关键词: 侧钻, 水平井, 三维, 轨道, 优化设计, 数学模型

Abstract: This paper first discusses some trajectory-design methods that are commonly used,then develops new mathematical model for designing 3-D trajectory in re-entry horizontal drilling based on optimization theory and the trajectory-control characteristics.The new model regards the length of curve section as its objective,in which main factors affecting 3-D trajectory design &control are considered quantitatively.Theoretical analysis and more than 10 case studies show that the new model has many advantages comparison with traditional design methods.It embodies the features of trajectory design &control,can greatly simplify the design process and hit the prescribed point or target with much higher accuracy.

Key words: re-entry, horizontal well, three dimensions, trajectory, optimal design, mathematical model