Horizontal well electric heating assisted steam injection oil recovery device

Abstract

The present application relates to the field of oil exploitation, and particularly relates to a horizontal well electric heating assisted steam injection oil recovery device, which comprises a steam pipe for injecting high-temperature and high-pressure steam into a horizontal well, and at least two self-adapting heating pieces arranged in the steam pipe in sequence along a steam conveying direction; the self-adapting heating piece comprises a steam distribution piece and a support piece arranged in the steam pipe in sequence along the steam conveying direction; a plurality of steam channels are formed in the support piece, and an electric heating piece is fixedly installed on a side of the support piece away from the steam distribution piece; the steam distribution piece comprises a plurality of pipes fixedly installed in the horizontal well, and the diameter of the pipe gradually increases from one end away from the support piece to one end of the support piece. The existing horizontal well electric heating assisted steam injection oil recovery device has the problem of uneven heat distribution in each horizontal section after heating, and the horizontal well electric heating assisted steam injection oil recovery device provided by the present application has the problem of uniform heat distribution in each horizontal section after heating.

Description

Technical Field

[0001] This invention relates to the field of oil extraction, specifically to a horizontal well electrothermal assisted steam injection oil production device. Background Technology

[0002] Petroleum is an indispensable strategic resource in modern society, but about 70% of the world's remaining petroleum resources are heavy oil. Heavy oil is a heavy crude oil with a viscosity exceeding 50 mPa·s and a density greater than 0.92 g / cm³. It has high viscosity and poor fluidity, making it very difficult to extract. Because the viscosity of heavy oil decreases by about half for every 10°C increase in temperature, steam injection is usually used for thermal recovery of heavy oil. This involves injecting steam into the well to increase the temperature of the crude oil in the formation and reduce its viscosity to achieve well production. Commonly used steam injection thermal recovery methods include: steam huff and puff, steam drive, SAGD (steam as-sisted gravity drainage), and VHSD (vertical-horizontal well steam drive).

[0003] VHSD typically forms horizontal fractures at the bottom of vertical wells and in the horizontal section of horizontal wells. Both vertical and horizontal wells are produced using steam injection. Vertical wells employ multiple rounds of safe pressure-controlled steam injection for self-flowing production to quickly connect with the horizontal wells and achieve "vertical well injection - horizontal well production".

[0004] In order to form a steam cavity and connect with the vertical well as soon as possible before horizontal wells are connected, people have developed an electric heating-assisted steam injection oil production device. By arranging an electric heating-assisted steam injection oil production device in the horizontal section of the horizontal well, the heavy oil in the wellbore or near the well is preheated or heated to improve the fluidity of the crude oil. Then, the electric heating is stopped and steam injection is switched to further heat the oil layer by using the heat energy of high temperature and high pressure steam.

[0005] The existing electric heating method mainly uses heating cables as electric heating devices in horizontal wells. However, the thermal properties of oil cores in different horizontal sections are different, while the heating temperature of each section of the heating cable is the same. This results in inconsistent heating rates in each horizontal section and a large temperature difference between them.

[0006] Therefore, existing horizontal well electrothermal assisted steam injection oil production devices have the problem of uneven heat distribution in different horizontal sections after heating. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a horizontal well electrothermal assisted steam injection oil production device that makes the heat distribution in each horizontal section more uniform after heating.

[0008] To solve the above-mentioned technical problems, the present invention provides a horizontal well electrothermal assisted steam injection oil production device, comprising a steam pipe for injecting high-temperature and high-pressure steam into the horizontal well and at least two adaptive heating elements arranged sequentially in the steam pipe along the steam delivery direction; the adaptive heating element includes a steam distribution element and a support element arranged sequentially in the steam pipe along the steam delivery direction; the support element has multiple steam channels, and an electric heating element is fixedly installed on the side of the support element away from the steam distribution element; the steam distribution element includes multiple pipes fixedly installed in the horizontal well, and the diameter of the pipes gradually increases from the end away from the support element to the end of the support element.

[0009] As a further improvement of the present invention, a rectifier grid for rectifying the steam entering the steam pipe is fixedly installed in the steam inlet of the steam pipe.

[0010] As a further improvement of the present invention: the support member includes an integrally formed cylinder and a frustum, the side of the cylinder away from the steam distributor is connected to the bottom surface of the frustum, and a plurality of spirally arranged guide vanes are installed on the curved surface of the frustum of the support member.

[0011] As a further improvement of the present invention, a plurality of heat-sensing channel cross-sectional area adjustment components are installed on the inner wall of the steam channel for reducing the channel cross-sectional area of ​​the steam channel when the temperature inside the steam channel is low.

[0012] Preferably, the heat induction channel cross-sectional area adjustment component includes a baffle for flow obstruction that can reciprocate in a direction perpendicular to the central axis of the steam channel, a first spring made of shape memory alloy, and a groove provided on the inner wall of the steam channel for the baffle to reciprocate in a direction perpendicular to the central axis of the steam channel.

[0013] As a further improvement of the present invention, a shape memory alloy temperature control valve is provided in the tube.

[0014] Preferably, the shape memory alloy temperature control valve includes a housing fixedly installed in the pipe inlet section and at least one valve plate capable of reciprocating along a direction perpendicular to the central axis of the pipe. The end of the valve plate away from the central axis of the pipe is fixedly connected to a second spring made of shape memory alloy, and the end of the second spring away from the valve plate is fixedly connected to the inner wall of the housing. The central axis of the second spring is perpendicular to the central axis of the pipe.

[0015] As a further improvement of the present invention: the electric heating element is at least two electric heating rods, each electric heating rod including a metal sheath and a heating element fixedly installed in the metal sheath, the metal sheath being filled with an insulating filler to ensure that the heating element is insulated from the metal sheath.

[0016] Preferably, the metal sheath is made of a metal material that is resistant to high temperature and high pressure; the heating element is made of nickel-chromium alloy resistance wire or iron-chromium-aluminum resistance wire; and the insulating filler is magnesium oxide powder.

[0017] The beneficial effects of the present invention are as follows: The horizontal well electrothermal assisted steam injection oil production device provided by the present invention makes the heat distribution in each horizontal section more uniform after heating.

[0018] The adaptive heating element of this device can both distribute and heat steam, and these adjustments can autonomously follow temperature changes. Therefore, the steam is sensed and decided by the support component, the inlet flow is distributed on demand by the steam distribution component, and the residence time within the section is dynamically adjusted by the thermal sensing channel cross-sectional area adjustment component. Ultimately, it achieves the goals of precise on-demand heat supply, effective activation of cold zones, suppression of steam channeling in hot zones, improvement of steam dryness, and homogenization of thermal waves, significantly improving the recovery rate and oil-steam ratio of heavy oil reservoirs, and realizing efficient, economical, and intelligent horizontal well electrothermal assisted steam injection oil production. Attached Figure Description

[0019] Figure 1 This is a schematic diagram showing the positional relationship between the horizontal well and the steam pipe in this invention; Figure 2 This is a schematic diagram showing the positional relationship between the rectifier grid, adaptive heating element, etc., and the steam pipe in this invention; Figure 3 This is a schematic diagram of the overall structure of the rectifier grille in this invention; Figure 4 This is a schematic diagram of the overall structure of the adaptive heating element in this invention; Figure 5 This is a schematic diagram showing the positional relationship between the support member and the electric heating element in this invention; Figure 6 This is a schematic diagram of the cross-section of the electric heating element in this invention; Figure 7 This is a schematic diagram showing the positional relationship between the support member and the thermal induction channel cross-sectional area adjustment member in this invention; Figure 8 This is a partial cross-sectional view of the support member in this invention; Figure 9 This is a partial cross-sectional schematic diagram of the support member and the thermal induction channel cross-sectional area adjustment member in this invention; Figure 10 This is a schematic diagram showing the positional relationship between the shape memory alloy temperature control valve and the pipe in this invention; The names of the components corresponding to the markings in the above figures are as follows: 1. Steam distribution component; 101. Pipe; 2. Support component; 201. Steam passage; 2011. Slide groove; 20111. Slide track; 202. Guide vane; 3. Electric heating component; 301. Metal sheath; 302. Heating element; 303. Insulating filler; 4. Thermal induction channel cross-sectional area adjustment component; 401. Baffle; 402. First spring; 403. Slider; 4031. Protrusion; 5. Shape memory alloy temperature control valve; 501. Housing; 502. Valve plate; 503. Second spring; 10. Horizontal well; 11. Steam pipe; 1101. Rectifying grid. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0021] like Figure 1 , Figure 2 , Figure 3 As shown, the present invention provides a horizontal well electrothermal assisted steam injection oil production device, comprising a steam pipe 11 for injecting high-temperature and high-pressure steam into a horizontal well 10, and at least two adaptive heating elements arranged sequentially along the steam transport direction in the steam pipe 11. A rectifier grid 1101 for rectifying the steam entering the steam pipe 11 is fixedly installed in the steam inlet of the steam pipe 11. The rectifier grid 1101 has a cylindrical structure, with multiple uniformly arranged square holes on the bottom surface of the cylinder. A protective layer made of aerogel composite material is provided on the inner wall of the steam pipe 11. The aerogel composite material includes silica aerogel particles and an organic-inorganic hybrid resin. The protective layer can significantly reduce the heat loss of steam in the direction perpendicular to the pipe wall during transport, allowing the steam to reach the steam outlet section of the steam pipe 11 at a high temperature as much as possible. Simultaneously, the protective layer has good adhesion and erosion resistance, and can adapt to the long-term steam injection environment inside the steam pipe 11. The adaptive heating element is mainly arranged in the horizontal section of the steam pipe 11, but can also be arranged in the vertical section of the steam pipe 11 to reheat the steam entering the steam pipe 11. The adaptive heating element includes a steam distributor 1 and a support 2 arranged sequentially in the steam pipe 11 along the steam conveying direction.

[0022] like Figure 2 , Figure 4 , Figure 10As shown, the steam distribution unit 1 includes multiple pipes 101 fixedly installed in the horizontal well 10. The diameter of the pipes 101 gradually increases from the end away from the support member 2 to the end of the support member 2. All pipes 101 are located on the same horizontal plane. One pipe 101 is located at the central axis of the horizontal section and / or vertical section of the horizontal well 10. The other pipes 101 are circumferentially installed on the inner wall of the horizontal section and / or vertical section of the horizontal well 10 by fixing blocks around the central axis of the horizontal section and / or vertical section of the horizontal well 10. The pipe located at the central axis of the horizontal section and / or vertical section of the horizontal well 10 is fixedly connected to its adjacent pipe 101 by fixing blocks. A shape memory alloy temperature control valve 5 is provided in the pipe 101. The shape memory alloy temperature control valve 5 includes a housing 501 fixedly installed in the inlet section of the pipe 101 and at least one valve plate 502 capable of reciprocating along a direction perpendicular to the central axis of the pipe 101. One end of the valve plate 502 away from the central axis of the pipe 101 is fixedly connected to a second spring 503 made of shape memory alloy. One end of the second spring 503 away from the valve plate 502 is fixedly connected to the inner wall of the housing 501. The central axis of the second spring 503 is perpendicular to the central axis of the pipe 101.

[0023] like Figure 4 , Figure 5 As shown, the support member 2 includes an integrally formed cylinder and a frustum. The side of the cylinder away from the steam distributor 1 is connected to the bottom surface of the frustum, which has a larger diameter. Multiple spirally arranged guide vanes 202 are mounted on the curved surface of the frustum of the support member 2. Multiple steam channels 201 are provided on the support member 2, with the central axis of each steam channel 201 parallel to the central axes of the cylinder and the frustum of the support member 2. The cylinder can be welded into the steam pipe 11, or an annular groove can be formed on the inner wall of the steam pipe 11, and an annular locking block corresponding to the annular groove can be machined on the curved surface of the cylinder. The cylinder is secured in the steam pipe 11 through the cooperation of the annular groove and the annular locking block. A high-temperature resistant sealing ring can also be provided between the annular locking block and the annular groove. The high-temperature resistant sealing ring can be a metal C-ring or a flexible graphite composite seal, used to prevent steam leakage from the connection gap, avoiding a decrease in thermal efficiency or structural failure due to steam leakage. The guide vanes 202 are made of nickel-based high-temperature alloy material. The support component 2 is made of a high thermal conductivity metal matrix composite material, which has high mechanical strength, can provide sufficient support force, and can efficiently conduct the heat generated by the electric heating component 3, and reheat the steam flowing through its steam channel 201 to improve the overall heat exchange efficiency.

[0024] like Figure 4 , Figure 5 , Figure 7 , Figure 8 , Figure 9As shown, multiple heat-sensing channel cross-sectional area adjustment components 4 are installed on the inner wall of the steam channel 201 to reduce the channel cross-sectional area of ​​the steam channel 201 when the temperature inside the steam channel 201 is low. The heat-sensing channel cross-sectional area adjustment component 4 includes a baffle 401 for flow obstruction that can reciprocate along a direction perpendicular to the central axis of the steam channel 201, and a first spring 402 made of shape memory alloy. A groove 2011 is provided on the inner wall of the steam channel 201 for the baffle 401 to reciprocate along a direction perpendicular to the central axis of the steam channel 201. The central axis of the first spring 402 is parallel to the direction of reciprocating motion of the baffle 401. One end of the first spring 402 is fixedly connected to the side of the slider 403 near the bottom of the groove 2011, and the other end of the first spring 402 is fixedly connected to the bottom of the groove 2011. The baffle 401 is fixedly installed on the side of the slider 403 away from the bottom of the groove 2011. The opposite surface of the slider 403 has a raised ridge 4031. A slide rail 20111 is provided on the inner wall of the groove 2011 for the two raised ridges 4031 to slide. The baffle 401 is made of a high thermal conductivity copper alloy, and the slider 403 is made of a high-temperature resistant and corrosion-resistant nickel-based alloy or stainless steel. The shape memory alloy is a TiNi-Pd (titanium-nickel-palladium) alloy or a TiNiPdPt (titanium-nickel-palladium-platinum) alloy. The set temperature of the shape memory alloy is adjusted by regulating the proportion of each element or by adding high-melting-point metal elements or platinum group elements. Among them, the high-melting-point metal elements include Hf (hafnium) and Zr (zirconium), and the platinum group elements include Ir (iridium) and Ru (ruthenium). The set temperature of the shape memory alloy used to make the first spring 402 can be different from that used to make the second spring 503.

[0025] like Figure 4 , Figure 5 , Figure 6As shown, an electric heating element 3 is fixedly installed on the upper surface of the frustum, the side of the support member 2 away from the steam distribution member 1. The electric heating element 3 consists of at least two electric heating rods, five of which are shown in the figure. Four of them are arranged circumferentially around the central axis of the support member 2, and the other is located at the central axis of the support member 2. The electric heating rod includes a metal sheath 301 and a heating element 302 fixedly installed in the metal sheath 301. The metal sheath 301 is tightly filled with insulating filler 303 to ensure insulation between the heating element 302 and the metal sheath 301. The cross-section of the electric heating rod is a regular hexagonal structure, which can increase the contact area between the electric heating rod and the steam. The heating element 302 is made of high-temperature and high-pressure resistant metal material, specifically titanium alloy, which can operate at 300℃ and 20MPa for extended periods. This effectively protects the heating element 302 and reduces the probability of it being eroded by steam, chemically corroded, or mechanically damaged. The heating element 302 is made of nickel-chromium alloy resistance wire or iron-chromium-aluminum resistance wire, which has high resistivity, good high-temperature oxidation resistance, and good long-term stability. The insulating filler 303 is magnesium oxide powder, used to reduce the probability of leakage from the electric heating rod to ensure operational safety.

[0026] The working principle of this invention is as follows: Steam is injected into the steam pipe 11 through the steam inlet and the mass flow rate and density of the injected steam are monitored in real time. When the steam passes through the rectifier grid 1101, the grid bars of the rectifier grid 1101 will block the disorderly flow part of the steam. The steam can only flow through the holes in all directions, so that the steam flows more evenly, smoothly and orderly in the designed direction.

[0027] The rectified steam approaches the first adaptive heating element. Subsequently, some steam passes through the gap between the tubes 101 and some steam enters the tubes 101. The shape memory alloy temperature control valve 5 can achieve adaptive steam distribution at the inlet section of the tubes 101. When the temperature inside the tubes 101 reaches the set temperature, the second spring 503, made of shape memory alloy, is heated and elongated, generating a restoring force. This pushes the valve plate 502 to approach the central axis of the tubes 101 along a direction perpendicular to the central axis of the tubes 101, blocking some steam and thus reducing steam supply and suppressing gas leakage. When the temperature inside the tubes 101 is lower than the set temperature, the restoring force of the second spring 503 decreases, causing the valve plate 502 to move away from the central axis of the tubes 101 along a direction perpendicular to the central axis of the tubes 101, keeping the tubes 101 fully open so that a large flow of steam can pass through to activate the cold zone.

[0028] Steam then enters the steam channels 201 opened on the support member 2. The steam temperature in each steam channel 201 and the steam temperature near the electric heating element 3 are monitored in real time. When the temperature in the steam channel 201 falls below the desired value, the electric heating element 3 is activated. The temperature of the electric heating element 3 is conducted to the support member 2. When the temperature of the support member 2 rises to a specific temperature, the first spring 402, made of shape memory alloy, is heated and elongated, generating a restoring force. This causes the slider 403 to move away from the bottom of the groove 2011 within the groove. During this movement, the two protrusions 4031 of the slider 403 slide in the two slide rails 20111 respectively, thereby causing the baffles 401 to gradually approach the central axis of the steam channel 201 along a direction perpendicular to the central axis of the steam channel 201. Multiple baffles 401 appear in the steam... After entering the channel 201, the cross-sectional area of ​​the steam channel 201 decreases, the residence time of steam in the steam channel 201 increases, and the heat exchange efficiency between the steam and the electric heating element 3 is improved, thereby enhancing heat exchange and increasing the temperature inside the steam channel 201. Both the steam temperature and dryness are improved. When the temperature inside the steam channel 201 is higher than the expected value, the electric heating element 3 stops heating, the temperature of the support 2 gradually decreases, the restoring force of the first spring 402 decreases, and the slider 403 drives the baffle 401 to gradually move away from the central axis of the steam channel 201 along a direction perpendicular to the central axis of the steam channel 201, returning to the slide groove 2011. This increases the cross-sectional area of ​​the steam channel 201, restores full flow, accelerates the steam flow speed, and weakens heat exchange.

[0029] After steam flows out of steam channel 201, some of the steam will come into contact with guide vanes 202. Guide vanes 202 can prolong the contact time between the steam and the heating surface, improve the convective heat transfer efficiency, and their spiral arrangement can guide the surrounding steam to flow along the spiral path, enhancing the turbulence intensity.

[0030] The steam continues to flow, and when it comes into contact with the next adaptive heating element, the above process is repeated until it maintains a high temperature and flows to the outlet of steam pipe 11.

[0031] It should be noted that the present invention is not limited to the specific structure shown in the accompanying drawings in the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art.

Claims

1. A horizontal well electrothermal assisted steam injection oil production device, characterized in that, Includes a steam pipe (11) for injecting high-temperature and high-pressure steam into a horizontal well (10) and at least two adaptive heating elements arranged sequentially in the steam pipe (11) along the steam transport direction; The adaptive heating element includes a steam distributor (1) and a support (2) arranged sequentially in the steam pipe (11) along the steam conveying direction; Multiple steam channels (201) are provided on the support member (2), and an electric heating element (3) is fixedly installed on the side of the support member (2) away from the steam distribution member (1). The steam distribution unit (1) includes multiple pipes (101) fixedly installed in the horizontal well (10), the diameter of which gradually increases from one end away from the support (2) to the other end of the support (2).

2. The horizontal well electrothermal assisted steam injection oil production device according to claim 1, characterized in that, A rectifier grid (1101) for rectifying the steam entering the steam pipe (11) is fixedly installed in the steam inlet.

3. The horizontal well electrothermal assisted steam injection oil production device according to claim 1, characterized in that, The support member (2) includes an integrally formed cylinder and a frustum. The side of the cylinder away from the steam distributor (1) is connected to the bottom surface of the frustum. Multiple spirally arranged guide vanes (202) are installed on the curved surface of the frustum of the support member (2).

4. A horizontal well electrothermal assisted steam injection oil production device according to any one of claims 1 to 3, characterized in that, The inner wall of the steam channel (201) is equipped with a plurality of heat-sensing channel cross-sectional area adjustment components (4) for reducing the channel cross-sectional area of ​​the steam channel (201) when the temperature inside the steam channel (201) is low.

5. A horizontal well electrothermal assisted steam injection oil production device according to claim 4, characterized in that, The heat induction channel cross-sectional area adjustment component (4) includes a baffle (401) for blocking the flow that can reciprocate along the direction perpendicular to the central axis of the steam channel (201), a first spring (402) made of shape memory alloy, and a groove (2011) provided on the inner wall of the steam channel (201) for the baffle (401) to reciprocate along the direction perpendicular to the central axis of the steam channel (201).

6. A horizontal well electrothermal assisted steam injection oil production device according to any one of claims 1 to 3, characterized in that, A shape memory alloy temperature control valve (5) is installed in the tube (101).

7. A horizontal well electrothermal assisted steam injection oil production device according to claim 6, characterized in that, The shape memory alloy temperature control valve (5) includes a housing (501) fixedly installed in the inlet section of the pipe (101) and at least one valve plate (502) capable of reciprocating along a direction perpendicular to the central axis of the pipe (101). One end of the valve plate (502) away from the central axis of the pipe (101) is fixedly connected to a second spring (503) made of shape memory alloy. One end of the second spring (503) away from the valve plate (502) is fixedly connected to the inner wall of the housing (501). The central axis of the second spring (503) is perpendicular to the central axis of the pipe (101).

8. A horizontal well electrothermal assisted steam injection oil production device according to any one of claims 1 to 3, characterized in that, The electric heating element (3) consists of at least two electric heating rods, each electric heating rod including a metal sheath (301) and a heating element (302) fixedly installed in the metal sheath (301). The metal sheath (301) is filled with an insulating filler (303) to ensure that the heating element (302) is insulated from the metal sheath (301).

9. A horizontal well electrothermal assisted steam injection oil production device according to claim 8, characterized in that, The metal sheath (301) is made of high temperature and high pressure resistant metal material; the heating element (302) is made of nickel-chromium alloy resistance wire or iron-chromium-aluminum resistance wire; the insulating filler (303) is magnesium oxide powder.

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