低渗油田出砂机理分析

Analysis of sanding mechanism of low-permeability oilfields

通常认为低渗透油田不会发生地层出砂.然而,延长油矿樊学区块严重出砂,大大影响了正常的生产.根据现场调研、矿物成分对比、粒径分析、驱替实验验证、出砂指数、采油污水检验、临界井底流压和临界产量等,首先确定出砂为地层砂,而不是通常认为的压裂砂.根据该区块的实际地质情况,认为地层出砂的主要原因是地层岩石胶结物———黏土的剥离.制定了相应的防砂治砂方案,建议在维持一定产液量携带砂粒出井筒的同时,采取黏土稳定剂、滤砂管和清蜡剂的综合治砂措施.

It is generally considered that formation sand production does not happen in low-permeability oilfields. However, serious sand production affects oil production a lot in Fanxue tract of Yanchang Oilfield. Based on field investigation, mineralogical composition, particle diameter of the sand, displacement experiment, sanding index, produced water, critical flowing bottomhole pressure and critical oil production, it is held that the sand comes from formation but is not frac sand. According to the geologic situation, it is also held that the causeof sand production is the slabbing of formation rock cementing matter--clay. And an integrated sand controlproject is drawn out. That is to make sure a certain liquid yield to carry the sand out of wellbore, and at the same time, to use clay stabilizer, paraffin remover and sand screen.