Sticky card early warning method based on uniform distribution sensing principle

Abstract

This invention discloses a sticking warning method based on the principle of uniformly distributed sensing, comprising the following steps: Step S1, setting up the logging instrument sub; uniformly arranging resistance sensors on the surface of the instrument sub at 360 degrees; Step S2, when the instrument sub is immersed in the mud cake, the change in water content of the medium on the surface of the resistance sensor causes a continuous change in the output of the resistance sensor at the corresponding position, obtaining the number of resistance sensors immersed in the mud cake and the degree of immersion of the immersion sub; Step S3, calculating the area of ​​the immersion sub in the mud cake to provide data support for the sticking resistance of the instrument; This invention distributes resistance sensors on the measuring sub, and displays the sticking situation in real time through the resistance relative change rate display graph transmitted from the upper computer warning interaction interface; it can not only display the sticking situation, but also obtain the size of the sticking area, making subsequent unsticking more convenient and efficient; it greatly reduces the time cost of the instrument being unable to continue working due to sticking, enabling logging work to continue efficiently.

Description

Technical Field

[0001] This invention belongs to the field of precision instrument sensing and measurement, and particularly relates to a method for early warning of sticky cards based on the principle of uniformly distributed sensing. Background Technology

[0002] In recent years, with the continuous increase in offshore logging operations, the phenomenon of logging instruments sticking in the well has become commonplace. Especially in open-hole wells with complex conditions, the probability of instruments sticking increases exponentially. Every year, a lot of operating time is spent dealing with such incidents, which greatly increases the operating costs.

[0003] To obtain downhole pressure distribution, logging instruments typically require pressure sensors to measure the liquid column. However, during the instrument sticking process, the logging sub comes into direct contact with the mud cake and mud, and the medium on the pressure sensor's measuring surface gradually changes from liquid to solid. Currently available sensors cannot simultaneously meet both measurement requirements.

[0004] To reduce the risks of well logging operations, it is necessary to conduct an in-depth analysis of the causes of cable logging instrument sticking and explore the mechanism of cable logging instrument sticking. Based on this, it is necessary to develop a downhole sticking early warning device for cable logging instruments to provide effective information support for on-site construction personnel, prevent instrument sticking from the root cause, thereby improving operation efficiency and reducing production costs.

[0005] To overcome the shortcomings of the existing technology, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a method for online acquisition of the surface resistance distribution of experimental sections, directly measuring the state of the instrument section's intrusion into the mud cake, indirectly obtaining the contact area between the mud cake and the experimental section, and finally calculating the instrument's sticking resistance using liquid column pressure, thus realizing a sticking warning method based on the principle of uniformly distributed sensing.

[0007] To achieve the objective of this invention, the technical solution provided by this invention is as follows: A method for early warning of card sticking based on the principle of uniformly distributed sensing includes the following steps: Step S1, setting the logging instrument sub; Under hydraulic pressure, the resistance of logging instruments sticking to the mud cake is determined by the coefficient of friction between the mud cake and the instrument, expressed as: (1.1) in: f The coefficient of friction, P This refers to the liquid column pressure. S This refers to the contact area between the instrument section and the mud. Resistance sensors are evenly arranged on the surface of the instrument's short section at 360 degrees. The resistance sensor consists of two copper core sections whose end faces are in contact with the downhole medium to measure the medium resistance; the copper core surface is treated with potting compound to achieve insulation and sealing; the other end of the copper core is connected to a wire to transmit the signal for measuring the contents of the short section; and finally, the signal is processed by a digital processor to obtain the resistance distribution on the surface of the short section. Several temperature sensors and liquid column pressure sensors are installed in the first and last rows at both ends of the short section to obtain downhole environmental parameters, which are used to help determine the sticking status of the instrument and provide real-time feedback on the sticking status. Step S2: When the instrument section is immersed into the mud cake, the change in the water content of the medium on the surface of the resistance sensor causes a continuous change in the output of the resistance sensor at the corresponding position, thus obtaining the number of resistance sensors immersed in the mud cake and the degree of immersion of the immersion section. When the resistance sensor is covered by mud cake, the original mud on the electrode surface slowly turns into solid due to the loss of water, which leads to an increase in resistivity. The detection circuit detects the continuous change in resistance between the electrodes of the resistance sensor and displays it on the host computer. The specific design method for the detection circuit is as follows: The detection circuit includes the following functional modules: Resistor voltage divider circuit, Rd The preset voltage divider resistors, Rc To measure the mud resistance, the DSP controls the DAC to output a gradually varying voltage from 0 to 15V, which is then compared with the voltage output by a comparator. Rd and Rc The partial voltage value ( u 1 、u 2 …u n Compare to obtain the logic level ( S 1 、S 2 …S n When the logic level changes, record the current voltage divider value. u c ), and according to the preset settings Rd Calculate the resistance of mud or mud cake Rc ; The filter circuit, consisting of resistors and capacitors, forms a first-order low-pass filter to suppress measurement noise. The filter circuit is set in the measured mud resistance. Rc Between comparators; The multi-purpose detection circuit uses a DSP to control the DAC output voltage, which gradually changes from 0 to 15V. This voltage can be called the scanning voltage. The scanning voltage continuously changes between 0 and 15V to detect changes in the output level of different comparators and update the resistance measurement value in real time. Analog switch MUX module; The comparator's output enters the MUX module, which scans and switches in the module via the DSP's address bus to transfer data to the DSP. Design a CAN bus transceiver circuit to communicate with the host computer via the bus. Step S3: Calculate the area of ​​the intrusion mud cake of the logging sub to provide data support for the instrument sticking resistance; The specific calculation is as follows: the area occupied by each sensor on the cylindrical surface of the equally divided measurement section is denoted as S. 均 Then the resistance experienced by a sensor is: (1.2) in P 1 S is the pressure measured by the sensor. 均 This represents the area evenly divided by the sensor on the measuring segment. f 1 Let be the coefficient of friction over this area.

[0008] Then, the resistance of all sensors is summed to obtain the sticking resistance: (1.3) n represents the number of sensors.

[0009] A further preferred technical solution provided by the present invention is: It also includes step S4, an intelligent card-sticking warning application based on a BP neural network; By utilizing a BP neural network algorithm in conjunction with matched downhole pressure, temperature, and resistance sensors for data monitoring and intelligent early warning, the obtained pressure, resistance, and temperature values ​​are continuously trained and reinforced. Environmental data analysis is stored in the connection weights of neurons to further improve the accuracy of sticking warnings.

[0010] Another preferred technical solution provided by the present invention is: In step S2, the continuous change in resistance between the electrodes of the resistance sensor is detected by the detection circuit and displayed on the host computer. Specifically, this process involves designing a host computer-based early warning interactive interface, including: After the digital processor inside the short section measures the resistance, it periodically uploads the resistance data to the host computer via the CAN bus at a baud rate of 5Mbps / S. The software on the host computer then calculates and evaluates the sticking condition. Step S21, resistance measurement; When the card sticking warning function is enabled, the resistance value Rc0 of each measurement point at the current moment is calculated in the DSP. Step S22, normalize the resistance value; The resistivity of mud and mud cake varies under different geological environments and logging depths. To enhance the environmental adaptability of the measurement sub, the initial resistance value at the time of measurement can be used. R c0 A normalized design is performed, therefore the rate of change of resistance is defined. η = R c / R c0 ,in R c Real-time updates R c = R c0 +Δ R ΔR represents the measured resistance change; Step S23, Measurement of relative rate of change of resistance; By combining the resistance normalization method in step S22, the resistance change at each measurement point can be evaluated and sent to the host computer; the rate of resistance change can also be measured in real time to indicate the downhole condition. Step S24, the host computer displays the information; The real-time resistance value is displayed using color units of different depths, reflecting the working status of the downhole instrument.

[0011] The beneficial effects of this invention are: Existing technologies only detect instrument sticking during re-drilling, failing to monitor for sticking incidents in real time. This invention proposes a real-time, efficient instrument sticking early warning scheme. Resistance sensors are distributed on the measuring sub, and the sticking status is displayed in real time via a resistance relative change rate display graph transmitted through a host computer's early warning interface. This not only displays the sticking status but also obtains the area of ​​sticking, making subsequent unsticking easier and more efficient. It significantly reduces the time cost of instrument downtime due to sticking, allowing logging operations to continue continuously and efficiently. This invention is primarily applicable to scenarios where sticking is likely to occur during downhole mining, providing valuable assistance for rapid logging. Attached Figure Description

[0012] Figure 1 This is a schematic diagram showing the distribution of the surface resistance sensor for measuring the short section of the present invention; Figure 2 This is a schematic diagram illustrating the sticky card warning principle of the present invention; Figure 3 This is a schematic diagram of the resistance sensor of the present invention; Figure 4 This is a schematic diagram of the instrument's adhesive card measurement circuit design according to the present invention; Figure 5 This is a schematic diagram of the CAN bus communication scheme of the present invention; Figure 6 This is a schematic diagram of the upper computer early warning interaction interface design scheme of the present invention; Figure 7 This is a diagram of the intelligent monitoring and early warning framework of the present invention; Figure 8 This is a schematic diagram of the intelligent card-sticking early warning framework of the present invention. Detailed Implementation

[0013] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0014] To obtain downhole pressure distribution, logging instruments typically require pressure sensors to measure the liquid column. However, during the sticking process, the logging sub comes into direct contact with both the mud cake and the mud slurry, and the medium on the pressure sensor's measuring surface gradually changes from liquid to solid. Currently available sensors cannot simultaneously meet both measurement requirements. Considering the differences in resistance between the mud column, mud cake, and their different depths, this solution employs online acquisition of the surface resistance distribution of the experimental sub. This directly measures the sub's intrusion into the mud cake and indirectly obtains the contact area between the mud cake and the experimental sub. Finally, the sticking resistance is calculated using the liquid column pressure to achieve early warning of sticking. The specific solution is as follows: A method for early warning of card sticking based on the principle of uniformly distributed sensing includes the following steps: Step S1, setting the logging instrument sub; Under liquid column pressure, the resistance to sticking to the instrument is determined by the coefficient of friction between the mud cake and the instrument, which can be expressed by a simplified formula as follows: (1.1) in: f The coefficient of friction, P This refers to the liquid column pressure. S This refers to the contact area between the instrument section and the mud.

[0015] According to formula (1), one of the key physical quantities for obtaining the sticking resistance is the contact area between the short section and the mud cake, such as Figure 1 As shown in the figure, in this scheme, self-developed resistance sensors are uniformly arranged on the surface of the instrument sub section at 360 degrees. When part of the experimental sub section invades the mud cake, the water content of the medium on the surface of the resistance sensor changes, causing the output of the resistance sensor at the corresponding position to change continuously. The number of resistance sensors invading the mud cake and the degree of invasion of the sub section can be obtained, thereby estimating the area of ​​the mud cake invading the logging sub section and providing data support for the instrument sticking resistance.

[0016] The resistivity of a logging instrument surface is determined by the water content of its surface medium. Therefore, in this scheme, the following method is adopted: Figure 3 The resistance measurement method shown involves contacting the end faces of two copper core sections with the downhole medium to measure its resistance. The copper core surfaces are potted to achieve insulation and sealing. A wire is connected to the other end of the copper core to transmit the signal for measuring the short section's resistance. Finally, a digital processor processes this signal to obtain the resistance distribution on the short section's surface.

[0017] The main steps for determining the water content of a surface medium using an experimental method with a resistance sensor are as follows: (1) Obtain the required mud cake for the experiment using a filtration apparatus; (2). By using the designed sensor to simulate downhole conditions by changing the depth of the embedded mud cake, the resistance value at different depths can be measured. Based on the resistance value, the water content of the medium can be roughly reflected.

[0018] When the resistance sensor is covered by mud cake, the original mud on the electrode surface gradually solidifies due to water loss, causing an increase in resistivity. This continuous change in resistivity can be measured by the resistance sensor and displayed on the host computer. The determination of resistance is made by observing the significant changes in resistance measured by the resistance sensor. Figure 2 In this method, the approximate area of ​​the mud cake is estimated based on the area of ​​a resistive sensor.

[0019] In addition, several temperature sensors and liquid column pressure sensors are installed at the first and last rows at both ends of the experimental sub to acquire downhole environmental parameters, which can help determine the instrument sticking condition, such as... Figure 2 As shown, it provides real-time feedback on the sticking status of the card.

[0020] Step S2: When the instrument section is immersed into the mud cake, the change in the water content of the medium on the surface of the resistance sensor causes a continuous change in the output of the resistance sensor at the corresponding position, thus obtaining the number of resistance sensors immersed in the mud cake and the degree of immersion of the immersion section. When the resistance sensor is covered by mud cake, the original mud on the electrode surface slowly turns into solid due to the loss of water, which leads to an increase in resistivity. The detection circuit detects the continuous change in resistance between the electrodes of the resistance sensor and displays it on the host computer. The specific design method for the detection circuit is as follows: As mentioned above, the surface of the experimental section is covered with a large number of resistance sensors, which places high demands on the number of analog-to-digital conversion channels of the digital processor. To reduce costs and simplify circuit configuration, such as Figure 4 As shown, the proposed design scheme uses a combination of multiplexers and comparators.

[0021] The detection circuit is divided into the following functional modules: (1) Resistor voltage divider circuit like Figure 4 middle Rd The preset voltage divider resistors, Rc To measure the mud resistance, the DSP controls the DAC to output a gradually varying voltage from 0 to 15V, which is then compared with... Rd and Rc The partial voltage value ( u 1 、u 2 …u n The logic level is obtained by comparison. S 1 、 S 2 …S n When the logic level changes, record the current voltage divider value. u c ), and according to the preset settings Rd Calculate the resistance of mud or mud cake Rc .

[0022] (2) Filtering circuit

[0023] Resistors and capacitors form a first-order low-pass filter to suppress measurement noise.

[0024] (3) Multiplexing detection circuit

[0025] The DSP controls the DAC output voltage, which gradually changes from 0 to 15V. This voltage can be called the scanning voltage. The voltage continuously changes between 0 and 15V to detect changes in the output level of different comparators and update the resistance measurement value in real time.

[0026] (4) Analog switch MUX module

[0027] The comparator's output enters the MUX module, which scans and switches in the module via the DSP's address bus to transmit data to the DSP.

[0028] (5) Communication circuit

[0029] Design a CAN bus transceiver circuit to communicate with a host computer via the bus.

[0030] In step S2, the continuous change in resistance between the electrodes of the resistance sensor is detected by the detection circuit and displayed on the host computer. Specifically, this process involves designing a host computer-based early warning interactive interface, including: After the digital processor inside the experimental section measures the resistance, it periodically uploads the resistance data to the host computer via the CAN bus at a baud rate of 5 Mbps / S. The software on the host computer then calculates and evaluates the card sticking condition.

[0031] like Figure 6 As shown, in this scheme, the surface resistance measurement and display process of the experimental short section is divided into the following four parts: Step S21, resistance measurement; like Figure 3 When the card sticking warning function is enabled, the resistance value of each measurement point at the current moment is calculated in the DSP. R c0 ; Step S22, normalize the resistance value; The resistivity of mud and mud cake varies under different geological environments and logging depths. To enhance the environmental adaptability of the measurement sub, the initial resistance value at the time of measurement can be used. R c0 A normalized design is performed, therefore the rate of change of resistance is defined. η = R c / R c0 ,in R c Real-time updates R c = R c0 +Δ R ΔR represents the measured resistance change; Step S23, Measurement of relative rate of change of resistance; By combining the resistance normalization method in step S22, the resistance change at each measurement point can be evaluated and sent to the host computer; the rate of resistance change can also be measured in real time to indicate the downhole condition. Step S24, the host computer displays the information; The real-time resistance is displayed using color units of different depths, reflecting the working status of the downhole instruments and providing effective guidance for on-site personnel. In addition, the above information can be used to estimate the area of ​​the mud cake that the instrument has invaded. For example, in the first display scheme, the blackened area can be identified as being invaded by mud cake. The area of ​​the mud cake can be roughly estimated based on the size of these sensors and the distribution spacing of the sensors on the measuring sub. Combined with the bottom hole pressure calculated using the liquid column depth, the resistance of sticking can be assessed. Step S3: Calculate the area of ​​the intrusion mud cake of the logging sub to provide data support for the instrument sticking resistance; The specific calculation is as follows: the area occupied by each sensor on the cylindrical surface of the equally divided measurement section is denoted as S. 均Furthermore, the pressure and friction coefficient of each sensor surface are theoretically different, and the relationship between the measured resistance and pressure needs to be further obtained through experiments. Therefore, the resistance experienced by a single sensor is: (1.2) in P 1 S is the pressure measured by the sensor. 均 This represents the area evenly divided by the sensor on the measuring segment. f 1 Let be the coefficient of friction over this area.

[0032] Then, the resistance of all sensors is summed to obtain the sticking resistance: (1.3) Step S4, Intelligent Sticky Card Early Warning Application Based on BP Neural Network; Finally, as Figure 7 As shown in the intelligent monitoring and early warning framework diagram, this invention utilizes a BP neural network algorithm with matched downhole pressure sensors, temperature sensors, and resistance sensors for data monitoring and intelligent early warning. The obtained pressure, resistance, and temperature values ​​are continuously trained and reinforced, and environmental data analysis is stored in the connection weights of neurons, which can further improve the accuracy of sticking warning.

[0033] Downhole environments are often characterized by high temperatures and pressures, making drilling tools prone to sticking and adhesion during prolonged operation. In many cases, the problem is only discovered after prolonged sticking, leading to time-consuming and costly attempts to unstick the equipment. With the continuous development and advancement of artificial intelligence algorithms, applications based on backpropagation (BP) neural networks are widespread, and this approach offers significant advantages in processing large amounts of data. For example... Figure 8 As shown, the sensors on the experimental sub can acquire a large amount of downhole environmental data, such as pressure, temperature, temperature change rate, resistance, resistance change rate, and resistance characteristic values. By using a neural network to train on this data and continuously reinforce learning, the connections between neurons become stronger, thereby enabling predictive analysis of subsequent data. Because the BP neural network has good fault tolerance, even if a few data points are abnormal, the neural network will not issue an early warning. Only when a large number of abnormal data points exceed a certain threshold will the system issue an early warning, allowing for faster and more efficient detection and removal of stuck metal, reducing losses caused by stuck metal.

[0034] The described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for early warning of card sticking based on the principle of uniformly distributed sensing, characterized in that: Includes the following steps, Step S1, setting the logging instrument sub; Under hydraulic pressure, the resistance of logging instruments sticking to the mud cake is determined by the coefficient of friction between the mud cake and the instrument, expressed as: (1.1) in: f The coefficient of friction, P This refers to the liquid column pressure. S This refers to the contact area between the instrument section and the mud. Resistance sensors are evenly arranged on the surface of the instrument's short section at 360 degrees. The resistance sensor consists of two copper core sections whose end faces are in contact with the downhole medium to measure the medium resistance; the copper core surface is treated with potting compound to achieve insulation and sealing; the other end of the copper core is connected to a wire to transmit the signal for measuring the contents of the short section; and finally, the signal is processed by a digital processor to obtain the resistance distribution on the surface of the short section. Several temperature sensors and liquid column pressure sensors are installed in the first and last rows at both ends of the short section to obtain downhole environmental parameters, which are used to help determine the sticking status of the instrument and provide real-time feedback on the sticking status. Step S2: When the instrument section is immersed into the mud cake, the change in the water content of the medium on the surface of the resistance sensor causes a continuous change in the output of the resistance sensor at the corresponding position, thus obtaining the number of resistance sensors immersed in the mud cake and the degree of immersion of the immersion section. When the resistance sensor is covered by mud cake, the original mud on the electrode surface slowly turns into solid due to the loss of water, which leads to an increase in resistivity. The detection circuit detects the continuous change in resistance between the electrodes of the resistance sensor and displays it on the host computer. The specific design method for the detection circuit is as follows: The detection circuit includes the following functional modules: Resistor voltage divider circuit, Rd The preset voltage divider resistors, Rc To measure the mud resistance, the DSP controls the DAC to output a gradually varying voltage from 0 to 15V, which is then compared with the voltage output by a comparator. Rd and Rc The partial voltage value ( u 1 、u 2 …u n Compare to obtain the logic level ( S 1 、S 2 …S n When the logic level changes, record the current voltage divider value. u c ), and according to the preset settings Rd Calculate the resistance of mud or mud cake Rc ; The filter circuit, consisting of resistors and capacitors, forms a first-order low-pass filter to suppress measurement noise. The filter circuit is set in the measured mud resistance. Rc Between comparators; The multi-purpose detection circuit uses a DSP to control the DAC output voltage, which gradually changes from 0 to 15V. This voltage is called the scanning voltage. The scanning voltage continuously changes between 0 and 15V to detect changes in the output level of different comparators and update the resistance measurement value in real time. Analog switch MUX module; The comparator's output enters the MUX module, which scans and switches in the module via the DSP's address bus to transfer data to the DSP. Design a CAN bus transceiver circuit to communicate with the host computer via the bus. Step S3: Calculate the area of ​​the intrusion mud cake of the logging sub to provide data support for the instrument sticking resistance; The specific calculation is as follows: the area occupied by each sensor on the cylindrical surface of the equally divided measurement section is denoted as S. 均 Then the resistance experienced by a sensor is: (1.2) in P 1 S is the pressure measured by the sensor. 均 This represents the area evenly divided by the sensor on the measuring segment. f 1 Let be the coefficient of friction over this area; Then, the resistance of all sensors is summed to obtain the sticking resistance: (1.3) n represents the number of sensors.

2. The method for early warning of card sticking based on the principle of uniformly distributed sensing according to claim 1, characterized in that: It also includes step S4, an intelligent card-sticking warning application based on a BP neural network; By utilizing a BP neural network algorithm in conjunction with matched downhole pressure, temperature, and resistance sensors for data monitoring and intelligent early warning, the obtained pressure, resistance, and temperature values ​​are continuously trained and reinforced. Environmental data analysis is stored in the connection weights of neurons to further improve the accuracy of sticking warnings.

3. The method for early warning of card sticking based on the principle of uniformly distributed sensing according to claim 1, characterized in that: In step S2, the continuous change in resistance between the electrodes of the resistance sensor is detected by the detection circuit and displayed on the host computer. Specifically, this process involves designing a host computer-based early warning interactive interface, including: After the digital processor inside the short section measures the resistance, it periodically uploads the resistance data to the host computer via the CAN bus at a baud rate of 5Mbps / S. The software on the host computer then calculates and evaluates the sticking condition. Step S21, resistance measurement; When the card sticking warning function is enabled, the resistance value Rc0 of each measurement point at the current moment is calculated in the DSP. Step S22, normalize the resistance value; The resistivity of mud and mud cake varies under different geological environments and logging depths. To enhance the environmental adaptability of the measurement sub, the initial resistance value during measurement is used. R c0 A normalized design is performed, therefore the rate of change of resistance is defined. η = R c / R c0 ,in R c Real-time updates R c = R c0 +Δ R ΔR represents the measured resistance change; Step S23, Measurement of relative rate of change of resistance; By combining the resistance normalization method in step S22, the resistance change at each measurement point can be evaluated and sent to the host computer; the rate of resistance change is measured in real time to indicate the downhole condition. Step S24, the host computer displays the information; The real-time resistance value is displayed using color units of different depths, reflecting the working status of the downhole instrument.

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