Abstract: An instrument system capable of automatically detecting wellhead parameters was developed. It features real-time wireless data transmission, wireless alarm, wireless start/stop control, automated inspection, and unattended operation, while also possessing some anti-theft capabilities. Practical application has shown excellent results, making it worthy of widespread adoption. The design concept and methods are described in detail.
Keywords: Wireless data transmission, automatic inspection, data management, PCC
Changes in field parameters during the production process directly reflect the production situation, making timely and effective acquisition of these parameters crucial. Currently, wellhead data in my country's oilfields is primarily obtained through manual meter reading, especially in remote areas. This method is extremely labor-intensive and costly, resulting in poor data real-time performance. Data management also relies entirely on manual reports, which are often inaccurate. The main problems include: difficult inspections, untimely reports, incomplete information (lack of continuous measurement), low monitoring accuracy, and poor real-time performance. This also hinders comprehensive digital management and data analysis. Therefore, we have developed a networked wireless automatic detection, alarm, and management system for wellhead parameters. This system enables real-time wireless data transmission, wireless alarms, wireless start/stop control, automated inspections, and unattended operation. It reduces losses caused by human error, lowers labor intensity, and also provides some anti-theft functionality.
The intelligent wireless network field parameter automatic inspection system is a large-scale computer monitoring and control system integrating state-of-the-art wireless transmission technology, computer technology, sensor technology, and automatic control technology. It is suitable for unmanned operation in various oilfields or mining stations, and in special environments of large-scale factories and mines. This system is mainly used for real-time data acquisition, data communication, transmission, alarm, data management, and analysis in oilfields, achieving fully automated monitoring and inspection. It improves the automation level and management level of the wellhead surface monitoring system, ensuring the reliability and stability of the surface instrument system; and realizes distributed data management, full information detection and recording, long-term data storage, and automatic data analysis and management.
1. Basic Design Concept and System Structure
The system consists of two main parts: the field section and the central station section. The field section is mainly responsible for data acquisition and transmission; the central station section is mainly responsible for data loop calling and data communication, data management and maintenance, alarm management, and other functions.
1.1 On-site section
The field instrument development will utilize an AT89C51-based microcontroller development system as its core. It will primarily monitor three-phase current, one-phase voltage, power factor, and wellhead pressure. Under normal circumstances, it will perform a check every 500ms, recording and saving the results each time. Normally, the recorded data can be continuously logged in the field instrument for 185 days. It will also record start/stop data, abnormal data, alarms, and cumulative power consumption. The basic circuit structure is shown in Figure 1.
1.2 Central Station Section
The central station has a simple structure, mainly including: one IPC industrial control computer, one printer, one long-term UPS power supply, one 25W wireless data transmission MODEM, and supporting omnidirectional antenna, sound and light alarm system, GSM alarm system, supporting control and management software, etc. The system structure block diagram is shown in the central station part of Figure 2.
1.3 System Structure
This system offers great flexibility in its installation structure, supporting both point-to-point communication and a point-to-multipoint distributed structure. Regardless of the usage method, the field installation structure remains identical. The point-to-point structure is primarily used in wells in peripheral areas. When a well cannot communicate directly with the central station, it can relay data through a neighboring well's instrument system. This enables data communication between neighboring wells and between the main control room and the field. The layout of the point-to-point wireless data transmission system is shown in Figure 2. From a microscopic perspective, at any given moment, the entire system is actually operating in a point-to-point structure, therefore, there are no strict limitations on the system's scale, and theoretically, the number of field stations is unlimited.
2 System Software Design and Function Implementation
2.1 System Software
The centralized monitoring and management software is developed using the currently popular Delphi 6. The main application, named JW-3.EXE, runs on the Windows 98 operating system. Its main modules include: interface management, data communication, data processing, status recognition, data management, system settings, query, reporting, network management, access control, and dictionary management. The main operational modules are listed in Table 1. The system features automatic alarm, automatic data transmission, historical data management, and manual call functionality based on data analysis.
Table 1. Main Operational Function Modules of JW-3 System
Two methods are used: ① Audible and visual alarm: an abnormal flashing sign is set at the corresponding station coordinates on the central control room and display screen, and saved in the abnormal record data file for future reference; ② A short message is sent to the mobile phone of the duty manager via an industrial GSM mobile phone to indicate the abnormal operation of a certain well.
After multiple field tests, the call-response method can fully guarantee the authenticity and reliability of system data during use. When an anomaly occurs in data verification, a request is made to re-call and transmit data.
2.2 System Functions and Features
The JW-3 system field instruments have the following main functions and features:
① Real-time monitoring of on-site parameters, enabling dynamic monitoring of wellhead pressure, three-phase current and one-phase voltage, pump start-up and shutdown records, abnormal records, power consumption, etc., and storing them for a long time.
② Real-time wireless data transmission and networked system design facilitate system expansion and networked management.
③ Centralized management and decentralized control, enabling real-time data acquisition, data transmission, abnormal alarms, emergency shutdown, self-start delay, and long-term data recording (continuous storage of monitoring data from 1 to 185 days) on-site.
④ Data management and analysis software, including daily, monthly, quarterly, and annual reports, with historical data analysis and management capabilities.
⑤ To achieve centralized well inspection function, determine the cause of start-up and shutdown on site, and alarm in case of failure (on site and in main control room), the most advanced GSM technology is introduced to realize abnormal alarm.
⑥ It can realize wireless control of start and stop, etc.
⑦ The instrument system can display locally. The fully sealed housing design features dustproof, anti-theft, moisture-proof, and anti-electromagnetic interference characteristics. The integrated design makes installation and maintenance simpler and faster.
⑧ Design of low-temperature automatic heating device.
3. Conclusion
Our JW-3 wireless network-based automatic field parameter inspection system, designed for wireless transmission, has undergone multiple rounds of debugging and operation. Operating in 9600 B/s interrupt mode, our communication system functions normally even over long distances. Months of debugging and operation have proven the system's reasonable design and reliable operation. Therefore, this implementation method is a convenient and reliable communication approach, fully capable of widespread application in oilfield data transmission and control.
References
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3 Zhou Deze, Yuan Nan'er, Ying Ying. Design and Application of Computer Intelligent Monitoring and Control System. Beijing: Tsinghua University Press, 2002.1: 100-130
