目标垂深不确定条件下的水平井轨道设计

Design of horizontal well trajectory under the uncertainty condition of vertical depth of target

目标垂深不确定在水平井钻井中是普遍存在的情况,这使得水平井井眼准确进入目标窗口的难度大大增加,甚至导致脱靶。文中提出了解决目标垂深不确定时水平井轨道设计问题的基本思路和方法。采用双增型水平井轨道设计出中间稳斜段的最佳稳斜角,在钻进过程中及时发现标志层或油层顶界面等方法,可以解决目标垂深不确定的问题。在前人基础上,同时考虑标志层倾角和储层倾角不平行的情况,对最优稳斜角的计算公式进行了推导,最后采用2个算例进行了验证。

The uncertainty of vertical depth of target exists generally in the drilling of horizontal well, which greatly increases the difficulty of which the wellhore of horizontal well accurately enters into the target window and even misses the target. This paper has put forward the basic ideas and methods of trajectory design of horizontal well to solve the uncertainty of vertical depth of target. Research shows that the problem can he snlved by designing the optimal hold angle within middle maintain angle section with bibuild horizontal well and finding the marker bed or the top boundary of oil reservoir during drilling. Based on previous calculation, the calculation of optimal hold angle is derived in this paper. Meanwhile, the inclined conditions of marker bed dip and reservoir dip are considered. At last, the paper uses two examples to conduct the verification.