WO2008007718A1

WO2008007718A1 - Enhanced recovery process for petroleum or natural gas, enhanced recovery system for the same, and injector for gas-liquid mixed fluid

Info

Publication number: WO2008007718A1
Application number: PCT/JP2007/063862
Authority: WO
Inventors: Hitoshi Koide; Junji Shinoda
Original assignee: Mizuho Information & Research Institute Inc.
Priority date: 2006-07-13
Filing date: 2007-07-11
Publication date: 2008-01-17
Also published as: JP2008019644A

Abstract

The invention provides an enhanced recovery process and an enhanced recovery system by which a larger amount of crude oil or natural gas can be recovered. The enhanced recovery process comprises the step of converting an injection gas into microbubbles in injection water to form a gas-liquid mixed fluid, the step of injecting the mixed fluid into a petroleum or gas reservoir through an injection well to make the microbubbles contained in the mixed fluid permeate into fine crevices in the petroleum or gas reservoir, and the step of recovering crude oil or natural gas expelled from the crevices by the microbubbles through a production well. The enhanced recovery system comprises an injector unit for injection water, a micorbubbling unit, and a recovery unit for recovering crude oil or natural gas.

Description

Specification

Oil or natural gas enhanced recovery method, enhanced recovery system thereof, and gas-liquid mixed fluid injection device

Technical field

[0001] The present invention relates to crude oil contained in an oil layer or gas layer by mixing the injected gas into the injected water by microbubbles and penetrating it into fine gaps in the oil layer or gas layer. Relates to an enhanced recovery method and an enhanced recovery system for oil or natural gas capable of efficiently recovering natural gas.

Background art

[0002] Oil Reservoir There are primary to tertiary extraction methods for extracting crude oil. The primary collection method is self-collection and artificial collection using a pump. With this sampling method, 20-30% of the crude oil existing underground cannot be recovered. The water pressure injection method is known as the secondary sampling method. After the decline in production by the primary sampling method, water is injected into the oil reservoir to restore the oil reservoir pressure and increase the oil production. The recovery rate can be increased to 30-40%.

[0003] The third sampling method is a sampling method applied after the second sampling, and includes a chemical method, a heat method, a gas injection method, a microbe method, and the like. It is said that the recovery rate can be increased to about 50-60% by the third sampling method. The third sampling method is also called Enhanced Oil Recovery (hereinafter abbreviated as EOR). The enhanced recovery method is the “collection method for the purpose of higher replacement efficiency obtained by the normal gas pressure injection method or the water pressure injection method”. These include heat and chemicals injected into the oil reservoir to increase the fluidity of the crude oil, reduce the interfacial tension acting between water and oil, and miscible conditions between the injected gas and oil (under supercritical pressure). To improve the yield of crude oil.

[0004] The gas injection method is a method for injecting carbon dioxide into an oil reservoir to enable a very high crude oil recovery rate, and has been commercialized in the United States since the 1970s. Currently, approximately 200,000 barrels of crude oil is being increased every day, as well as in Canada, Turkey and Hungary. In the United States, CO2 is supplied from gas fields, but in regions where CO2 sources are limited, CO2 can be recovered and supplied from exhaust gas from factories and power plants. so is there. However, in the gas injection method, since the injection gas has high fluidity, the injection gas tends to diffuse along a large gap in the oil layer and not enter into a fine gap. Therefore, in order to reduce the fluidity of the injected gas, a gas-liquid alternating injection method (WAG injection method: Water Alternating Gas) in which the injected gas and the injected water are alternately injected has been put into practical use. Along with the development of new oil fields, there is a need to further improve the recovery rate of existing oil fields.

[0005] In Patent Document 1, pressurized diacid carbon is injected into an injecting well oil layer, and the oil expelled by carbon dioxide is entrained in diacid carbon to recover production well force. An oil extraction method is shown that separates the oil and recirculates the carbon dioxide to the injection well. Patent Document 1: JP-A-8-158774

Disclosure of the invention

Problems to be solved by the invention

[0006] An object of the present invention is to provide a device for efficiently mixing injected water and injected gas, and to infiltrate the gas-liquid mixed fluid into the fine gaps in the oil layer or gas layer, so that crude oil or natural gas can be mixed. It is an object of the present invention to provide an enhanced recovery method for oil or natural gas and an enhanced recovery system for oil or natural gas that can increase sales.

Means for solving the problem

[0007] In order to achieve the above object, according to the enhanced recovery method of oil or natural gas according to claim 1 of the present invention, a gas-liquid mixed fluid is obtained by mixing an injected gas into the injected water by microbubbles. And a step of injecting the gas-liquid mixed fluid into a press-fit well oil layer or gas layer to infiltrate microbubbles in the gas-liquid mixed fluid into fine gaps in the oil layer or gas layer; And recovering crude oil or natural gas expelled from the gap by the microbubbles from the production well.

[0008] Claim 2 is the invention according to claim 1, wherein the injection gas is a hydrocarbon gas, an oil field flare gas, a nitrogen gas, a carbon dioxide gas, a combustion exhaust gas, or a gas mixed thereof. Preferably there is.

[0009] Claim 3 is the invention according to claim 1, wherein the microbubbles of the injected gas are preferably performed inside a press-fit well.

[0010] In order to achieve the above object, the oil or natural gas according to claim 4 according to the present invention. The enhanced recovery system includes an injection water injection device that injects injection water from an injection well into an oil or gas layer, an injection gas supply device that sends injection gas toward the injection water, and an injection gas from the injection gas supply device. From the production well, and a microbubbler that mixes the injected water with microbubbles and the microbubbles in the injected water to remove the fine pore force in the oil layer or gas layer. And a crude oil recovery device for recovery.

[0011] Claim 5 is the invention according to claim 4, wherein the casing pipe into which the injected water is sent, the tubing pipe inserted into the casing pipe and into which the injected gas is sent, and the tubing pipe are rotated. It is preferable that a rotary drive device is provided in the press-fit well, and the micro-banolay dredger device is provided at an upper part of the casing pipe and attached to a lower end of the tubing pipe.

[0012] Claim 6 is the invention according to claim 4, wherein the side surface includes an injection pipe that injects the injected gas obliquely downward, and is configured by a cylindrical body that rotates by rotation of the tubing pipe. It is preferable.

[0013] The gas-liquid mixed fluid injection device according to claim 7 of the present invention is a casing tube that is used as a press-fitting well and into which injection water is fed, a tubing tube that is inserted into the casing tube and into which injection gas is fed, A rotation driving device that rotates the tubing tube, and a microbubble that is attached to the lower end of the tubing tube, rotates by the rotation of the tubing tube, and has an injection tube that injects the injected gas obliquely downward on the side surface. And a quantifying device.

The invention's effect

[0014] According to the enhanced recovery method of oil or natural gas according to claim 1 of the present invention, the injection gas is microbubbled (ultrafine bubbles) in the injection water, and the oil layer or gas is used as a gas-liquid mixed fluid. Because it is a method of press-fitting into the layer, the force can be evenly diffused over a wider range than the WAG press-fitting method. In addition, the microbubbles can permeate the injected gas well into the oil layer or fine gaps in the gas layer. And it reduces the interfacial tension of crude oil that cannot move finely. Microbubbles also have low flow resistance, allowing crude oil or natural gas to be expelled from the gap. As a result, about 70% of buried crude oil or natural gas Can be recovered. Since the gas-liquid mixed fluid is injected, it can be applied to submerged oil and gas fields. This can be applied to oil or gas fields where production is declining to contribute to increased production of crude oil or natural gas. Microbubbles are used because microbubbles have a longer residence time in the injected water than bubbles with a diameter of several millimeters.

[0015] According to the invention described in claim 2, the injection gas is a hydrocarbon gas such as methane, an oil field flare gas such as propane gas, nitrogen gas, carbon dioxide gas, an incinerator discharged from an incinerator or the like. Exhaust gas (main components are nitrogen gas and carbon dioxide gas) or a mixture of them can be used. Since these gases have low solubility and do not dissolve much in water, bubbles can be maintained for a long time. This makes it possible to select the injection gas that is most readily available at the site where the oil or gas field is located.

[0016] According to the invention of claim 3, since the microbubbles of the injection gas are performed inside the injection well, the injection water containing the microbubbles generated in the injection well is immediately put into the deep underground injection zone. Can be press-fitted. In addition, there is no need for facilities to store the microbubble gas-liquid mixture in a tank on the ground.

[0017] According to the enhanced recovery system for oil or natural gas according to claim 4 of the present invention, the same effect as that of claim 1 can be obtained.

[0018] According to the invention of claim 5, since the microbubble device is attached to the lower end of the tubing tube, the gas-liquid mixed fluid in which the microbubbles are mixed inside the press-fit well can be generated. it can. The generated microbubbles receive pressure as they move deeper into the casing tube and can be made into even smaller bubbles. The tubing tube does not need to be extended to the same length as the casing tube. Since the microbubble device itself is rotated at high speed, fine microbubbles can be generated efficiently.

[0019] According to the invention of claim 6, the swirling flow is given to the injected water by the rotation of the cylinder, and the generation efficiency of the microbubbles is good. In addition, since the injection pipe is in a place where the flow rate of the injected water is high, the flow is fast! Mixing can be easily performed by microbubbles.

[0020] According to the gas-liquid mixed fluid injection device according to claim 7 of the present invention, since the microbubble device is rotated by the rotation drive device, the injected gas is efficiently injected into the injected water. Microbubbles can be mixed and sent into the ground.

Brief Description of Drawings

FIG. 1 is a configuration diagram of an oil or natural gas enhanced recovery system according to the present invention. (Example 1)

FIG. 2 is a cross-sectional view of a microbubble device. (Example 1)

FIG. 3 is a diagram showing the relationship between the pressure of injected water and injected gas in a pressure well. (Example 1)

FIG. 4 is a flow chart showing the processing procedure of the method for enhanced recovery of oil or natural gas according to the present invention. (Example 1)

Explanation of symbols

1 Injection water production facility

2 Pumping device

3 Filtration equipment

4 Deaerator

5 Sterilizer

6 Casing tube

7 Tubing tube

8 Power plant

9 Combustion furnace

10 Carbon dioxide recovery device

12 tanker truck

15 Injection water injection device

16 Catchment tank

17 Press-in pump

18 slits

20 Injection gas supply device

21 Gas storage tank

22 Compressor 30 Microbubble device

31 Rotation drive

35 Crude oil or natural gas recovery equipment

36 Pumping pump

37 Oil or natural gas storage tanks

38 Nose Mouth Lick Pump

39 Crude or natural gas processing plant

40 cylinder

41 Injection pipe

51 Cap lock layer

52 Oil or gas reservoir

53 Ground surface

55 Injection water

56 Injection gas

57 Gas-liquid mixed fluid

58 Crude oil or natural gas

59 Micro Bubble

60 Gas-liquid mixed fluid injection device

100 Enhanced oil or natural gas recovery system

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail with reference to the drawings.

Example 1

FIG. 1 is a configuration diagram of an oil or natural gas enhanced recovery system according to the present invention. The enhanced recovery system 100 for oil or natural gas according to the present invention includes a gas-liquid mixed fluid 57 obtained by mixing the injected gas 56 into the injected water 55 by microbubbles and injected from the injection well 25, and from the production well 26. It is a system that pumps crude oil or natural gas 58 from an oil layer or gas layer 52 confined in a cap lock layer 51. Here, the oil reservoir or gas reservoir 52 is crude oil (heavy oil Is a porous rock layer containing or adsorbing a hydrocarbon-based gas in the gap. Injection water injection device 15 for injecting injection water 55, injection gas supply device 20 for sending injection gas 56 toward injection water 55, injection gas from injection gas supply device 20, on the injection well 25 side of ground surface 53 There is provided a microbubble device 30 that micro-bubbles 56 into the injected water 55 and mixes them. And a crude oil recovery device 35 that recovers crude oil or natural gas 58 expelled from the fine gaps in the oil layer or gas layer 52 by the microbubbles 59. The injected water press-fitting device 15 is a force for injecting the injected water 55 into the oil layer or gas layer 52. Since the injected gas 56 that has been microbubbled in the middle is mixed, the gas-liquid mixed fluid 57 becomes the oil layer or gas layer. Press fit into 52.

The injection water press-fitting device 15 is provided with a water collection tank 16 for storing the injection water 55, a press-fitting pump 17, and the like. As the injected water 55, for example, brine containing a lot of salt pumped up from the deep aquifer can be used. Therefore, groundwater can be pumped from the pumping well (not shown) reaching the deep aquifer with the injection water production facility 1 and supplied to the water collection tank 16. The infused water production facility 1 is provided with a pumping device 2 including a pump, a filtration device 3, a deaeration device 4 for extracting gas dissolved in groundwater, and a sterilization device 5. The injection water with a high salt content contains a large amount of electrolyte ions, and therefore has the effect of suppressing the disappearance of microbubbles. Therefore, the injection water production facility 1 may be configured as a device for pumping seawater. Brine has a salinity of 30% or more of seawater and cannot be used for daily life. Aquifers with brine are widely distributed in the strata of oil basins. Brine water reduces the solubility of gas in proportion to the concentration of electrolyte ions (Salting out phenomenon), thus preventing the escape of bubbles and generating microbubbles with high density.

The injection gas supply device 20 includes a gas storage tank 21 and a high-pressure compressor 22. As the injection gas 56, for example, carbon dioxide that is discharged from the power plant 8 can be used. The power plant 8 has a combustion furnace 9, which separates and recovers carbon dioxide from the exhaust gas that is also discharged by the carbon dioxide recovery device 10. This carbon dioxide can be sent to the gas storage tank 21 by pipeline. It may be transported by tank truck 12. The injected gas 56 may be carbon dioxide or a hydrocarbon gas such as methane. Nitrogen gas and combustion exhaust gas (those mainly composed of nitrogen gas and carbon dioxide) are also acceptable. Gas mixed with these But you can. The injected gas 56 stored in the gas storage tank 21 is increased in pressure by the compressor 22 and sent to the injection well 25. In FIG. 1, it is illustrated that there are a plurality of injection wells 25.

The press-fit well 25 includes a casing pipe 6 and a tubing pipe 7 inserted into the casing pipe 6. The injected water 55 is press-fitted between the casing pipe 6 and the tubing pipe 7, and the injected gas 56 is pressed into the tubing pipe 7. A micro-bubble device 30 is attached to the lower end of the tubing tube 7. The tubing tube 7 is rotated at a high speed by a rotation drive device 31 on the ground side. A slit 18 is provided on the bottom side surface of the casing tube 6. The micro-bubble device 30 is located above the injection well 25. The reason for the top of the injection well 25 is that while the generated microbubbles 59 move toward the bottom of the injection well 25, the bubble volume gradually decreases as the water pressure increases, starting from the time of microbubble generation. Can be changed to finer bubbles. The casing 6, the tubing 7, the microbubble device 30, and the rotation drive device 31 constitute a gas / liquid mixed fluid injection device 60.

[0028] The microbubble device 30 employs a method in which the tubing tube 7 is rotated at a high speed to mix a shearing method of gas-liquid fluid mixing and a high-speed swirling method (for example, 500 to 2000 rpm). The bubble size of microbubble 59 is usually about 50 μm or less to about 10 μm. Since the microbubble 59 has a small diameter, it stays in the water for a long time without disappearing. The injected gas 56 injected from the microbubble device 30 is mixed with the injected water 55 in a microbubble manner to become a milky white gas-liquid mixed fluid 57 and is pressed into the oil layer or gas layer 52 through the slit 18. The microbubbles 59 of the gas-liquid mixed fluid 57 are widely diffused in the oil layer or the gas layer 52. The microbubble 59 has a small bubble diameter and has a large effect of expelling crude oil or natural gas in a fine gap in the oil layer or gas layer.

[0029] When the gas-liquid mixed fluid 57 diffuses, the layer pressure of the oil layer or gas layer 52 is increased. Crude oil or natural gas expelled from the gap between the oil layer or gas layer 52 by the micro bubble 59 is pumped from the production well 26 together with brine, gas-liquid mixed fluid 57, etc. contained in the oil layer or gas layer 52, and crude oil or gas. Or, it is sent to the natural gas recovery unit 35. The production well 26 is provided with a casing pipe 6 and a tubing pipe 7, and a high-mouth lick pump 38 is provided at the lower end of the tubing pipe 7. The crude oil or natural gas recovery unit 35 has a pump 36 and a storage tank 37 for crude oil or natural gas. The Hyde mouth lick pump 38 uses the liquid part of the collected crude oil or natural gas 58, which is also fed with the ground side force by the pump 36, as the power medium oil. The piston (not shown) in the hide port lick pump 38 moves up and down by the power medium oil. First, power medium oil is introduced to one side of the piston to pressurize the piston downward. Then, the piston descends and reaches the lower end. Here, the engine valve reverses hydraulically, the flow of power oil is switched, and the piston is pushed upward. By such reciprocating motion, crude oil or natural gas 58 is pumped together with brine and the like, and is stored between the casing pipe 6 and the tubing pipe 7 in the storage tank 37. The crude oil or natural gas 58 in the storage tank 37 is sent to a crude oil or natural gas treatment plant 39 through a pipeline or the like for processing. Oil field flare gas (oil-related gas) such as propan contained in crude oil or natural gas 58 is sent from the non-burning storage tank 37 to the gas storage tank 21 of the injection gas supply device 20 by the compressor 22 and injected gas 56 It can also be used. In addition, water separated from crude oil or natural gas 58 is sent from the crude oil or natural gas processing plant 39 to the injection water production facility 1 and used as injection water.

FIG. 2 is a cross-sectional view of the microbubble device. The microbubble generator 30 is installed at the upper part of the press-fit well 25, and the upper end is connected to the lower end of the tubing pipe 7. The micro-publishing device 30 is a cylindrical body 40, and a plurality of injection pipes 41 projecting obliquely downward are provided on the side of the cylindrical body 40. The cylinder 40 can be a square cylinder, for example. In the case of a rectangular tube, since a stronger swirl flow is given to the injected water 55 as compared to the cylinder, the generation of bubbles can be promoted. The injected gas 56 from the tubing pipe 7 is jetted from the jet pipe 41 with a directing force below the inner wall of the casing pipe 6. Since the tubular body 40 rotates at a high speed by the rotation of the tubing tube 7, the injected gas 56 that has exited the injection tube 41 is mixed with the injected water 55 that has been bubbled to increase the flow velocity, and becomes a gas-liquid mixed fluid 57. .

FIG. 3 is a diagram showing the relationship between the pressure of the injected water and the injected gas in the injection well. First, the force that is the pressure of the injected water 55 Pressure injection well 25 When the water depth to the injection point where the slit 18 near the bottom is provided is L 0, and the hydrostatic pressure at the LO point is PO, it does not contain microbubbles 59 In case of proper press-fitting, the water pressure required for press-fitting is PO + Pa. Here P a is to select the value of less than 10kg / cm ² Determine. In this embodiment, since the gas-liquid mixed fluid containing microbubbles is injected, there is a decrease in water pressure due to microbubbles near the bottom of the injection well 25. It is necessary to pressurize P β by the pressure decrease. Therefore, in order for the injection water pressure at the injection point with the slit 18 to be ΡΟ + Ρα, the injection water is pressurized into the injection well 25 and injected into Ρα + Ρβ. As a rough guide of [rho beta, if this disappears within injection well 25 exception of microbubbles, e.g. microbubbles average, 0. lm ³ into the injection water lm ³ is included apparently, in water This means that 10% of gas is mixed in, and the pressure decrease Ρ | 8 becomes (PO— P1) Χ Ο.

Next, the pressure of the injection gas 56 varies depending on the installation position of the microbubble device 30. As for the installation position, the micro-bubble device 30 integrated with the tubing tube 7 is cantilevered in the injection water in the injection well 25 in a cantilever state (a beam-like structure supported at the top). When rotating, the rotational force, the dynamic torsional rigidity of the tubing tube 7 and the force depending on the magnitude of the rotational resistance of the injected water received by the microbubble device The three-dimensional torsional rotational deformation occurs, so it is durable Considering the characteristics, the depth L1 is preferably 5 to 50 m. If the hydrostatic pressure of the injected water 55 at the depth L1 is P1, the pressure at the L1 of the injected water 55 is P1 + Pa + Pj8. Since the injection gas 56 is injected so as to overcome this pressure, the pressure of the injection gas 56 becomes Pl + Ρα + P j8 + C. Pl + Ρ α + P j8 <Ρ1 + Ρ α + P j8 + C Make the relational expression hold. Although it depends on the depth L1, C was 10-30 kg / cm ² here.

[0033] FIG. 4 is a flowchart showing a processing procedure of the enhanced recovery method of oil or natural gas. S60 to S64 indicate each processing stage.

Industrial applicability

[0034] The present invention is suitable for a low-cost oil or natural gas enhanced recovery system because the injection gas is microbubbled and mixed with the injection water, and facilities such as concentration of the injection gas are required.

Claims

The scope of the claims

[1] A stage in which the injected gas is microbubbled into the injected water and mixed to generate a gas-liquid mixed fluid, and the gas-liquid mixing is performed by injecting the gas-liquid mixed fluid from an injection well into an oil layer or a gas layer. A step of permeating microbubbles in a fluid into a fine gap in the oil layer or gas layer, and a step of recovering crude oil or natural gas expelled from the gap by the microbubble from the production well. A featured enhanced recovery method for oil or natural gas.

[2] The oil or natural gas according to claim 1, wherein the injection gas is hydrocarbon gas, oil field flare gas, nitrogen gas, carbon dioxide gas, combustion exhaust gas, or a gas mixed thereof. Enhanced collection method.

[3] The method for enhanced recovery of oil or natural gas according to claim 1, wherein the microbubbles of the injected gas are performed inside a press-fit well.

[4] An injection water injection device that injects injection water from an injection well into an oil layer or a gas layer, an injection gas supply device that sends injection gas toward the injection water, and an injection gas from the injection gas supply device. A microbubble device that microbubbles and mixes with the injected water, and a well that produces the crude oil or natural gas that is ejected by the microbubbles in the injected water and fine pore force in the oil layer or gas layer. An oil or natural gas enhanced recovery system characterized by including a crude oil recovery unit that recovers from

[5] A casing pipe into which the injected water is fed, a tubing pipe that is inserted into the casing pipe and into which the injected gas is fed, and a rotary drive device that rotates the tubing pipe are provided in the injection well, The enhanced recovery system for oil or natural gas according to claim 4, wherein the bubbler apparatus is attached to a lower end of the tubing pipe at an upper part of the casing pipe.

[6] The microbubble device according to claim 5, wherein the microbubble device has an injection pipe that injects the injection gas obliquely downward on a side surface, and is configured by a cylindrical body that is rotated by rotation of the tubing pipe. Oil or natural gas enhanced recovery system as described.

[7] A casing pipe used as a injection well to which injected water is sent,

A tubing tube that is inserted into the casing tube and into which an injection gas is sent, a rotation drive device that rotates the tubing tube,

A micro-bubble device that is attached to a lower end of the tubing tube, rotates by the rotation of the tubing tube, and has an injection tube that injects the injected gas obliquely downward on a side surface thereof. Gas-liquid mixed fluid injection device.