油井化学防垢复合挤注技术室内研究及现场应用

油井化学防垢复合挤注技术的基本原理是将化学防垢液挤入油井近井地带，使防垢剂被物理吸附或形成沉淀而滞留于地层孔隙中，再通过堵水剂选择性堵水将防垢剂封堵在地层孔隙内，以形成一个地下防垢剂“仓库”。当油井进行生产作业时，防垢剂将被地层流体带出并进入井筒、地面管线及设备，从而达到防垢剂连续释放、长效防垢的目的。通过对防垢剂防垢效果、吸附性能等的室内测试，优选出了适合胜利油田牛25-C砂体的防垢剂；通过填砂管封堵试验优选出了选择性堵水剂；通过岩心驱替试验预测了防垢剂在地层中的有效期。岩心驱替试验结果表明，与堵水技术相结合的复合防垢挤注技术能大幅度提高防垢剂的挤注寿命。在胜利油田牛25-C砂体的应用表明，利用复合防垢挤注技术不但延长了防垢剂的有效期，而且提高了油井产油量。

Lab Tests and Field Applications of Chemical Anti-Scale and Squeezing Technique

The fundamental principles of chemical anti-scale squeezing technique refer to squeezing chemical anti-scale agent into formations around the well,thus allowing them to reside in porous media of the formation due to the physical absorption or precipitation,then generating an underground anti-scale "storehouse" through using water plugging to selectively plug the anti-scale agent in the formation.During the field production,the anti-scale agent would be carried by the formation fluid into the well bores,surface pipelines and other devices so that the anti-scale agent would be released continuously for the purpose of anti-scale in the long term.Based on lab tests on anti-scale results and absorption properties,an optimized anti-scale agent suitable for Niu25-C sandstone in Shengli Oilfield was identified.The selective water shutoff agents were optimized through sand pack experiments and the validation time of the anti-scale agent in formation was predicted using core flooding laboratory experiments.The application results in Niu25-C sandstone in Shengli Oilfield indicate that using anti-scale and squeezing technique prolonged the validation time of anti-scale agent and increased the well's oil production rate.