A low-voltage intelligent control device based on downhole electric control layering residual liquid emptying and liquid sample collection

Abstract

The application belongs to the field of petroleum industry devices, and discloses a low-voltage intelligent control device for controlling layer-by-layer emptying of residual liquid and collecting liquid samples based on downhole electric control. The device is composed of a sampling module, an electric control module and a liquid discharge module. The device can quickly realize rapid discharge of residual liquid between two seals and rapid pressure drop between the two seals by controlling the opening of the liquid discharge channel on the ground. The device is of great significance for data collection in the initial stage of pressure buildup testing. Compared with the traditional electric control liquid discharge pump and electric control sampler, the device is simple to operate, and the safety performance and reliability are doubled.

Description

Technical Field

[0001] This invention belongs to the field of petroleum industry equipment, specifically relating to a low-voltage intelligent control device based on downhole electrical control for stratified drainage of residual liquid and collection of liquid samples. Background Technology

[0002] Collecting stratified fluid samples from oil wells is the most direct technical means to gain a detailed understanding of the reservoir and thus improve oil recovery. Currently, the pump discharge method or differential pressure method is commonly used in field operations to collect formation pressure data and fluid samples. The former is limited by the wellbore space size, and the discharge capacity of the downhole electrically controlled pump can never completely empty the annular residual fluid, so the pressure recovery data cannot be reduced to the initial pressure recovery stage, affecting the accuracy of pressure recovery test interpretation. The conventional differential pressure method can only collect wellbore fluid samples at the current depth. For oil wells with complex well conditions, well washing and well control operations are carried out before the operation, and the intrusion of foreign fluids seriously affects the purity of the true fluid sample. Therefore, this method cannot collect true formation fluid samples.

[0003] Patent CN217007265U discloses a liquid sampling and drainage device with a metering module. The device is used for sampling and draining liquid from a mobile sampling container, which has an inlet and a outlet. The device includes a frame, a lifting drive, a moving component, and a metering module. The frame has an inlet for allowing liquid samples to enter. The lifting drive is mounted on the frame and drives the moving component to move along its length. The moving component includes an integrated sampling component and a draining component. The sampling component connects the inlet and outlet. The draining component opens the outlet. The metering module is mounted on the sampling component and senses when the liquid level in the sampling container reaches a set position. This invention provides a liquid sampling and drainage device that can automatically sample, drain, and meter, solving the problem of inaccurate metering and frequent calibration required by existing samplers due to aging peristaltic pump tubing. However, the patent uses an integrated unit for sampling and drainage, which makes it impossible to control the device continuously and simultaneously. In addition, its overall structure is not suitable for downhole production and drainage. There is no device in the existing technology that can intelligently control downhole production and drainage. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a low-voltage intelligent control device for downhole electronically controlled stratified drainage of residual fluid and collection of liquid samples. Through the original design of this patented invention, it successfully solves the technical problem of rapidly establishing pressure differential at the downhole rapid stratified sampling site, driving the bottom hole pressure to recover, and collecting stratified real liquid samples. It is expected to become an important technical means for fine understanding of reservoirs in high water-cut old oilfields.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution: a low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual fluid and collection of fluid samples, comprising a sampling module, an electrical control module, and a drainage module, wherein:

[0006] The electrical control module is connected to the sampling end motor and the drain end motor via a control circuit. The sampling end motor is connected to a sampling end valve, which is connected to one end of the sampling channel. The other end of the sampling channel is connected to the sampling bottle of the sampling module. The sampling end valve is also connected to an inlet a. The drain end motor is connected to a drain end valve, which is connected to one end of the drain channel. The other end of the drain channel is connected to the storage tube of the drain module. The drain end valve is also connected to an inlet b.

[0007] Sampling module: includes sampling bottles for collecting samples;

[0008] Drainage module: includes a liquid storage pipe, which is used for liquid to flow in through the inlet b when drainage is required.

[0009] Furthermore, the sampling end valve column and the drain end valve column are surrounded by valve bodies.

[0010] Furthermore, the motor drive, sampling end motor and drain end motor are surrounded by cylinders.

[0011] Furthermore, the sampling bottle has an upper connector on its periphery.

[0012] Furthermore, a settling chamber is provided inside the liquid storage pipe.

[0013] Furthermore, the sampling end valve column is a cylinder that is thinner in the middle and thicker at both ends, with sampling end combination seals on both sides, and a sampling channel and liquid inlet a connected in the space between the middle and the valve body.

[0014] Furthermore, the drain valve stem is a cylinder that is thinner in the middle and thicker at both ends, with drain end combination seals on both sides, and a drain channel and inlet b connected in the space between the valve body and the middle.

[0015] Furthermore, the sampling bottle is equipped with a pressure gauge a, and the liquid storage tube is equipped with a pressure machine b.

[0016] Furthermore, the motor drive is also connected to a power supply cable.

[0017] Furthermore, the sampling bottle volume includes, but is not limited to, 300mL, 500mL, and 600mL.

[0018] Another object of the present invention is to protect the method of using the above-mentioned low-voltage intelligent control device based on downhole electronically controlled stratified drainage of residual fluid and collection of fluid samples, including the drainage process and the sampling process, wherein:

[0019] Drainage process:

[0020] The ground control system issues a command to open inlet b, which is transmitted through a cable to the motor drive. The motor drive executes the power supply command, controls the motor at the discharge end to rotate forward, and outputs torque to pull the combined seal at the discharge end open. At this time, the liquid in the well flows into the storage pipe through inlet b. The pressure gauge b can measure the pressure change in the storage pipe at any time. When it is consistent with the pressure in the wellbore, the storage pipe is considered to be full, reaching the calculated theoretical discharge capacity.

[0021] Sampling process:

[0022] The ground control system issues a command to open inlet a, which is transmitted through a cable to the motor drive. The motor drive executes the power supply command, controlling the sampling end motor to rotate forward. The output torque pulls the combined seal of the discharge end to open. At this time, the liquid in the well flows into the sampling bottle through inlet a. The sampling bottle adopts a one-way valve design. The liquid enters the sampling bottle under a certain pressure difference but cannot return. The pressure gauge a can measure the pressure change inside the sampling bottle at any time, and can determine whether the sampling bottle is full based on the pressure change.

[0023] The advantages of this invention compared to the prior art are:

[0024] (1) By controlling the opening of the drainage channel from the ground, the residual fluid between the two seals can be quickly discharged, and the pressure between the two seals can be quickly reduced. This is of great significance for data collection in the initial stage of pressure recovery testing.

[0025] (2) The volume of the liquid storage tube can be expanded. According to calculations, theoretically, emptying three times the liquid volume between the two seals is enough to collect real formation fluid samples, providing accurate and detailed formation fluid information for subsequent detailed understanding of the stratification.

[0026] (3) Pressure sensors are installed inside the liquid storage tube and the sampling tube, which can monitor the pressure changes during sample collection and liquid discharge in real time. The volume of discharged liquid and collected liquid can be calculated through calculation, thereby realizing quantitative monitoring of liquid discharge sampling.

[0027] (4) Compared with conventional downhole electrically controlled pumps, the device of the present invention adopts low voltage and low current control, which has lower requirements for the current and voltage carrying capacity of the circuit and hardware and software, and lower cost. In actual field operation, it reduces the risk to operators.

[0028] (5) The device of the present invention is easy to operate and has complete monitoring methods, and can directly judge the liquid collection and drainage status on the ground software. It can monitor various parameters such as temperature and pressure in real time.

[0029] (6) Compared with traditional electrically controlled liquid pumps and electrically controlled samplers, the operation is simple, and the safety performance and reliability are greatly improved. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] Figure 1 This is a schematic diagram of the low-voltage intelligent control device for bottom-hole electrical-controlled stratified drainage of residual liquid and collection of liquid samples, based on the present invention.

[0032] In the diagram: 1. Motor drive; 2. Sampling end motor; 3. Draining end motor; 4. Sampling end valve stem; 5. Sampling end combined seal; 6. Valve body; 7. Inlet a; 8. Sampling bottle; 9. Upper connector; 10. Pressure gauge a; 11. Sampling channel; 12. Draining end valve stem; 13. Draining end combined seal; 14. Inlet b; 15. Draining channel; 16. Settling chamber; 17. Pressure gauge b; 18. Storage pipe; 19. Cable; 20. Cylinder. Detailed Implementation

[0033] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially.

[0034] Example 1

[0035] The low-voltage intelligent control device for electrically controlled stratified drainage of residual fluid and collection of liquid samples involved in this invention is used in conjunction with an electrically controlled packer and is lowered into the target formation via a logging cable. The surface control system and the device of this invention communicate and are powered remotely via a CAN bus. During operation, the downhole packer is set by surface control, isolating the formation to be tested into an independent test unit. The fluid inlet channel of the drainage module of this device is activated. At the moment of opening, the liquid in the isolated formation can be instantly squeezed into the storage tube, causing the pressure between the two seals to drop rapidly. After the drainage device channel is closed by surface control, the formation pressure can be quickly restored, realizing the collection of pressure data. After the collection is completed, the sampling module of this invention is turned on. The pressure difference effect is used to collect the newly produced liquid from the formation into the sampling tube, realizing the collection of liquid samples.

[0036] The device of this invention consists of three parts: a sampling module, an electrical control module, and a drainage module. The sampling module is responsible for collecting liquid samples, the electrical control module is responsible for opening and closing the bidirectional switch, and the drainage module is responsible for emptying and settling the liquid in the sealed space. A ground control system can monitor various parameters of the device, including pressure changes, motor operating status, and temperature.

[0037] The sampling module includes a sampling bottle with an adjustable volume, including but not limited to 300mL, 500mL, and 600mL sizes to meet the needs of different testing projects. The sample inlet is controlled by a one-way valve; when the sampling channel is opened, the external pressure exceeds the internal pressure of the sample, allowing for rapid sample insertion and collection. Alternatively, an electrically controlled sampling bottle can be used, with an internal motor structure and a combination of an electronic switch and a one-way valve for pressure-maintaining sampling. The outer protective tube serves as a channel for storing the sample bottle. Theoretically, during sample collection, the pressure difference will compress the air inside the sample, preventing it from being fully filled. Therefore, the outer protective tube provides a certain amount of space for depressurization of the sample bottle.

[0038] The electronic control module consists of three parts: a motor, a valve body switch, a sampling (drainage channel), and a motor drive and control circuit. The motor is a permanent magnet synchronous motor, primarily providing power for sampling and opening the drainage channel. When the drainage channel is open, the right-side motor rotates, driving the right-side valve body axially to open and close the drainage channel. When the sampling channel is open, the left-side motor rotates, driving the left-side valve body axially to open and close the sampling channel. The valve body switch is a valve stem with a built-in bidirectional sealing ring. An inlet is designed between the drainage and sampling outlets and the internal overnight channel. When the channel is open, the valve stem with the bidirectional sealing ring moves away from the inlet; when closed, the valve stem with the bidirectional sealing ring completely covers the inlet, achieving complete closure of the inlet channel. The motor drive and control unit consists of two circuit boards: a motor drive unit and a motor control power supply. The motor drive unit can simultaneously convert 48VDC voltage to 48VDC, 10VDC, 5VDC, 3.3VDC, and 3.3VDC, respectively, providing power to the drive motor, stroke position monitoring unit, limit protection unit, microcontroller, and pressure acquisition unit. The motor control unit processes the analog signals from each electronic control unit through the microcontroller and exchanges data with the ground control system for real-time control. Motor status, stroke position changes, limit switches, current limits, and pressure acquisition data are 4-20mA analog signals, which are converted into digital signals by a digital-to-analog converter and the microcontroller before being sent to the ground.

[0039] The drainage module is structurally similar to the sampling module, consisting of a storage tube. When drainage is required on-site, the drainage channel switch is opened, and liquid flows into the storage tube through the inlet. According to calculations, the internal volume of the 5m long storage tube is three times the volume between the two seals. Therefore, the storage tube can be configured according to the on-site drainage requirements and the actual formation flow rate. Considering the on-site cable load-bearing capacity and ease of operation, a maximum of 15m of storage tube can be configured to meet the actual needs of on-site testing.

[0040] Example 2

[0041] The method of using the low-voltage intelligent control device for stratified drainage of residual fluid and collection of fluid samples based on downhole electrical control in Example 1 includes the drainage process and the sampling process, wherein:

[0042] Drainage process:

[0043] The ground control system issues a command to open the inlet b14, which is transmitted through cable 19 to motor drive 1. Motor drive 1 executes a power supply command, controlling the discharge end motor 3 to rotate forward. The output torque pulls the discharge end combined seal 5 open, at which point the liquid in the well flows into the storage pipe 18 through the inlet b14. The pressure gauge b17 can measure the pressure change in the storage pipe at any time. When the pressure is consistent with the pressure in the wellbore, the storage pipe 18 is considered to be full, reaching the calculated theoretical discharge capacity.

[0044] Sampling process:

[0045] The ground control system issues a command to open the inlet a7, which is transmitted through cable 19 to motor drive 1. Motor drive 1 executes the power supply command, controlling the sampling end motor 2 to rotate forward. The output torque pulls the drain end combined seal 13 open, and the liquid in the well flows into the sampling bottle 8 through the inlet a7. The sampling bottle 8 adopts a one-way valve design. The liquid enters the sample bottle under a certain pressure difference but cannot return. The pressure gauge a10 can measure the pressure change inside the sampling bottle 8 at any time, and can determine whether the sampling bottle 8 is full based on the pressure change.

[0046] Using the downhole electrically controlled rapid fluid drainage and sampling device of this invention in conjunction with an electrically controlled packer, commands can be sent via a surface control system to rapidly isolate the producing reservoir downhole, quickly completing the discharge of residual fluid in the wellbore and the collection of real formation fluid samples. In practical applications, the device can be quickly operated from the surface to drain residual fluid from the annulus between the two seals. Pressure data monitoring allows for real-time calculation of the discharged fluid volume. After drainage, the collection of real formation fluid samples can be quickly initiated. Internal pressure sensors and surface calculations allow for the calculation of the sample volume inside the sample bottle, providing accurate information about the formation fluid for a detailed understanding of the reservoir. Furthermore, the device employs a 48VDC low-voltage drive and low-current control, significantly improving the safety of on-site operation and demonstrating broad application prospects.

[0047] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible embodiments of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual fluid and collection of fluid samples, characterized in that, It consists of three parts: a sampling module, an electronic control module, and a drainage module. Electrical control module: The motor drive (1) is connected to the sampling end motor (2) and the drain end motor (3) through the control circuit. The sampling end motor (2) is connected to the sampling end valve column (4). The sampling end valve column (4) is connected to one end of the sampling channel (11). The other end of the sampling channel (11) is connected to the sampling bottle (8) of the sampling module. The sampling end valve column (4) is also connected to the inlet a (7). The drain end motor (3) is connected to the drain end valve column (12). The drain end valve column (12) is connected to one end of the drain channel (15). The other end of the drain channel (15) is connected to the liquid storage tube (18) of the drain module. The drain end valve column (12) is also connected to the inlet b (14). Sampling module: includes sampling bottles (8) for collecting samples; Drainage module: includes a liquid storage pipe (18), which is used for liquid to flow in through the liquid inlet b (14) when drainage is required.

2. The low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual liquid and collection of liquid samples as described in claim 1, characterized in that, The sampling end valve column (4) and the drain end valve column (12) are surrounded by valve bodies (6).

3. The low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual fluid and collection of fluid samples as described in claim 1, characterized in that, The motor drive (1), sampling end motor (2) and drain end motor (3) are surrounded by a cylinder (20).

4. The low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual fluid and collection of fluid samples as described in claim 1, characterized in that, The sampling bottle (8) has an upper connector (9) on its periphery.

5. The low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual liquid and collection of liquid samples as described in claim 1, characterized in that, The liquid storage tube (18) is equipped with a settling chamber (16).

6. The low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual liquid and collection of liquid samples according to claim 1, characterized in that, The sampling end valve column (4) is a cylinder that is thinner in the middle and thicker at both ends, with sampling end combination seals (5) on both sides, and the sampling channel (11) and the liquid inlet a (7) are connected in the space between the middle and the valve body (6); the drain end valve column (12) is a cylinder that is thinner in the middle and thicker at both ends, with drain end combination seals () on both sides, and the drain channel (15) and the liquid inlet b (14) are connected in the space between the middle and the valve body (6).

7. The low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual liquid and collection of liquid samples according to claim 1, characterized in that, The sampling bottle (8) is equipped with a pressure gauge a (10), and the liquid storage tube (18) is equipped with a pressure machine b (17).

8. The low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual fluid and collection of fluid samples according to claim 1, characterized in that, The motor drive (1) is also connected to a power supply cable (19).

9. The low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual fluid and collection of fluid samples according to claim 1, characterized in that, The volume of the sampling bottle (8) includes, but is not limited to, 300mL, 500mL, and 600mL.

10. The method of using the low-voltage intelligent control device for downhole electrically controlled stratified drainage of residual fluid and collection of fluid samples as described in claim 1, characterized in that, This includes the drainage process and the sampling process, among which: Drainage process: The ground control system sends a command to open the inlet b (14), which is transmitted to the motor drive (1) via the cable (19). The motor drive (1) executes the power supply command, controls the motor (3) at the discharge end to rotate forward, and outputs torque to pull the combined seal (5) at the discharge end to open. At this time, the liquid in the well flows into the storage pipe (18) through the inlet b (14). The pressure gauge b (17) can measure the pressure change in the storage pipe at any time. When it is consistent with the pressure in the well, the storage pipe (18) is considered to be full, reaching the calculated theoretical discharge capacity. Sampling process: The ground control system sends a command to open the inlet a (7), which is transmitted to the motor drive (1) via the cable (19). The motor drive (1) executes the power supply command, controls the sampling end motor (2) to rotate forward, and outputs torque to pull the drain end combined seal (13) open. At this time, the liquid in the well flows into the sampling bottle (8) through the inlet a (7). The sampling bottle (8) adopts a single-flow valve design. The liquid enters the sample bottle under a certain pressure difference, but cannot return. The pressure gauge a (10) can measure the pressure change in the sampling bottle (8) at any time, and can determine whether the sampling bottle (8) is full based on the pressure change.

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