Research On Sand Monitoring Vibration Monitoring System For Gas Gathering Pipelines

As the supply-demand imbalance of energy has become increasingly severe, in order to meet the economic development, the mining power of oil and gas field is strengthened and the influence of sand production becomes stronger. Problems need to be solved in time, or it will give a great deal of harm to the normal production of the oil and gas field, such as decrease of well productivity, sand bury of gas layer and environmental pollution. Moreover, during the transportation of nature gas, gathering line and equipment damage often occur because of the sand erosion. Sanding production is a common problem during the production of oil and gas wells. How to use a effective method to monitor and predict the sand conditions becomes a problem demanding prompt solution. In order to reduce the harm caused by sand production, a system of real-time monitoring using reasonable sanding technology should be developed to get the information of sanding. Thus, it helps to provide evidence for sand governance and raise production capacity.In order to investigate the sand-carrying situation in gas gathering pipeline, a noninvasive monitoring method of sand-carrying vibration signal based on acoustic detection solution has been proposed. In this method, piezoelectric accelerometer is used to feel the impact of sand, data acquisition equipment to obtain this kind of impact signal, and the software to analysis and process the signal. The sand-carrying signal belongs to random vibration, the period is indefinite and there is no regularity. This paper analyzes the characteristics of sand-carrying vibration signal, chooses statistics and probability method to process it, establishs a calculation model about the relationship between the sand signal and the sand content based on the relationship between average peak value of the output of the piezoelectric sensor and the sand impact energy, researchs and evaluates the de-noising methods of extracting sand-carrying signal from the high background noise. By this means, wavelet threshold denoising method is chosen as the best way to remove the noise, and its parameters are explored by simulation. The same time, the sensor and the acquisition card which belong to the hardware part of the monitoring system are studied and selected, and the signal processing software is designed.Meanwhile, the paper also designs an experimental system of sand monitoring to carry out experiment with different amount of sand, different particle size and different flow rate. The results show that, when particle size of sand and gas velocity are constant, increasing sand content increases the amplitude of time-frequency domain and the characteristic values of the signals, meanwhile it decreases the measurement errors. Under a given amount of sand injection and gas velocity, the amplitude of time-frequency domain and the characteristic values of the signals increase with the increase of sand diameter, while the measurement errors decrease with the increase of sand diameter. At fixed sand content and sand diameter, the amplitude of time-frequency domain and the characteristic values of the signals increase and the measurement errors reduce along with gas velocity being increased. It verifies the feasibility of the model and effectiveness of the monitoring system and provides conditions for development of field sand out monitoring equipment and further study on detection techniques.