分1井大井眼空气可循环泡沫钻井液技术

Recycling Air Foam Mud Technology in Large Hole Well Fen-1

针对川东北地区上部地层砂泥岩互层频繁、硬度大、研磨性强、可钻性差，用常规钻井液机械钻速较慢，而因地层出水也无法顺利实施空气钻井的问题，研究了适合该地区上部地层钻进的空气可循环泡沫钻井液配方，并在分1井进行了应用。空气可循环泡沫钻井液钻进井段为103～938．5m，平均机械钻速为4．48m／h，其中429～840m泥岩（夹砂岩）段平均钻速达5．83m／h，比同条件下使用常规钻井液的机械钻速提高4倍多；钻进中控制空气排量为80～120m。／min，液体流量为3～7L／s，满足了测斜、起下钻等作业的顺利进行，同时也保证了泡沫钻井顺利地转化为常规钻井。应用结果表明，该技术较好地解决了上部大井眼地层钻速慢及地层出水问题。

A recycling air foam mud was tested in Well Fen-1 in northeast Sichuan where the top formation rocks are mainly hard and abrasive sand shale sequence with poor drillability.Air drilling in this area cannot be used because of water invasion.Average rate of penetration was 4.48 m/h from 103 m to 938.5 m,in which 5.83 m/h was achieved in the mudstone from 429 m to 840 m(four times of that obtained with water base muds).The flow rates of air and liquid were 80-120 m3/h and 3-7 L/s,respectively.Field operation showed that the recycling air foam was suitable for drilling the top section of the well,and can be successfully converted to conventional water base muds.