偏心钻头底部钻具组合稳定器的适宜安放位置研究

采用静力分析的方法 ,建立了偏心钻头底部钻具组合的力学模型 ,并对力学模型进行了求解。对单稳定器及双稳定器钻具组合的力学分析结果表明 ,在设计钻具组合的稳定器位置时 ,应该以偏心块位于上方时计算的稳定器与钻头的最小距离为参考值。在钻具组合设计过程中最好使用钻压分配比一定且该值较小的钻头。采用双稳定器钻具组合时 ,钻头侧向力大于零的下稳定器与钻头的最小距离比单独采用一个稳定器时要小 ,且下稳定器位置的变化对钻头侧向力的影响要比上稳定器大得多。因此 ,在钻具组合的设计过程中对下稳定器安放位置的要求应该比上稳定器更为严格。

Suitable position of stabilizer at bottom hole assembly fitting an off-balance bit

A mechanical model for the bottom hole assembly (BHA) with an off-balance bit was established. The solution of the model was given by means of numerical method. The mechanical analysis on BHA with single stabilizer and double stabilizers shows that the proper position of the stabilizer should refer to the result gotten when the off-balance body is on upside, and the proportion of weight of bit is a constant and smaller value. When the BHA with double stabilizers is used, the position of the lower stabilizer easily resulting in the positive lateral acting force on bit is lower than that of the single stabilizer. For the BHA with double stabilizers, the effect of position change of the lower stabilizer is greater than that of the upper stabilizer. So the positioo design of the lower stabilizer should be more accurate than that of the upper one.