The Working Parameters’ Real-time Monitoring System About The Multi-layer Drainage Well Of CBM

China has a abundant of Coalbed Methane(CBM) resource, the total CBM resource under less than 2000m depth is 36.81 X 1012m3 and is the third in the world. In order to take full advantage of the CBM resource, the government of china strengthen the research and development efforts in recent years and drilled out many test wells to explore the technology about the CBM Multiple Laterals Horizontal Well (MLHW). But as the limited of the technology level, the vertical well are still in the majority in china.As to the vertical well, the fluid situation, including the pressure, the flow, the temperature and the two-phase flow parameters,which at the bottom of the well are important parameters. It play a decisive role to consider the drainage and mining strength, judge the downhole’s fault and estimate the gas potential. And it’s also the objective evidence to make a reasonable gas extraction technology.The underground’s fluid situation plays a decisive role to consider the drainage and mining, especially to the multi-layer drainage. The reasonable drainage and mining technology can exhaustive release each coal seams’CBM and get the best production of a signal well. On the contrary, an unreasonable drainage and mining technology might lead to permanent damage of some coal seam and greatly reduced the gas production of a signal well. So, the underground’s fluid situation is also important to the multi-layer drainage well of CBM. On the basis of above considerations, the "12th Five-Year national major science and technology projects (2011ZX05034-002) " was approved to research this problem, namely "The working parameters’real-time monitoring system about the multi-layer drainage well of CBM ". The monitoring system monitor the working parameters about the each coal seams and then transmit the collected data to the ground. By coupling and inversing analysis the collected data and combine with the established physical model, the drainage and mining parameters can be got.This paper are mainly about the theory and practical work about the above-mentioned monitoring system. Combine with the theory research, prototype fabrication, laboratory tests and filed tests, the monitoring system is implemented. After nearly five years of research work, the paper have finished the follow work.(1) The working parameters’real-time monitoring system about the multi-layer drainage well of CBMIn order to develop the monitoring system, a great deal of work were done during the research. To satisfy the measurement requirements of the bubble, a brand new bubble sensor which can be used to measure the two-phase’s flow pattern at the bottle of the well is developed. Moreover, the ameliorated’ bubble sensor can be used to measure the speed and the volume of the bubble. To satisfy the measurement requirements of the flow of downhole, a brand new flow sensor about the two-phase is developed. According to numerous tests, the pressure sensor and the temperature sensor are chosen and the data processing circuit about the sensors are designed. By the optimal design, the dimensional check and the simulated analysis, the structure of the downhole monitoring probe is developed. Moreover, the paper also solve the problems about the sealing method and sealant. Then the data acquisition, processing and storage circuit is designed by chose the suitable chip. By researching the theory about the the long-distance signal transmission, the problem about the signal distortion is solved. By programming the Microprogrammed Control Unit(MCU), the collected data can be displayed on the computer in the form of graph. Moreover, the paper also make a deep research about the network communications technology of the software. The simulator which can simulate the actual working environment about the CBM well is developed and in which the collected data can be coupled and inverted analysis.(2) The couple and inverse analysis about the different measurement parameters of the downholeThe filed tests were carried out when the monitoring system was designed and assembled. The monitoring system keep function well nearly six months form September 11th,2015 to now. According to inverse analysis the pressure and the bubble data, and combine with the calculation model about the dynamic liquid level height, one can get the dynamic liquid level height of the test well. According to inverse analysis the bubble data, one can get the two-phase’s flow pattern of the test well. According to inverse analysis the pressure data, the flow data, the bubble data and the temperature data, and combine with the calculation model about the gas production, one can get the gas production of each coal seams.The innovation points about this paper are as follows.(1) A brand new bubble sensor about the two-phase is developedA brand new bubble sensor which can be used to measure the two-phase’s flow pattern at the bottle of the well is developed base on the theory of the electrical conductivity. At the same time, the ameliorated’bubble sensor can be used to measure the speed and the volume of the bubble.(2) A brand new flow sensor about the two-phase is developedA brand new flow sensor which can be used to measure the two-phase’s flow at the bottle of the well is developed base on the theory of the target flowmeter.(3) The working parameters’real-time monitoring system about the multi-layer drainage well of CBM.The working parameters’real-time monitoring system which can be used to collect the each coal seams’working data,including the bubble data, the flow data, the pressure data and the temperature data,is developed. In addition, the collected data can be display in real time or to be store.(4) The calculation model about the different measurement parameters’couple and inverse analysisCombine with the calculation model and the different measurement parameters’ couple and inverse analysis, one can get the test well’s dynamic liquid level height, the distribution of the two-phase’s flow pattern, the distribution of the temperature and the gas production of each coal seams.In conclusion, this paper do some theory and practical research at the working parameters’real-time monitoring system about the multi-layer drainage well of CBM. The research work combine multi-disciplinary theory and technology and is a typical application of the cross-disciplines. The relevant theory research and practical test prove that the monitoring system have achieved the intended purpose and realize the breakthrough from nothing. But some correlational research still need to further study.