The objective optimization function was set by the summary of the insulation materials' annual sharing cost and the annual heat losing cost after insulation and the calculating model of buried hot oil pipelines' insulation economical thickness was given. The model included the burying depth's influences on around pipelines ambient temperature, the heat transfer coefficient of the outer wall insulation, and the overall heat transfer coefficient. With the help of C# programming language, a computer program was developed to optimize the thickness of insulation layer of buried hot oil pipeline with EXCEL to work out economic evaluation procedures, combining with examples of calculation. The results showed that: The determination of buried hot oil pipeline insulation thickness would have some impact on the economic benefits of the project, and it should take the double requirements into account determining the thickness on both technology and economy. That could provide a theoretical reference to the hot oil transportation construction's optimizing design.

The main index factors of the soil corrosion detection， for the section of pipeline in service in Qinghai Oilfield Huatugou, included resistivity, natural corrosion potential, redox potential, pH, moisture content, salt content, chloride ion content and soil corrosion rate. Combined with three theories, gray correlation, fuzzy evaluation, and improved AHP, the appropriate comprehensive evaluation model was established, the 15point set of measured data was used in Huatugou areas of this field to clarify its application of this method, and evaluation results reached by the comparison model with the original evaluation results were contrasted. The results of this evaluation model showed that the evaluation results was closer to reality than the original evaluation results.