CA2909385C

CA2909385C - Layered ignition device, injection production system and injection production method

Info

Publication number: CA2909385C
Application number: CA2909385A
Authority: CA
Inventors: Hongjun Zhang; Xiaocong Yu; Xianzhi YANG; Shujie Zhao; Lisi Lu; Jin Liu; Shaogang Qu; Baochun Yang; Hua Long
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2014-10-21
Filing date: 2015-10-19
Publication date: 2017-04-25
Anticipated expiration: 2035-10-19
Also published as: CA2909385A1

Abstract

The present invention provides a layered ignition device, an injection production system and an injection production method applied to air injection oil deposition, the layered ignition device comprising: a heat insulation pipe sleeving a non- upset oil pipe, and a casing sleeving the heat insulation pipe; an electric ignition device disposed in an inner cavity of the non-upset oil pipe, comprising: an electric igniter cable and an electric igniter heating section, the electric igniter cable being connected to a power supply; a first annular space formed between the casing and the heat insulation pipe; a second annular space formed between the heat insulation pipe and the non-upset oil pipe; a first packer and a second packer disposed in the first annular space and spaced by certain distance, an upper layer air injection space being partitioned between the first packer and the second packer; an upper layer air distribution device positioned in the upper layer air injection space being disposed on the heat insulation pipe; an enhanced heat transfer device comprising: a winding section and a contact section; the enhanced heat transfer device is wholly wound on the electric ignition device when temperature is lower than a preset value, and the contact section is put up to come into contact with the non-upset oil pipe when temperature is higher than or equal to another preset value.

Description

LAYERED IGNITION DEVICE, INJECTION PRODUCTION
SYSTEM AND INJECTION PRODUCTION METHOD
10 Technical Field The present invention relates to an ignition technology by combustion of oil in situ, and specifically relates to a layered ignition device, an injection production system and an injection production method.
Background of the Invention Currently, common ignition technologies for air injection oil deposition mainly include four ignition methods as follows: chemical ignition, steam injection spontaneous ignition, steam injection + chemical agent combustion-supporting ignition and electric ignition, and on-site ignition mainly adopts general ignition. For thick-layer oil deposition or multilayer oil deposition, especially for the developed oil deposition, currently there are mainly three problems: firstly, on-site general ignition easily causes uneven vertical employment and bad ignition efficiency; for the thick-layer oil deposition, combustion of only an upper portion easily causes premature gas channeling;
and for the multilayer oil deposition, part of layers or sections is ignited, and those not II

' ignited may be subjected to the secondary operation, which greatly increases quantity of ignition operation and ignition difficulty; secondly, for the employed oil deposition, remaining oil in the immediate vicinity of wellbore has low saturation and contains much water; at the beginning of ignition, before the oil deposition reaches a spontaneous ignition point (generally above 300 C), evaporation of water may take away a great quantity of heat, therefore low-temperature oxidation for long time is needed to reach such temperature; ignition fails for part of oil wells because that ignition temperature of oil layer cannot be reached due to long low-temperature oxidation time (quantity of heat generated in low-temperature oxidation < quantity of heat absorbed by formation +
quantity of heat that air takes away); after the failure, because crude oil low-temperature oxidation product is heavy oil that contains much colloid asphalt which blocks the formation and reduces intake capability of air, thereby greatly increasing difficulty of the secondary ignition; thirdly, since tubular column space for the layered injection is limited, it is impossible to implement layered ignition using a mobile electric igniter;
on-site layered ignition mainly adopts the steam injection spontaneous ignition and the steam injection + chemical agent combustion-supporting ignition; however, the above two ignition methods have the following problem: because temperature of oil deposition is low, low-temperature oxidation time is long, and success rate of ignition is not high.
Accordingly, there is a need to provide a new sectioned/layered ignition device and injection production method, which achieves rapid successful ignition and oil production for the developed oil deposition, so as to improve thick-layer/multilayer fireflood ignition effect and provide broader range for development of thick-layer/multilayer combustion of oil in situ.
Summary of the Invention Main purpose of the embodiment of the invention is to provide a layered ignition device, an injection production system and an injection production method, to achieve rapid and successful ignition and oil production of the developed oil deposition, thereby improving fireflood ignition effect of multilayer oil layer and improving oil production work efficiency.
To achieve the above purpose, the embodiment of the present invention provides a layered ignition device, comprising: a casing, a heat insulation pipe, a non-upset oil pipe, an electric ignition device, an upper layer air distribution device, a first packer, a second

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' packer and at least one enhanced heat transfer device, wherein the electric ignition device includes: an electric igniter cable and an electric igniter heating section, the electric igniter cable is connected to a power supply to provide heat to the electric igniter heating section so as to heat the oil layer; the electric ignition device is disposed in an inner cavity of the non-upset oil pipe, the heat insulation pipe sleeves the non-upset oil pipe, and the casing sleeves the heat insulation pipe; a first annular space into which nitrogen is injected is formed between the casing and the heat insulation pipe; a second annular space into which, together with the inner cavity, air is injected is formed between the heat insulation pipe and the non-upset oil pipe; the first packer and the second packer are disposed in the first annular space and spaced by certain distance, and an upper layer air-injection space is partitioned between the first packer and the second packer; the heat insulation pipe is provided thereon with the upper layer air distribution device, and the upper layer air distribution device is positioned in the upper layer air injection space, for injecting air in the heat insulation pipe into the upper layer air injection space; the enhanced heat transfer device includes: a winding section and a contact section; when temperature of the electric ignition device is lower than a first preset temperature, the contact section is attached on the electric ignition device, and the enhanced heat transfer device is wholly wound on the electric ignition device, and when temperature of the electric ignition device is larger than or equal to a second preset temperature, the contact section is put up to come into contact with the non-upset oil pipe, to transfer heat to the non-upset oil pipe.
The embodiment of the present invention further provides an injection production system, comprising an oil production device and the layered ignition device as described above, the layered ignition device is used for igniting the oil layer to make the oil layer generate a combustion front to drive the crude oil to move to the position of the oil production device; the oil production device is used for collecting the crude oil; wherein, the oil production device comprises: an outer tubular column which from bottom to top in sequence includes: a first plug for sealing a lower part of the outer tubular column; a first pipe of which a lower end is fixedly connected to the first plug, the first pipe is opened with a first hole for communicating with the outside, and a packer that partitions the first pipe from the casing is further provided above the first hole; and an inner tubular column between which and the first pipe an annular passage is formed, the inner tubular column includes from bottom to top in sequence: a second plug, a sand setting gas

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' ' anchor, an oil well pump, an oil pipe, and a first sand discharging valve is further provided on the second plug.
The embodiment of the present invention further provides an injection production method applied to the injection production method as described above, comprising:
injecting air into the inner cavity of the layered ignition device at a first preset speed, and injecting air into the second annular space of the layered ignition device at a second preset speed; tripping in the electric ignition device in the non-upset oil pipe to the lowest end of the non-upset oil pipe, and turning on the power supply to start the electric ignition device; injecting heating gas in the non-upset oil pipe into the lower layer air injection space by an end of the non-upset oil pipe, to heat and ignite the lower oil layer;
after ignition time lasts for a first preset time, turning off the electric ignition device, moving the electric ignition device upward to be a certain distance apart from the upper oil layer, and continuously injecting air into the inner cavity of the layered ignition device at the first preset speed; and injecting air into the second annular space of the layered ignition device at the first preset speed, and injecting air into the inner cavity of the layered ignition device at the second preset speed; injecting comburent into the second annular space, and injecting the comburent and the heating gas in the heat insulation pipe into the upper layer air injection space by the upper layer air distribution device; starting the electric ignition device to heat and ignite the upper oil layer, and igniting the upper oil layer under the action of heat released from combustion of the comburent and air; after heating by the electric ignition device for a second preset time, turning off the power supply of the electric ignition device and taking out the electric ignition device; collecting, by the oil production device, crude oil that moves to the position of the oil production device driven by the combustion front of the oil layer.
The embodiment of the present invention has beneficial effects that, the invention can improve success rate of ignition of thick-layer/multilayer combustion of oil in situ, ignition efficiency and oil production efficiency, thereby reducing high-temperature time of the tubular column and improving thick-layer/multilayer oil layer fireflood ignition effect. In addition, multi-separation of oil-gas mixture can be realized in the oil production process, efficiency of oil-gas separation is increased to 50% or higher, so as to reduce influence of gas on pump efficiency; furthermore, the invention has sand prevention functions such as sand setting, sand blocking, sand discharging and the like, which can improve pump efficiency of the oil pump and further improve fireflood

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development effect.
Brief Description of the Drawings In order to describe the embodiment of the invention or technical solutions in prior art more clearly, hereinafter accompanying figures required to be used in description of the embodiment will be introduced briefly. Obviously, the accompanying figures in the following description are merely some embodiments of the invention, and it is practicable for those skilled in the art to obtain other accompanying figures according to these ones in the premise of making no creative efforts.
Fig. 1 is a structural schematic of the layered ignition device in accordance with the embodiment of the present invention;
Figs. 2A to 2C are structural schematics of the enhanced heat transfer device 8 in accordance with the embodiment of the present invention;
Fig. 2D is a top view of the enhanced heat transfer device 8 in the use state in accordance with the embodiment of the present invention;
Fig. 3 is a structural schematic of the oil production device in accordance with the embodiment of the present invention;
Fig. 4 is a structural schematic of the second sand discharging valve in accordance with the embodiment of the present invention;
Fig. 5 is a use state diagram of the oil production device in accordance with the embodiment of the present invention; and Fig. 6 is a flowchart of the injection production method in accordance with the embodiment of the present invention.
Detailed Description of the Embodiment Hereinafter technical solutions in the embodiments of the invention will be described clearly and completely incorporating accompanying figures in the embodiments of the invention. Obviously, the described embodiments are merely part of embodiments of the invention, but not all of the embodiments. On the basis of the embodiment in the invention, all of the other embodiments obtained by those skilled in the art in the premise that no creative efforts are made fall within the protection scope of the invention.
The embodiment of the present invention provides a layered ignition device.

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Hereinafter, the present invention will be described in detail incorporating accompanying drawings.
The embodiment of the present invention provides a layered ignition device which, as shown in Figs. 1 and 2A, mainly comprises: a casing 1, a heat insulation pipe 2, a non-upset oil pipe 3, an electric ignition device 4, an upper layer air distribution device 5, a packer 6, a packer 7 and an enhanced heat transfer device 8 and the like.
The aforementioned heat insulation pipe 2 sleeves the non-upset oil pipe 3, and the casing 1 sleeves the heat insulation pipe 2. The electric ignition device 4 is disposed in an inner cavity of the aforementioned non-upset oil pipe 3, and mainly includes: an electric igniter cable 11 and an electric igniter heating section 12, one end of the electric igniter cable 11 is connected to a power supply (not shown), and the other end thereof is connected to the electric igniter heating section 12. The aforementioned power supply is used for supplying heat to the electric igniter heating section 12.
The aforementioned casing 1 sleeves the heat insulation pipe 2, and an annular space 9 is formed between the casing 1 and the heat insulation pipe 2, nitrogen can be injected into the annular space 9 by an air injection device 16, so as to have the effect of heat preservation. The aforementioned heat insulation pipe 2 sleeves the non-upset oil pipe 3 so as to form an annular space 10 between the heat insulation pipe 2 and the non-upset oil pipe 3, and air is injected into the annular space 10 and the inner cavity of the non-upset oil pipe 3 by the air injection device 16, to heat the multilayer oil layer, and hereinafter the process will be described in details in which the multilayer oil layer is ignited in a layered manner by heating air.
The packer 6 and the packer 7 are disposed in the aforementioned annular space 9, and the packer 6 is a certain distance apart from the packer 7, so as to partition an upper layer air injection space. The position of the upper layer air injection space corresponds to the upper oil layer.
The aforementioned heat insulation pipe 2 is provided thereon with an upper layer air distribution device 5 which is positioned in the aforementioned upper layer air injection space; when the heat insulation pipe 2 is injected with air, the air can be injected into the upper layer air injection space by the upper layer air distribution device 5. In practical application, the function of the upper layer air distribution device 5 can be realized by a screen pipe that is provided with a plurality of through holes, but the present invention is not limited thereto.

6 In practical application, the aforementioned annular space 10 is further used for injecting comburent to perform chemical ignition on the upper oil layer.
In one embodiment, the aforementioned comburent can be a mixed product of petroleum and capsule mixture having a volume ratio of 1: 1; wherein, the capsule mixture is prepared by the process of uniformly mixing sodium nitrite, ammonium nitrate, combustion improver and formamidine disulfide dihydrochloride to obtain a mixture, and wrapping the mixture with a water soluble capsule of which a diameter is 0.2 to 0.5 times of a pore throat diameter of the formation, and dissolving for 48 to 72 hours so as to obtain the capsule mixture.
In specific implementation, it is required that mass ratio of sodium nitrite to ammonium nitrate is 1: 1, molar ratio of total injection amount of sodium nitrite and ammonium nitrate to total injection amount of formamidine disulfide dihydrochloride is 1: 10 (preferably 1: 1), injection amount of formamidine disulfide dihydrochloride is N, N=Q/3191, Q=7EH(r12-r22)po(t,-tr); wherein, H is thickness of oil layer, ri is heating maximum radius boundary, r2 is heating minimum radius boundary, pc is volumetric heat capacity of oil layer, t, is temperature after heating, tr is original oil layer temperature, it is set to be 3.14.
The aforementioned combustion improver may be combination including one or more of platinum, palladium and rhodium, or a compound of organic copper manganese, or combination of one or more of an oxide of platinum, an oxide of palladium and an oxide of rhodium; more preferably, the used combustion improver is ferrocene.
Use amount of the combustion improver is calculated according to the following formula:
m---AporH(re2-r,2)9S01, wherein, H is thickness of oil layer, re is heating radius, rõv is oil well radius, A is 0.2, So, is remaining oil saturation, pv is density of the combustion improver, it is set to be 3.14, 9 is porosity of oil layer; wherein, A is determined according to parameters such as porosity, permeability and intake capability and the like of the formation.
In one embodiment, the ingredients in the aforementioned capsule mixture have such a ratio that 80kg formamidine disulfide dihydrochloride, 3.5kg ammonium nitrate, 3.5kg sodium nitrite and 74kg ferrocene, but the above ratio is only an example and not for limiting the content of the ingredients in the capsule mixture in the embodiment of the present invention, and the specific content can be adjusted according to actual demand.

7 In another embodiment, the aforementioned combustion improver can be iron pulverized coal. Due to the combustion and heat release of the iron pulverized coal, the oil layer can be ignited smoothly under the action of the heat and air; since a large pore path of the oil layer has low pressure, the injected iron pulverized coal preferably enters the large pore path having low pressure to play a role of profile control and channel plugging, and the product from combustion of the iron pulverized coal contains solid iron oxides which remain in pore space after combustion, to play a role of continuing to adjust gas entry profiling, which is more beneficial to ignition, and ignition time is reduced. The iron pulverized coal is burned in the oil layer to rapidly release heat to rapidly heat the oil layer, and even if oil saturation in the immediate vicinity of wellbore is smaller than 0.35, the oil layer can also be ignited.
In practical application, particle size of the added iron pulverized coal is 100 to 200 meshes, and injection amount N of the iron pulverized coal can be calculated according to the following formula: N=A7rhOr2, wherein, A is set to be within the range of 0.3 to 0.5, h is thickness of oil layer, (1) is formation porosity, r is injection radius. The formation porosity is (13 which can be tested by coring when in drilling; the thickness of oil layer h can be judged according to well-logging when in drilling; the injection radius r is generally 0.5m to 0.8m. Generally speaking, the oil layer can be ignited 6 to 8 days after both air and iron pulverized coal are injected at the above speed.
As shown in Figs. 2A and 2B, the aforementioned enhanced heat transfer device

8 includes a winding section 81 and a contact section 82. Wherein, the contact section 82 of the enhanced heat transfer device 8 is composed of memory material having high temperature resistance and high conductivity capabilities (capable of transferring heat), the contact section 82 is connected to both ends of the winding section 81 and forms a helical structure of the enhanced heat transfer device 8 together with the winding section 81, and the contact section 82 and the winding section 81 can be wound on the electric ignition device 4. The enhanced heat transfer device 8 can be disposed to be at the same height as the position of the electric igniter heating section 12 of the electric ignition device 4.
The memory material that forms the aforementioned contact section 82 can have corresponding deformation along with change of temperature. When in cooled status, i.e., when temperature of the contact section 82 is lower than a preset temperature (for example 50 C), as shown in Fig. 2A, the contact section 82 is in a retraction state =
(attached on the electric ignition device 4) and is wound on the non-upset oil pipe 3 together with the winding section 81 (i.e., the enhanced heat transfer device 8 is wholly wound on the electric ignition device 4); when in heated status, i.e., when temperature of the contact section 82 is higher than another preset temperature value (for example 200 C), as shown in Fig. 28, the contact section 82 of the enhanced heat transfer device 8 is put up so that it can come into contact with inner wall of the non-upset oil pipe 3, thereby being capable of transferring heat by the enhanced heat transfer device 8 to improve heat transfer effect. It is necessary to note that, the specific numerical value of the preset temperature value in the above text is only illustrative, but not for limiting the present invention.
Furthermore, in order to further improve heat transferring and heating effect on the layered ignition device, as shown in Figs. 2C and 2D, a plurality of enhanced heat transfer devices 8 with intervals of 5-8m therebetween can be disposed on the aforementioned non-upset oil pipe 3. It is necessary to note that, although two enhanced heat transfer devices 8 are shown in Figs. 2C and 2D, the number is not limited thereto, and one or more than one enhanced heat transfer device can be disposed according to the actual need of the layered ignition device.
As shown in Fig. 1, the layered ignition device according to the embodiment of the present invention may further comprise a retractable pipe 13 which is disposed at an upper part of the heat insulation pipe 2 and is connected within the heat insulation pipe 2 for adjusting the heat insulation pipe 2 to move up and down. When the heat insulation pipe 2 is subjected to the action of heat expansion and cold contraction, the retractable pipe 13 can be compressed or stretched to drive the heat insulation pipe 2 to move up and down, whereby ensuring stability of the heat insulation pipe 2, so as to be able to ensure tightness of the packer 6 and the packer 7.
In specific implementation, corresponding gas can be injected into the layered ignition device by an air injection device 16 as shown in Fig. 1. In the embodiment of the present invention, air is injected into the inner cavity of the non-upset oil pipe 3 and the annular space 10, and nitrogen is injected into the annular space 9. When applied to different environment, different gas can be injected according to different need, and the present invention is not limited thereto.
Due to partitioning function of the packer 6, the nitrogen injected into the annular space 9 is only injected into a portion above the packer 6, and the injected nitrogen can

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' have the effect of heat preservation. The air injected into the inner cavity of the non-upset oil pipe 3 can be injected into a portion of the annular space 9 below the packer 7 by an opening at a lower end of the non-upset oil pipe 3, and position of the portion of the annular space 9 below the packer 7 corresponds to the lower oil layer.
In addition, the air injected into the annular space 10 can, on one hand, be injected into the aforementioned upper layer air injection space by the upper layer air distribution device 5; and can, on the other hand, be injected into a portion of the annular space 9 below the packer 7 by an opening at a lower end of the heat insulation pipe 2.
Furthermore, the layered ignition device may further comprise: a seal ring 15 and a conductive seeker 14, wherein the seeker 14 is disposed at the lowest end of the non-upset oil pipe 3, and the seeker 14 is mainly composed of a tubular part and a bullet-shaped head. The seal ring 15 is disposed in the aforementioned annular space 10 and is adhered with the tubular part of the seeker 14 to have the function of blocking, so that the air injected into the heat insulation pipe 2 is totally injected into the upper layer air injection space by the upper layer air distribution device 5, so as to be able to heat and ignite the upper oil layer. A vent hole is disposed at the lowest end of the seeker 14, so that the air in the non-upset oil pipe 3 can be injected into the portion of the annular space 9 below the packer 7 by the seeker 14, to heat and ignite the lower oil layer.
Since the disposed seal ring 15 reduces space of the non-upset oil pipe 3 that is tripped in the heat insulation pipe 2, the bullet-shaped head of the seeker 14 causes the non-upset oil pipe 3 to be able to easily pass through the space in the seal ring 15. When it is necessary to trip out the non-upset oil pipe 3, in order to avoid collision between the non-upset oil pipe 3 and the lowest end edge of the heat insulation pipe 2 to the greatest extent, the lowest end of the heat insulation pipe 2 can be set into a horn-shaped opening, so as to increase tripping-out space of the non-upset oil pipe 3.
When the power supply connected to the electric ignition device 4 is started, the electric igniter heating section 12 of the electric ignition device 4 works to heat the air injected into the inner cavity of the non-upset oil pipe 3 and the annular space 10, and after the air injected into the aforementioned upper layer air injection space is heated, the upper oil layer can be heated and ignited; in addition, the air injected into the portion of the annular space 9 below the packer 7 is heated and then the lower oil layer is heated and ignited.
In practical application, the air in the non-upset oil pipe 3 is heated by the electric =
ignition device 4, and temperature of the air when it reaches the outlet of the non-upset oil pipe 3 can reach 250 C-350r; after the gas injected into the annular space

10 is heated by the non-upset oil pipe 3, its temperature can reach 250r ¨350r . It is necessary to note that, the above temperature that the gas can reach is only illustrative, but not for limiting the present invention, and the temperature can be adjusted according to actual need of the oil layer, so that temperature of the heated gas can reach different range intervals.
To sum up the above, the layered ignition device of the present invention can improve success rate of ignition and ignition efficiency of multilayer combustion of oil in situ, so as to reduce high-temperature time of the tubular column and improve fireflood ignition effect of multilayer oil layer.
The embodiment of the present invention further provides an injection production system, comprising an oil production device and a layered ignition device, wherein the layered ignition device is the layered ignition device described in the above text and therefore is not repeated here. The layered ignition device is used for igniting the oil layer so that the oil layer generates a combustion front, and crude oil moves to the position of the oil production device driven by the combustion front; the oil production device is used for collecting crude oil.
As shown in Fig. 3, the oil production device comprises: an outer tubular column 17 and an inner tubular column 18 that is disposed within the outer tubular column 17. Both of the outer tubular column 17 and the inner tubular column 18 are disposed within a casing 19.
Wherein, the outer tubular column 17 comprises in sequence from bottom to top:
a first plug 20 and a first pipe 21. Furthermore, the first pipe 21 comprises a first tail pipe 22, a screen pipe 23 and a lining pipe 24.
The aforementioned first plug 20, first tail pipe 22, screen pipe 23 and lining pipe 24 all can be connected by screw thread.
The first plug 20 is disposed at a lower end of the first tail pipe 22, for sealing the lower end of the first tail pipe 22 to prevent leakage thereof.
The lower end of the first tail pipe 22 is sealed by the first plug 20, an upper end of the first tail pipe 22 is connected to the screen pipe 23. Generally speaking, bore diameters of the first tail pipe 22 and the screen pipe 23 are not matched with each other, at this time, an oil pipe short connection for the screen pipe can be disposed at the

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position where the first tail pipe 22 is connected to the screen pipe 23. The oil pipe short connection can realize transition connection between different pipe diameters.
The lower end of the first tail pipe 22 is disposed to be 5-10m apart from a lower bound of the oil layer. The lower bound of the oil layer is a boundary of bottom of the oil layer and the formation.
The lower end of the screen pipe 23 is connected to the first tail pipe 22, and an upper end thereof is connected to the lining pipe 24. The screen pipe 23 has a length of 5-10m, the screen pipe 23 is provided thereon with a screen hole 230 which has a bore diameter of 0.2 to 0.5mm. The first pipe 21 is opened with a first hole for communicating with the outside. When the first pipe 21 is provided with the screen pipe 23, the first hole is the screen hole 230 that is opened for the screen pipe 23.
The lining pipe 24 can be a hollow oil pipe. Generally speaking, bore diameters of the lining pipe 24 and the screen pipe 23 are not matched with each other, at this time, an oil pipe short connection for the screen pipe can be disposed at the position where the lining pipe 24 is connected to the screen pipe 23. The oil pipe short connection can realize transition connection between different pipe diameters.
Tail gas may be generated in the process of combustion of oil in situ, the tail gas comprising: carbon dioxide, light hydrocarbon gases, hydrogen sulfide, and mixed gas such as nitrogen contained in the air generated from air and crude oil oxidation and combustion in the process of combustion of oil in situ. The tail gas, especially hydrogen sulfide therein, may cause corrosion to the tubular column. In the embodiment of the present invention, the first tail pipe 22 and the lining pipe 24 both adopt corrosion-resistant stainless steel materials containing element chromium.
Content of the element chromium is 3%. It is better corrosion resistant than the existing common tubular column which adopts N80 steel.
A packer 25 is disposed in the annular space of the lining pipe 24 and the casing 19.
The annular space of the lining pipe 24 and the casing 19 is sealed by the packer 25, so that oil gas that enters the tubular column from the oil layer does not flow into the annular space of the lining pipe 24 and the casing 19 that is sealed by the packer 25, so as to have the function of protecting the casing 19.
The first plug 20 is further provided with at least one second sand discharging valve 26. When there are multiple second sand discharging valves 26, the multiple second sand discharging valves 26 can be distributed evenly on the first plug 20.

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Referring to Fig. 4, the second sand discharging valve 26 comprises: an inner valve cylinder 263, an outer valve cylinder 264 that sleeves the inner valve cylinder 263, a spring 262 that is disposed between the inner valve cylinder 263 and the outer valve cylinder 264, and a valve ball 261 that is clamped at a lower end of the inner valve cylinder 263 through tensioning function of the spring 262. When a certain amount of sand grains are deposited at the lower end of the first tail pipe 22 and gravity of the sand grains is larger than a pretightening force of the spring 262 on the valve ball 261, the sand grains may urge the valve ball 261 to move downward under the effect of gravity, and with the valve ball 261 moves downward, the second sand discharging valve 26 is opened, the deposited sand grains are discharged, and deposited at bottom of the oil layer under the effect of gravity. When the sand grains are discharged, under the action of the spring 262, the valve ball 261 moves upward to close the second sand discharging valve 26 again.
The first plug 20 can be provided thereon with threaded holes which can be screwed with corresponding threads correspondingly disposed on the outer valve cylinder 264 of the second sand discharging valve 26. The first plug and the second sand discharging valve 26 can also be connected in other manners, as long as they can communicate with each other and can be sealed and fixed.
The inner tubular column 18 comprises in sequence from bottom to top: a second plug 27, a sand setting gas anchor 28, an oil well pump 29 and an oil pipe 30.
A second tail pipe 31 may further be provided between the second plug 27 and the sand setting gas anchor 28. The second plug 27, the second tail pipe 31, the sand setting gas anchor 28, the oil well pump 29 and the oil pipe 30 all can be connected by screwed thread.
The second plug 27 is disposed at a lower end of the second tail pipe 31, for sealing the lower end of the second tail pipe 31 to prevent leakage thereof.
A first sand discharging valve 32 is provided on the second plug 27. The first sand discharging valve 32 has the same structure and working principle as the second sand discharging valve 26. By providing the first sand discharging valve 32, after the sand grains separated by the sand setting gas anchor 28 are deposited within the second tail pipe 31, they can be automatically discharged into the first tail pipe 22, so as to prevent the sand grains entering the oil well pump 29 to cause pump blocking.
The lower end of the second tail pipe 31 is sealed by the second plug 27, and an upper end thereof is connected to the sand setting gas anchor 28. The second tail pipe 31

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is a hollow tubular column having a length of 4-8m. By providing the second tail pipe 31 having a certain length at the lower end of the sand setting gas anchor 28, it is beneficial to settle sand grains contained in the oil-gas mixture into the second tail pipe 31, to prevent the sand grains entering the oil well pump 29 and causing pump blocking.
The lower end of the sand setting gas anchor 28 is connected to the second tail pipe 31, and an upper end thereof is connected to the oil well pump 29. As shown in Fig. 3, the sand setting gas anchor 28 is provided thereon with a plurality of in-and-out holes 280 for providing inlets and outlets for the gas separated from the oil-gas mixture. The position of the in-and-out holes 28 is lower than that of the screen hole 230 of the screen pipe 23, for the sake of performing one oil-gas separation process under the action of gravity before the oil-gas mixture enters from the screen hole 230 of the screen pipe 23 into the in-and-out holes 280 of the sand setting gas anchor 28. The sand setting gas anchor 28 is provided therein with a spiral sheet, when the oil-gas mixture passes through the spiral sheet, gas having low density may return from the in-and-out holes 280 along a center of the sand setting gas anchor 28, while oil fluid having high density may move downward under the action of gravity along side wall of the sand setting gas anchor 28.
The lower end of the oil well pump 29 is connected to the sand setting gas anchor 28, and an upper end thereof is connected to the oil pipe 30. The oil well pump 29 can be an oil well pump that has the function of sand prevention.
The oil pipe 30 may also adopt corrosion-resistant stainless steel materials containing element chromium. Content of the element chromium is 3%. It is better corrosion resistant than the existing common tubular column which adopts N80 steel.
Fig. 5 is a use state diagram of the oil production device in accordance with the embodiment of the present invention. As shown in Fig. 5, an annular passage 33 is formed between the inner tubular column 18 and the outer tubular column 17.
Burned tail gases generated in the process of combustion of oil in situ, comprising mixed gases of carbon dioxide, light hydrocarbon gases and hydrogen sulfide generated from crude oil oxidation and combustion in the air and nitrogen and the like contained in the air, are mixed with the oil fluid in the oil layer and enter the oil production device, and then are subjected to the following separation:
For the first time, after the oil-gas mixture enters from the oil layer into a shaft position A, in the process that the oil-gas mixture enters into the annular space B of the

14 casing 19 and the first tail pipe 22 and continues to move vertically upward, the gas rises at a fast speed due to minimum density, in the rising process, small bubbles gradually become large bubbles and are separated from the oil-gas mixture. When the oil-gas mixture does not reach a position C where the screen pipe 23 is positioned, the separated gas is discharged from the annular passage 33 by the screen hole 230 of the screen pipe 23, to complete one separation.
For the second time, when the oil-gas mixture migrates upward to the position C
where the screen pipe 23 is positioned, the oil-gas mixture that would have moved vertically upward needs to enter the horizontally disposed screen hole 230, at this time since velocity direction is changed, when the oil-gas mixture enters the screen hole 230 of the screen pipe 23, large bubbles of which the diameter is larger than the bore diameter of the screen hole 230 of the screen pipe 23 cannot pass through the screen hole 230 of the screen pipe 23, besides, collision and disturbance may occur when the oil-gas mixed fluid enters the screen hole 230 of the screen pipe 23, thus part of gas in the oil-gas mixture is separated to complete the second separation.
For the third time, when the oil-gas mixture enters from the screen hole 230 of the screen pipe 23 into the annular passage 33, under the action of gravity, the oil-gas mixed fluid transforms from horizontal migration into vertical downward motion, to enter an annular space position E of the second tail pipe 31 and the first tail pipe 22. Due to the gas-liquid density difference, liquid having larger density migrates downward under the action of gravity, while part of gas having smaller density is gathered from small bubbles into large bubbles to be separated from the mixed fluid and from an annular space position D of the lining pipe and the oil pipe, to complete the third separation.
After three times of separation of the oil-gas mixture, the product enters a position F
of the sand setting gas anchor 28 by the in-and-out holes 280 of the sand setting gas anchor 28 from an annular space position E of the second tail pipe 31 and the first tail pipe 22. At this time the velocity of the oil-gas mixture is changed from the original vertical direction into a horizontal direction. Since liquid and gas have great difference in density, the liquid having larger density moves downward in a vertical direction G along an outer side of the sand setting gas anchor 28; the gas having smaller density gets close to an axis H and moves upward, to be discharged by the in-and-out holes 280 of the sand setting gas anchor 28, to complete the fourth separation.
The oil production device in accordance with the embodiment of the present =
=
invention can perform at least three times of separation of the oil-gas mixture more than the prior art, can better separate the gas in the oil-gas mixture, thereby effectively reducing influence of gas on the pump efficiency.
Since the oil-gas mixture generally contains a large number of sand grains, in order to make the oil well can perform production normally, sand prevention measures are generally necessary. The oil production device of the present invention further has sand prevention functions such as sand setting, sand blocking, sand discharging and the like.
Wherein the sand setting function means, in the process of the first separation of the oil-gas mixture, the sand grains having the maximum density can be settled into the well in the annular space B of the casing 19 and the first tail pipe 22.
The sand blocking function means, in the process of the second separation of the oil-gas mixture, when the oil-gas mixture migrates upward to the position C
where the screen pipe 23 is located, due to the function of the screen pipe 23, when diameters of the sand grains are larger than that of the screen hole 230 of the screen pipe 23, the sand grains may be blocked within the annular space B of the casing 19 and the first tail pipe 22, to be settled into the well.
The sand discharging function means, after the oil-gas mixture enters the second tail pipe 31, when the deposited sand grains reach a certain amount, the sand grains in the second tail pipe 31 can be discharged into the first tail pipe 22 by using the first sand discharging valve 32, so as to be able to prolong pump inspection period. In addition, the sand grains that are discharged into the first tail pipe 22 can also be discharged down into the well by the second sand discharging valve 26 disposed on the first plug 20.
To sum up the above, the oil production device of the present invention can, as compared with the prior art, realize multi-separation of oil-gas mixture, increase efficiency of oil-gas separation to 50% or higher, so as to reduce influence of gas on pump efficiency; furthermore, the invention has sand prevention functions such as sand setting, sand blocking, sand discharging and the like, which can not only reduce influence of gas on pump efficiency, but also greatly reduce probability of occurrence of an pump blocking accident after the sand grains enter the oil well pump 29. In a word, the oil production device in accordance with the embodiment of the present invention has high sand prevention and gas prevention capabilities, can improve pump efficiency of the oil well pump, thereby improving fireflood development effect.
The embodiment of the present invention further provides an injection production II

. .
method, more preferably, the injection production method can be applied to the injection production system as described in the above, but the present invention is not limited thereto. As shown in Fig. 6, the injection production method mainly includes the following steps:
A step SI01: injecting air into the inner cavity of the layered ignition device at the first preset speed, and injecting air into the second annular space of the layered ignition device at the second preset speed. In specific implementation, it is firstly necessary to establish a passage through which air in the immediate vicinity of wellbore of an injection well flows to a production well, to prevent well fluid from returning to the well at the ignition stage and causing the well cylinder to be on fire, and the specific operation method is as follows: injecting air for 7-15 days into the inner cavity of the layered ignition device (the injection well) at a first injection speed that is 400 Nm3/(m=d)-500Nm3/(m=d); and injecting air into the annular space 10 of the layered ignition device at a second injection speed that is 50 Nm3/(m=d)-100Nm3/(m=d).
It is necessary to note that, the aforementioned first injection speed and the second injection speed have such relationship: the first injection speed is larger than the second injection speed, and the specific numerical values of the first injection speed and the second injection speed are only illustrative, and the specific value of injection speed can be adjusted according to the actual need of application, the present invention is not limited thereto.
A step S102: tripping in the electric ignition device in the non-upset oil pipe to the lowest end of the non-upset oil pipe, and turning on the power supply to start the electric ignition device in the non-upset oil pipe.
A step S103: injecting heating gas in the non-upset oil pipe into the lower layer air injection space by an end of the non-upset oil pipe, to heat and ignite the lower oil layer.
Through the above steps S102 and S103, the lower oil layer is ignited through electric ignition, and temperature of air at the outlet is maintained to be higher than A step S104: after ignition time lasts for a first preset time, turning off the electric ignition device, moving the electric ignition device upward to be a certain distance apart from the upper oil layer, and continuously injecting air into the inner cavity of the layered ignition device at the first preset speed.
The lower oil layer is ignited for 7-10 days by the electric ignition device of the =
layered ignition device, and a small amount of air is injected into the upper layer air injection space corresponding to the upper oil layer, and air is injected into a space corresponding to the upper oil layer at the second injection speed (for example 50 Nm3/(m.d)-100Nm3/(m=d)) maintained by the annular space 10. After the lower layer ignition time ends, the electric ignition device is turned off, and the electric ignition device is raised upward to a position 50-100m apart from an upper portion of the upper oil layer, and in this process, air is still injected into the inner cavity of the non-upset oil pipe 3 continuously at the speed 400Nm3/(m.d)-500Nm3/(m.d).
A step S105: injecting air into the second annular space of the layered ignition device at the first preset speed, and injecting air into the inner cavity of the layered ignition device at the second preset speed. After ignition of the lower oil layer is finished, ignition of the upper oil layer is prepared. At this time, the injection speed at which air is injected into the lower oil layer is reduced to the second injection speed (for example 50 Nm3/(m.d)-100Nm3/(m-d)), and the injection speed at which air is injected into the upper oil layer is increased to the first injection speed (400 Nm3/(m.d)-500Nm3/(m-d)).
A step S106: injecting comburent into the second annular space, and injecting the comburent and the heating gas in the heat insulation pipe into the upper layer air injection space by the upper layer air distribution device.
A step S107: starting the electric ignition device to heat and ignite the upper oil layer, and igniting the upper oil layer under the action of heat released from combustion of the comburent and air.
Through the above steps S106 and S107, the comburent (i.e., the aforementioned iron pulverized coal or capsulse mixture or the like) is injected into the annular space 10 along with the injected air, so as to transport air and comburent into the upper layer air injection space corresponding to the upper oil layer by the upper layer air distribution = device 5. Then, the electric ignition device is started, and chemical ignition of the upper oil layer is motivated by heating of the electric ignition device.
A step S108: after heating by the electric ignition device for a second preset time, turning off the power supply connected to the electric ignition device and taking out the electric ignition device. In the process in which the upper oil layer is ignited, temperature of air at the outlet of the upper oil layer is ensured to be 250 C or above.
After the ignition lasts for 2-3 days, the power supply of the electric ignition device can be turned off, and the electric ignition device can be raised upward slowly. At this time, the injection speed at which air is injected into the lower oil layer is increased to 400 Nm3/(m.d)-500Nm3/(m.d).
A step S109: collecting, by the oil production device, crude oil that moves to the position of the oil production device driven by the combustion front of the oil layer. After ignition of the oil layer is completed through the above steps S101 to S108, in the passage through which air in the immediate vicinity of wellbore of the injection well flows to the production well, a combustion front that slowly moves forward and a combustion region that has predetermined size may be formed. A combustion region that has the highest temperature can be regarded as a mobile heat source, in front of the combustion region front edge, the crude oil continuously has complex chemical reactions of various macromolecule organic compounds, such as distillation, thermal cracking, low-temperature oxidation and high-temperature oxidation, under the action of high-temperature heat, and the products are also complex. Besides liquid products, the products can also be the burned smoke, including carbon monoxide, carbon dioxide and natural gas and the like. Hot water, hot steam and gas all can carry or transfer heat to the oil layer at front, so as to form a series of complex oil displacement effects such as thermal viscosity reduction, thermal expansion, distillation vaporization, oil-phase and miscible-phase displacement, gas displacement, high temperature changing relative permeability and the like. It is generally acknowledged that, it is the final product of cracking, i.e., a coked zone formed by coke, that is in the vicinity of the combustion front, and then a hot water-steam zone that is formed by water generated from reaction of steam and hot water, primitive water and the injected water for wet combustion and the like, a distilled light hydrocarbon oil zone, and a viscosity-reduced primary oil rich zone at the forefront in sequence outwards.
At this time, the aforementioned oil production device can collect crude oil after multiple separation by performing at least three times of separation of the oil-gas mixture, which can better separate the gas in the oil-gas mixture out, so as to effectively reduce the influence of gas on the pump efficiency; furthermore, the oil production device in accordance with the embodiment of the invention has sand prevention functions such as sand setting, sand blocking, sand discharging and the like, which can not only reduce influence of gas on pump efficiency, but also greatly reduce probability of occurrence of an pump blocking accident after the sand grains enter the oil well pump.
Therefore, the injection production method in accordance with the embodiment of the =
present invention can improve pump efficiency of the oil well pump, so as to improve development effect of the oil layer.
The above specific embodiment further describes in details the object, the technical solution and beneficial effect of the present invention. It shall be understood that, the above descriptions are merely a specific embodiment of the present invention, but not for limiting the protection scope of the invention. Any modification, equivalent replacement, improvement and the like within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A layered ignition device, comprising: a casing, a heat insulation pipe, a non-upset oil pipe, an electric ignition device, an upper layer air distribution device, a first packer, a second packer and at least one enhanced heat transfer device, wherein, the electric ignition device includes: an electric igniter cable and an electric igniter heating section, the electric igniter cable is connected to a power supply to provide heat to the electric igniter heating section so as to heat the oil layer;
the electric ignition device is disposed in an inner cavity of the non-upset oil pipe, the heat insulation pipe sleeves the non-upset oil pipe, and the casing sleeves the heat insulation pipe;
a first annular space into which nitrogen is injected is formed between the casing and the heat insulation pipe; a second annular space into which, together with the inner cavity, air is injected is formed between the heat insulation pipe and the non-upset oil pipe;
the first packer and the second packer are disposed in the first annular space and spaced by certain distance, and an upper layer air-injection space is partitioned between the first packer and the second packer;
the heat insulation pipe is provided thereon with the upper layer air distribution device, and the upper layer air distribution device is positioned in the upper layer air injection space, and the upper layer air distribution device is used for injecting air in the heat insulation pipe into the upper layer air injection space;
the enhanced heat transfer device includes: a winding section and a contact section;
when temperature of the electric ignition device is lower than a first preset temperature, the contact section is attached on the electric ignition device, and the enhanced heat transfer device is wholly wound on the electric ignition device, and when temperature of the electric ignition device is larger than or equal to a second preset temperature, the contact section is put up to come into contact with the non-upset oil pipe, to transfer heat to the non-upset oil pipe.

2. The layered ignition device according to claim 1, wherein the enhanced heat transfer device is a spiral structure composed of memory materials.

3. The layered ignition device according to claim 1, wherein when the layered ignition device is provided therein with a plurality of the enhanced heat transfer devices, the enhanced heat transfer devices have intervals of 5-8m therebetween.

4. The layered ignition device according to claim 1, wherein the layered ignition device further comprises a retractable pipe which is disposed at an upper part of the heat insulation pipe and is connected within the heat insulation pipe, for adjusting the heat insulation pipe to move up and down.

5. The layered ignition device according to claim 1, wherein the layered ignition device further comprises a seeker disposed at the lowest end of the non-upset oil pipe, wherein the seeker is mainly composed of a tubular part and a bullet-shaped head, and a vent hole is disposed at the lowest end of the seeker.

6. The layered ignition device according to claim 1, wherein the layered ignition device further comprises a seal ring which is disposed in the second annular space and is adhered with the tubular part.

7. The layered ignition device according to claim 1, wherein the second annular space is further used for injecting comburent.

8. The layered ignition device according to claim 7, wherein the comburent is a mixed product of petroleum and capsule mixture having a volume ratio of 1: 1;
wherein the capsule mixture is generated by wrapping the uniformly mixed sodium nitrite, ammonium nitrate, combustion improver and formamidine disulfide dihydrochloride by a water soluble capsule.

9. The layered ignition device according to claim 8, wherein the combustion improver is combination of one or more of platinum, palladium and rhodium, or a compound of organic copper manganese, or combination of one or more of an oxide of platinum, an oxide of palladium and an oxide of rhodium.

10. The layered ignition device according to claim 8, wherein mass ratio of sodium nitrite to ammonium nitrate is 1: 1, and molar ratio of total injection amount of sodium nitrite and ammonium nitrate to total injection amount of formamidine disulfide dihydrochloride is 1: 10;
injection amount of the formamidine disulfide dihydrochloride is N, N=Q/3191, Q=.pi.H(r1 2-r2 2).rho.c(t i-t r);
wherein, H is thickness of oil layer, r1 is heating maximum radius boundary, r2 is heating minimum radius boundary, .rho.c is volumetric heat capacity of oil layer, t i is temperature after heating, t r is original oil layer temperature, .pi. is set to be 3.14.

11. The layered ignition device according to claim 8, wherein use amount m of the combustion improver is calculated according to the following formula:
m=A.nu..rho..pi.H(r e2-r w2).phi.So1, wherein, H is thickness of oil layer, re is heating radius, r w is oil well radius, A is 0.2, S o1 is remaining oil saturation, .rho.v is density of the combustion improver, .pi. is set to be 3.14, .phi. is porosity of oil layer.

12. The layered ignition device according to claim 7, wherein the combustion improver is an iron pulverized coal.

13. The layered ignition device according to claim 12, wherein injection amount N
of the iron pulverized coal is calculated according to the following formula:
N=A.pi.h.PHI.r2;
wherein, A is set to be within the range of 0.3 to 0.5, h is thickness of oil layer, .PHI.
is formation porosity, r is injection radius.

14. An injection production system, comprising an oil production device and the layered ignition device according to any one of claims 1 to 13, the layered ignition device is used for igniting the oil layer to make the oil layer generate a combustion front to drive the crude oil to move to the position of the oil production device;
the oil production device is used for collecting the crude oil;
wherein, the oil production device comprises:
an outer tubular column which from bottom to top in sequence includes:
a first plug for sealing a lower part of the outer tubular column;
a first pipe of which a lower end is fixedly connected to the first plug, the first pipe is opened with a first hole for communicating with the outside, and a packer that partitions the first pipe from the casing is further provided above the first hole; and an inner tubular column between which and the first pipe an annular passage is formed, the inner tubular column includes from bottom to top in sequence: a second plug, a sand setting gas anchor, an oil well pump, and an oil pipe, and a first sand discharging valve is further provided on the second plug.

15. The injection production system according to claim 14, wherein the first pipe comprises from top to bottom: a lining pipe, a screen pipe and a first tail pipe, wherein the lining pipe, the screen pipe and the first tail pipe are fixedly connected successively, and the first hole is a screen hole on the screen pipe.

16. The injection production system according to claim 15, wherein the sand setting gas anchor is provided with an in-and-out hole, and the screen hole is higher than the in-and-out hole of the sand setting gas anchor.

17. The injection production system according to claim 14, wherein the first plug is provided with at least one second sand discharging valve.

18. The injection production system according to claim 14, wherein a second tail pipe which has a length of 4-8m is further provided between the sand setting gas anchor and the second plug.

19. An injection production method, characterized in being applied to the injection production system according to any one of claims 15 to 18, comprising:
injecting air into an inner cavity of the layered ignition device at a first preset speed, and injecting air into a second annular space of the layered ignition device at a second preset speed;
tripping in the electric ignition device in the non-upset oil pipe to the lowest end of the non-upset oil pipe, and turning on the power supply to start the electric ignition device;
injecting heating gas in the non-upset oil pipe into the lower layer air injection space by an end of the non-upset oil pipe, to heat and ignite the lower oil layer;
after ignition time lasts for a first preset time, turning off the electric ignition device, moving the electric ignition device upward to be a certain distance apart from the upper oil layer, and continuously injecting air into the inner cavity of the layered ignition device at the first preset speed;
injecting air into the second annular space of the layered ignition device at the first preset speed, and injecting air into the inner cavity of the layered ignition device at the second preset speed;
injecting comburent into the second annular space, and injecting the comburent and heating gas in the heat insulation pipe into the upper layer air injection space by the upper layer air distribution device;
starting the electric ignition device to heat and ignite an upper oil layer, and igniting the upper oil layer under the action of heat released from combustion of the comburent and air;
after heating by the electric ignition device for a second preset time, turning off the power supply of the electric ignition device and taking out the electric ignition device;
and collecting, by the oil production device, crude oil that moves to the position of the oil production device driven by the combustion front of the oil layer.

20. The injection production method according to claim 19, wherein the first preset speed is larger than the second preset speed.