两个不准确条件下的水平井轨道设计

目标垂深的不准确和工具造斜率的不准确,在水平井钻井中是普遍存在的.这使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.本文按照这两个不准确是否存在。提出四种组合情况,并针对每种组合情况提出解决不准确问题的基本思路和方法.研究表明,用对应于最低造斜率的曲率半径和窗底可能滞后的最大垂深来计算第一造斜点的垂深和窗心水平位移;采用双增轨道,设计出最佳稳斜角,在钻进中及时发现标志层或油层顶界面等方法,可以解决两个不准确问题.本文推导了整套设计的计算公式.并给出了算例.

DESIGN OF HORIZONTAL WELL TRAJECTORIES UNDER THE CONDITIONS OF TWO UNCERTAINTIES

A very important problem in designing horizontal well paths is how to solve the uncertainties of vertical depth of target and tool built-up rate, which exist in most horizontal drilling and make the well path control more difficult. This paper classifies the conditions into four groups according to whether the two uncertainties exist or not. The basic idea and solution are proposed. A set of calculation formulas are derived for each group, and some calculation examples are given. The results show that the problem of two uncertainties can be solved by using the redius of curvature corresponding to the minimum build-up rate and the maximum vertical depth of the window bottom deeper than prediction to calculate the depth of the first KOP and the displacement of the window center. The design of the optimum target angle and determination of the maker zone or the top of the reservoir in time during drilling can also solve the two problems.