注水阻力分析及功能型减阻增注剂的性能评价
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摘要
为了提高低渗透油藏注水井的降压增注效率,本文研究了岩石表面润湿性、界面张力等因素对低渗透油藏注水阻力的影响规律,并在此基础上研究了一种多功能型减阻增注剂CNG,评价了CNG溶液改变油水界面张力、改变岩石表面电性和润湿性和改变岩心降压增注效果的能力。研究结果表明:CNG既能降低油水界面张力至10~(-3)mN/m数量级、消除岩心毛管阻力;又能吸附在岩石表面消除岩石表面负电荷、改善岩石表面润湿性至弱水湿。CNG即适用于含有残余油的岩心降压增注,又适用于强水湿油藏的减阻增注,还适用于即有残余油又强水湿油藏的降压减阻增注。对于胜利油田某区块天然岩心,CNG用于不洗油的原始岩心时,渗透率提高48.49%,驱替压差降低31.25%;CNG用于没有残余油、呈现水润湿状态的岩心时,渗透率提高36.32%,驱替压差降低27.66%。图10表1参10
In order to improve the efficiency of depressurization and injection increase of water injection wells in low permeability reservoirs,the influence of rock surface wettability,interfacial tension and other factors on water injection resistance was studied,on this basis,a multifunctional drag reduction and injection augmenter CNG was developed,the abilities of CNG solution to change oil-water interfacial tension,rock surface electrical property and wettability,and core pressure-lowering and injection-increasing effect were evaluated. The results showed that,CNG could reduce the oil-water interfacial tension to n × 10~(-3) mN·m~(-1)(n<10),eliminate core capillary resistance. CNG could also adsorb on rock surface to eliminate negative charge on rock surface and improve the wettability of rock surface to weak water-wet. Therefore,CNG was not only suitable for core depressurization and injection enhancement with residual oil,but also for drag reduction and injection enhancement in strong water-wet reservoirs,and also suitable for pressure reduction,drag reduction and injection enhancement in reservoirs with both residual oil and strong water-wet.For the natural core of a certain block in Shengli oilfield,when CNG was used in the original core without washing oil,the permeability was increased by 48.49% and the displacement pressure difference was reduced by 31.25%;while when CNG was used in the core without residual oil and with water wetting state,the permeability was increased by 36.32% and the displacement pressure difference was reduced by 27.66%.
In order to improve the efficiency of depressurization and injection increase of water injection wells in low permeability reservoirs,the influence of rock surface wettability,interfacial tension and other factors on water injection resistance was studied,on this basis,a multifunctional drag reduction and injection augmenter CNG was developed,the abilities of CNG solution to change oil-water interfacial tension,rock surface electrical property and wettability,and core pressure-lowering and injection-increasing effect were evaluated. The results showed that,CNG could reduce the oil-water interfacial tension to n × 10~(-3) mN·m~(-1)(n<10),eliminate core capillary resistance. CNG could also adsorb on rock surface to eliminate negative charge on rock surface and improve the wettability of rock surface to weak water-wet. Therefore,CNG was not only suitable for core depressurization and injection enhancement with residual oil,but also for drag reduction and injection enhancement in strong water-wet reservoirs,and also suitable for pressure reduction,drag reduction and injection enhancement in reservoirs with both residual oil and strong water-wet.For the natural core of a certain block in Shengli oilfield,when CNG was used in the original core without washing oil,the permeability was increased by 48.49% and the displacement pressure difference was reduced by 31.25%;while when CNG was used in the core without residual oil and with water wetting state,the permeability was increased by 36.32% and the displacement pressure difference was reduced by 27.66%.
引文
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[7]渠慧敏,丁子峰,门海英,等.分子膜增注剂的分子模拟、合成及性能评价[J].油田化学,2017,34(3):463-468.
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[9]付美龙,王何伟,罗跃,等.吴旗油田表面活性剂降压增注物模实验和现场试验[J].油田化学,2008,25(4):332-335.
[10]田志铭.石油磺酸盐复配体系改善低渗透油藏注水效果室内研究[J].油气地质与采收率,2009,16(3):71-73.
[2]袁建滨.黏土中结合水特性及其测试方法研究[D].广州:华南理工大学,2012.
[3]朱维耀,田英爱,于明旭,等.微圆管中流体的微观流动机制[J].科技导报,2014,32(27):23-27.
[4]徐绍良,岳湘安,侯吉瑞,等.边界层流体对低渗透油藏渗流特性的影响[J].西安石油大学学报(自然科学版),2007(2):26-28.
[5]谢全,焦春艳,崔丽萍,等.低渗透单相非线性渗流机制试验研究[J].岩石力学与工程学报,2011(S2):3975-3981.
[6]苏法卿,孙志刚,任忠斌.低渗透砂岩油藏油水两相最小启动压力梯度实验研究——以史南油田史深100区块为例[J].油气地质与采收率,2004,11(4):44-48.
[7]渠慧敏,丁子峰,门海英,等.分子膜增注剂的分子模拟、合成及性能评价[J].油田化学,2017,34(3):463-468.
[8]渠慧敏,罗杨,戴群,等.低渗透砂岩油藏分子膜增注性能和机理研究[J].油田化学,2013,30(3):354-357.
[9]付美龙,王何伟,罗跃,等.吴旗油田表面活性剂降压增注物模实验和现场试验[J].油田化学,2008,25(4):332-335.
[10]田志铭.石油磺酸盐复配体系改善低渗透油藏注水效果室内研究[J].油气地质与采收率,2009,16(3):71-73.