In order to study the failure law of string integrity under multi-factor coupling effect in deepwater wells,compre-hensively considering the joint effect of corrosion,wear and temperature,an evaluation method of casing strength attenuation was established.The strength attenuation degrees of different pipe materials under the action of multiple factors were com-pared,and the measures to reduce the strength attenuation rate of casing were proposed.The results show that under the action of corrosion,the strength attenuation rate of casing accelerates as the production life increases.When the corrosion rate is 1.0 mm/a,the internal pressure strength of P110 casing decreases by 7.21%per year on average.The strength of casing decrea-ses as the wear depth increases.When the wear depth is 0.3 mm,the average reduction percentage of the external extrusion strength of L80,13Cr-P110 and Q125 pipe materials is 6.47%.The strength of pipe material generally decreases as the temperature increases.When the temperature is100℃,the internal pressure strength of P110 casing decreases by6.37%.The selection of corrosion-resistant,wear resistance and high-temperature resistance pipe materials can effectively reduce the strength attenuation rate.The research results can provide a reference for the development of deepwater wells.
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