| Austral marine facies area contains affluent hydrocarbon resources, and it is important exploration activity strategic area of our country. But there are many problems in casing strength design of this area. Be aimed at particular complex geology in southeast of Sichuan, this paper researches casing material choosing, sulfate resistant casing intensity imitation, ground stress calculation and reliability design method based on theory study. Through the research of performance introduction and test result of many casing product, we generalize a casing choosing chart through different temperature and differential pressure of H2S and CO2. This paper proceeds material choosing recommendation in view of some special block based on our summarized method. Through the imitation result of casing strength completed with Monte-Carlo method, we can know the collapsing strength, internal pressure strength and tensile strength of casing all present normal distribution, and obtain relevant distribution curve. Compile a ground stress of northeast of Sichuan calculator program based on VB program, and draw the ground stress isocoene diagram of Puguang structure with the program result. Obtain casing reliability computation formula through the research of reliability design method, and further obtain the calculation procedure of casing strength security factor based on reliability we needed and nonuniformity coefficient of casing strength and loading. Based on the casing deformation of Puguang 12 well and computing method generalized before, we analyze the reason of casing deformation, and then gain the conclusion that salt rock creeping, absurdity design of casing string and salt rock disregard by people are the main reasons of the casing deformation accident. Compile a casing strength optimize design program which is fit for austral marine facies area.
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