长庆油田短靶前距水平井钻井关键技术

摘要

短靶前距水平井钻井技术在井眼轨道优化设计、下部钻具组合造斜能力预测等方面存在着难以准确预测最大造斜率和恒定曲率等技术难点。针对这些难点进行了分析，明确关键技术攻关方向为井眼轨道设计中靶前距与造斜率对摩阻扭矩的影响分析及下部钻具组合造斜能力预测方法的优选，提出了短靶前距水平井井眼轨道设计的主要思路，即采用单增剖面，考虑稳定器与结构弯角、井眼扩径、钻压等因素建立了基于平恒曲率法的下部钻具组合造斜能力预测方法，结合实例，论证了上述关键技术的可行性，证明所建立的预测方法能够有效地指导实钻条件下对下部钻具组合造斜能力的要求。%Drilling technology of horizontal well with short frontal didtance from target point has a lot of technical dififculties in the optimization design of wellbore trajectory and prediction of delfecting force of bottom hole assembly, such as the dififculties in predicting the maximum build-up rate and constant curvature very accurately. Analysis has been made against all these dififculties. The key technical point will be focused on the analysis on the inlfuence of frontal distance from the target and build-up rate in wellbore trajectory design on friction torque and the optimization of the prediction method of delfecting force of bottom hole assembly, and the main ideas on the wellbore trajectory design of horizontal well with short frontal distance from the target have been proposed, which means establishing constant curvature-based prediction method of delfecting force of bottom hole assembly with monotone increasing proifle by considering such factors as the stabilizer and structure corner, borehole enlargement and bit pressure. The feasibility of relevant key techniques has been demonstrated by combining cases and the prediction method established can effectively guide the requirements for delfecting force of bottom hole assembly when drilling is really made.