注聚后低浓度交联聚合物驱提高原油采收率

Crosslinked Polymer Flood for Further Enhancing Oil Recovery After Polymer Flood Performed

孤岛油田中一区馆 3单元聚合物驱先导试验区 (4个反五点法注采井组 )注入质量浓度 10 0 0～ 2 0 0 0mg/L的聚合物溶液 0 .2 9PV后转入后续注水 ,到 1999年 5月底采出程度 34.4 % ,综合含水 87.3% ,接近注聚前的值 ,1999年 10月起在该井组又开始了注低浓度交联聚合物溶液 (LPS)试验。所用聚合物为HPAM 35 30S ,-M =1.5× 10 7～1.8× 10 7,HD =30 % ,交联剂为Al3 + 质量浓度 10mg/L的AlCit溶液 ,聚合物与Al3 + 质量比为 2 0∶1。室内实验结果表明 :在温度 70℃、渗透率 4 .5 μm2 的人造岩心中注入在 4 5℃反应 2 4h的HPAM浓度 2 0 0mg/L的LPS共 4 .0PV ,阻力系数达到 135 ,注入 18.3PV后残余阻力系数仍达 5 5 ;气测渗透率 1.2 μm2 的人造岩心在 70℃水驱 5PV后原油采收率 33% ,再水驱 5PV后采收率增加 1.7% ,用 12 0 0mg/LHPAM溶液驱替 0 .35PV后采收率增加13% ,再水驱 5 .3PV后采收率增加 1.7% ,用 2 0 0mg/LHPAM / 10mg/LAl3 + LPS驱替 5 .6PV使采收率增加11.3%。在现场试验中 ,注入 0 .0 6 8PVLPS(第一阶段 2 0 0mg/LHPAM/ 15 0mg/LAlCit溶液 ,第二阶段 35 0mg/LHPAM / 5 5 0mg/LAlCit溶液 ) ,然后水驱 ,仍获得了增油减水的效果 。

In the pilot polymer flood experimental area (an inverse five pot flood wellnet) at unit Ng3 of central region I, Gudao, Shengli, 0.29 PV of 1 000-2 000 mg/L polymer solution had been injected with water injection followed and at the end of May, 1999 the recovery percentage reached 34.4% and the water cut-87.3%, a value close to that before polymer injection. In October, 1999 low concentration crosslinked polymer flood was started at the area. The polymer used-HPAM 3530S of AM-U2 =1.5×10 7-1.8×10 7 and HD =30%; the crosslinker-Al citrate solution of Al 3+ concentration 10 mg/L; polymer to Al 3+ mass ratio 20∶1. The laboratory results showed that injecting 4.0 PV of 200 mg/L HPAM crosslinked solution cured at 45℃ for 24 hrs through an artificial core of k 0 =4.5 μm 2 at 70℃ created resistance factor of 135 and successive injection of 18.3 PV of water-residual resistance factor of 55; on an artificial core of k g=1.2 μm 2 at 70℃ the oil recovery percentage is: 33% after 5 PV of water injected; 1.7% after additional 5 PV of water injected; 13% after 0.35 PV of 1 200 mg/L polymer solution injected; 1.7% after 5.3 PV of successive water injected; 11.3% after 5.3 PV of 200 mg/L HPAM/10 mg/L Al 3+ crosslinked polymer solution injected. In field trial in the experimental area, increased oil productivity and decreased water cut and some economic benifits were obtained as a result of 0.068 PV of crosslinked polymer solution (200 mg/L HPAM/150 mg/L AlCit solution at the 1st stage and 350 mg/L HPAM/550 mg/L AlCit solution at the 2nd) injected with successive water flood.