Electric control water injection tubular column device and control method

Abstract

An electric control water injection tubular column device and a control method belong to the technical field of fine water injection of water injection oil fields, and comprise an electric steel pipe cable, a first electric cable control water injection packer, a first electric cable control intelligent water distributor, an electric control valve, a wellhead sealing device, a ground control device and a remote terminal system, a first electric cable control water injection packer and a first electric cable control intelligent water distributor are arranged on the water injection tubular column, an electric control valve is arranged at the bottom end of the water injection tubular column, and a wellhead sealing device is arranged at a wellhead. The first electric cable control water injection packer, the first electric cable control intelligent water distributor and the electric control valve penetrate through the wellhead sealing device through an electric steel pipe cable to be sequentially connected with a ground control device and a remote terminal system. An electric control water injection packer, an electric control valve, an integrated control system and the like are developed, electric intelligent control over a whole-well pipe column is achieved, and therefore the digitization and intelligentization level of the water injection oilfield separate injection technology is further improved.

Description

Technical Field

[0001] This invention belongs to the field of fine water injection technology in water-injected oilfields, specifically relating to an electrically controlled water injection tubing device and control method. Background Technology

[0002] After an oil field is put into development, as the extraction time increases, the energy of the oil layer itself is continuously consumed, leading to a continuous decrease in oil layer pressure, significant degassing of underground crude oil, increased viscosity, and a substantial reduction in well production, sometimes even resulting in shutdown or cessation of production. A large amount of unrecoverable dead oil remains underground. To compensate for the underground deficit caused by crude oil extraction, maintain or increase oil layer pressure, achieve high and stable oil production, and obtain a high recovery rate, water injection development is necessary. Currently, water injection technology mainly uses bridge-type eccentric injection, supplemented by surface dual-pipe injection and ball-drop selective injection technologies. The main problems encountered in its application are as follows:

[0003] First, the adjustment workload for concentric injection wells is large, and some wells cannot have their nozzles adjusted. Currently, bridge-type concentric injection wells require 150 well-times of testing, adjustment, and sealing verification annually, with annual supporting costs exceeding 3.06 million yuan. The workload and cost are both high. Furthermore, the resistance rate is high for testing and adjustment in oil-concentrated and sand-producing wells, with 5-7 encounters per year, and some wells cannot have their nozzles adjusted. Second, data is measured periodically, making real-time monitoring of downhole data impossible. Currently, periodic manual testing and adjustment only allows for instantaneous stratified water injection dynamics, not continuous monitoring. Statistics show that the qualified rate of each layer in the injection well decreases by about 15-20% after 3 months of adjustment. Therefore, the current injection process cannot continuously reflect changes in water absorption in each sub-layer over a long period, limiting the reliability of reservoir dynamic analysis. Third, the sealing status of the injection tubing cannot be monitored in real time. The sealing status of existing water injection packers can only be detected by running a sealing verification instrument. If the packer seal fails, it is impossible to monitor or determine the failure time in a timely manner.

[0004] Meanwhile, currently, all tiered water injection tubing, regardless of whether it is eccentric or concentric, uses compressible washable packers for segmental sealing. After the tubing is sealed and lowered, it needs to be pressure-tested and set via a cement truck tubing, adding an extra opening test. The tubing unsealing load is high during multi-stage injection, which can easily lead to well sticking risk. The area of ​​the packer washing channel is limited by space, with an equivalent area generally less than 1010 mm2, and the backwashing effect of conventional water injection packers is not ideal. Affected by formation backflow of dead oil, sand production, injected water quality, washing frequency, and washing quality, the packer washing valve may not close tightly or the washing channel may be blocked, leading to packer leakage and affecting the packer sealing reliability. Currently, the success rate of well sealing verification for tiered injection is only 80%, and the sealing reliability of the packer directly affects the tiered injection effect. Meanwhile, the stratified water distributors currently used in eccentric / concentric sub-injection technology are all mechanical downhole water distribution structures. Although they can achieve stratified water injection, they have problems such as complex manual construction, difficult measurement and adjustment, large workload, low efficiency and poor stratified water injection effect.

[0005] Currently, the fourth-generation injection systems in China mainly include cable-controlled intelligent injection and cableless wavecode intelligent injection technologies, which have been applied on a large scale in Daqing, Changqing, Xinjiang, and Jilin. The principle is to control the opening and water volume of the downhole water distributor using either cabled or cableless methods, enabling remote measurement, adjustment, and sealing verification of the well, and allowing for monitoring of data such as injection volume, temperature, and pressure at each layer. Research focuses primarily on intelligent water distributors and surface controllers. However, the injection tubing, especially the water injection packer, still uses a compressible, washable packer, and full-well string electric control has not yet been achieved, indicating that the level of intelligence needs further improvement. Furthermore, issues such as limited well-washing effectiveness, high unsealing load, and the need to improve packer sealing reliability remain. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes an electrically controlled water injection string device, comprising an electric steel pipe cable, a first electrically controlled cable-operated water injection packer, a first electrically controlled cable-operated intelligent water distributor, an electric control valve, a wellhead sealing device, a ground control device, and a remote terminal system. The first electrically controlled cable-operated water injection packer and the first electrically controlled cable-operated intelligent water distributor are installed on the water injection string, an electric control valve is installed at the bottom of the water injection string, and a wellhead sealing device is installed at the wellhead. The first electrically controlled cable-operated water injection packer, the first electrically controlled cable-operated intelligent water distributor, and the electric control valve are connected to the ground control device and the remote terminal system in sequence via an electric steel pipe cable passing through the wellhead sealing device.

[0007] Furthermore, it also includes a second electrically controlled cable-operated water injection packer, which is installed on the water injection string. The second electrically controlled cable-operated water injection packer is connected to the ground control device and the remote terminal system in sequence through an electric steel pipe cable passing through the wellhead sealing device.

[0008] Furthermore, it also includes a second electrically controlled intelligent water distributor, which is installed on the water injection string. The second electrically controlled intelligent water distributor is connected to the ground control device and the remote terminal system in sequence through an electric steel pipe cable passing through the wellhead sealing device.

[0009] Furthermore, the first and second electrically controlled water-filled packers are equipped with an expansion-type rubber sleeve electrically controlled setting seal.

[0010] Furthermore, the electric control valve cleans the well using both forward and reverse washing methods.

[0011] Furthermore, a first electrically controlled cable-operated water injection packer and a second electrically controlled cable-operated water injection packer are installed at the water injection layer section of the water injection string in the well.

[0012] A control method for an electrically controlled water injection string device includes the following steps:

[0013] S1. Using cable clamps, connect the electric control valve, cable-controlled intelligent water distributor, and electric cable-controlled water injection packer from bottom to top to form a whole-well control intelligent water injection string, and lower them to the designed positions in the well in sequence.

[0014] S2. After the water injection string is in place, test whether the electrical signal is normal. If it is normal, complete the wellhead and seal the wellhead cable, and then connect the surface cable.

[0015] S3. After verifying the tool depth, the cement truck pressurizes the cement at 5, 10, and 18 MPa, stabilizes the pressure for 5 minutes, sets the first and second electric cable-controlled water injection packers, and then slowly releases the pressure.

[0016] S4. Connect the electric steel pipe cable to the ground control device and supply power; connect to the remote terminal system to adjust the water volume of the intelligent water distributors on each floor.

[0017] Furthermore, when well washing is required, the remote terminal system sends a command to the ground control device, which controls the first and second electric cable-controlled water injection packers to open their internal setting valves. This releases the pressure inside the packer sleeve to the tubing, causing the packer sleeve to retract. Simultaneously, the lower electric control valve opens, enabling high-volume well washing.

[0018] The beneficial effects of this invention are as follows:

[0019] To achieve fully electric and intelligent control of the entire well tubing string, the core tools are an electric cable-controlled water injection packer and an electric cable-controlled control valve. Through electric control, the water injection packer can be repeatedly set and unsealed, and the electric control valve can be opened and closed. This expands the well washing channel, enables high-volume well washing, increases the flow area, and solves the sealing hazards that are easily caused by poor water quality, formation backflow of dead oil and sand, etc. It also reduces the unsealing load during tubing string tripping and improves the reliability of unsealing.

[0020] ① The electric cable-controlled water injection packer adopts an expansion-type rubber cylinder electric control setting seal, which does not require oil pipe pressure testing. It only requires water injection pressure + electric control to close the setting valve, and the tubing is subjected to balanced force.

[0021] ② The electric cable-controlled packer is electrically controlled for unsealing, eliminating the need for pin control and additional unsealing load. The unsealing of the tubing string is reliable, avoiding major well overhauls. It is suitable for multi-stage injection wells and sand-producing wells.

[0022] ③ After the packer is unsealed, the tubing has a large well-washing channel, resulting in a better well-washing effect. The unidirectional well-washing effect is improved by 1.67 times, making it especially suitable for wastewater reinjection wells and heavy oil and sand-producing wells.

[0023] ④ The bottom backwash valve is electrically controlled, which, compared with conventional injection tubing which can only backwash wells, can achieve both forward and reverse washing.

[0024] ⑤ By working in conjunction with an intelligent water distributor, the entire tubing can be electrically controlled, and production parameters such as injection volume, injection pressure and temperature of the injection well sections can be monitored and automatically adjusted in real time from the ground or remotely. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the electric intelligent water injection pipe column device of the present invention. Detailed Implementation

[0026] To make the technical means and objectives of this invention easier to understand, the invention is further described below in conjunction with specific embodiments. An electrically controlled water injection string device includes an electric steel pipe cable 1, a first electrically controlled cable-operated water injection packer 2, a first electrically controlled cable-operated intelligent water distributor 3, an electric control valve 6, a wellhead sealing device 7, a ground control device 8, and a remote terminal system 9. The first electrically controlled cable-operated water injection packer 2 and the first electrically controlled cable-operated intelligent water distributor 3 are installed on the water injection string. The electric control valve 6 is installed at the bottom of the water injection string. The wellhead sealing device 7 is installed at the wellhead. The first electrically controlled cable-operated water injection packer 2, the first electrically controlled cable-operated intelligent water distributor 3, and the electric control valve 6 are connected to the ground control device 8 and the remote terminal system 9 in sequence via the electric steel pipe cable 1 passing through the wellhead sealing device 7.

[0027] It also includes a second electrically controlled cable-operated water injection packer 4, which is installed on the water injection string. The second electrically controlled cable-operated water injection packer 4 is connected to the ground control device 8 and the remote terminal system 9 in sequence through the wellhead sealing device 7 via the electric steel pipe cable 1.

[0028] It also includes a second electric cable-controlled intelligent water distributor 5, which is installed on the water injection string. The second electric cable-controlled intelligent water distributor 5 is connected to the ground control device 8 and the remote terminal system 9 in sequence through the wellhead sealing device 7 via the electric steel pipe cable 1.

[0029] Among them, the first electric cable-controlled water-filled packer 2 and the second electric cable-controlled water-filled packer 4 adopt an expansion-type rubber cylinder electric control setting seal.

[0030] The electric control valve 6 cleans the well using both forward and reverse washing methods.

[0031] Among them, a first electrically controlled cable-controlled water injection packer 2 and a second electrically controlled cable-controlled water injection packer 4 are installed at the water injection layer section of the water injection string in the well.

[0032] A control method for an electrically controlled water injection tubing device, characterized by comprising the following steps:

[0033] S1. Using cable clamps, connect the electric control valve, cable-controlled intelligent water distributor, and electric cable-controlled water injection packer from bottom to top to form a whole-well control intelligent water injection string, and lower them to the designed positions in the well in sequence.

[0034] S2. After the water injection string is in place, test whether the electrical signal is normal. If it is normal, complete the wellhead and seal the wellhead cable, and then connect the surface cable.

[0035] S3. After verifying the tool depth, the cement truck pressurizes the cement to 5, 10 and 18 MPa, stabilizes the pressure for 5 minutes, sets the first electric cable-controlled water injection packer 2 and the second electric cable-controlled water injection packer 4, and then slowly releases the pressure.

[0036] S4. Connect the electric steel pipe cable 1 to the ground control device 8 and supply power; connect the remote terminal system 9 to adjust the water volume of the intelligent water distributors in each floor.

[0037] When well washing is required, the remote terminal system 9 sends a command to the ground control device 8, and the electric steel pipe cable 1 controls the opening of the setting valves inside the first electric cable-controlled water injection packer 2 and the second electric cable-controlled water injection packer 4. The pressure inside the rubber sleeve is released to the tubing, the packer rubber sleeve retracts, and at the same time, the lower electric control valve 6 is opened to achieve high-volume well washing.

[0038] The water injection tubing primarily seals the water injection sections using packers. Each section is equipped with an electrically controlled intelligent water distributor, which distributes water to each section via the injection tubing. When water volume needs to be adjusted for each section, the remote terminal system 9 sends a command to the ground control device 8, which controls the first and second electrically controlled intelligent water distributors 3 and 5 via the electric steel pipe cable 1 to distribute water volume to each section according to the injection requirements. This method solves the problems of conventional injection techniques that rely on testing instruments for water volume adjustment and sealing verification at each level, resulting in high workload, low efficiency, and the inability to monitor water volume at each level in real time. It enables online measurement and control of water injection volume, significantly reducing labor intensity, improving work efficiency, and saving on testing and adjustment costs.

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An electrically controlled water injection string device, characterized in that, The system includes an electric steel pipe cable (1), a first electric cable-controlled water injection packer (2), a first electric cable-controlled intelligent water distributor (3), an electric control valve (6), a wellhead sealing device (7), a ground control device (8), and a remote terminal system (9). The first electric cable-controlled water injection packer (2) and the first electric cable-controlled intelligent water distributor (3) are installed on the water injection string. The electric control valve (6) is installed at the bottom of the water injection string. The wellhead sealing device (7) is installed at the wellhead. The first electric cable-controlled water injection packer (2), the first electric cable-controlled intelligent water distributor (3), and the electric control valve (6) are connected to the ground control device (8) and the remote terminal system (9) in sequence through the electric steel pipe cable (1) and the wellhead sealing device (7).

2. The electrically controlled water injection string device as described in claim 1, characterized in that, It also includes a second electric cable-controlled water injection packer (4), which is installed on the water injection string. The second electric cable-controlled water injection packer (4) is connected to the ground control device (8) and the remote terminal system (9) in sequence through the wellhead sealing device (7) via the electric steel pipe cable (1).

3. The electrically controlled water injection string device as described in claim 2, characterized in that, It also includes a second electric cable-controlled intelligent water distributor (5), which is installed on the water injection string. The second electric cable-controlled intelligent water distributor (5) is connected to the ground control device (8) and the remote terminal system (9) in sequence through the wellhead sealing device (7) via an electric steel pipe cable (1).

4. The electrically controlled water injection string device as described in claim 3, characterized in that, The first electric cable-controlled water-filled packer (2) and the second electric cable-controlled water-filled packer (4) adopt an expansion-type rubber tube electric control setting seal.

5. The electrically controlled water injection string device as described in claim 1, characterized in that, The electric control valve (6) cleans the well using both forward and reverse washing methods.

6. The electrically controlled water injection string device as described in claim 3, characterized in that, The first electrically controlled cable-operated water injection packer (2) and the second electrically controlled cable-operated water injection packer (4) are installed at the water injection layer section of the water injection string.

7. A control method for the electrically controlled water injection string device as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Using cable clamps, connect the electric control valve, cable-controlled intelligent water distributor, and electric cable-controlled water injection packer from bottom to top to form a whole-well control intelligent water injection string, and lower them to the designed positions in the well in sequence. S2. After the water injection string is in place, test whether the electrical signal is normal. If it is normal, complete the wellhead and seal the wellhead cable, and then connect the surface cable. S3. After verifying the tool depth, the cement truck pressurizes the cement at 5, 10, and 18 MPa, stabilizes the pressure for 5 minutes, sets the first electric cable-controlled water injection packer (2) and the second electric cable-controlled water injection packer (4) in place, and then slowly releases the pressure. S4. Connect the electric steel pipe cable (1) to the ground control device (8) and supply power; connect the remote terminal system (9) to adjust the water volume of the intelligent water distributors in each section.

8. The control method for the electrically controlled water injection tubing device as described in claim 7, characterized in that, When well washing is required, the remote terminal system (9) sends a command to the ground control device (8), and the electric steel pipe cable (1) controls the opening of the inner setting valve of the first electric cable-controlled water injection packer (2) and the second electric cable-controlled water injection packer (4), the pressure in the rubber sleeve is released to the oil pipe, the packer rubber sleeve retracts, and at the same time the lower electric control valve (6) is opened to achieve large-volume well washing.

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