| With the rapid growth of China's energy demand and consumption,shale oil and gas has become a hot spot in the oil industry in recent years.However,the deformation and damage of the shale gas well casing was very serious,which causing a large number of gas well losses,and affecting the shale gas production schedule and efficiency.Shale gas well high-parameter complex fracturing casing deformation is serious,and casing damage morphology shows non-uniform external extrusion deformation and shear deformation,effectively improving the casing string's anti-extrusion performance and shear resistance will greatly suppress casing damage rate.This paper proposes to use strain strengthening theory to study the large deformation failure of shale gas casing.Using the method of finite element simulation,a simulation model of the shear deformation of the casing was established.The action law of the slope of the tangent modulus and the maximum radial deformation of the casing was analyzed.Strengthen the correspondence of the index.The strength of the material can be improved through the alloy element strengthening and heat treatment processes.The alloy element strengthening increases the yield strength and tensile strength of the material by about 32.1% and 21%,respectively;compared with the alloy element strengthening,the heat treatment process makes the material The tensile strength has been greatly improved,up to 1380 MPa.Shear loading verification of strain-enhanced casing through physical experiments,The results show that the shear deformation resistance of the casing is enhanced,the maximum shear deformation of the element-reinforced new casing decreases by 17.1%,and the maximum shear deformation of the heat-treated strengthened new casing decreases by 13%;Combined with the observation of the microstructure of the new material casing after strengthening,the strain strengthening behavior is analyzed and evaluated from the perspective of the microstructure. |
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