水平井钻井技术在苏里格低压低渗储层的现场应用

Application of Horizontal Well Drilling Technology to Low-Pressure Low-Permeability Reservoirs in Sulige Gasfield

苏里格气田属于低渗透、低丰度、低压、低产的“四低”气田，油藏埋深为3500～3550m。实施水平井的主要技术难点为：井眼轨迹控制难度大；井眼净化困难；摩阻、扭矩较高；地层岩性复杂，易发生井漏、井塌等复杂情况：产层保护技术；地层研磨性强，钻头选型困难，钻井周期长。针对这些问题，进行如下优化：优化井眼轨迹，缩短靶前位移．减小施工难度；优选钻井液体系，抑制地层复杂情况的发生并保护好产层；应用个性化PDC钻头；合理调整井眼尺寸，提高钻井速度。通过现场应用，取得了良好效果。

Sulige gasfield belongs to＂ four low＂ gasfield of low permeahility, low abundance, low pressure and low yield. The reservoir was buried at depth of 3500 - 3550 m. The main technical difficulties of the horizontal well drilling are： high difficulty to control the borehole trajectory; difficult to clean the borehole; high friction resistance and torque; reservoir lithology is complex, to occur easily lost circulation, well collapse and other complex situations; payzone protection technology; the formations with strong abrasiveness, bit selection difficulty and long drilling period. In light of these problems, we conducted the following optimization： optimize wellbore trajectory; reduce the pre-target displacement; reduce the difficulty of construction; optimize the drilling fluid system; inhibit the occurring of complex situations of the formation and protect the payzone; apply personalized PDC bits; properly adjust the borehole size and increase the drilling speed. On site application shows the optimization achieved good results.