Underground heating and testing integrated device for steam injection well

Abstract

The invention discloses a steam injection well underground heating and testing integrated device, a plurality of heating pipes are arranged in the device in the radial direction, each heating pipe comprises a wire section and a resistance section, and the wire section is used for transmitting electric energy and comprises a high-temperature wire and a mineral insulating material which are located in a first protection pipe; the resistance section is a heating section and comprises a high-temperature resistance wire and a mineral insulating material which are positioned in a first protection tube; the high-temperature wire and the high-temperature resistance wire are connected through a connector; ground steam does not need to be injected into a well from a steam injection pipe column, but directly enters an inner channel of the device through an injection port in the ground end, when the steam flows through a heating section, the injected steam is continuously heated along the way, and after the steam dryness is improved, the steam is directly injected into a stratum; meanwhile, by monitoring underground temperature and pressure changes, the working state of the heating section can be reasonably adjusted, the optimal steam heating effect is achieved, the electric heating efficiency can be maximized, and the development problems of medium-deep SAGD, steam drive and steam huff and puff wells are effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of heavy oil exploitation by steam injection in oil and gas fields, and in particular to an integrated downhole heating and testing device for a steam injection well. Background Art

[0002] As the largest heavy oil / high-condensate oil production base in China, Liaohe Oilfield mainly relies on steam injection thermal recovery, with an annual natural gas consumption of 1.52 billion cubic meters and a total carbon emission of 6.15 million tons. It is in urgent need of clean energy substitution to reduce carbon emissions. The effective development of difficult-to-recover reserves such as deep heavy oil / super-heavy oil steam drive, SAGD, shallow high-condensate oil and low-maturity shale oil is an important successor guarantee for Liaohe Oilfield to increase production and stabilize production. The traditional ground-generated steam injection method has large heat loss and low steam dryness in the well, so it is urgent to optimize the energy consumption structure and improve the heating efficiency. Summary of the invention

[0003] The purpose of the present invention is to provide an integrated downhole heating and testing device for steam injection wells, which directly injects steam into the heating device on the ground, performs secondary heating on the injected steam in the designed layer section downhole, and improves the downhole steam dryness. The device is applicable to both vertical wells and horizontal wells, and can also be used for downhole heating of other injected fluids.

[0004] To achieve the above-mentioned purpose, the technical solution of the present application is: an integrated downhole heating test device for a steam injection well, wherein a plurality of heating tubes are radially arranged inside the device, each heating tube includes a conductor segment and a resistance segment, the conductor segment is used to transmit electrical energy, and includes a high-temperature conductor and a mineral insulating material located in a first protective tube, the mineral insulating material is filled in the first protective tube for insulation and heat conduction between the high-temperature conductor and the pipe wall, and at the same time wraps the high-temperature conductor to ensure that the high-temperature conductor does not contact the pipe wall; the resistance segment is a heating segment, and includes a high-temperature resistance wire and a mineral insulating material located in the first protective tube, the mineral insulating material is filled in the first protective tube for insulation and heat conduction between the high-temperature resistance wire and the pipe wall, and at the same time wraps the high-temperature resistance wire to ensure that the high-temperature resistance wire does not contact the pipe wall; the high-temperature conductor and the high-temperature resistance wire are connected by a connector and welded and smoothed; the ends of the high-temperature resistance wire in each heating tube are connected to each other.

[0005] Furthermore, a thermocouple test tube is provided inside the device, and the thermocouple test tube includes a thermocouple wire and a mineral insulating material located in a second protective tube. The mineral insulating material is filled in the second protective tube to insulate and conduct heat between the thermocouple wire and the tube wall, and at the same time wraps the thermocouple wire to ensure that the thermocouple wire does not contact the tube wall.

[0006] Furthermore, a pressure measuring tube is provided inside the device, one end of which is connected to a pressure sensor, which is located at the wellhead and is used to measure the downhole pressure value.

[0007] Furthermore, the outside of the device is a high-temperature resistant continuous oil pipe, one end of which is provided with a steam injection port, through which ground steam is injected into the well along the high-temperature resistant continuous oil pipe, and the other end is provided with a high-temperature resistant continuous oil pipe head, on which are provided multiple steam outlets.

[0008] Furthermore, the high temperature resistant coiled tubing is connected to a sealing cover, and the sealing cover is used to seal the high temperature resistant coiled tubing at the wellhead end, the thermocouple test tube, multiple heating tubes, and the pressure measuring tube.

[0009] Furthermore, at least one first fixing frame and a second fixing frame are provided inside the high temperature resistant coiled tubing for fixing the thermocouple test tube, multiple heating tubes and pressure measuring tube to prevent them from contacting the wall of the high temperature resistant coiled tubing.

[0010] Furthermore, a protective tube head is provided at the end of the thermocouple test tube.

[0011] Furthermore, the ends of the plurality of heating tubes are connected and fixed via a high-temperature connecting frame.

[0012] As a further step, the high-temperature conductor material is a copper wire core, the high-temperature resistant continuous oil pipe, the first protective tube, the second protective tube, the pressure measuring tube, the high-temperature connecting frame, the sealing cover, the first fixing frame, the second fixing frame, the pipe head, and the high-temperature resistant continuous oil pipe head are made of high-temperature resistant alloy steel, and the high-temperature resistance wire is made of a high-temperature resistant resistance material nickel-chromium alloy.

[0013] As a further step, the device is lowered into a horizontal well or a vertical well through a thermal recovery steam injection wellhead. After reaching the target layer, a wellhead sealer is installed at the wellhead, and the conductor segment is connected to a high-pressure ground power regulator. The working state of the heating segment is controlled at the ground end to adjust the heating power. During steam injection, steam is injected from the steam injection port into the interior of the high-temperature resistant continuous oil pipe. The steam flows downward along the pipe wall. After passing through the heating segment, the high-temperature resistance wire starts to work. The steam is continuously heated along the way through the heating segment. After the steam dryness is increased, it flows out from the steam outlet and is injected into the formation.

[0014] By adopting the above technical scheme, the present invention can achieve the following technical effects: for steam throughput, steam drive and SAGD long-term steam injection wells, the ground steam does not need to be injected from the insulated pipe, but is directly injected into the internal channel of the device through the steam injection port, and after being heated along the way by the heating section, it flows out from the steam outlet at the end of the device and is injected into the formation, achieving the purpose of steam extraction. For horizontal wells, the heating section can be lowered into the horizontal section, and the steam is directly injected into the formation after extraction, which greatly reduces the heat loss along the way.

[0015] By monitoring the changes in downhole temperature and pressure, the working state of the high-temperature resistance wire can be reasonably adjusted to achieve the best heating effect. By rationally utilizing the green electricity + grid electricity working system, the electrification rate of heavy oil thermal recovery development can be comprehensively improved to achieve the goal of clean energy substitution and carbon emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0017] Figure 1 A cross-sectional view of an integrated downhole heating and testing device for a steam injection well;

[0018] Figure 2 This is an end view of an integrated downhole heating and testing device for a steam injection well;

[0019] Figure 3 This is a usage status diagram of an integrated downhole heating test device for a steam injection well;

[0020] Explanation of the numbers in the figure: 1-thermocouple test tube; 2-first heating tube; 3-second heating tube; 4-third heating tube; 5-pressure sensor; 6-pressure measuring tube; 7-first protection tube; 8-mineral insulation material; 9-high temperature wire; 10-connector; 11-high temperature resistance wire; 12-high temperature connection frame; 13-sealing cover; 14-steam injection port; 15-first fixing frame; 16-high temperature resistant continuous oil pipe; 17-second fixing frame; 18-thermocouple wire; 19-second protection tube; 20-tube head; 21-high temperature resistant continuous oil pipe head; 22-steam outlet. 2-1-high pressure ground power regulator, 2-2-wellhead sealer, 2-3-thermal recovery steam injection wellhead, 2-4-wire segment, 2-5-thermal packer, 2-6-resistance segment. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] like Figure 1-2As shown, this embodiment provides an integrated device for underground heating and testing of steam injection wells. In order to meet the requirements of underground high-power heating, a plurality of heating tubes are radially arranged inside the device of the present invention. This embodiment is described by taking three as an example. That is, the first heating tube 2, the second heating tube 3, and the third heating tube 4. Each heating tube includes a wire segment and a resistance segment. The wire segment is used to transmit electrical energy, including a high-temperature wire 9, a mineral insulating material 8, and a first protective tube 7; the resistance segment is a heating segment, including a high-temperature resistance wire 11, a mineral insulating material 8, and a first protective tube 7. The high-temperature wire 9 and the high-temperature resistance wire 11 are connected by a connector 10 and welded and smoothed; the high-temperature wire 9 and the high-temperature resistance wire 11 are located in the first protective tube 7, and the first protective tube 7 is filled with a mineral insulating material 8 for insulation and heat conduction, and at the same time, it is ensured that the high-temperature wire 9 and the high-temperature resistance wire 11 do not contact the pipe wall. The ends of the three heating tubes are connected and fixed by a high-temperature connecting frame 12, and the ends of the high-temperature resistance wires inside are also connected to each other.

[0023] In order to monitor the temperature of the injected steam downhole, a thermocouple test tube 1 is provided inside the device of the present invention. The thermocouple test tube includes a thermocouple wire 18, a mineral insulating material 8, and a protective tube head 20. The thermocouple wire 18 is located in a second protective tube 19. The second protective tube 19 is filled with a mineral insulating material 8 for insulation and heat conduction between the thermocouple wire 18 and the wall of the second protective tube, while also ensuring that the thermocouple wire 18 does not contact the tube wall.

[0024] In order to monitor the changes in downhole pressure, a pressure measuring tube 6 is provided inside the device of the present invention, and the surface end of the pressure measuring tube 6 is connected to a pressure sensor 5. When the device is working, the downhole pressure value can be obtained through the test value of the pressure sensor 5 at the wellhead, thereby realizing real-time monitoring of the downhole pressure.

[0025] The outside of the device is a high temperature resistant coiled tubing 16, and a steam injection port 14 and a sealing cover 13 are provided at the wellhead end. The ground steam is injected into the well along the coiled tubing through the steam injection port 14. The sealing cover 13 is used to seal the high temperature resistant coiled tubing 16, the thermocouple test tube 1, the first heating tube 2, the second heating tube 3, the third heating tube 4, and the pressure measuring tube 6 at the wellhead end; the other end of the high temperature resistant coiled tubing 16 is provided with a high temperature resistant coiled tubing head 21, which is provided with a plurality of steam outlets 22. The first fixing frame 15 and the second fixing frame 17 are located inside the high temperature resistant coiled tubing 16, which can be one or more, and are used to fix the positions of the thermocouple test tube 1, the first heating tube 2, the second heating tube 3, the third heating tube 4, and the pressure measuring tube 6 in the high temperature resistant coiled tubing 16 to prevent them from contacting the coiled tubing wall to ensure steam heating and testing effects. For steam drive / SAGD development wells and steam huff-and-puff wells, ground steam is directly injected into the well through the steam injection port 14 of the device, flows through the heating section for heating along the way, and then flows out from the terminal steam outlet 22 of the heating device and injected into the formation to achieve the purpose of steam extraction. For horizontal wells, the heating section can be lowered into the horizontal section, and the steam is directly injected into the formation after extraction, which greatly reduces the heat loss along the way.

[0026] This device can be used for vertical wells and horizontal wells, such as Figure 3 As shown, the horizontal well is mainly described here. At present, many test instruments are lowered through cables or steel wires, so the instruments cannot be lowered into the horizontal section. Because this device is a continuous oil pipe, it can push the heating section to the horizontal section to work. The specific implementation method is: it is lowered into the well through the thermal recovery steam injection wellhead 2-3. The design of the continuous oil pipe can realize the lowering of the heating section into the horizontal section. After reaching the target layer section, it is insulated by the thermal packer 2-5, and then the wellhead sealer 2-2 is installed at the wellhead, and the integrated device is fixed at the wellhead. The ground end is connected to the high-pressure ground power regulator 2-1, which can control the working state of the heating section on the ground and adjust the heating power. When injecting steam, steam is injected into the device from the steam injection port 14. Under the designed injection flow rate, the steam flows downward along the high-temperature resistant continuous oil pipe 16. After flowing through the heating section, the high-temperature resistance wire starts to work. The steam continues to heat along the heating section. After the steam dryness is increased, it flows out from the steam outlet 22 and is injected into the formation. The design of non-insulated pipes can ensure that the steam flow channel is not affected by the downhole space, casing size, and well conditions. The steam is heated and dried and then directly injected into the formation, which greatly reduces heat loss along the way. The heating fluid of the present invention can be steam or other fluids.

[0027] In order to ensure long-term high-temperature operation underground, all materials of the present invention need to meet certain temperature resistance indicators. The material of the high-temperature conductor 9 can be a copper wire core, the high-temperature resistant continuous oil pipe 16, the first protective tube 7, the second protective tube 19; the pressure measuring tube 6, the high-temperature connecting frame 12, the sealing cover 13, the first fixing frame 15; the second fixing frame 17, the protective pipe head 20, and the high-temperature resistant continuous oil pipe head 21 are high-temperature resistant alloy steel, and the high-temperature resistance wire 11 is made of a high-temperature resistant resistance material nickel-chromium alloy, and the mineral insulating material 17 is preferably used for insulation and heat conduction.

[0028] The present invention is a continuous tubular heating and testing integrated device. The outer tube thereof can continuously work for a long time under the environment of high-temperature steam corrosion and scouring in the steam injection pipe column through optimization of materials and process structures, thereby achieving a breakthrough in the downhole electric heating process of the steam injection well, solving the restrictions on the downhole space, casing size and well conditions of the development well, and realizing large-scale promotion and application in the later stage.

[0029] The present invention is aimed at steam throughput, steam drive and SAGD long-term steam injection electric heating development, and can make full use of the existing green electricity in the oil field to power the electric heater, realize green electricity consumption, and reasonably use the green electricity + grid electricity working system to power the electric heater, comprehensively improve the electrification rate of heavy oil development, and achieve the purpose of clean energy substitution and carbon emission reduction. The ground steam does not need to be injected from the insulated pipe, but is directly injected into the internal channel of the device of the present invention through the steam injection port, which reduces the cross-sectional area of ​​the steam flow, and also makes the steam directly contact with the heating section of the heating pipe, increasing the steam heating efficiency and making the steam heating more sufficient.

[0030] The manufacturing process of the above device is as follows: the thermocouple test tube 1 is manufactured by continuous welding powder filling method and wire threading and tube passing method. The metal strip for manufacturing the second protection tube 19 is continuously longitudinally wrapped by a set of forming rollers to form a cylindrical second protection tube 19. The edge of the metal strip is continuously longitudinally welded by argon arc welding under argon protection. The thermocouple wire 18 enters the second protection tube 19 through a fixed pipe. The outlet of the fixed pipe is set on one side of the metal strip. The mineral insulating material 8 powder after magnetic separation is sent from the hopper through the pipe into the second protection tube 19 and vibrated. Then, after continuous rolling or cold drawing and annealing, the thermocouple test tube 1 is manufactured. Similarly, the three heating tubes are manufactured by continuous welding powder filling method, and the ends are connected by a high-temperature connecting frame 12. The thermocouple test tube 1, the pressure measuring tube 6 and the connected three heating tubes are connected and fixed by the first fixing frame 15 and the second fixing frame 17, and then inserted into the high-temperature continuous oil pipe 16 by wire threading and tube passing, and the integrated device is manufactured.

[0031] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0032] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An integrated downhole heating and testing device for a steam injection well, characterized in that: A plurality of heating tubes are radially arranged inside the device, each of which includes a conductor segment and a resistance segment. The conductor segment is used to transmit electric energy, including a high-temperature conductor and a mineral insulating material located in a first protective tube. The mineral insulating material is filled in the first protective tube for insulation and heat conduction between the high-temperature conductor and the tube wall, and at the same time, the high-temperature conductor is wrapped to ensure that the high-temperature conductor does not contact the tube wall; the resistance segment is a heating segment, including a high-temperature resistance wire and a mineral insulating material located in the first protective tube. The mineral insulating material is filled in the first protective tube for insulation and heat conduction between the high-temperature resistance wire and the tube wall, and at the same time, the high-temperature resistance wire is wrapped to ensure that the high-temperature resistance wire does not contact the tube wall; the high-temperature conductor and the high-temperature resistance wire are connected through a connector and welded and smoothed; the ends of the high-temperature resistance wire in each heating tube are connected to each other.

2. According to claim 1, a steam injection well downhole heating test integrated device is characterized in that: A thermocouple test tube is also provided inside the device, and the thermocouple test tube includes a thermocouple wire and a mineral insulating material located in a second protective tube. The mineral insulating material is filled in the second protective tube to insulate and conduct heat between the thermocouple wire and the tube wall, and at the same time wraps the thermocouple wire to ensure that the thermocouple wire does not contact the tube wall.

3. According to claim 1, a steam injection well downhole heating test integrated device is characterized in that: A pressure measuring tube is also provided inside the device, one end of which is connected to a pressure sensor, which is located at the wellhead and is used to measure the downhole pressure value.

4. The downhole heating and testing integrated device for a steam injection well according to claim 1, characterized in that: The outside of the device is a high-temperature resistant continuous oil pipe, one end of which is provided with a steam injection port. Ground steam is injected into the well along the high-temperature resistant continuous oil pipe through the steam injection port. The other end is provided with a high-temperature resistant continuous oil pipe head, which is provided with multiple steam outlets.

5. The downhole heating and testing integrated device for a steam injection well according to claim 4, characterized in that: The high temperature resistant coiled tubing is connected to a sealing cover, and the sealing cover is used to seal the high temperature resistant coiled tubing at the wellhead end, a thermocouple test tube, a plurality of heating tubes, and a pressure measuring tube.

6. The downhole heating and testing integrated device for a steam injection well according to claim 4, characterized in that: One or more first fixing frames and second fixing frames are arranged inside the high temperature resistant coiled tubing for fixing the thermocouple test tube, multiple heating tubes and pressure measuring tube to prevent them from contacting the wall of the high temperature resistant coiled tubing.

7. The downhole heating and testing integrated device for a steam injection well according to claim 2, characterized in that: A protective tube head is provided at the end of the thermocouple test tube.

8. The downhole heating and testing integrated device for a steam injection well according to claim 1, characterized in that: The ends of the plurality of heating tubes are connected and fixed via a high-temperature connecting frame.

9. The downhole heating and testing integrated device for a steam injection well according to claim 1, characterized in that: The high-temperature conductor material is a copper wire core, the high-temperature resistant continuous oil pipe, the first protective tube, the second protective tube, the pressure measuring tube, the high-temperature connecting frame, the sealing cover, the first fixing frame, the second fixing frame, the pipe head, and the high-temperature resistant continuous oil pipe head are made of high-temperature resistant alloy steel, and the high-temperature resistance wire is made of a high-temperature resistant resistance material nickel-chromium alloy.

10. The downhole heating and testing integrated device for a steam injection well according to claim 1, characterized in that: The device is lowered into a horizontal well or a vertical well through the thermal recovery steam injection wellhead. After reaching the target layer, a wellhead sealer is installed at the wellhead, and the conductor segment is connected to a high-pressure ground power regulator. The working state of the heating segment is controlled at the ground end to adjust the heating power. During steam injection, steam is injected from the steam injection port into the high-temperature resistant coiled tubing. The steam flows downward along the pipe wall. After passing through the heating segment, the high-temperature resistance wire starts to work. The steam is continuously heated along the heating segment. After the steam dryness is increased, it flows out from the steam outlet and is injected into the formation.

Images