邻井随钻电磁测距防碰计算方法研究

A Method of Calculating of Avoiding Collisions with Adjacent Wells Using Electromagnetic Ranging Surveying while Drilling Tools

为了解决丛式井邻井井眼防碰问题,对邻井随钻电磁测距防碰计算方法进行了初步研究。在了解邻井随钻电磁测距防碰工具结构与工作原理的基础上,将磁源看作磁偶极子,利用磁偶极子法分析了磁源周围磁场的分布规律,建立了邻井套管磁化磁场计算模型和探管处磁感应强度计算模型,确立了丛式井邻井随钻电磁测距防碰计算方法,并利用数值模拟方法分析了探管内磁源间距、磁源磁矩和套管相对磁导率等参数对探管处磁感应强度的影响。探管处磁感应强度与磁源间距、磁源磁矩、套管相对磁导率和直径等参数呈正相关,合理设计工具的关键参数,可以增强探管处的磁感应强度,提高工具测量的准确性。研究结果表明,邻井随钻电磁测距防碰工具应用确立的邻井随钻电磁测距防碰计算方法,实时测量计算正钻井与邻井的间距和方位,基本可以满足丛式井导向钻井工程需求,这对丛式井邻井随钻电磁防碰技术的发展具有非常重要的现实意义。

To eliminate the possibility of colliding with other wells in cluster wells, preliminary research has been performed to determine a ranging calculation method to avoid collision with adjacent wells using ranging electromagnetic surveying while drilling tools. Based on structure and fundamental principles of such electromagnetic tools, the magnetic source was regarded as a magnetic dipole to determine the distribution of magnetic fields around the magnetic source in accordance with the magnetic dipole theory. In this way, models for calculation of magnetic fields around the adjacent casing and intensity of magnetic in duction around probe. In addition, the ranging calculation method of anti-collision while drilling by using electromagnetic anti-collision tools was established. Numerical simulation and other methods were adopted to determine the impact of parameters such as the magnetic source spacing inside the probe, the magnetic moment of magnetic source, the relative permeability of the casing, the diameter of casing, and the includ ed angle between the drilling well and the adjacent well. It also included the magnetic induction intensity a round the probe （positively correlated to spacing between sources）, magnetic moments, relatively magnetic conductivity and diameter of casing, and other parameters. The proper design of key parameters of such tools could effectively enhance the intensity of magnetic induction around the probe and promote the accu- racy of such tools. Research results showed that the newly developed ranging methods for avoiding colli- ding with adjacent wells while drilling by using electromagnetic tools could be used to determine the spac ing and azimuth between the well being drilled and adjacent well in real time. These tools could basically satisfy demands for the drilling of cluster wells and may have great significance in the development of such anti-collision surveying tools.