丛式井组直井段交碰风险评价及设计优化

Collision risk evaluation and design optimization on vertical section of well in cluster wells

直井段井眼防碰是丛式定向井施工过程中需要解决的主要难题之一。为了有效减小丛式定向井直井段的交碰风险,对井眼交碰概率与井眼间距、井眼交碰概率与两井眼平行段长度的关系进行了研究,得出了丛式定向井直井段总体交碰概率的求取方法。基于该方法,对由4口井组成的线形井口丛式井直井段井眼交碰概率进行了计算,通过分析找出了交碰概率最小的直井段排列方式。研究结果表明:随着井眼间距的增大,井眼交碰概率呈快速下降趋势,井眼间距超过某一距离后,井眼交碰概率趋近于平稳;随着两井眼平行段长度的增加,井眼交碰概率呈增长趋势;通过优化排列及设计方式可有效减小丛式定向井直径段的交碰风险。研究为减小丛式开发井整体风险提供了新思路。

The well- bore anti- collision in vertical section of well is one of the main problems to be resolved in the construction process of cluster directional wells. In order to effectively reduce the collision risk in vertical section of well for cluster directional wells,the relationship between well- bore collision probability and well- bore separation was studied,as well as that between well- bore collision probability and parallel section length of two well- bores. The calculation method on overall collision probability in vertical section of well for cluster directional wells was presented. based on the method,the well- bore collision probability in vertical section of well of linear wellhead cluster wells consisting of 4 wells was calculated,and the arrangement way on vertical section of well with the minimum collision probability was found. The results showed that with the increase of well- bore separation,the well- bore collision probability presents a trend of rapid decrease. When the well- bore separation exceeds a certain distance,the well- bore collision probability flattens out. With the increase in parallel section length of two well- bores,the well- bore collision probability presents a trend of increase. The collision risk in vertical section of well of cluster directional wells can be effectively reduced through optimizing the arrangement and design ways. It provides a new idea to reduce the overall risk of cluster development well.