CN117948119A - In-situ oil recovery system and method for inclined oil shale stratum - Google Patents
In-situ oil recovery system and method for inclined oil shale stratum Download PDFInfo
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- CN117948119A CN117948119A CN202211337941.5A CN202211337941A CN117948119A CN 117948119 A CN117948119 A CN 117948119A CN 202211337941 A CN202211337941 A CN 202211337941A CN 117948119 A CN117948119 A CN 117948119A
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- oil shale
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- shale formation
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- 239000004058 oil shale Substances 0.000 title claims abstract description 118
- 238000011065 in-situ storage Methods 0.000 title claims abstract description 40
- 238000011084 recovery Methods 0.000 title claims description 24
- 238000000034 method Methods 0.000 title abstract description 7
- 238000010438 heat treatment Methods 0.000 claims abstract description 45
- 238000000605 extraction Methods 0.000 claims abstract description 25
- 150000003839 salts Chemical class 0.000 claims abstract description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 133
- 238000004519 manufacturing process Methods 0.000 claims description 21
- 238000005485 electric heating Methods 0.000 claims description 5
- 238000012986 modification Methods 0.000 claims 1
- 230000004048 modification Effects 0.000 claims 1
- 239000012530 fluid Substances 0.000 abstract description 9
- 238000007599 discharging Methods 0.000 abstract 1
- 238000005755 formation reaction Methods 0.000 description 103
- 239000007789 gas Substances 0.000 description 15
- 238000005516 engineering process Methods 0.000 description 4
- 230000002411 adverse Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000005416 organic matter Substances 0.000 description 3
- 239000008398 formation water Substances 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 238000000197 pyrolysis Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000003079 shale oil Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
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- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention relates to the technical field of oil and gas exploitation and discloses an in-situ oil extraction system and method for an inclined oil shale stratum, wherein the system and the method comprise plugging wells (1), heating wells (2) and oil extraction wells (3) which are sequentially arranged at intervals along the downward inclined direction of the oil shale stratum (5), the plugging wells (1) extend to an inclined high-point area of the oil shale stratum (5), the heating wells (2) comprise inclined well sections (22) which extend along the inclined direction of the oil shale stratum (5), and the oil extraction wells (3) extend to an inclined low-point area of the oil shale stratum (5). The well pattern layout is suitable for high-dip stratum, can effectively reduce the influence of stratum water on in-situ heating by discharging the stratum water to the ground, and is convenient for plugging by injecting molten salt into a plugging well so as to prevent high-dip stratum fluid from leaking to the ground along the bedding direction.
Description
Technical Field
The invention relates to an oil and gas exploitation technology, in particular to an in-situ oil exploitation system for an inclined oil shale stratum. On the basis, the invention also relates to an in-situ oil extraction method for the inclined oil shale stratum.
Background
Pyrolysis of organic matter in formations to produce hydrocarbons by heating the formations rich in organic matter is believed to be a mining technique that may be used effectively to produce oil shale and low maturity shale oil. Various methods of heating formations have been proposed, including electrical heating, fluid heating, and the like. Wherein, the electric heating method has low economic feasibility due to low stratum heat conductivity, slow heat transfer, long heating time and large energy consumption; the fluid heating needs fuel gas and combustion-supporting gas, the gas enthalpy value is low, and the high injection flow is needed to meet the heating temperature requirement.
With the development of oil and gas exploration technology, some oil and gas fields with large single-layer thickness and high oil content are found. But some of these areas present large formation dip angles (up to 30 ° or more, even 60 ° or more) which present new challenges for in situ heated well placement and production of oil shale. There is no report of oil shale heating exploitation technology aiming at high dip stratum.
Disclosure of Invention
The invention aims to provide an oil shale heating exploitation technology suitable for a high-dip-angle stratum, and provides an in-situ oil extraction system for an inclined oil shale stratum, which has a well pattern layout suitable for the high-dip-angle stratum, can effectively reduce the influence of stratum water on in-situ heating, and is convenient for preventing high-dip-angle stratum fluid from leaking to the ground along the bedding direction.
To achieve the above object, in one aspect, the present invention provides an in-situ oil recovery system for an inclined oil shale formation, comprising a plugging well, a heating well and an oil recovery well sequentially arranged at intervals along a downward inclined direction of the oil shale formation, wherein the plugging well extends to an inclined high-point region of the oil shale formation, the heating well comprises an inclined well section extending along the inclined direction of the oil shale formation, and the oil recovery well extends to an inclined low-point region of the oil shale formation.
Preferably, the plugged well comprises a first straight well section extending from the surface through a top formation above the oil shale formation and to the oil shale formation and a first horizontal well section extending in the direction of formation strike.
Preferably, the inclined oil shale formation in situ oil recovery system comprises a plurality of said plugged wells arranged at intervals from each other along the formation strike direction.
Preferably, the production well comprises a second vertical well section extending from the surface through a top formation above the oil shale formation and to the oil shale formation and a second horizontal well section extending in a formation strike direction.
Preferably, the heating well comprises a third vertical well section extending from the surface through a top formation above the oil shale formation and extending to the oil shale formation, the inclined well section extending at a position intermediate in the thickness direction of the oil shale formation and communicating to the third vertical well section, and/or the inclined oil shale formation in situ oil recovery system comprises a plurality of the heating wells arranged at intervals from each other in the formation strike direction.
Preferably, molten salt is injected into the oil shale formation through the plugged well, the molten salt being configured to solidify when the temperature of the oil shale formation is below a predetermined temperature.
Preferably, a gas product collecting device is connected to the wellhead of the plugged well.
Preferably, cracks which extend to the oil extraction well and are reformed by electric pulses are formed in the oil shale stratum, and/or molten salt and an electric heating device which are arranged in the oil shale stratum through the heating well are arranged in the oil shale stratum.
Preferably, the production well is used as a drainage well to drain the water from the oil shale formation to the surface with the production well.
The second aspect of the invention provides an in-situ oil extraction method of an inclined oil shale stratum, which is executed by the in-situ oil extraction system of the inclined oil shale stratum.
According to the technical scheme, the in-situ oil extraction system for the inclined oil shale stratum is characterized by arranging well pattern layouts which are sequentially arranged at intervals along the downward inclined direction of the oil shale stratum and are composed of the plugging wells, the heating wells and the oil extraction wells, and can drain stratum water to the ground by using the oil extraction wells as drainage wells before exploitation, so that energy consumption and adverse effects on in-situ heating are avoided when the stratum is heated. Through injecting molten salt into the plugging well, heat loss in the stratum heating process can be reduced, and the stratum reason cracks can be plugged after the molten salt is cooled, so that fluids such as oil gas products and the like are prevented from leaking to the ground along the stratum direction.
Drawings
FIG. 1 is a schematic diagram of an in situ oil recovery system for a sloped oil shale formation in accordance with a preferred embodiment of the present invention;
FIG. 2 is a schematic illustration of the formation dip of the slant oil shale formation in situ extraction system of FIG. 1;
FIG. 3 is a schematic illustration of a well pattern layout of the slant oil shale formation in situ extraction system of FIG. 1;
Fig. 4 is a schematic diagram of an in situ oil recovery system for a sloped oil shale formation in accordance with another preferred embodiment of the present invention.
Description of the reference numerals
1-Plugging a well; 11-a first straight well section; 12-a first horizontal well section; 2-heating the well; 21-a third vertical section; 22-inclined shaft section; 3-oil production well; 31-a second vertical section; 32-a second horizontal leg; 4-top formation; 5-an oil shale formation; 6-bottom formation.
Detailed Description
The following describes specific embodiments of the present invention in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
Referring to fig. 1, an in-situ oil recovery system for an inclined oil shale formation according to a preferred embodiment of the present invention is suitable for oil shale exploitation from a high-inclination formation having an inclination angle of a with respect to a horizontal plane, which may be up to 30 ° or more, even 60 ° or more. The high dip formation has an organic-rich oil shale formation 5 with a top formation 4 on the upper side exposed to the ground and a bottom formation 6 on the lower side. Depending on the geologic formation, the top formation 4, the oil shale formation 5, and the bottom formation 6 may generally have substantially the same inclination angle relative to the horizontal. It will be appreciated that the dip angle of the dipping formations may vary in magnitude or may exhibit a relatively small dip angle (e.g., less than 30 °) over a relatively wide area. For purposes of clarity of illustration of the present invention, the pattern layout of an inclined oil shale formation in situ extraction system in an inclined formation, which may be used in the in situ extraction of oil shale at a relatively low inclination, is shown only schematically in fig. 1.
As shown in fig. 2 and 3, the inclined oil shale formation in-situ oil recovery system of the present invention comprises a plugging well 1, a heating well 2 and an oil recovery well 3 which are sequentially spaced apart from each other in a downward inclined direction of an oil shale formation 5. That is, in the inclined formation, the oil shale formation 5 extends obliquely downward in a direction in which the plugged well 1, the heating well 2, and the production well 3 are sequentially spaced apart from each other, as in the left-to-right direction shown in fig. 2. It should be understood that the above-described pattern layout only requires an arrangement in the direction of inclination of the oil shale formation 5, and does not represent a collinear arrangement of wellbores of the plugged 1, heater 2, and production 3 wells.
Wherein the plugged well 1 extends to an inclined high point region of the oil shale formation 5, or it may further comprise a first horizontal well section 12 extending in the formation strike direction in the inclined high point region. The inclined high-point region of the oil shale formation 5 refers to a region of the oil shale formation 5 where an extension of the oil shale formation 5 with respect to the heating well 2 and the production well 3 is high. In connection with fig. 2, the bottom end of the plugged well 1 (including the first horizontal well section 12) is located at a level not lower than the level of the portions of the heating well 2 and the production well 3 extending in the oil shale formation 5, i.e. at an inclined high point region of the oil shale formation 5.
The heating well 2 comprises an inclined well section 22 extending in an inclined direction of the oil shale formation 5. It will be appreciated that because the direction of inclination of the oil shale formation 5 may vary from location to location and that the well inclination formed during formation drilling may vary, although depicted as extending in the direction of inclination of the oil shale formation 5, the inclined leg 22 may be at least partially non-parallel to the direction of inclination of the oil shale formation 5, such as in the schematic diagram shown in fig. 2, the path of extension of the inclined leg 22 having an arc.
The production well 3 extends to an inclined low point region of the oil shale formation 5, or it may further comprise a second horizontal well section 32 extending in the formation strike direction in the inclined low point region. Similar to the previously described high-point zone of inclination, the low-point zone of inclination of the oil shale formation 5 refers to a zone of the oil shale formation 5 in which the extension of the relatively plugged well 1 and the heating well 2 in the oil shale formation 5 is low. In connection with fig. 2, the bottom end of the production well 3 (including the second horizontal well section 32) is located at a height not higher than the height of the sections, i.e. in the inclined low point region of the oil shale formation 5, compared to the sections of the plugged well 1 and heater well 2 extending in the oil shale formation 5.
Therefore, aiming at the formation distribution characteristics of the high-dip-angle stratum, the in-situ oil extraction system of the inclined oil shale stratum provides well pattern layout suitable for the high-dip-angle stratum, and plugging wells, heating wells and oil extraction wells are sequentially arranged at intervals along the downward dip direction of the oil shale stratum. By extending the production well to the sloped low point region of the oil shale formation, it may be used as a drainage well prior to production to drain formation water to the surface, thereby avoiding energy consumption and adverse effects caused by such formation water when the formation is heated by the heating well. In addition, can also reduce the heat dissipation in the stratum heating process through injecting molten salt into the shutoff well, and can shutoff layer reason crack after the molten salt cools off, prevent fluids such as oil gas product from revealing to ground along the layer reason direction. When the molten salt melts due to higher stratum temperature, the plugging well can also collect gas products by using a gas product collecting device arranged at the wellhead of the plugging well, so that yield loss and environmental pollution caused by the fact that the plugging well is transported out of the ground along the bedding direction are prevented.
The plugged well 1, the heater well 2, and the production well 3 may be appropriately configured to form a pattern layout, depending on the specific characteristics of the formation. In the preferred embodiment shown in fig. 1 to 3, the plugged well 1 comprises a first straight well section 11 extending from the surface through the top formation 4 and to the oil shale formation 5 and a first horizontal well section 12 extending in the formation strike direction, wherein the bottom end of the first straight well section 11 may extend to an intermediate position in the thickness direction of the oil shale formation 5, and accordingly the first horizontal well section 12 may extend horizontally at the height of this intermediate position. Thus, the molten salt injected through the plugging well 11 can well plug the channel through which the fluid flows upward in the bedding direction, and ensure the heating efficiency of the formation.
For situations where the oil shale formation is shallowly buried, it may be difficult to implement a horizontal well section in an inclined high-point region of the oil shale formation. Thus, multiple vertical wells may be employed instead of the function of a horizontal well section. For example, in another preferred embodiment shown in fig. 4, an in situ oil recovery system for an inclined oil shale formation includes a plurality of plugged wells 1 spaced apart from one another along the formation strike direction so that molten salt may be injected through each of the plugged wells 1 to perform plugging and fluid collection operations over the length of the formation strike. Other aspects of the embodiment shown in fig. 4 are substantially the same as the embodiment shown in fig. 1, and thus the description will not be repeated for the same.
Similar to the plugged well 1 described above, the production well 3 may also comprise a second vertical section 31 extending from the surface through the top formation 4 and to the oil shale formation 5 and a second horizontal section 32 extending in the formation strike direction, wherein the bottom end of the second vertical section 31 may extend to an intermediate position in the thickness direction of the oil shale formation 5, and accordingly the second horizontal section 32 may extend horizontally at the height of this intermediate position. Thus, through the production well 3, the water content of the oil shale formation 5 can be fully drained before production and subsequently used as a passage for oil and gas to rise to the surface.
The heating well 2 may comprise a third vertical section 21 extending from the surface through the top formation 4 and to the oil shale formation 4, and the inclined section 22 may extend at a mid-position in the thickness direction of the oil shale formation 5 and communicate to the third vertical section 21. Through the heating well 2, organic matter in the oil shale formation 5 may be heated to pyrolyze it to produce oil and gas. As shown in fig. 3, the inclined oil shale formation in situ extraction system of the present invention may include a plurality of heating wells 2 spaced apart from each other along the formation strike direction.
The manner in which the formation is heated using the heating well 2 may be electrical heating, fluid heating, combustion heating, and the like. In a preferred embodiment of the present invention, the oil shale formation 5 has molten salt and an electric heating device which are put in through the heating well 2, so that the electric heating device can be used for maintaining the molten state of the molten salt, and the organic matters in the oil shale formation 5 can be continuously heated by utilizing the characteristic that the specific heat capacity of the molten salt is higher, so as to fully exploit oil and gas resources contained in the molten salt.
In general, fractures may be formed in the oil shale formation by hydraulic fracturing means such that pyrolysis-generated oil and gas flows through the fractures to the production well 3. However, such reservoir retrofit can have an adverse effect on subsequent pyrolysis. To this end, in a preferred embodiment of the invention, the reservoir may be modified with high frequency electrical pulses such that fractures are formed in the oil shale formation 5 extending to the production well 3 for conducting oil and gas.
The invention also provides an in-situ oil extraction method of the inclined oil shale stratum, which is executed by the in-situ oil extraction system of the inclined oil shale stratum.
The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of individual specific technical features in any suitable way. The various possible combinations of the invention are not described in detail in order to avoid unnecessary repetition. Such simple variations and combinations are likewise to be regarded as being within the scope of the present disclosure.
Claims (10)
1. The utility model provides an inclined oil shale stratum normal position oil recovery system which characterized in that, includes shutoff well (1), heating well (2) and oil recovery well (3) that follow oil shale stratum (5) downward sloping direction mutual interval in proper order, shutoff well (1) extend to the slope high-point area of oil shale stratum (5), heating well (2) include along inclined shaft section (22) that the incline direction of oil shale stratum (5) extends, oil recovery well (3) extend to the slope low-point area of oil shale stratum (5).
2. The slant oil shale formation in situ extraction system according to claim 1, wherein the plugged well (1) comprises a first straight well section (11) extending from the surface through a top formation (4) above the oil shale formation (5) and to the oil shale formation (5) and a first horizontal well section (12) extending in the formation strike direction.
3. The inclined oil shale formation in situ oil recovery system according to claim 1, characterized in that it comprises a plurality of said plugged wells (1) arranged spaced apart from each other along the formation strike direction.
4. The inclined oil shale formation in situ oil recovery system according to claim 1, wherein the oil recovery well (3) comprises a second vertical section (31) extending from the surface through a top formation (4) above the oil shale formation (5) and to the oil shale formation (5) and a second horizontal section (32) extending in a formation strike direction.
5. The inclined oil shale formation in situ oil recovery system according to claim 1, characterized in that the heating well (2) comprises a third straight well section (21) extending from the surface through the top formation (4) above the oil shale formation (5) and to the oil shale formation (4), the inclined well section (22) extending at a mid-position in the thickness direction of the oil shale formation (5) and communicating to the third straight well section (21), and/or the inclined oil shale formation in situ oil recovery system comprises a plurality of the heating wells (2) arranged spaced apart from each other in the formation strike direction.
6. The inclined oil shale formation in situ extraction system according to claim 1, characterized in that molten salt is injected into the oil shale formation (5) through the plugged well (1), the molten salt being arranged to solidify when the temperature of the oil shale formation (5) is below a predetermined temperature.
7. The in situ oil recovery system of an inclined oil shale formation according to claim 6, characterized in that the wellhead of the plugged well (1) is connected with a gas product collection device.
8. The inclined oil shale formation in situ oil recovery system according to claim 1, characterized in that cracks extending to the oil recovery well (3) are formed in the oil shale formation (5) by electric pulse modification and/or that the oil shale formation (5) has molten salt and electric heating means put in through the heating well (2).
9. The inclined oil shale formation in situ extraction system according to claim 1, characterized in that the extraction well (3) is used as a drainage well for draining the water of the oil shale formation (5) to the surface with the extraction well (3).
10. An in situ production method of an inclined oil shale formation performed with the in situ production system of an inclined oil shale formation according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211337941.5A CN117948119A (en) | 2022-10-28 | 2022-10-28 | In-situ oil recovery system and method for inclined oil shale stratum |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211337941.5A CN117948119A (en) | 2022-10-28 | 2022-10-28 | In-situ oil recovery system and method for inclined oil shale stratum |
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| Publication Number | Publication Date |
|---|---|
| CN117948119A true CN117948119A (en) | 2024-04-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211337941.5A Pending CN117948119A (en) | 2022-10-28 | 2022-10-28 | In-situ oil recovery system and method for inclined oil shale stratum |
Country Status (1)
| Country | Link |
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| CN (1) | CN117948119A (en) |
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2022
- 2022-10-28 CN CN202211337941.5A patent/CN117948119A/en active Pending
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