CA1173353A - In situ recovery of viscous materials - Google Patents
In situ recovery of viscous materialsInfo
- Publication number
- CA1173353A CA1173353A CA000394246A CA394246A CA1173353A CA 1173353 A CA1173353 A CA 1173353A CA 000394246 A CA000394246 A CA 000394246A CA 394246 A CA394246 A CA 394246A CA 1173353 A CA1173353 A CA 1173353A
- 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
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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. optimizing the spacing of wells
- E21B43/305—Specific pattern of wells, e.g. optimizing the spacing of wells comprising at least one inclined or horizontal well
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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 DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
Abstract
Case 5554 GLR/gs/ejl 1.0/12/81 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 borehole into the underburden, drilling second boreholes upwardly and radially into the formation, injecting steam into these boreholes until the temperature of parts of the formation is such that the viscosity of the material is reduced, and collecting the liberated material. 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 borehole into the underburden, drilling second boreholes upwardly and radially into the formation, injecting steam into these boreholes until the temperature of parts of the formation is such that the viscosity of the material is reduced, and collecting the liberated material. Variations of this basic procedure are discussed.
Description
Case 5554 ~L~/~s/ejl 10/12~81 BACKGROUND OF THE INVENTION
This invention relates to a rnethod for the recover~ of materials such as minerals and viscous hydrocarbons from subsurface earth formations. In a particular application S 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 ~rom tar sand formations that are too deep for sur-face mining. These techniques typically involve raising the temperature of the forma-tion to reduce the viscosity of the bitumen, to assist in the separation of the bit~lmen from the sand matrix, and to promote movement of the liberated bitumen. The temperature can be raised by various means, such as electri.cal heating, fire flooding, steam flooding, etc. Due to the high expenses and low recovery rates, these techniques typically have not been . too successful.
There are also various types of mining techniques fre-quently used in the prior art to reach and process these 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 discusses some of these techniques.
The inherent and expressed disadvantages of the pri.or art are overcome with the present invention.
SUM~ARY OF THE INVENTION
There are several embodiments involved in the present invention, and these generally involve different methods of ;` '' :
Case 5554 GLR/gs/ejl entering and then thermally treating the tar sand forma-tion. All of the embodiments involve a first step of drilling or excavating a borehole or shaft to the base of the subsurface formation to be exploited. Typically this formation is a tar sands or oil sands Formation, but the ` technique can be used in other subsurface formations that comprise solid and semisolid 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 shaf-t below the base of the formation. This involves drilling or excavating into the stratum immediately below the formation to be exploited. This terminal end of the `~ shaft or borehole, in t`he stratum below the desirecl forma-tion, is then, optionally ? enlarged to form an operating ; chamber below the base of the desired formation.
~` The next step concerns the drilling of a plurality of second boreholes extending substantially upwardly and ra-dially outward into the desired formation from this oper-ating chamber.
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 embodiment, steam is conducted down the first borehole or shaft and thence injected into the plurality of second boreholes drilled from the oper-ating chamber. Or steam can be generated in the chamber and then injected into the plurality of boreholes. I~ is a ; feature of this embodiment that the steam used is at a pressure above the fracture pressure of the formation to be . ~
: Case 5554 GLR/gs/ejl .73~ ~ 3 10/12/81 exploited. It is a characteristic of oil sands or similar hydrocarbon deposits that any flow channels in the forma tion matrix are effectively plugged with the solid or semi-solid hydrocarbon material. The rate of injection for s-team or any other heating medium at subfracture pressures would be too low to achieve the rate of heat input neces-sary to recover economically the hydrocarbon. Steam pres-sures above fracture pressure will permit high rates o~
injection. The injection of this s-team is maintained for a time period resulting in an increase of the temperature of that portion of the formation surrounding the boreholes and the chamber. A "soaking" cycle can follow, for a cliscrete . 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 pres-sure due to the steam injection, to the lower portions of the second boreholes and thence to the lower portion of the chamber found in the stratum below the desired formation.
The injection/production cycle is repeated until insuffi-cient additional hydrocarbon is produced to warrant furthercycles. The recovered viscous material can be moved to the surface, by means well-known in the art, for further processing.
The above-mentioned injection/produc-tion cycle is one of several methods for recovering heavy hydrocarbons from underground formations. In this invention, two recovery mechanisms are described and used.
One mechanism involves a stimulation process, such as by steam. This process involves a single well and is well-, .
Case 5554 GLR/gs/ejl 3~ 10/12/81 ~.
known in the ar-t 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 entrance is then noted. Several s-timulation cycles may be needed for an appreciable outflow of desired material. The injection well and the production well are the same well, depending on the time during the stimulation process.
The other mechanism is called a "drive," and at least two wells are used. Here, for example, steam 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 steam pres-sure, can be used for either mechanism.
15In another embodiment, steam, at a pressure above the fracture pressure of the formation to be exploited, is injected 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 collecting the liberated material of reduced viscosity as before.
In another embodiment, after the second boreholes are `extended substantially upward and radially outward into the desired formation from the operating chamber, some of these second ~oreholes sre completed as in~ector wells, and the Case 5554 CLR/gs/ejl ~ 3 ~?~- ~? 10/12/81 remainder of -the seconcl boreholes are completed as producer wells. Then steam, at or above fracturing pressure, is injected into the second boreholes completed as injector wells. A number of injection/procluction cycles are carried out so as to increase the temperature of that portion of the formation surrounding the boreho:Les. The steam flow into the boreholes designated as injector wells is then stopped, and a flooding procedure is initiated, using the same or a different procedure from the choices noted above, such that the flooding material flows from injector wells to producer wells. The liberated material of reduced vis-cosity 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.
20Selected second boreholes are completed as producer i 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 previousl~
,j.~
decribed.
25In another embodiment, af-ter the second boreholes are drilled from the chamber into the desired formation, some of these second boreholes are completed as injec-tor 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.
Case 5554 GLR/gs/ejl 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. Liberated hydrocarbon material is then treated as discussed above.
The embodiments discussed above have one or more of the advantages discussed below.
A central shaft, with associated radial boreholes, has - 10 the advantages over wells drilled from the surface of:
- (a) reduced drilling costs~
(b) horizontal wells or boreholes are easier to drill, (c) there is less heat loss between the surface and 15the tar sands or oil sands, formation, or reser-; voir, and ~ (d) the movement of recovered oil from the formation ; to the surface is more efficient than when wells ;.
are drilled from the surface.
20The advantages of continuing the shaft or borehole into the zone below the formation or reservoir include:
(a) increased safety, since an operating chamber is ~ formed in the zone below the formation, ; (b) wells can be cemented in the zone below the for-25mation, while there is great difficulty in ce-- menting wells in an oil sands or tar sands forma-tion, and (c) it is easier and safer to complete wells that have their beginning or terminus in the operating 30chamber below the formation.
Case 555 GLR/gs/ejl ~ 3~ ~ 3 10/12/81 Using a steam pressure greater than the fracturing pressure of the formation allows injection of the steam into the formation or reservoir a-t a su-fficient rate to recover the hydrocarbon product economically. The greater pressure also allows a higher percentage of the formation or reservoir to be contacted, and this gives a higher usage efficiency for the injected steam. This greater pressure also allows a greater percentage o~ the formation to be processed.
Cyclical operation involving varying the steam pres-sure improves the recovery of the product and ofEers an improved oil/steam ratio. The steam pressure can be varied from about atmospheric pressure to the operating pressure.
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 DRAWINGS
The ~igure shows a side view of the borehole, the subsurface formations, the chamber in the formation below the hydrocarbon-containing formation, and the secondary boreholes ex-tending from the chamber into the hydrocarbon-containing formation.
DETAILED DESCRIPTION OF T~IE INVENTION
The described process for the in si-tu recovery of viscous materials can be used where the desired ~ormation or reservoir is greater than about 30 meters ~rom the sur-Eace. For example, the invention is operable where the Case 5554 GLR/gs/ejl 733S~
formation or reservoir is from about 90 to about 900 m.
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 satura-ted steam at the injection pressure in the formation will give a gradient of operating tempera-tures, being hi~hest near the injection nozzle and becoming lower as the distance from the injection nozzle increases.
The q~lality of the steam used for injection can vary from about 50% to about 100%. The injec-tion pressure used should be of the order of about 17 kPa/m or more, prefer-ably from about 22 to about 44 kPa per meter of depth.
The steam injection rate should be about the water equiva-lent of 15 m3/day/well or more, preferably from about 80 to about 350 m3/day/well.
The number of vertical shafts penetrating the over-burden, and the material ~mderlying 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 ~- 25 working number can vary between about ~ and about 25.
; The drawing illustrates a simplified cross-section ., :
`~ view of an in SitU operation. A shaft, or first bore-hole 2, is sunk through overburden 1 into the desired '; formation 3. The borehole is continued into the underlying stratum 4 below the desired ~ormation 3, and chamber 5 is ,'. 9 ., .
.
Case 5554 GLR/gs/ejl 33~3 an optional structure at the base of the first borehole 2.
From chamber 5, second boreholes 6 are drilled upwardly and radially outwardly, to penetrate formation 3. ~asing 7 is used to reduce the probability of collapse of borehole 6 while in stratum 4. One embodiment of production tubing (borehole 6 completed as a producing well) is shown as 8.
Some known method of moving material libera-ted from the borehole to the surface, such as a pump~ is not shown.
The stimulation in~ection time should be 5 days or more, such as from about 10 to about 100 days. The stimu-lation cycles are l or more, such as from about 5 to about 25.
The number of second borehol.es extending upwardly and radially outwardly from -the lower formation into the hydrocarbon-bearing formation can vary from about 2 to about 40~ preferably from about 2 to about 20. The radial length of these second boreholes can vary from a few . meters, such as about 10, 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.
'~
This invention relates to a rnethod for the recover~ of materials such as minerals and viscous hydrocarbons from subsurface earth formations. In a particular application S 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 ~rom tar sand formations that are too deep for sur-face mining. These techniques typically involve raising the temperature of the forma-tion to reduce the viscosity of the bitumen, to assist in the separation of the bit~lmen from the sand matrix, and to promote movement of the liberated bitumen. The temperature can be raised by various means, such as electri.cal heating, fire flooding, steam flooding, etc. Due to the high expenses and low recovery rates, these techniques typically have not been . too successful.
There are also various types of mining techniques fre-quently used in the prior art to reach and process these 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 discusses some of these techniques.
The inherent and expressed disadvantages of the pri.or art are overcome with the present invention.
SUM~ARY OF THE INVENTION
There are several embodiments involved in the present invention, and these generally involve different methods of ;` '' :
Case 5554 GLR/gs/ejl entering and then thermally treating the tar sand forma-tion. All of the embodiments involve a first step of drilling or excavating a borehole or shaft to the base of the subsurface formation to be exploited. Typically this formation is a tar sands or oil sands Formation, but the ` technique can be used in other subsurface formations that comprise solid and semisolid 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 shaf-t below the base of the formation. This involves drilling or excavating into the stratum immediately below the formation to be exploited. This terminal end of the `~ shaft or borehole, in t`he stratum below the desirecl forma-tion, is then, optionally ? enlarged to form an operating ; chamber below the base of the desired formation.
~` The next step concerns the drilling of a plurality of second boreholes extending substantially upwardly and ra-dially outward into the desired formation from this oper-ating chamber.
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 embodiment, steam is conducted down the first borehole or shaft and thence injected into the plurality of second boreholes drilled from the oper-ating chamber. Or steam can be generated in the chamber and then injected into the plurality of boreholes. I~ is a ; feature of this embodiment that the steam used is at a pressure above the fracture pressure of the formation to be . ~
: Case 5554 GLR/gs/ejl .73~ ~ 3 10/12/81 exploited. It is a characteristic of oil sands or similar hydrocarbon deposits that any flow channels in the forma tion matrix are effectively plugged with the solid or semi-solid hydrocarbon material. The rate of injection for s-team or any other heating medium at subfracture pressures would be too low to achieve the rate of heat input neces-sary to recover economically the hydrocarbon. Steam pres-sures above fracture pressure will permit high rates o~
injection. The injection of this s-team is maintained for a time period resulting in an increase of the temperature of that portion of the formation surrounding the boreholes and the chamber. A "soaking" cycle can follow, for a cliscrete . 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 pres-sure due to the steam injection, to the lower portions of the second boreholes and thence to the lower portion of the chamber found in the stratum below the desired formation.
The injection/production cycle is repeated until insuffi-cient additional hydrocarbon is produced to warrant furthercycles. The recovered viscous material can be moved to the surface, by means well-known in the art, for further processing.
The above-mentioned injection/produc-tion cycle is one of several methods for recovering heavy hydrocarbons from underground formations. In this invention, two recovery mechanisms are described and used.
One mechanism involves a stimulation process, such as by steam. This process involves a single well and is well-, .
Case 5554 GLR/gs/ejl 3~ 10/12/81 ~.
known in the ar-t 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 entrance is then noted. Several s-timulation cycles may be needed for an appreciable outflow of desired material. The injection well and the production well are the same well, depending on the time during the stimulation process.
The other mechanism is called a "drive," and at least two wells are used. Here, for example, steam 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 steam pres-sure, can be used for either mechanism.
15In another embodiment, steam, at a pressure above the fracture pressure of the formation to be exploited, is injected 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 collecting the liberated material of reduced viscosity as before.
In another embodiment, after the second boreholes are `extended substantially upward and radially outward into the desired formation from the operating chamber, some of these second ~oreholes sre completed as in~ector wells, and the Case 5554 CLR/gs/ejl ~ 3 ~?~- ~? 10/12/81 remainder of -the seconcl boreholes are completed as producer wells. Then steam, at or above fracturing pressure, is injected into the second boreholes completed as injector wells. A number of injection/procluction cycles are carried out so as to increase the temperature of that portion of the formation surrounding the boreho:Les. The steam flow into the boreholes designated as injector wells is then stopped, and a flooding procedure is initiated, using the same or a different procedure from the choices noted above, such that the flooding material flows from injector wells to producer wells. The liberated material of reduced vis-cosity 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.
20Selected second boreholes are completed as producer i 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 previousl~
,j.~
decribed.
25In another embodiment, af-ter the second boreholes are drilled from the chamber into the desired formation, some of these second boreholes are completed as injec-tor 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.
Case 5554 GLR/gs/ejl 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. Liberated hydrocarbon material is then treated as discussed above.
The embodiments discussed above have one or more of the advantages discussed below.
A central shaft, with associated radial boreholes, has - 10 the advantages over wells drilled from the surface of:
- (a) reduced drilling costs~
(b) horizontal wells or boreholes are easier to drill, (c) there is less heat loss between the surface and 15the tar sands or oil sands, formation, or reser-; voir, and ~ (d) the movement of recovered oil from the formation ; to the surface is more efficient than when wells ;.
are drilled from the surface.
20The advantages of continuing the shaft or borehole into the zone below the formation or reservoir include:
(a) increased safety, since an operating chamber is ~ formed in the zone below the formation, ; (b) wells can be cemented in the zone below the for-25mation, while there is great difficulty in ce-- menting wells in an oil sands or tar sands forma-tion, and (c) it is easier and safer to complete wells that have their beginning or terminus in the operating 30chamber below the formation.
Case 555 GLR/gs/ejl ~ 3~ ~ 3 10/12/81 Using a steam pressure greater than the fracturing pressure of the formation allows injection of the steam into the formation or reservoir a-t a su-fficient rate to recover the hydrocarbon product economically. The greater pressure also allows a higher percentage of the formation or reservoir to be contacted, and this gives a higher usage efficiency for the injected steam. This greater pressure also allows a greater percentage o~ the formation to be processed.
Cyclical operation involving varying the steam pres-sure improves the recovery of the product and ofEers an improved oil/steam ratio. The steam pressure can be varied from about atmospheric pressure to the operating pressure.
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 DRAWINGS
The ~igure shows a side view of the borehole, the subsurface formations, the chamber in the formation below the hydrocarbon-containing formation, and the secondary boreholes ex-tending from the chamber into the hydrocarbon-containing formation.
DETAILED DESCRIPTION OF T~IE INVENTION
The described process for the in si-tu recovery of viscous materials can be used where the desired ~ormation or reservoir is greater than about 30 meters ~rom the sur-Eace. For example, the invention is operable where the Case 5554 GLR/gs/ejl 733S~
formation or reservoir is from about 90 to about 900 m.
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 satura-ted steam at the injection pressure in the formation will give a gradient of operating tempera-tures, being hi~hest near the injection nozzle and becoming lower as the distance from the injection nozzle increases.
The q~lality of the steam used for injection can vary from about 50% to about 100%. The injec-tion pressure used should be of the order of about 17 kPa/m or more, prefer-ably from about 22 to about 44 kPa per meter of depth.
The steam injection rate should be about the water equiva-lent of 15 m3/day/well or more, preferably from about 80 to about 350 m3/day/well.
The number of vertical shafts penetrating the over-burden, and the material ~mderlying 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 ~- 25 working number can vary between about ~ and about 25.
; The drawing illustrates a simplified cross-section ., :
`~ view of an in SitU operation. A shaft, or first bore-hole 2, is sunk through overburden 1 into the desired '; formation 3. The borehole is continued into the underlying stratum 4 below the desired ~ormation 3, and chamber 5 is ,'. 9 ., .
.
Case 5554 GLR/gs/ejl 33~3 an optional structure at the base of the first borehole 2.
From chamber 5, second boreholes 6 are drilled upwardly and radially outwardly, to penetrate formation 3. ~asing 7 is used to reduce the probability of collapse of borehole 6 while in stratum 4. One embodiment of production tubing (borehole 6 completed as a producing well) is shown as 8.
Some known method of moving material libera-ted from the borehole to the surface, such as a pump~ is not shown.
The stimulation in~ection time should be 5 days or more, such as from about 10 to about 100 days. The stimu-lation cycles are l or more, such as from about 5 to about 25.
The number of second borehol.es extending upwardly and radially outwardly from -the lower formation into the hydrocarbon-bearing formation can vary from about 2 to about 40~ preferably from about 2 to about 20. The radial length of these second boreholes can vary from a few . meters, such as about 10, 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.
'~
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) drilling a plurality of second boreholes extending substantially upwardly and radi-ally outwardly into said formation from the lower portion of the borehole of step (b), d) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface forma-tion, e) maintaining the injection of step (d) for a time period so as to increase the tempera-ture of that portion of the formation surrounding said second boreholes and any fracture fissures formed by the injection, f) releasing the pressure on the system of second boreholes, thus allowing any lib-erated material of reduced viscosity to move to the lower portions of said second bore-holes and thence to the lower portion of the first borehole, Case 5554 GLR/gs/ejl g) collecting the liberated material, and h) repeating the injection/production cycle of steps d-g.
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) drilling a plurality of second boreholes extending substantially upwardly and radi-ally outwardly into said formation from the lower portion of the borehole of step (b), d) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface forma-tion, e) maintaining the injection of step (d) for a time period so as to increase the tempera-ture of that portion of the formation surrounding said second boreholes and any fracture fissures formed by the injection, f) releasing the pressure on the system of second boreholes, thus allowing any lib-erated material of reduced viscosity to move to the lower portions of said second bore-holes and thence to the lower portion of the first borehole, Case 5554 GLR/gs/ejl g) collecting the liberated material, and h) repeating the injection/production cycle of steps d-g.
2. The method of Claim 1 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 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/day/well, d) the plurality of second boreholes varies from about 2 to about 40, e) the injection time period of step (d) is at least 5 days, and f) the repeated injection/production cycles of step (h) number at least two.
3. The method of claim 2, wherein a) the number of second boreholes varies from about 2 to about 20, b) the steam injection rate has a water equiva-lent of from about 80 to about 350 m3/day/
well, Case 5554 GLR/gs/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 5554 GLR/gs/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.
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) drilling a plurality of second boreholes extending substantially upwardly and radi-ally outwardly into said formation from the lower position of the borehole of step (b), d) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface formation, e) maintaining the injection of step (d) 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, f) 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, Case 5554 GLR/gs/ejl g) collecting the liberated material, h) repeating the injection/production cycle until the viscous material between at least some of the second boreholes is made mobile, i) stopping the steam flow into the second boreholes, j) completing selected second boreholes as producer wells, k) 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 l) 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, b) the lower portion of the borehole is en-larged to form an operating chamber below the base of the formation, c) 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/day/well, Case 5554 GLR/gs/ejl d) the plurality of second boreholes varies from about 2 to about 40, e) the injection time period of step (d) is at least 5 days, and f) the repeated injection/production cycles of step (h) number at least two.
6. The method of claim 5, wherein a) the number of second boreholes varies from about 2 to about 20, 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.
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.
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) drilling a plurality of second boreholes ex-tending substantially upwardly and radially outwardly into said formation from the lower portion of the first borehole of step (b), d) completing at least one of said second bore-holes as an injector well, while completing Case 5554 GLR/gs/ejl the remainder of said second boreholes as producer wells, e) 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, 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 in-jector boreholes, thus allowing any liber-ated material of reduced viscosity to move to the lower portion of the first borehole, h) repeating the injection/production cycle of steps (e) - (g) until hydrocarbon between at least some of said second boreholes is mobilized, i) stopping the steam flow to the injector well and collecting the liberated material, j) 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 k) collecting the liberated material.
8. The method of claim 7, wherein Case 5554 GLR/gs/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 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/day/well, d) the plurality of second boreholes varies from about 2 to about 40, e) the injection time period of step (d) is at least 5 days, and f) 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 20, 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 5554 GLR/gs/ejl
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 5554 GLR/gs/ejl
10. 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) drilling a plurality of second boreholes extending substantially upwardly and radi-ally outwardly into said formation from the lower portion of the borehole of step (b), d) injecting steam into said second boreholes, with the steam having a pressure above the fracture pressure of the subsurface formation, e) maintaining the injection of step (d) 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, f) 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.
g) collecting the liberated material, h) repeating the injection/production cycle until the viscous material between at least some of the second boreholes is mobilized, Case 5554 GLR/gs/ejl i) stopping the steam flow, j) completing selected second boreholes as producer wells, k) initiating a steam flooding procedure, l) cyclically varying the steam pressure during the operation of step (k), and m) collecting the liberated material.
g) collecting the liberated material, h) repeating the injection/production cycle until the viscous material between at least some of the second boreholes is mobilized, Case 5554 GLR/gs/ejl i) stopping the steam flow, j) completing selected second boreholes as producer wells, k) initiating a steam flooding procedure, l) cyclically varying the steam pressure during the operation of step (k), and m) collecting the liberated material.
11. The method of claim 10, 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 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 that 15 m3/day/well, d) the plurality of second boreholes varies from about 2 to about 40, e) the injection time period of step (d) is at least 5 days, f) the repeated injection/production cycles of step (h) number at least two, and g) the steam pressure of step (e) varies from about atmospheric to the operating pressure.
Case 5554 GLR/gs/ejl
Case 5554 GLR/gs/ejl
12. The method of claim 11, wherein a) the number of second boreholes varies from about 2 to about 20, 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.
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.
13. 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) drilling a plurality of second boreholes extending substantially upwardly and radi-ally outwardly into said formation from the lower portion of the borehole of step (b), d) completing at least one of said second boreholes as an injector well, while com-pleting the remainder of said second bore-holes as producer wells, e) injecting steam into said second boreholes designated injector wells, with the steam having a pressure above the fracture pres-sure of the subsurface formation, Case 5554 GLR/gs/ejl f) maintaining the injection of Step (e) for a time period so as to increase the tempera-ture of that portion of the formation surrounding said second boreholes and any fracture fissures formed by the injection, g) 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, h) repeating the injection/production cycle until hydrocarbon between at least some of said second boreholes is mobilized, i) initiating a steam flooding procedure, and j) cyclically varying the steam pressure during the operation of step (i), and k) 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 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 injection rate at a water equivalent of greater than 15 m3/day/well, Case 5554 GLR/gs/ejl d) the plurality of second boreholes varies from about 2 to about 40, e) the injection time period of step (d) is at least 5 days, f) the repeated injection/production cycles of step (h) number at least two, and g) the steam pressure of step (j) varies from about atmospheric to the operating pressure.
15. The method of claim 14, wherein a) the number of second boreholes varies from about 2 to about 20, b) the steam injection rate has a water equiva-lent of from about 80 to about 300 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.
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 |
|---|---|---|---|
| CA000394246A CA1173353A (en) | 1982-01-15 | 1982-01-15 | In situ recovery of viscous materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000394246A CA1173353A (en) | 1982-01-15 | 1982-01-15 | In situ recovery of viscous materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1173353A true CA1173353A (en) | 1984-08-28 |
Family
ID=4121834
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000394246A Expired CA1173353A (en) | 1982-01-15 | 1982-01-15 | In situ recovery of viscous materials |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1173353A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6050335A (en) * | 1997-10-31 | 2000-04-18 | Shell Oil Company | In-situ production of bitumen |
| US9010419B2 (en) | 2006-09-15 | 2015-04-21 | C-Fer Technologies (1999) Inc. | Subterranean system and method for treating and producing oil |
| CN111550222A (en) * | 2019-02-11 | 2020-08-18 | 中国石油天然气股份有限公司 | Method for exploiting natural gas hydrate by injecting steam |
-
1982
- 1982-01-15 CA CA000394246A patent/CA1173353A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6050335A (en) * | 1997-10-31 | 2000-04-18 | Shell Oil Company | In-situ production of bitumen |
| US9010419B2 (en) | 2006-09-15 | 2015-04-21 | C-Fer Technologies (1999) Inc. | Subterranean system and method for treating and producing oil |
| CN111550222A (en) * | 2019-02-11 | 2020-08-18 | 中国石油天然气股份有限公司 | Method for exploiting natural gas hydrate by injecting steam |
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