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大庆油田海拉尔、延吉、汤原等新探区地层倾角大,井外控制困难,严重影响了钻井速度并增加了钻井成本、研制的偏重偏心防斜钻具,经理论分析和现场试验证明,该钻具在井下旋转过程中所产生的离心力使其偏重段重边的稳定器始终贴向井壁,使钻具产生公转特性,有效地克服钻头自转引起的井斜,其离心力与转速平方成正比,转速越高产生的离心降斜力越大。该钻具能防斜、稳斜和降斜,其结构简单,安装方便,能较好地解决钻定向丛式井直井段的防碰技术难题。该钻具还适应地层倾角大的软到中硬地层,其偏心距的确定、优化组合钻具结构以及合理地选择钻压和转速,对防斜钻井及提高钻速均具有十分重要的作用。在12口井的现场试验中,井斜角均控制在1°以内,满足了钻定向丛式井造斜点井斜角小于1°的要求。
The new dip in Hailaer, Yanji and Tangyuan, Daqing Oilfield, has large dip angle and difficult control outside the well, which has seriously affected the drilling speed and increased the drilling cost. The over-center anti-inclined drilling tool was developed. Theoretical analysis and field tests show that Drilling tools in the downhole rotation of the centrifugal force generated by the heavy side of the heavy edge of the stabilizer is always affixed to the shaft wall, the drilling tool to produce revolution, effectively overcome the drill stem rotation caused by the inclination, the centrifugal force is proportional to the square of the speed, The higher the rotational speed, the greater the centrifugal descending force. The drilling tool can prevent slanting, steady inclination and descending inclination. The utility model has the advantages of simple structure and convenient installation, and can well solve the anti-collision technical problems of drilling a straight well of a cluster well. The drilling tool is also suitable for soft to medium hard formations with large dip angle. The determination of its eccentricity, optimizing the structure of the combined drilling tools and selecting the weight-on-bit and rotation speed rationally are very important for anti-inclined drilling and increasing the drilling speed. In the field test of 12 wells, the well inclination angle is controlled within 1 °, which meets the requirement that the inclination angle of the tapping point of the drilling directional cluster wells is less than 1 °.