膨胀水泥环空界面径向应力理论解及试验验证.PDF

2012 10 PETROLEUM EXPLORATION AND DEVELOPMENT Vol.39 No.5 605 文章编号：1000-0747(2012)05-0605-07 膨胀水泥环空界面径向应力理论解及实验验证 1 1 2 2 1. 2. 基金项目：10KW-8 摘要： 3 7 21 关键词： 中图分类号：TE256.7 文献标识码：A The theoretical radial stress solution and its experimental verification of expansion cement at annulus interfaces 1 1 2 2 Yang Zhifu , Meng Qingyuan , Chen Xiaolou , Gao Lili (1. School of Astronautics, Harbin Institute of Technology , Harbin 150001, China; 2. CNPC Drilling Research Institute, Daqing 163413, China) Abstract: To determine the initial loading state of the casing and cement sheath during cement setting, the theoretical solution of radial stresses at the annulus interfaces during cement setting is derived considering volume expansion and material parameter variation. During the theoretical derivation, cement setting is divided into many time steps. In each step, the original radii of cement sheath without loading are calculated and the radial stresses are calculated according to the compatible deformation condition among the casing, cement sheath after free expansion and the stratum in this time step. The calculated radial stresses and radii of the cement sheath are used as initial data for the next step. The circumferential strains of casing and stratum are measured during cement setting process. The experimental result verifies the correctness of the theoretical solution. The calculated results and experimental data show that the radial stresses on both inner and outer boundaries of cement sheath are compressive stresses during the cement