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在定向钻孔施工中,结合地层促斜规律进行跟踪设计,控制钻头运行轨迹十分重要。实践证明,在具层理的二叠系地层中定向钻进,当钻孔定向弯曲方向相逆于岩层倾向(α=65°～80°),常规稳斜孔段自然弯曲表现为增斜;当钻孔定向弯曲方向相顺于岩层倾向(α=45°～65°),常规稳斜孔段自然弯曲表现为降斜,其顶角变化率均为1°～3°/100m。同时,钻孔方位也发生漂移,其方位漂移率为10°～30°/100m。因此在调整增斜孔段的终点方位和顶角时,要为稳斜孔段预留提前量。在定向造斜时,造斜钻具的工作角(β)决定着钻孔轴线的空间位置变化,理论计算的β值经过修正后才能作为造斜器在孔内的装置工作角(ω_0)。
In the directional drilling construction, tracking design is combined with the law of stratum promotion and it is very important to control the trajectory of the drill bit. It has been proved that in the directional drilling of a layered Permian formation, when the direction of the directional bending of the borehole is reversed to the tendency of the rock formation (α=65° to 80°), the natural curve of the conventional steady inclined section shows an increase in slope; When the directional bending direction of the borehole conforms to the tendency of the rock formation (α=45°～65°), the natural curved section of the conventional steady inclined section shows a descending slope, and its vertical angle change rate is 1°~3°/100m. At the same time, the drilling orientation also drifts, and its azimuth drift rate is 10° to 30°/100m. Therefore, when adjusting the end point and the apex angle of the sloping hole section, an advance amount must be reserved for the stable sloping hole section. In directional whipstocking, the working angle (β) of the whipstock drill determines the spatial position change of the drilling axis, and the theoretically calculated β value can be used as the device working angle (ω_0) of the whipstock in the hole.