垦利3-2油田注入水结垢与防垢试验研究

Scaling Tendency and Compatibility of Injected Water in Kenli 3-2 Oilfield

注入水能有效维持和进一步补充储层压力与地层能量，提高采收率。若注入水水质不稳定或与储层不配伍，不但达不到稳产增产的效果，而且可能对储层造成伤害。为分析垦利3-2油田注入水可行性，对垦利3-2油田注入水水质、注入水自身结垢趋势预测与静态结垢程度等进行了分析研究。结果表明，垦利3-2油田注入水在地层温度范围内会产生CaCO3垢，且其结垢趋势与程度随温度的升高而增大，在注水过程中能对储层岩心渗透率造成明显的损害。同时优选出了具有良好抗温性的防垢剂HEDP，当加量为20-30mg／L，其防垢率≥90％，加入25mg／LHEDP后，注入水在注入过程中岩心渗透率保留值可达95％以上，可有效避免因地层流体不配伍而结垢造成的地层伤害。

The injected water can effectively maintain and further supplement the reservoir pressure and formation energy and enhance oil recovery.If the injected water quality is not stable or not compatible with the reservoir,it can not achieve the stable production effect,also may induce damage to the reservoir.For analyzing the feasibility of injected water in Kenli 3-2Oilfield,the quality of injected water,its scaling trend forecasting and its static scaling degree are analyzed.The results show that CaCO3 scale would be induced in the injected water of Kenli 3-2Oilfield at formation temperature,and its scaling tendency and the extent increase with the increase of temperature.In the injection process it would cause significant damage to the rock permeability of reservoirs.Meanwhile an optimal scale inhibitor HEDP which has good temperature resistance is chosen and when the dosage is 20~30mg/L,its scale resistance is≥90%,After adding 25mg/L HEDP to the injected water,more than 95% of core permeability retention is maintained.It can effectively avoid formation damage caused by scaling from incompatible formation fluids.