | 1988-01-07 | Institut Français du Pétrole | Enhanced recovery method to continually produce a fluid contained in a geological formation |
| FR2601998A1 (en) * | 1986-06-26 | 1988-01-29 | Inst Francais Du Petrole | Method and system for production using a central well and collecting drains |
| US9010419B2 (en) | 2006-09-15 | 2015-04-21 | C-Fer Technologies (1999) Inc. | Subterranean system and method for treating and producing oil |
-
1982
- 1982-01-15 CA CA000394280A patent/CA1173356A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0251881A1 (en) * | 1986-06-26 | 1988-01-07 | Institut Français du Pétrole | Enhanced recovery method to continually produce a fluid contained in a geological formation |
| FR2601998A1 (en) * | 1986-06-26 | 1988-01-29 | Inst Francais Du Petrole | Method and system for production using a central well and collecting drains |
| US9010419B2 (en) | 2006-09-15 | 2015-04-21 | C-Fer Technologies (1999) Inc. | Subterranean system and method for treating and producing oil |
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