关键词: 水平井, 定向井, 多目标井, 三维井眼轨道, 设计, 数学模型, 精确解, 计算

Abstract: A reasonable well-path planning is the key to control well path successfully.It is expected to solve the problem about accurate,quick and reasonable design of three-dimensional well-path subject to various constraints.A general mathematical model for 3D well-path planning was established with given target position and direction of wellbore.The exact mathematical expressions of constraint variables and well-path calculation formulae were derived using space vectors theory.The new method has no need for solving the constraint equations group,and the design calculation is simple and accurate.The model was used to solve the difficult multi-constraint problems in complex 3D well-path planning successfully.This method can be widely used to plan all kinds of horizontal wells,directional wells and multiple target wells and may provide more accurate theory foundations for well-path control.

Key words: horizontal well, directional well, multiple target well, 3D well path, design, mathematical model, exact solution, calculation