Corrosion In Wet Gas Gathering And Transportation Pipelines. Sichuan Gas Field Prediction Method

With the continuous growth of operation time of Sichuan Gas Field wet gas gathering and transportation system, a serious corrosion appeared in Gathering pipeline, which posed a serious threat to the safe operation of pipelines and the surrounding environment. How to make a reasonable prediction to the corrosion in the pipes and how to make an accurate judgment to those corrosion sensitive areas are urgent needs for gas safety production.Compared with the evaluation standards which were built in dry gas transportation corrosion, the corrosion rule in wet gas pipeline is different and even more complex. what's more, there is no reliable way to evaluate its corrosion degree in China.Therefore, it has profound theoretical significance and extensive practical value to guide gas field production departments to take on detection and protective measures by analyzing the fluid's flowing pattern within the wet gas gathering pipes and the corrosion rules caused by some medium and other factors and establishing a suitable internal corrosion forecasting model (WG-ICDA) to determine the distribution of internal corrosion in pipes.According to the corrosion in the Sichuan Gas Field for natural gas gathering and transportation system,this paper collected and sorted out a large number of pipe parameters and operation condition as well as the of historical data of corrosion inspection. Then, by referring to relevant material research, different corrosion rules in different medium, running condition and flow patterns of Sichuan Gas Field for natural gas gathering and transportation system were analyzed. At last, fluid flowing pattern was found out to explain the main cause of corrosion rate changes throughout the pipe.Next, this paper will have a concrete analysis for the fluid rule in Sichuan Gas Field for natural gas gathering and transportation system. With the support of rich pipeline basic data, Multiphase Flow Simulation Software, like PipePhase will be used to simulate the pipeline flow field. When simulating, the combination calculation is mainly used to calculate the pipeline pressure, temperature, flow velocity and the liquid rate distribution, which will provide useful data to establish the Multiphase Flow corrosion model.On the basis of the calculation results in the simulation and pipe elevation profile, considering the influence of pipeline elevation difference, pipeline obliquity, the liquid rate, pressure, Reynolds number on the wet natural gas pipeline corrosion rate, and adopting the artificial neural network method which has been analyzed and optimized by Niche genetic, the idea of establishing the WG-ICDA model is proposed in this paper.