At present,the research on the corrosion rate of the oil casing in the wellbore containing CO2/H2S is the current research hot spot in the field of corrosion and protection. In order to accurately study the corrosion situation of the oil casing and predict the corrosion rate,the weight loss method was first adopted to study the corrosion rate under different corrosion time,and the experimental results were fitted. Secondly, combining the research results of this paper with the previous research content,the Table Curve 3D software for multiple regression was used to determine the corrosion rate prediction model.The results show that the corrosion rate decreases continuously with the increase of time.The fitting of the experimental results R2 is 0.989 3,the error is small.The model established by multiple regression can accurately predict the corrosion rate and the error is within 5%,which meets the accuracy requirements,and can lay the foundation for the on⁃site oil and gas well safety evaluation.

After the low permeability oil field of Ansai enters the medium and high watercut stage, the main oil reservoir is washed, the production of many wells is low, and the direction of remaining oil digging is unknown. Taking Chang 6 oil layers of Yanchang formation in Wangyao area as the object, on the basis of modern sedimentology, highresolution sequence stratigraphy, basic logging theory and development geology, combining the rock outcrop, sealing core drilling in-spection well and test data, the characteristics of single oil sands scale reservoir heterogeneity, injection and mining connectivity and distribution of residual oil are revealed. The results show that the heterogeneity of single sand bodies has an important influence on the water flooding process of low permeability reservoir, and it also has important inspiration for the division and combination of the development oil layer, the form of well network and the adjustment of water injection. The recovery rate is increased by 4%~6% through comprehensive adjustment as pattern infilling, adjustment of injection-production relation of the single sand body, the precise fracturing and profile control.

The conductivity of artificial fractures and coefficient of nonDarcy gas flow in gas wells are affected by many factors. It is difficult to predict them accurately through mathematical methods. To get a more accurate value through the experiments of actual fracture conductivity, laboratory tests are conducted to measure fracture permeability and nonDarcy flow coefficient βunder different conditions. Computational formula of productivity based on the experimental data is established and the influential factors of the production of the artificial fractured gas well are studied. The results show that closure pressure and sanding concentration are the most important factors affecting the productivity and that gaswater production will greatly decrease the productivity of the gas well. The optimization methods in fracturing design based on the experimental data is set, that is: obtaining fracture permeability and nonDarcy flow coefficient β under different conditions through nonDarcy flow experiments and twophase flow experiments, and then using them to forecast the productivity of fractured gas well, finally optimizing the fractured length, sanding concentration and other parameters accordingly. 