三元复合体系性能及其对驱油效率影响研究

The Performance of ASP Compound Sytem and Its Effect on Flooding Efficiency

研究了碱/表面活性剂/聚合物(ASP)三元复合体系黏度、界面张力、聚合物分子线团尺寸(Dh)、分子聚集态和驱油效率及其影响因素,并对提高采收率机理进行分析。结果表明,NaOH质量分数由0增至1.2%,三元复合体系黏度由246.9降至138.8 mPa·s、界面张力降低、Dh由324.7降至263.5 nm。表面活性剂质量分数由0增至0.3%,体系黏度由127.0降至122.1再增至138.8 mPa·s,界面张力降低,Dh由139.7增至263.5 nm。随固液质量比增加和吸附次数增多,三元复合体系界面张力升高。在碱/聚合物体系中,聚合物分子结构形态以'片状'为主,'网状'为辅;在重烷基苯石油磺酸盐/聚合物体系中,聚合物分子形态出现大面积的'珠状'结构,'网状'结构不明显;在ASP体系中,聚合物分子呈现'网状-片状'结构形态。驱油实验表明,与水驱相比,三元复合体系、聚合物溶液和碱/表面活性剂二元复合体系采收率增幅分别为14.8%、12.2%和4.8%。随驱油剂黏度增加,化学驱采收率增大,但增幅逐渐减小。聚合物质量分数为0.12%、0.18%和0.25%时,聚合物驱采收率增幅分别为12.2%、15.8%和18.7%,三元复合体系驱采收率增幅分别为14.8%、18.3%和21.0%。在聚合物加量相同的条件下,与聚合物溶液相比,三元复合体系采收率增幅高2.3%~2.6%。驱油剂扩大波及体积作用对采收率的贡献要大于提高洗油效率的贡献。

The performance of ASP(alkali/surfactant/polymer) was studied in the aspects of viscosity,interfacial tension,molecular clew dimension(Dh),molecular configuration,flooding effect and their influencing factors. The mechanism of enhancing oil recovery was analyzed. The results showed that the viscosity of ASP system decreased from 246.9 mPa·s to 138.8mPa·s,the interfacial tension decreased and Dh fell from 324.7 nm to 263.5 nm when the mass fraction of NaOH increased from 0to 1.2%. As the dosage of surfactant increased from 0 to 0.3%,the viscosity of ASP system decreased from 127.0 mPa·s to 122.1mPa·s and then increased to 138.8 mPa·s,the interfacial tension decreased and Dh increased from 139.7 nm to 263.5 nm. As the mass ratio of solid to liquid and adsorption times increased,the interfacial tension of ASP system increased. In alkali/polymer system,structural morphology of polymer molecules gave priority to'sheet',the'nets'came with complementary. In heavy alkyl benzene sulfonate/polymer system,there appeared a big area of'bead'for structural morphology of polymer molecules,however,structure of'nets'wasn't obvious. In ASP system,structure of'nets-sheet'presented for structural morphology of polymer molecules. The results of oil displacement experiment showed that the recovery efficiency increment of ASP system,polymer solution and alkali/surfactant system was 14.8%,12.2% and 4.8% respectively in comparison to water flooding. With increasing viscosity of oil-displacement agent,the chemical recovery efficiency increased,but its increment decreased gradually. When the mass fraction of polymer was 0.12%,0.18% and 0.25%,the recovery efficiency increment of polymer flooding was 12.2%,15.8%and 18.7%,and that of ASP flooding was 14.8%,18.3% and 21.0%,respectively. In the condition of same polymer dosage,the recovery efficiency increment of ASP flooding was higher than that of polymer flooding by 2.3%—2.6%. The contribution of the effect of oil-displacement agent on enlarging swept volume to recovery efficiency was greater than that on improving oil-displacement efficiency to recovery efficiency.