套管坐标截面法推算磁干扰轨迹的研究与应用

Study and application of calculating the magnetic interference track by means of casing coordinate section method

针对密集丛式井施工中,套管磁干扰情况复杂、防碰施工困难和井间关系难以定位等问题,提出了采用套管坐标截面法对出现套管磁干扰的丛式井直井段进行井眼轨迹定位的方法。通过合理简化套管附近空间磁化模型,建立了套管横截面磁场的数学模型。同时,通过套管磁干扰的模拟实验,获取了套管横截面磁场的分布规律,在此基础上提出了套管坐标截面法,并利用此方法反演测点所处的套管空间位置,绘制正钻井的磁干扰井段井眼轨迹,实现在磁干扰井段准确判断测点与邻井套管的相对空间关系。通过华北油田10口丛式井的现场施工试验,验证了套管坐标截面法的正确性和准确性,实现了丛式井防碰关系的精准定位,解决了密集丛式井施工中的防碰问题。

During the construction of dense cluster wells,the magnetic interference of casing is complicated,the anti-collision construction is difficult and the location relationships between wells can be hardly determined.To solve these problems,it was proposed to adopt the casing coordinate section method to locate the well trajectory in the vertical section of cluster well with the magnetic interference of casing.The mathematical model of the magnetic field on the cross section of casing was established by simplifying the magnetization model of the space near the casing.In addition,the distribution laws of the magnetic field on the cross section of casing were figured out by performing simulation experiments on the magnetic interference of casing.Based on this,the casing coordinate section method was put forward.Then,it was used to invert the spatial location of measurement points in the casing and plot the trajectory of the hole section with magnetic interference in the well being drilled,so that the relative spatial relation between the measurement points and the neighboring casing can be discriminated accurately in the hole section with magnetic interference.The field construction test in 10 cluster wells of Huabei Oilfield verifies the accuracy and validity of casing coordinate section method.Thus,the anti-collision relation of cluster well is located accurately and the anti-collision problem in the construction of dense cluster well is solved.