推靠式旋转导向井眼轨迹预测与控制方法

旋转导向钻井系统是现代导向钻井技术的发展方向。通过导向机构调节导向参数来预测和控制井眼轨迹,是旋转导向钻井系统的关键技术之一。为解决推靠式旋转导向钻具的导向力和工具面角对井眼轨道的控制问题,对导向力分别在井斜平面和方位平面进行解耦;并应用了纵横弯曲理论建立了底部钻具组合三维力学分析模型,得出了导向参数与钻头侧向力和转角的定量关系。在考虑钻头和地层的各向异性因素的影响下,利用在UPC模型基础上提出的有效钻力的概念,通过计算钻头有效钻力来预测实钻过程中的钻进趋势。在此理论基础上,计算了按设计的井眼轨道钻进所需要的导向参数,并讨论了井眼轨迹参数、钻压、钻头各向异性参数和地层参数对钻具导向性能的影响;分析了其中的规律,并得出只有综合考虑上述各项因素,才能准确计算出导向参数,确保钻头沿设计轨迹钻进,也为旋转导向井眼轨迹控制提供了理论依据。

Predict and Control Method of Well Path For Push the Bit Rss

Rotary steerable system is the development direction of modern steering drilling techniques, it is one of the key technologies of the rotary steerable drilling system by adjusting the steering parameters to predict and control the well trajectory. To solve the problem of well trajectory control by adjusting steering force and tool face angle for push the bit RSS, the steering force is decoupled in deviation plane and azimuth plane, the 3D mechanical analysis of the bottom borehole assembly is carried out with the beam-column theory, the quantitative relationship between the steering parameters and bit side force and angle is obtained. In consideration of the anisotropy of the drill bit and formation, the effective drilling force which is based on the UPC model can be used to predict the drilling tendency. Based on the theoretical research above, the steering parameters required can be calculated according to the designed wellbore trajectory. we discuss the influence of borehole trajectory, drilling pressure, and the bit anisotropy index and formation parameters on the deflecting characteristics of RSS, and conclude that only consider the above factors can we accurately calculate the steering parameters, which can also provide the theoretical basis for the control of the trajectory .