平衡倾角法防斜技术探讨

在煤层气钻井施工中,选择合理防斜技术手段是防止井内质量事故以及提高钻井效率的关键。平衡倾角法是依据钻井区地层倾角及岩层的发育情况,利用木板、铁板和枕木等材料来垫高塔角,从而使转盘面与地层倾角部分平衡,进而控制井斜的一种防斜技术方法。介绍了近几年在煤层气钻井中总结出来的塔角所垫高度的经验公式。应用实践表明,该方法具有防斜效果好,钻井效率高的特点,同时认为它适用于地层倾角10°～40°、软硬相间的地层。

Probe into Balanced Inclination Method Deviation Prevention Technology

In CBM drilling operations,rational selection of deviation prevention means is the key to prevent borehole quality accidents and improve drilling efficiency.The balanced inclination method is based on strata inclination and development,using wood board,sheet iron or sleeper to block up derrick foot,thus to balance rotary table and stratigraphic dip partially,and then control borehole deviation.The paper introduces empirical formula of derrick foot block-up height summing-up in CBM drilling in recent years.The practices demonstrated that the method has characteristics of good deviation prevention effect,high drilling efficiency,and adequate for strata with dip angle 10o~40o and alternating hard and soft beds.