中文摘要：

为解决单弯双稳导向钻具组合长时间复合钻进时实钻井眼轨迹偏离设计井眼轨道的问题，对单弯双稳导向钻具组合的稳斜能力及其影响因素进行了分析。根据底部钻具组合复合钻进导向力的拟动态计算模型，编制了相应的计算机程序，模拟计算了钻具组合结构参数、井斜角和钻压对单弯双稳导向钻具组合复合钻进稳斜能力的影响规律。结果表明：第一稳定器如果外径过小，在复合钻进中将处于悬空状态，失去支撑井壁的作用；随着第二稳定器外径的增大，单弯双稳导向钻具组合复合钻进的钻头井斜力减小；螺杆弯角、井斜角和钻压对单弯双稳导向钻具组合复合钻进的钻头井斜力影响均不显著。根据模拟计算结果，对南堡13-斜1025井稳斜段所用单弯双稳导向钻具组合进行了优化设计。实钻结果表明，采用优化设计的钻具组合复合钻进时稳斜效果很好，井斜变化率只有0．18°／30m。这说明，根据各因素对复合钻进稳斜能力的影响规律，对单弯双稳导向钻具组合进行优化设计，可以提高其稳斜能力。

英文摘要：

When steerable assembly with two stabilizers and one bend was used to drill a section in composite drilling mode, the well trajectory would always deviate from the designed well trajectory. To solve this problem, the angle holding-inclination capability of steerable assembly with two stabilizers and one bend,as well as factors affecting it were analyzed. Based on the quasi-dynamic model for side force of steerable assembly,a computer program was developed to simulate the effects of structural parameters,in- clination and weight on bit（WOB）on holding-inclination performance of steerable assembly with two stabi- lizers and one bend. The results show that if the O. D. of the first stabilizer is too small, the stabilizer will have no contact with borehole. And as the increase of O. D. of the second stabilizer,the rotary side force of steerable assembly with two stabilizers and one bend decreases. In addition,the effects of the bent angle of PDM, inclination, and WOB on the rotary side force of steerable assembly with two stabilizers and one bend are all slight. By using the above simulated results, steerable assembly with two stabilizers and one bend was designed to hold-inclination in Well NP13-X1025. The result of actual drilling indicates the optimized assembly works well in holding-inclination,with the inclination curvature being only 0.18°/30m. It is con- cluded that,the holding-inclination capability of steerable assembly with two stabilizers and one bend can be improved by optimum design according to the analysis of its influencing factors.