Oilfield polymer injection concentric dual passage tubing

Abstract

A concentric two-channel oil pipe for polymer injection in oilfields includes: a coaxially nested outer pipe and a central pipe, forming an independent central channel and an annular channel; the outer pipe has external pipe joints at both ends for connecting to the outer pipes of adjacent oil pipes; the central pipe has central pipe joints at both ends and is positioned and connected to the inner wall of the outer pipe through a channel bridge for connecting to the central pipes of adjacent oil pipes. This utility model has a novel structure and ingenious design. Through the concentric two-channel design, it can realize the separate injection of different polymer solutions, accurately drive oil out of the heterogeneity of the oil layer, effectively improve the oil-water mobility ratio, increase the swept volume of the injected polymer solution, and thus significantly improve the oil recovery rate. The concentric two-channel oil pipe has a flexible structural design, and the specifications of the dual channels and the polymer injection scheme can be easily adjusted according to the geological conditions and mining needs of different oilfields. It has wide applicability and reduces the technical difficulty and cost of oilfield mining.

Description

Technical Field

[0001] This utility model relates to oil pipes, specifically a concentric two-channel oil pipe for polymer injection in oil fields. Background Technology

[0002] In the mid-to-late stages of oilfield development, polymer flooding technology is widely used as an important tertiary oil recovery method to improve crude oil recovery. This technology improves crude oil extraction efficiency by injecting polymer solutions into the oil reservoir, thereby improving the oil-water mobility ratio and expanding the swept volume. However, traditional single-channel polymer injection tubing has gradually revealed insurmountable technical limitations in application, as follows:

[0003] Lack of stratified polymer injection capability: Traditional single-channel tubing can only deliver a single type of polymer solution, and cannot inject differentiated polymer solutions to address the stratified characteristics of heterogeneous reservoirs (such as permeability differences between different layers). For complex reservoirs where high-permeability and low-permeability layers coexist, a single solution is insufficient to meet the needs of each layer, resulting in insufficient utilization of some oil layers and affecting the overall recovery rate.

[0004] Poor equipment adaptability: Traditional tubing has a fixed structure, making it difficult to adapt to the dynamic changes in reservoir development. When reservoir formation conditions (such as permeability and porosity) change with the extraction process, single-channel tubing cannot flexibly adjust the polymer injection scheme, requiring frequent replacement of tubing strings or adjustment of the process, which increases extraction costs and technical difficulty. Utility Model Content

[0005] In view of the above situation and to overcome the defects of the prior art, this utility model provides a concentric two-channel oil pipe for oilfield polymer injection, which effectively solves the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: This utility model includes:

[0007] The coaxially nested outer tube and central tube form independent central channels and annular channels;

[0008] The outer tube is provided with outer tube joints at both ends for connecting the outer tubes of adjacent oil tubes;

[0009] The central tube is provided with central tube joints at both ends and is positioned and connected to the inner wall of the outer tube through a channel bridge, which is used to connect the central tube of the adjacent oil pipe.

[0010] Preferably, the channel bridge is a ring structure, fixed between the inner wall of the outer tube and the outer wall of the central tube, ensuring that the central tube and the outer tube are coaxially nested.

[0011] Preferably, both the outer pipe joint and the central pipe joint adopt a sealed connection structure to achieve independent sealing of the dual channels.

[0012] Preferably, the inner and / or outer walls of the outer tube and the central tube are provided with a drag-reducing coating.

[0013] Preferably, it also includes a pressure monitoring device for real-time monitoring of the injection pressure in at least one channel.

[0014] Preferably, it also includes a flow sensor and a polymer molecular weight analyzer, which are respectively installed at the inlet or outlet of the channel.

[0015] Beneficial effects: Improved oil displacement effect: Through the concentric two-channel design (the inner tube forming the central channel and the inner tube and outer tube forming the annular channel), different polymer solutions can be injected separately, which can accurately drive oil out of the heterogeneity of the oil layer, effectively improve the oil-water mobility ratio, increase the swept volume of the injected polymer solution, and thus significantly improve the oil recovery rate.

[0016] Enhanced tubing adaptability: The concentric two-channel tubing (outer and inner tubes) structure of this invention is flexible in design and can be easily adjusted in terms of dual-channel specifications and polymer injection schemes according to the geological conditions and mining needs of different oilfields. It has wide applicability and reduces the technical difficulty and cost of oilfield mining.

[0017] Easy to install and maintain: The outer and inner pipes are connected by a special annular channel bridge structure (upper annular channel connecting bridge, lower annular channel connecting bridge), and the oil pipes are connected by sealed plug joints (inner pipe sealing plug joint) and oil pipe couplings (upper joint, lower joint), which makes the installation and disassembly of the oil pipes more convenient, reducing operation time and labor intensity; at the same time, the sealing performance is reliable, reducing the risk of leakage, improving the operational stability and safety of the oil pipes, and facilitating later maintenance and management. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model. Detailed Implementation

[0020] The following is in conjunction with the appendix Figure 1 The specific embodiments of this utility model will be described in further detail.

[0021] Example 1, by Figure 1 This utility model provides a concentric two-channel oil pipe for polymer injection in oil fields, comprising:

[0022] The coaxially nested outer tube 7 and central tube 6 form an independent central channel 4 and an annular channel 5;

[0023] The outer tube 7 is provided with outer tube joints 2 and 9 at both ends for connecting the outer tubes of adjacent oil pipes;

[0024] The central tube 6 is provided with central tube joints 1 at both ends, and is positioned and connected to the inner wall of the outer tube through channel bridges 3 and 8, for connecting the central tube of adjacent oil pipes.

[0025] This tubing mainly consists of a coaxially nested outer tube 7 and a central tube 6. The two are concentrically arranged to form two independent channels, namely the central channel 4 inside the central tube and the annular channel 5 between the central tube and the outer tube.

[0026] Outer tube 7: As the outer layer of the tubing, it provides support and protection for the entire tubing. Its inner wall fits with the outer wall of the central tube to form an annular channel 5. The outer tube is made of high-strength, corrosion-resistant alloy steel, which can adapt to the complex and harsh working environment of oilfields and effectively extend the service life of the tubing.

[0027] Central tube 6: Located inside the outer tube, it forms a central channel 4 for conveying specific polymer solutions. The central tube is also made of corrosion-resistant alloy steel, possessing excellent pressure resistance and wear resistance.

[0028] External pipe joints 2 and 9: Located at both ends of the external pipe 7, used to connect adjacent oil pipes. The external pipe joints adopt a sealed connection structure to ensure the sealing of the connection, prevent polymer solution leakage, and ensure the independence of the annular channel 5.

[0029] Central tube connector 1: Located at both ends of the central tube 6, it connects to the central tubes of adjacent oil pipes, enabling the central channel 4 to continuously transport polymer solution. The central tube connector also adopts a sealed connection structure to ensure the sealing performance of the central channel 4.

[0030] Channel bridges 3 and 8 are annular structures fixed between the inner wall of the outer tube and the outer wall of the central tube. Their main function is to position the central tube, ensuring that the central tube and the outer tube always maintain a coaxial nested state, guaranteeing the stability and independence of the two channels, and enhancing the overall robustness of the tubing structure.

[0031] The inner and / or outer walls of the outer tube 7 and the central tube 6 are provided with a drag-reducing coating. This coating can reduce the resistance of the polymer solution when flowing in the tube, reduce energy loss, improve polymerization efficiency, and at the same time reduce the adhesion of the polymer solution on the tube wall, reduce the possibility of scaling inside the tube, and facilitate subsequent maintenance and cleaning.

[0032] Pressure monitoring device: Used to monitor the injection pressure in at least one channel in real time. By acquiring pressure data in real time, it provides a basis for adjusting the injection process, ensuring that the polymer solution is injected into the oil layer at an appropriate pressure, avoiding the impact of excessively high or low pressure on the oil displacement effect. At the same time, it can also detect abnormalities such as blockages and leaks in the oil pipes in a timely manner. Existing pressure monitoring instruments are used.

[0033] Flow sensor: Installed at the inlet or outlet of the channel, it is used to monitor the flow rate of the polymer solution in both channels in real time. By monitoring the flow rate, the injection volume of the polymer solution can be determined, and combined with the preset injection scheme, precise control of the injection process can be achieved.

[0034] Polymer molecular weight analyzer: Also installed at the channel inlet or outlet, it is used to detect the molecular weight of the polymer solution flowing through the channel. This detection data helps ensure that the injected polymer solution meets design requirements and guarantees the oil displacement effect, especially in scenarios where polymers with different molecular weights need to be injected separately, playing a crucial monitoring role.

[0035] Working principle: In use, this utility model consists of two independent channels formed by the coaxial nesting of the outer tube 7 and the central tube 6: the interior of the central tube 6 is the central channel 4, and the space between the central tube 6 and the outer tube 7 is an annular channel 5. The two tubes are positioned and fixed by the upper annular channel connecting bridge 3 and the lower annular channel connecting bridge 8 to ensure coaxiality and prevent channel deformation. The two ends are sealed together by the outer tube connectors (upper connector 2 and lower connector 9) and the central tube sealing connector 1 to prevent solution cross-flow.

[0036] Differentiated solution injection: Based on the heterogeneity of the oil reservoir, polymer solutions with different properties are injected into two channels respectively: for example, for high-permeability formations, a high molecular weight polymer solution with low injection pressure is injected through annular channel 5; for low-permeability formations, a low molecular weight polymer solution with high injection pressure is injected through central channel 4, so as to achieve targeted treatment for different layers.

[0037] Real-time monitoring and feedback: Molecular weight analyzers, flow sensors, and pressure sensors are installed at key locations at the wellhead to collect real-time data on the mass, flow rate, and pressure of the polymer solution in the two channels, ensuring that the solution parameters and injection status meet the design requirements.

[0038] Intelligent control operation: After the monitoring data is transmitted to the intelligent control system, the system automatically adjusts the opening of the electric regulating valve according to the preset polymer injection plan, and accurately controls the injection flow and pressure of each channel, so that the polymer solution enters the corresponding oil layer in the best condition and ensures the oil displacement effect.

[0039] Synergistic oil recovery: The polymer solution injected through the dual channels improves the oil-water mobility ratio of the corresponding oil layers and expands the swept volume; the corrosion-resistant alloy material and drag-reducing coating on the inner wall of the outer tube 7 and the central tube 6 reduce the flow resistance of the solution, improve the transportation efficiency, and ultimately achieve the equalization of the oil layer utilization and improve the crude oil recovery rate.

[0040] Beneficial effects: Improved oil displacement effect: Through the concentric two-channel design (the inner tube 6 forms the inner tube center channel 4 and the inner tube 6 and outer tube 7 form the annular channel 5), different polymer solutions can be injected separately, and oil displacement can be accurately carried out for the heterogeneity of the oil layer, effectively improving the oil-water mobility ratio, increasing the swept volume of the injected polymer solution, and thus significantly improving the crude oil recovery rate.

[0041] Enhanced tubing adaptability: The concentric two-channel tubing (outer tube 7 and inner tube 6) of this invention has a flexible structural design, which can be easily adjusted according to the geological conditions and mining needs of different oil fields. It has wide applicability and reduces the technical difficulty and cost of oil field mining.

[0042] Easy to install and maintain: The outer tube 7 and the inner tube 6 are connected by a special annular channel bridge structure (upper annular channel connecting bridge 3 and lower annular channel connecting bridge 8), and the oil pipes are connected by sealing plugs (inner tube sealing plugs 1) and oil pipe fasteners (upper connectors 2 and lower connectors 9), which makes the installation and disassembly of the oil pipes more convenient, reduces working time and labor intensity; at the same time, the sealing performance is reliable, reducing the risk of leakage, improving the operational stability and safety of the oil pipes, and facilitating later maintenance and management.

[0043] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A polymer injection concentric two pass tubing for oil fields, characterized by, include: The coaxially nested outer tube (7) and central tube (6) form an independent central channel (4) and an annular channel (5); The outer tube (7) is provided with outer tube joints (2, 9) at both ends for connecting the outer tubes of adjacent oil pipes; The central tube (6) is provided with central tube joints (1) at both ends and is positioned and connected to the inner wall of the outer tube through channel bridges (3, 8) for connecting the central tube of adjacent oil pipes.

2. The concentric dual access tubular of claim 1, wherein: The channel bridge (3, 8) is a ring structure, fixed between the inner wall of the outer tube and the outer wall of the central tube, ensuring that the central tube and the outer tube are coaxially nested.

3. A concentric dual passage tubing for use in the injection of a polymer into an oilfield as claimed in claim 1 or 2, characterised in that: Both the outer pipe joint (2, 9) and the central pipe joint (1) adopt a sealed connection structure to achieve independent sealing of the dual channels.

4. The concentric dual access tubular of claim 1, wherein: The inner and / or outer walls of the outer tube (7) and the central tube (6) are provided with drag-reducing coatings.

5. The concentric dual access tubular of claim 1, wherein: It also includes a pressure monitoring device for real-time monitoring of the injection pressure in at least one channel.

6. The concentric dual access tubular of claim 1, wherein: It also includes a flow sensor and a polymer molecular weight analyzer, which are respectively installed at the channel inlet or outlet.

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