Jia Han, Zhang Xuehao, Wang Qiuxia, Xu Mingming, Zhang Lingyu, Dai Jiajun, Wang Qiang, Fan Fangning, Liu Dexin, Wu Hongyan
Shandong Key Laboratory of Oilfield Chemistry, School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China.
Ministry of Education, Key Laboratory of Unconventional Oil & Gas Development (China University of Petroleum (East China)), Qingdao 266580, China.
Langmuir. 2023 Aug 15;39(32):11448-11458. doi: 10.1021/acs.langmuir.3c01431. Epub 2023 Aug 3.
Nanoparticles (NPs) exhibit great potential to improve various properties of viscoelastic surfactant (VES) fracturing fluids in the development of low-permeability reservoirs. In the present study, the amphiphilic Janus NPs (JANPs) were fabricated via the Pickering emulsion method and employed to construct the novel JA12C (JANPs with dodecyl hydrophobic carbon chains)-assisted VES fracturing fluid (JAVES). The successful fabrication of JANPs was confirmed via Fourier transform infrared spectroscopy (FTIR) measurements and water contact angle tests. The rheology behavior of the VES fracturing fluid incorporating various SiO NPs including hydrophilic SiO NPs (HLNPs), JA8C (JANPs with octyl hydrophobic carbon chains), and JA12C was systematically investigated. It was revealed that the additional JA12C significantly improved the tolerance and proppant suspension properties. To explore the subsequent oil recovery performance of various gel breaking liquids, the formation wettability and the oil-water interfacial tension (IFT) were studied after the evaluation of breaking properties and formation damage properties of various fracturing fluids. The results suggested that the JAVES gel breaking liquid showed remarkable wettability alternation capability and moderate oil-water IFT reduction ability, which can partially reduce the impact on reservoir permeability. Moreover, the formation mechanism of the JAVES was proposed by molecular dynamics simulations at the molecular level, which was further visually verified via the cryo-TEM images. The improved viscoelasticity of developed the JAVES with moderate interfacial activity is advantageous to enhance subsequent oil recovery.
在低渗透油藏开发中，纳米颗粒（NPs）在改善粘弹性表面活性剂（VES）压裂液的各种性能方面具有巨大潜力。在本研究中，通过皮克林乳液法制备了两亲性Janus纳米颗粒（JANPs），并用于构建新型JA12C（具有十二烷基疏水碳链的JANPs）辅助的VES压裂液（JAVES）。通过傅里叶变换红外光谱（FTIR）测量和水接触角测试证实了JANPs的成功制备。系统研究了包含各种SiO NPs（包括亲水性SiO NPs（HLNPs）、JA8C（具有辛基疏水碳链的JANPs）和JA12C）的VES压裂液的流变行为。结果表明，添加JA12C显著提高了耐受性和支撑剂悬浮性能。为了探索各种破胶液的后续原油采收性能，在评估了各种压裂液的破胶性能和地层损害性能后，研究了地层润湿性和油水界面张力（IFT）。结果表明，JAVES破胶液表现出显著的润湿性改变能力和适度的油水IFT降低能力，这可以部分降低对储层渗透率的影响。此外，通过分子动力学模拟在分子水平上提出了JAVES的形成机制，并通过冷冻透射电子显微镜（cryo-TEM）图像进一步直观验证。具有适度界面活性的JAVES改善的粘弹性有利于提高后续原油采收率。
