Study on the Application of Extremum Statistical Method to Corrosion Pit Depth of Buried Pipeline

Typical soil corrosive areas along the long-distance pipeline of Shengli Oilfield were chosen as test points. 16Mn steel specimens were buried and were taken individually in different time period. Average corrosion rates and corrosion depth are counted and extremun method is used to dope out maximum depth of corrosive pit. Comparative result shows that taking specimens'average corrosion rate and corrosion depth for jeopardizing evaluation of pipeline local corrosion is unscientific Statistics of extremes could be applied to count soil corrosion of pipeline, which shall be used as a basis of the evaluation. Test results also show that the soil corrosion in #2 and #101 areas is more serious than that of #1 area, especially climbing sharply in #101 area. Practical example verifies that statistics of extremes is of higher correlativity and preferable to pipeline corrosion test.