CN102902294A - Method and system for full-automatic intelligent program-control power supply of subsurface instrument in well logging system - Google Patents

Abstract

The invention relates to a method for full-automatic intelligent program-control power supply of a subsurface instrument in a well logging system. The method includes the following steps: a) setting a target value of power supply for the subsurface instrument; b) setting a partial voltage correction coefficient of a transformer; c) subtracting voltage measuring feedback value of a subsurface cable head with the target value of power supply for the instrument to obtain a difference value, multiplying the difference value with the partial voltage correction coefficient of the transformer, and obtaining a control variable for controlling the output of program-control alternating voltage; d) repeating the step c) again and again, judging each time whether the voltage measuring feedback value of the subsurface cable head is within an expected value range or not during continuous repeating, and if so, stopping the repeating; and e) waiting for a certain amount of time, and performing the step c) again to obtain a required value of the voltage of the subsurface cable head within a certain tolerance range. The invention further relates to a system for implementing the method.

Description

Fully automatic intelligent program-controlled power supply method and system for downhole instruments of logging system

technical field

The invention relates to a method for supplying power for fully automatic intelligent program control of downhole instruments in a geophysical logging system, and a system for supplying power for fully automatic intelligent program control of downhole instruments in the geophysical well logging system.

Background technique

Well logging, also known as geophysical well logging or petroleum well logging, referred to as well logging, is a method of measuring geophysical parameters using the electrochemical properties, electrical conductivity, acoustic properties, radioactivity and other geophysical properties of rock formations, which belongs to applied geophysical methods one. During oil drilling, well logging must be carried out after drilling to the designed well depth, also known as well completion logging, to obtain various petroleum geology and engineering technical data, that is, oil layer depth, thickness and other information, as a basis for completion and development of oil fields. source material.

The logging system is mainly divided into two parts: the surface system and the downhole instrument. The two are connected by a 7-core armored cable. Both the surface system and the cable are installed on the logging engineering vehicle. Pull the downhole instrument and supply power to the downhole instrument through the cable, and at the same time realize the data communication between the surface and the downhole.

Foreign logging technology mainly focuses on imaging logging, with highly integrated fast logging platform system as the frontier. The next-generation logging system currently being developed is characterized by high-speed transmission, complete openness, and high-precision imaging instruments, focusing on all directions. For the measurement and evaluation of heterogeneous, low-resistance and other complex oil and gas reservoirs, we are vigorously developing logging-while-drilling tools, harsh-environment logging tools, and through-casing tools to meet the needs of horizontal well drilling, ultra-deep well drilling, and re-evaluation of old wells. Well technology, focusing on solving the problem of nuclear well logging relying on chemical sources that are harmful to the environment. Focus on technologies such as multi-dimensional information measurement, microscopic petrophysical parameter measurement, downhole direct sampling and analysis, etc., and attach importance to multidisciplinary comprehensive oil and gas reservoir evaluation. The software system integrating collection, interpretation and operation support is being vigorously developed.

At present, the method of powering up the downhole instrument of the logging system is the traditional manual powering up method. The conventional well logging system uses the power input to the step-up transformer, then to the voltage regulating transformer, and finally output to the logging cable. When the power is turned on, the voltage regulating transformer is manually adjusted, and the output voltage is controlled by the engineer to control the voltage of the cable head of the downhole instrument to power up the instrument.

Therefore, the manual power-on method adopts manual adjustment of the voltage regulating transformer knob. During the operation, the operating engineer should keep a close eye on the detection window and adjust slowly. The speed of power-on and the accuracy of the cable head voltage of the downhole instrument depend on the operating engineer. The level of proficiency requires long-term training and on-site operation, and it is easy to cause damage to the instrument due to misoperation.

Contents of the invention

Therefore, the task of the present invention is to provide a method and system for fully automatic intelligent program-controlled power supply for downhole instruments of the logging system, so as to improve the reliability of equipment use, simplify the operation difficulty of operating engineers, shorten training time, and reduce the possibility of misoperation ,Increase productivity.

The present invention is achieved through the following technical solutions.

According to the first aspect of the present invention, there is provided a method for fully automatic intelligent program-controlled power supply for downhole instruments of a logging system, the method comprising the following steps:

a) Set the target value of downhole instrument power supply;

b) Set the transformer voltage division correction coefficient;

c) Calculate the difference between the downhole cable head voltage measurement feedback value and the target value of the instrument power supply, and multiply the difference by the transformer voltage division correction coefficient, so as to obtain a control quantity used to control the output of the programmed AC voltage;

d) Step c) is repeated for continuous circulation. In the process of continuous circulation, each time it is judged whether the feedback value of the downhole cable head voltage measurement is within the expected value range, and if so, the circulation is stopped;

e) Wait for a certain period of time, and execute step c) again to obtain the required value of the downhole cable head voltage within the determined tolerance range.

According to another preferred embodiment, the voltage increment and the total number of steps for each adjustment are different according to different cable lengths and load conditions.

According to another preferred embodiment, the target value of the power supply of the downhole instrument is set to 250v.

According to another preferred example, in step a) of the method, before the power is turned off, the feedback value of the downhole cable head measurement is set to zero.

According to another preferred embodiment, the expected value range is 250VAC±5%.

According to yet another embodiment, the transformer voltage division correction coefficient is set to 1/3.

According to yet another embodiment, the tolerance range is ±5%, so that the downhole cable head voltage power supply requirement of 250VAC±5% can be finally met.

In addition, according to another aspect of the present invention, there is provided a system for fully automatic intelligent program-controlled power supply for downhole instruments of the logging system, the system includes a program-controlled AC power supply, and the program-controlled AC power supply is set to The control quantity outputs a corresponding power supply voltage, and a control box, the control box includes a casing, a step-up transformer and a central processing unit arranged in the casing, wherein the programmable AC power supply is connected to the step-up The input end of the transformer, the central control unit is connected with the programmable AC power supply through the serial interface to control the voltage of the programmable AC power supply, so that the voltage of the downhole instrument cable head reaches its required value.

According to an embodiment of the present invention, the transformer voltage division correction coefficient is related to the step-up transformer in the control box. Preferably, the voltage division correction coefficient of the transformer is 1/3.

According to another embodiment of the present invention, the required value of the cable head voltage of the downhole instrument is 250VAC±5%.

The modern control methods include PID control, PI control, P control or closed-loop regulation systems.

According to another embodiment of the present invention, the power supply of the downhole instrument of the logging system of the present invention is adjusted by the proportional factor P. The proportional factor adjustment is adopted, which is combined with the characteristics of the downhole instrument power supply of the logging system. The adopted control method can be adjusted quickly and accurately without overshoot. Finally, there is a confirmation adjustment, which can ensure the power supply voltage when the load changes slightly after the instrument is started. accurate.

Therefore, the fully automatic intelligent program-controlled power supply method runs in the CPU in the control box. Through advanced modern control methods, such as PID adjustment and closed-loop adjustment, the program-controlled AC power supply is controlled to meet the cable head voltage requirements of downhole instruments. The method of fully automatic intelligent program-controlled power supply for the downhole instrument of the well logging system is a new power supply method for the downhole instrument of the well logging system, which is different from the traditional manual power supply method. According to the method of the present invention for fully automatic intelligent program-controlled power supply of downhole instruments in the logging system, the program-controlled function of the program-controlled AC power supply is used, combined with the characteristics of the system, modern control methods such as PID adjustment are adopted, and the closed-loop feedback control is automatically calculated by the microcomputer. Execute, supply power to downhole instruments, and control cable head voltage. The fully automatic intelligent program-controlled power supply method does not require manual adjustment, and all adopt automatic control. It has the characteristics of accurate power supply voltage, fast speed, and automatic protection function.

According to the method of the present invention for fully automatic intelligent program-controlled power supply for downhole instruments of the logging system, fully automatic power supply can be realized without manual intervention, so that the power-on process can be fast and accurate, and the cable head voltage can reach 250VAC±5%. In addition, the method according to the present invention can automatically adapt to different cable lengths, that is to say, the voltage output is continuously adjusted through the feedback amount. When the feedback amount is 250VAC±5%, the adjustment is completed. Different cable lengths and load conditions, each The voltage increment and the total number of steps of the sub-regulation are different, and it has an intelligent automatic protection function.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings according to specific embodiments. in

The accompanying drawing shows a control circuit diagram for realizing automatic intelligent program-controlled power supply for downhole instruments of the logging system.

Detailed ways

The method of fully automatic intelligent program-controlled power supply for the downhole tools of the well logging system is a new method of powering up the downhole tools of the well logging system, which is different from the traditional manual power up method. The conventional well logging system uses the power input to the step-up transformer, then to the voltage regulating transformer, and finally output to the logging cable. When the power is turned on, the voltage regulating transformer is manually adjusted, and the output voltage is controlled by the engineer to control the voltage of the cable head of the downhole instrument to power up the instrument. This is achieved by manually adjusting the knob of the voltage regulating transformer. During the operation, the operating engineer should keep a close eye on the detection window and adjust slowly. The speed of power-on and the accuracy of the voltage of the cable head of the downhole instrument depend on the proficiency of the operating engineer. The hardware system consists of a control box and a program-controlled AC power supply. The output voltage of the program-controlled AC power supply is directly output to the logging cable after being boosted by the step-up transformer in the control box.

According to the present invention, the fully automatic intelligent program-controlled power supply method for the downhole instrument of the logging system runs in the CPU in the control box, and through advanced modern control methods, such as PID adjustment and closed-loop adjustment, the program-controlled AC power supply is controlled to reach the cable head voltage of the downhole instrument. Require.

The only figure schematically shows a control circuit diagram for realizing automatic intelligent program-controlled power supply for downhole instruments of a logging system according to an embodiment of the present invention. The power supply method adopts a closed-loop PI control method, and all controls are intelligently controlled by embedded processors, without manual operation, and can reach the cable head voltage of downhole instruments at 250VAC±5% in the shortest time.

According to the figure, the fully automatic intelligent program-controlled power supply system includes a control box and a program-controlled AC power supply AC1, wherein the control box is set downstream of the program-controlled AC power supply as the controlled object. The control box includes a housing, a central processing unit CPU and a step-up transformer arranged in the housing. The program-controlled AC power supply AC1 is connected to the input terminal of the step-up transformer provided in the control box. The central processing unit CPU in the control box can control the output voltage of the program-controlled AC power supply AC1 through the serial interface to realize automatic intelligent power supply.

In this embodiment, a closed-loop PI control method is used to control the output voltage of the programmable AC power supply, so as to achieve the desired voltage of the downhole cable head. In the present invention, the PID control adopted for the power supply of the downhole instrument of the well logging system has only P, the proportional factor, which is a control method adopted in conjunction with the characteristics of the power supply of the downhole instrument of the well logging system, and can be adjusted quickly and accurately without overshoot. There is a confirmation adjustment, which can ensure the accuracy of the supply voltage under slight load changes after the instrument is started.

In this embodiment, the set voltage target value is 250v. The voltage output by the program-controlled AC power supply AC1 forms negative feedback through the limiter, and then forms a deviation with the set voltage target value through the comparison link. The obtained deviation is sent to the proportional link. In this proportional link, the obtained deviation is multiplied by the transformer voltage division correction coefficient 1/3 to obtain the variable ΔV, wherein the transformer voltage division correction coefficient is the same as that in the control box related to the step-up transformer. The control quantity Vset(n-1) obtained in the previous cycle is accumulated with this variable ΔV, and then the control quantity Vset(n) of this cycle is obtained, where n is a natural number. The program-controlled AC power supply AC1 can output a corresponding power supply voltage according to the obtained Vset(n), which is used to deliver to the downhole cable head to supply power to downhole logging tools.

The following describes the method adopted to realize the automatic intelligent program-controlled power supply of downhole instruments:

In the first step, first set the target value of the instrument power supply to be 250v. Before the power is turned on, the feedback value of the downhole cable head voltage measurement is zero, so the difference between the downhole cable head voltage measurement feedback value and the target value can be calculated as 250v, multiplied by the transformer voltage division correction coefficient 1/3, and the variable ΔV is obtained It is 83.3v. Since it is not yet powered on, Vset(n-1) is 0. According to Vset (n) = Vset (n-1) + ΔV = 83.3v, the value of the control variable Vset (n) is obtained, and the program-controlled AC power supply outputs 83.3v through the control port.

In the second step, the difference between the downhole cable head voltage measurement feedback value and the given value 250v is calculated, and then multiplied by the transformer voltage division correction coefficient 1/3 to obtain ΔV, through the formula Vset(n) = Vset(n-1) +ΔV, get Vset(n), and then control the program-controlled power supply to output Vset(n) through the control system

In the third step, the process of the second step is repeated, and the cycle is continued. In the process of constant repetition, the downhole cable head voltage measurement feedback value is judged each time, and when it is within the range of 250VAC±5%, the cycle is stopped.

In the fourth step, wait for a certain period of time, and execute the second step again. At this time, it only needs to be executed once, and no circulation is required. After completion, the automatic power supply of the downhole instrument is completed. Finally, it can meet the design power supply requirement, 250VAC±5%.

Through the method described above, fully automatic power supply can be realized without manual intervention, so that the power-on process can be fast and accurate, and the cable head voltage can reach 250VAC±5%. In addition, the method according to the present invention can automatically adapt to different cable lengths, that is to say, the voltage output is continuously adjusted through the feedback amount. When the feedback amount is 250VAC±5%, the adjustment is completed. Different cable lengths and load conditions, each The voltage increment and the total number of steps of the sub-regulation are different, and it has an intelligent automatic protection function, wherein the intelligent automatic protection function can be realized by overvoltage protection, overcurrent protection and overload protection, for example.

Although the invention has been described above with reference to embodiments according to the accompanying drawings, it should be understood that the invention is not limited thereto. On the contrary, it is obvious to a person skilled in the art that the invention can be modified in many ways without departing from the scope of the inventive idea disclosed here.

Claims (12)

1. A method for fully automatic intelligent program-controlled power supply for logging system downhole instrument, said method may further comprise the steps: a) Set the target value of downhole instrument power supply; b) Set the transformer voltage division correction coefficient; c) Calculate the difference between the downhole cable head voltage measurement feedback value and the target value of the instrument power supply, and multiply the difference by the transformer voltage division correction coefficient, so as to obtain a control quantity used to control the output of the programmed AC voltage; d) Step c) is repeated for continuous circulation. In the process of continuous circulation, each time it is judged whether the feedback value of the downhole cable head voltage measurement is within the expected value range, and if so, the circulation is stopped; e) Wait for a certain period of time, and execute step c) again to obtain the required value of the downhole cable head voltage within the determined tolerance range. 2. The method according to claim 1, wherein the voltage increment and the total steps of each adjustment are different according to different cable lengths and load conditions. 3. The method according to claim 1 or 2, wherein the target value of the downhole instrument power supply is set to 250v. 4. The method according to claim 1 or 2, wherein in method step a), before power-on, the downhole cable head measurement feedback value is set to zero. 5. The method according to claim 1 or 2, wherein the expected value range is 250VAC ± 5%. 6. The method according to claim 1 or 2, wherein the transformer voltage division correction coefficient is set to 1/3. 7. The method according to claim 1 or 2, wherein the tolerance range is ±5%. 8. A system for fully automatic intelligent program-controlled power supply for downhole instruments of a logging system, said system comprising: a program-controlled AC power supply, the program-controlled AC power supply is configured to output a corresponding power supply voltage according to a given control quantity, and A control box, the control box includes a housing, a transformer and a central processing unit arranged in the housing, wherein the programmable AC power supply is connected to the input end of the transformer, and the central control unit is connected via a serial The interface is connected with the program-controlled AC power supply to control the voltage of the program-controlled AC power supply, so that the voltage of the downhole instrument cable head reaches its required value. 9. The system of claim 8, wherein a transformer voltage division correction factor is related to the transformer. 10. The system according to claim 9, wherein the transformer voltage division correction factor is 1/3. 11. The system according to any one of claims 8-10, wherein the required value of the cable head voltage of the downhole instrument is 250VAC±5%. 12. The system according to any one of claims 8-10, wherein the fully automatic intelligent program-controlled power supply is adjusted by a proportional factor.

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