一种预测井口抬升高度的新方法

井口装置抬升高度预测对高温高压高产油气井管柱设计、固井设计、完整性评价等至关重要，但井口抬升预测模型受各层套管自由段长度影响较大。为了准确地解释各层套管自由段长度并预测井口抬升高度，分析了井口抬升机理，建立了多管柱井口抬升计算模型，应用粒子群多目标优化算法，基于生产过程中的系列产量与井口抬升高度数据反演得到了各层套管自由段长度，形成了井口装置抬升高度的预测方法，并对四川盆地磨溪区块某高温气井不同产量下井口装置抬升高度进行了预测。预测结果与井口实际抬升量对比表明:本方法能够预测井口装置抬升，预测平均误差较小，满足工程需要，且不影响油气井正常生产，可行性强。研究成果可用于预测井口装置抬升高度、制定油气井完整性管理措施并且指导其安全生产。

An innovative technique for predicting wellhead uplift height

Accurate prediction of wellhead uplifting height is of great importance for the design of pipestrings, cementing program and integrity assessment of high-temperature, high-pressure and high-productivity oil/gas producers. But models for predicting wellhead uplifting height are strongly affected by the length of free sections of various layers of casing. To explain length of free interval of various layers of casing and predict wellhead uplifting height accurately, an innovative model for uplifting calculation of wellhead with multiple pipestrings has been built based on analysis of wellhead uplifting mechanisms. By using multi-target Particle Swarm Optimization (PSO), length of free casing intervals in various layers were obtained through inversion of productivities and wellhead uplifting data to establish an innovative technique to predict uplifting height of wellhead. The method was used to predict the height of wellhead uplifting of a high-temperature gas well at different productivities in Block Moxi of the Sichuan Basin. Comparisons of the predicted results and actual uplifting heights show the new technique can accurately predict height of wellhead uplift with relatively small error, meet engineering requirement, and does not affect normal production of oil/gas producers. Relevant research results can be used to predict wellhead uplifting height, stipulate measures to ensure integrity of oil/gas producers and provide guidelines for production safety.