Leakage detection and location for long range oil pipeline using negative pressure wave technique
Leakage accidents in oil transmission pipelines not only cause loss of material, but also bring about hidden troubles for people's property and the environment. Pipeline leakage accidents occur frequently in recent years, particularly in those developing countries, and most of which were done destructively. Negative pressure wave technique is an effective method for paroxysmal oil leakage detection and location. However, it is difficult to distinguish sources which led to the oil pressure drop. In order to solve the problem, wavelet transform algorithm was adopted to define inflexion of the negative pressure wave when it propagates along the pipe, and wavelet threshold denoise technique was used to separate the characteristic inflexion of negative pressure wave when calculating the leaking position. A new pipeline detection and location system on the basis of that was developed. The monitoring system acquires operational parameters of the pipeline from the existing SCADA system, which was installed on most oil transmission pipeline to monitor operational parameters for long range crude oil or product oil pipeline. Thus, the cost and complexity of the system was greatly reduced. The earliest leak detection and location system which installed on a crude oil transmission pipeline in the east of China 8 years ago is still working well. It responses to leakage in 2 minutes and location accuracy is lower than 2% of the whole length of the pipeline between two stations.