考虑方位漂移的水平井井眼轨道设计

Horizontal Well Trajectory Design Based on Azimuth Drift

目前,深层页岩气水平井在钻井过程中经常出现方位漂移的问题,方位漂移严重影响了水平井的井眼轨迹控制,进而影响水平井的准确中靶。在现场施工中,通常根据施工区以前的钻井经验,在进行定向造斜时,先估计出一个"方位超前角",这种现场的做法有着很大的不确定性,并且可能出现较大误差。本文提出了考虑方位漂移的水平井井眼轨道优化设计的方法,解决了仅凭现场经验给出的"超前角"不准确的问题。考虑方位漂移的水平井井眼轨道优化设计按照井段划分,将地层因素与井身剖面结合起来求取井段的平均方位漂移率。根据该方法研制开发了考虑方位漂移的水平井井眼轨道优化设计软件,并通过举例进行了验证,证明了方法是可行的。

At present,the azimuth drift often occurs in the drilling process of deep shale gas horizontal wells,which seriously affects the trajectory control of the horizontal well,and then affects the accurate target of the horizontal well.In the field construction in this area,usually according to the previous drilling experience,an ＂advanced azimuth angle＂should be estimated before the directional slanting is carried out,but there are a lot of uncertainties in this field practice and there may be some big error.In this paper,a method of horizontal well trajectory optimization design based on azimuth drift is proposed,which solves the inaccuracy of＂advanced azimuth angle＂only estimated by the field experience.The optimization design of horizontal well trajectory is devided according to the well sections;the average azimuth drift rate of the well section is obtained by combining the stratigraphic factors with the well profile.Based on this method,the software for the optimization design of horizontal well trajectory based on azimuth drift is developed.The feasibility of this method is proved by the examples.