控制定向装置方位角进行定向钻井实践

在定向钻井过程中,为了能顺利中靶,就需要不断控制定向装置修正井眼轨迹。但在实际定向井操作中,现场工程师通常使用如弯接头等的简单定向装置进行较长距离定向钻井,主要凭经验控制装置角,仅有一个可行范围,造成了实践中影响到轨迹调整速度,需要多次修正后才能获得所要的井斜角和方位角。文中将讨论一种方法,只通过控制定向装置的方位角进行定向井实践,并给出一个最优的定向装置的方位角计算方法,即通过当前定向点的井斜角和方位角方向至靶点所在水平面得到的矢量一和当前定向点至靶点得到的矢量二,由矢量二减矢量一后得到新矢量在水平面的投影方向确定定向装置的方位角,然后利用该方位角进行定向井操作。通过理论和实践,证明该方法不论在增斜或降斜模式都能够快速、稳定改变井眼方位,顺利中靶,简单、实用。

Control azimuth of the directional equipment to operate directional drilling

During directional drilling,the drilling trajectory needs to be adjusted by using directional devices to reach the target successfully.However,the field engineers usually use simple directional devices,such as an elbow sub,to conduct long-distance directional drilling during practical directional drilling.They control setting angles only based on subjective experience.As a result,only a feasible range is obtained,which has a negative effect on the trajectory adjustment speed.Deviation and azimuth angles needed can be gotten on the basis of many times of revision.In this paper,a new method is discussed to control directional drilling only by changing the azimuth angle of directional devices and as a result an optimum approach to calculating the azimuth angle of directional devices is achieved.The approach is to get the first vector from the present point to the level of target and the second vector from the present point to the target,and then the difference of the first vector from the second vector is a new vector.The horizontal projection of the new vector determines the azimuth angle of directional devices to operate directional drilling.The new method is simple and practical to change the azimuth of wellbore immediately and stably,so as to reach the target successfully either in the mode of increasing or decreasing inclination.