纳米颗粒在储层微流道中的减阻机理实验研究

用SNP1-1、SNP2-2和SNP2-4三种疏水纳米材料分别与柴油配制成3种油基纳米液,用SNP2-2分别与ND3和ND4配制成2种水基纳米液,通过岩心流动实验测试了这5种纳米液的减阻效果。实验结果显示,3种油基纳米液使岩心水相渗透率提高了42%、49%和24%,2种水基纳米液分别使岩心水相渗透率提高了17.5%和75%,5种纳米液都具有减阻效果,但不同纳米液的效果差异明显,这说明增注液不具有唯一性,但纳米粒径、修饰剂和分散剂对减阻效果有明显的影响。测试了SNP2-2油基纳米液处理岩心的耐冲刷能力,岩心经180倍孔隙体积（PV）水的驱替,仍具有一定的效果,说明纳米边界层流道壁面有较强的吸附能力。现场采用SNP2-2和ND4配制的纳米液进行了三口井的增注试验,注水压力最大降幅12.5MPa。研究结果与实验前的设想相符,较好地说明了纳米减阻机理。

Experiments on the drag-reduction mechanism of hydrophobic nanomaterial in reservoir microchannel

Three oil-based nanomaterial fluids（NFs） were made up of three various hydrophobic nanomaterials SNP1-1,SNP2-2,SNP2-4（SNP1-1 and SNP2-2 are same size of nanomaterials modified by two different modifiers.SNP2-2,SNP2-4 are different sizes of nanomaterials modified by same modifier） respectively and diesel oil,and two water-based nanomaterial fluids（NFs） were made up of SNP2-2 and two water-based dispersions ND3,ND4 respectively,the drag reduction effects of these five NFs were tested in core microchannel by core displacement experiments（CDEs）.The results show that,water-phase permeabilities of cores（WPPC） treated by three oil-based NFs were increased by 42 percent,49 percent,and 24 percent respectively.WPPC treated by two water-based NFs were increased by 17.5 percent and 75 percent respectively.In other words,five NFs all have drag reduction effects but significant difference of different NFs.It indicates NFs for enhancing water injection are not unique but multiple,and although drag reduction effects are influenced by nanoparticle size,surface modifier and nanomaterial dispersion.The experiment of wash-resistant ability of the cores treated by NFs of SNP2-2 dispersed in diesel oil were tested by CDEs.Its results show that the cores still have certain effect after they were washed by flooding water about 180 times core pore volume（PV）,it indicates the adsorption capacity of boundary layer of hydrophobic nanomaterial SNP2-2 on porous wall is strong.Field trials of three injection wells with NFs made up of SNP2-2 and ND4 were done,the largest decrease of injection pressure come up to 12.5MPa.The results are in agreement with the prediction views before experiment and to better verify the drag-reducing mechanism.