抗高温疏水缔合聚合物无固相钻井液研究及现场试验

针对现有无固相钻井液抗温能力弱、无法满足高温水平井钻井需要的问题，以两性离子型疏水缔合聚合物PL-5为主剂配制了抗高温疏水缔合聚合物无固相钻井液。对该钻井液的流变性、滤失性、悬浮稳定性、抑制性和储层保护性能进行了室内试验评价，并应用原子力显微镜（AFM）和环境扫描电镜（ESEM）对构建该钻井液液相的聚合物的微观结构进行了观测。室内试验结果表明:该钻井液在160℃下老化后，仍可保持良好的流变性、滤失性和悬浮稳定性；上部地层钻屑的一次滚动回收率达60.1%，下部地层钻屑的一次滚动回收率达87.2%，抑制泥页岩水化分散效果显著；油层岩心的渗透率恢复率可达82.0%以上。抗高温疏水缔合聚合物无固相钻井液在DF1-1气田3口井的水平段钻井中进行了现场试验，结果表明，该钻井液不仅具有良好的流变性、滤失性和悬浮稳定性，而且具有良好的储层保护效果，提速效果显著，能够满足高温水平井钻井需要。 

A Study and Field Test for Solid-Free High Temperature Resistance Hydrophobic Association Polymer Drilling Fluid

Existing solid-free drilling fluids may have low temperature resistant performance, but can not satisfy the demands for drilling of horizontal wells in a high temperature regime. To solve this problem, a solid-free high temperature resistant drilling fluid has been developed, taking a zwitterionic hydrophobic associated polymer (PL-5) as the main treatment agent. Its rheological property, filtration loss, suspension stability, inhibition and reservoir protection effectiveness were indoor tested and evaluated, and the microstructure of polymer in liquid drilling fluid was observed by means of atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM). Test results showed that the newly developed drilling fluid could maintain the desirable rheological property, filtration property and suspension stability after aging at the temperature of 160℃. The first cuttings rolling recovery rate at an upper formation was 60.1%, and later 87.2% at a lower formation. The new drilling fluid can effectively inhibit the hydration of mud shale, and the permeability recovery rate of reservoir core is up to 82.0%. The application effect in three high-temperature horizontal wells of DF1-1 Gas Field showed that the solid-free drilling fluid not only exhibited desirable property of rheology and filtration as well as suspension stability, but also had a good effect for reservoir protection and raising the drilling rate, which can meet the demands of drilling horizontal wells at high temperatures.