多控制点水平井靶体参数的计算

CALCULATING PARAMETERS OF HORIZONTAL WELL TARGETS WITH MULTIPLE CONTROL POINTS

石油天然气行业标准中只规定了两种水平井靶型:二维铅垂靶和三维铅垂靶,这远远不能满足水平井钻井设计等工作的实际需要。为了适应更加复杂的地质和工程上的需要,近年来更多采用拱形水平井或阶梯水平井靶区。为此,介绍了由多个关键点控制的水平井三维靶体的数学模型,给出了靶窗平面方程、靶体轴线上任意点的横向偏差和纵向偏差以及靶窗局部坐标变换等靶体参数的基础计算公式;并对描述实钻轨迹与水平井靶体的偏差的方法进行了探讨,建立了一个归一化实钻偏差模型。该模型用归一化正方形中的一条连续平面曲线直观地描述实钻轨迹与靶体轴线的距离和位置关系,可应用于水平井井眼轨道设计、井身质量评价、实钻轨迹控制等。

Only two types of horizontal well targets are stipulated in the industrial standard: 2D vertical target and 3D vertical target, which are far from meeting the practical needs in horizontal well design. In order to fulfill more complicated geologic and engineering needs, arch or stepped target areas are increasingly used for horizontal wells in recent years. By summarizing previous practical experiences on horizontal well design, a new mathematical model for 3D horizontal well target controlled by multiple key points is proposed, the target-window plane equation and basic computing formulas for target parameters such as lateral and vertical deviation at arbitrary points along target axis, the transform of local coordinate system of target-window plane are provided, and the method describing the deviation of well trajectory from horizontal well target has been discussed. A normalized deviation model has been set up, which depicts the distance and location relationship between well trajectory and target axis using a continuous plane curve in a normalized square. It can be used in horizontal well trajectory design, wellbore quality evaluation, and actual drilling trajectory control.