塔中地区的地层自然造斜能力及其规律

地层自然造斜能力及规律是定向井和丛式井井眼轨道控制的重要依据，根据钻头与地层相互作用的力学模式，从钻柱力学出发，用纵横弯曲法求钻头侧向分力，然后利用反算法对ＴＺ４号构造的地层各向异性指数、地层造斜系数和方位漂移系数进行了计算和分析，得出了该地萄地层自然造斜规律和最佳造斜点位置，定性地分析了各层段的自然造斜能力，为ＴＺ４号构造油藏丛式井的井眼轨道控制提供了理论依据。

Natural Deflecting of Formation in Tazhong Area

The natural deflecting ability and law of formation is the main control of well trajectory in directional wells and multiwells.Based on the rock-bit interactional model,and according to the drilling string mechanics,the bit side-force is calculated by beam-column theory.Then by using back-calculation method,we calculate and analyse the anisotropic index,formation deflecting factor and azimuth drift factor of No.4 reservoir in Tazhong area.The natural deflecting law of formation in the area is concluded. and the optium kick-off point,and the natural deflecting ability of each zone is qualitatively analysed,providing the theory basis for the control of well trajectory of multiwell,in Tazhong No.4 reservoir.