基于积分本构方程的盐膏岩蠕变参数反演

正确认识盐膏层蠕变规律是进行盐膏层钻井设计、合理确定起下钻时间及预防井下事故发生的关键。文中以相关系数作为盐膏岩本构模型辨识的准则函数，建立了井下盐膏岩蠕变模型的辨识方法。通过引入积分算子，建立了常见蠕变模型的积分型本构方程，并以此为基础提出了根据井径测量信息反演确定盐膏岩蠕变特性参数的位移反分析法。应用该方法可较好地预测井下盐膏层的蠕变规律，并由此确定井径缩小规律与钻井液密度的关系。在英买力区块的应用结果表明．理论预测结果和实际测试结果吻合较好。为盐膏层钻井工艺设计的合理编制提供了理论依据。

Creep parameters inversion of salt-gypsum rocks based on integral constitutive equation

A correct understanding on the creep law of sah-gypsum layer is the key to well design of salt-gypsum layer, rationally determination of tripping time and prevention the occurrence of underground accident. In this paper, using correlation cnefficient as the criterion function of the constitutive model identification nf salt-gypsum rocks, the identification method of creep model has been established to identify the undergrnund sah-gypsum rock. The integral constitutive equation of common creep model has been set up by using integral operator. On this basis, the displacement back analysis method is brought forward which is used to determine the creep parameler of salt-gypsum rocks according to information inversion of caliper measurement. Using this method, the creep law of the underground sah-gypsum layers will be predicted efficiently and the relation between well diameter narrowing rule and drilling fluid density will be determined. Application results in Yingmaili Block show that the theoretical prediction result is in good coincide with the practical application, which provides theoretical references for making out drilling technology design rationally.