定向钻井中方位角及其坐标的归化问题

Naturalization of azimuth angles and coordinates in directional drilling

刘修善

LIU Xiu-shan

中国石化石油勘探开发研究院德州石油钻井研究所, 山东德州 253005

Dezhou Petroleum Drilling Research Institute of Sinopec Exploration and Production Research Institute, Dezhou 253005, Shandong, China

随着油气勘探开发进程的不断深化,所钻遇的地质环境日趋复杂,对井眼轨迹监测与控制的要求越来越高。为有效地监测和控制井眼轨迹,必须将实钻轨迹和设计轨道归算到同一个坐标系内,这将涉及到磁偏角和子午线收敛角。文中介绍了磁偏角的测算原理和校正方法,论述了子午线收敛角的定义和计算方法,阐述了磁性测斜仪的测量原理,并重点研究讨论了方位角及坐标的归化方法。研究表明,国内的最大子午线收敛角在2°23’以上,这对于水平位移为1000 m的定向井,如果不考虑子午线收敛角的影响,井眼轨迹的计算结果在水平方向上将会产生超过41.68 m的位移误差。文中较系统地论述了方位角及其坐标归化的有关理论和方法,对提高井眼轨迹的监测精度和可靠性具有实用意义。

With the intensification of exploration and development for oil and gas,the geological environment tends to be more complex for drilling and the demand for measuring and controlling well trajectory is getting higher and higher.In order to effectively monitor and control the well trajectory,it is required to calculate the practical drilling trajectory and the designed one in the same coordinate system,in which magnetic declination and meridian convergence will be involved.This paper introduces the principle and method for determining and correcting the magnetic declination,discussing the definition and calculating method of the meridian convergence,illustrating the measuring principle of magnetic clinometers.It focuses on discussing the naturalization method of azimuth angles and coordinates.The research shows that the maximum meridian convergence is over 2°23’ in China.As of the directional well with 1000 meters of horizontal displacement,more than 41.68 meters of displacement error will be caused to the horizontal calculation of the well trajectory if the effect of the meridian convergence is not taken into account.What’s more,this paper systematically discusses some other theories and methods about the naturalization of azimuth angles and coordinates,which are of practical significance to improve the accuracy and reliability in monitoring well trajectory.

10.3969/j.issn.1000-7393.2007.04.001