含硫页岩气管道膜层电阻-剩余寿命反演模型OA

In order to address the 6-9 month lag in traditional time-corrosion model warnings and the frequent perforation accidents in Sichuan-Chongqing shale gas gathering and transmission pipelines in CO2-H2S-Cl--SRB multi factor coupling environment,a real-time residual life inversion model based on membrane resistance R was established.At a shale gas site,82 sets of L245NS steel hangers were engaged to note the measured perforation time and pre-perforation R.Following cleaning,R outliers were identified using autoencoder neural network combined with the box plot approach(IQR＞1.5).A corrosion environment similar to the field conditions was created using a Parr 4575 high-pressure reactor and dynamic immersion was performed for 1,4,and 7 days.Corrosion rate,R,and morphological evolution were obtained using weight loss technique,in-situ EIS,and SEM-EDS.Early warning accuracy and error analysis were carried out on 20 blind samples.The data from field steel hangers indicate that R drops in a three-stage pattern over time"gradual decline-platform-steep decline"Dynamic immersion acceleration test show that the corrosion rate rose from 0.184 mm/a to 0.863 mm/a exponentially.The remaining operating time was fitted to yield tR=9.94e0.065R(R≤2.0 kΩ·cm2)with linear compensation for high-resistance zone.Verification on site show that MAPE is 3.8%and the greatest error is 18.2%.Setting off a red warning when R is no higher than 0.20 kΩ·cm2 produced an accuracy rate of 75.0%and a false alarm rate of 0%.Sichuan-Chongqing shale gas gathering and transportation pipeline has a quantitative basis for the joint emergency response of"corrosion inhibitor+bactericide"thanks to the development of an engineering deployable"R-remaining life"index inversion model.This model can also be extended carbon steel pipelines in other high sulphur gas fields.