在定向钻井中常常会遇到表层直井段不能打直且直并段井底井斜方位偏离目标井斜方位较远，二开定向造斜时定向井工程师一般直接朝着目标井斜方位定向，由于井眼惯性的影响使实钻轨迹不能很快贴近轨道设计方位。为了解决这个问题，在造斜点初始定向时不应按照设计方位定向，可提出科学的定向方法使实钻轨迹尽快贴近轨道设计方位，当接近目标井斜方位时再朝着目标井斜方位定向。根据“空间斜面圆弧”模型以及在直井段没有打直的情况下定向工具面的“全力扭方位”计算模型，并以BZ13—1A2井为实例，计算出定向工具面角并用landmark软件计算了各个定向工具面角对井眼轨迹控制的影响。实例计算结果表明：通过该方法，能够尽快使实钻轨迹贴近设计线，从而减小扭方位井段的长度，提高定向造斜效率和控制精度，同时减小丛式井防碰的潜在风险。%Well trajectory of the first spud is not exactly vertical in directional drilling, and the directional driller generally kicking directly toward the target azimuth at the second spud, if the vertical well's bottom hole azimuth deviation from the target azimuth greatly, thanks to wellbore's inertia ,the well trajectory can't approach to the designed line quickly. In order to resolve this problem, don't kick to the designed azimuth at the beginning of the kicking at the position of KOP ,provide scientific deflection method, which can let well trajectory approach to the designed line quickly ,and then toward the target azimuth when the real drilling azimuth is approximately equal to the target azimuth. In this paper used directional tool face " full turning" reference model base on "space slant circle" model when the vertieal well inter- val is not exactly vertical, and took BZ13-1 A2 well for example, used software calculated how the downhole directional tool face affect the trajectory control. The example's calculate result shows that: when select the appropriate tool face, the well trajectory can approach to the designed line quickly, reduce the turning well interval, improve the kicking efficiency and control accuracy- ,and reduce the potential risk of group well's collision greatly'.
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