一种微泡沫基液体系在砂质黄土层雾化钻井中的应用

APPLICATION OF A MICRO-FOAM BASE FLUID SYSTEM IN SANDY CLAY MIST DRILLING

针对低压裂缝性易水敏砂质黄土层,钻井液钻井存在恶性井漏难题,转换为常规雾化基液体系实施雾化钻井,又难以满足井壁稳定性需要。通过室内实验,在对发泡剂、稳泡剂及降滤失剂种类、用量优化的基础上,研制出了强抑制性、良好流变性能的微泡沫基液体系,对该体系的流变性、抑制性及抗盐性进行了评价,经现场应用表明,采用该微泡沫基液体系实施雾化钻井,解决了钻井液钻井恶性井漏难题,该基液体系具有较好的维护井壁稳定能力及较强的携砂能力,为水敏地层雾化钻井提供了一条新方法。

The sandy clay formation has the features of lower pressure,fissured and water sensitivity,serious lost circulation often will be happened during drilling fluid drilling.If using conventional foam base fluids implement mist drilling,the formation caving is main trouble.On the basis of laboratory test,the type and usage of foaming agent,foam stabilizer and fluid loss agent have been optimized,the formula of micro-foam drilling fluid was developed and its rheological property,rejection characteristic and salt resistance were evaluated.Field application results showed that mist drilling by using this micro foam drilling fluid could successfully resolve serious mud losing problem,and the micro-foam drilling fluid system offered a new measure for mist drilling in sensitive formation,which has preferable maintaining formation stability and stronger carrying capacity.