高浓度、大段塞聚合物驱技术室内研究及矿场应用

Laboratory Research and Field Application of Polymer Flooding Technology with High Concentration and Large Pore Volume

林 杨 皇海权 王 琦 刘艳华 吕晓华 陈静怡

LIN Yang HUANG Hai-Quan WANG Qi LIU Yan-Hua Lü Xiao-Hua CHEN Jing-Yi

依据河南油田矿场生产实际需求，通过室内研究，定义了高浓度聚合物（ZL-I型部分水解聚丙烯酰胺）的下限值，优化了聚合物驱最佳注入段塞尺寸。研究结果表明：聚合物溶液质量浓度从500增至3000 mg/L时，黏度从11.8逐渐增至227.2 mPa·s；当聚合物质量浓度超过1670 mg/L后，溶液黏度大幅上升。在频率0.1 Hz下，黏性模量在聚合物质量浓度达到1643 mg/L后快速上升，而弹性模量在聚合物浓度达到1680 mg/L后快速上升。据此得到高浓度聚合物的下限值为1700 mg/L。当2000 mg/L聚合物注入量增至0.7 PV时，聚合物驱采收率大幅提高，增幅为19.77%；当注入量大于0.85 PV时，采收率增幅变缓。推荐下二门油田进行高浓度聚合物驱的注入浓度为1800～2000 mg/L，注入聚合物段塞量为0.85 PV。在该油田10口注聚井进行现场应用，日产液891.3 t，日产油77.9 t，累计增油143498 t，二次聚驱阶段提高采收率8.66%。表明注入高浓度、大段塞聚合物是挖掘聚合物驱增油潜能、提高经济效益的重要措施。

According to the actual demands of Henan oilfield, laboratory research was conducted to find out the lower limit concentration and the best pore volume of high concentration polymer (ZL-I partially hydrolyzed polyacrylamide) flooding. The results showed that the viscosity increased gradually from 11.8 to 227.2 mPa·s when the polymer concentration increased from 500 to 3000 mg/L. The viscosity increased greatly when the polymer concentration was higher than 1670 mg/L. At the frequency of 0.1 Hz, the viscous modulus increased obviously when the polymer concentration was higher than 1643 mg/L and the elastic modulus increased obviously when the polymer concentration was higher than 1680 mg/L. Therefore, the lower limit concentration of high concentration polymer flooding was 1700 mg/L. The enhanced oil recovery increased rapidly to 19.77% when the injection volume of 2000 mg/L polymer increased to 0.7 PV. But when the injection volume was more than 0.85 PV, the oil recovery increase improved slowly. It was suggested that the best polymer concentration suitable for Xia Er-men oilfield was 1800—2000 mg/L, and the most appropriate pore volume was 0.85 PV. After field application on 10 polymer injection wells, daily fluid production was 891.3 t and daily oil production was 77.9 t, the cumulative oil production was 143498 t, the oil recovery increase of second polymer flooding was 8.66%, which indicated that high concentration and large pore volume polymer flooding could enhance oil recovery dramatically and improve economic benefit greatly.