造斜率影响因素与预测方法研究

Research on Influential Factors of Build-up Rate and Prediction Method

科学高效的造斜率预测方法是优选钻井参数、提高井眼轨迹控制精度和效率的关键技术，对复杂定向井的高效、低成本开发具有重要意义。造斜率预测受多种因素的耦合影响，具有模糊性、随机性、非线性等特点，用数学力学模型难以描述。提出将Kriging代理模型应用到导向工具的造斜率预测中。从造斜率影响因素入手，重点分析了导向工具结构及造斜原理的差异对造斜率的影响；将现有的造斜率预测方法归纳为几何预测法、力学预测法和回归分析预测法3大类进行了综述和对比分析，指出了现有方法的局限性；从回归分析预测法的角度，提出了一种基于Kriging代理模型的造斜率预测新方法，分析了该方法的科学性和高效性，提出了使用该方法的具体预测步骤和应注意的关键问题，为造斜率预测提供了新途径。

The scientific and efficient prediction method of build-up rates was the key technology to optimize drilling parameters and to improve wellbore trajectory control accuracy and efficiency. It was of great significance for the efficient and low-cost development of complex directional wells. The prediction of build-up rate, which had the characteristics of fuzziness, randomness and nonlinearity, was affected by various coupling factors. As a result, it was difficult to describe with ma- thematical and mechanical models, and it was proposed that Kriging surrogate model was applied to predict the build-up rate of steering tools. Starting from the analysis of the factors affecting the build-up rate, the influence of difference between the structure and build-up principles of the steering tools was emphatically analyzed. The current methods were summarized into three types of geometric prediction, mechanic prediction and regression analysis and prediction. By compar- ison between them, their limitations were pointed out. From the aspect of regression analysis and prediction, a novel method based on the build-up rate of Kriging surrogate model is proposed; the scientificalness and high efficiency of the method are analyzed; the concrete procedures for prediction and key issues for attention are proposed; it provides new ways for predicting the build-up rate.