纳米颗粒对深部盐水层中CO2运移影响分析

The Analyses of Nanoparticles on CO2 Transport Characteristics in Deep Salt Water Layer

埋存CO2于深部盐水储集层中是当前可行的埋存方式之一,封存的CO2可能会沿着盖层中较大的孔道或者裂缝向上运移从而泄露返回到大气中。采用CT扫描仪测量岩心中流体饱和度的变化,研究了纳米颗粒对岩心中CO2运移的影响。在盐水试验中,CO2流体的驱替前缘不一致,在岩心中产生指进现象;在纳米颗粒试验中,CO2横向流动变化大可以减缓甚至消除指进,其流动压差是盐水试验流动压差的1.5~2.5倍;纳米颗粒使得CO2与盐水产生稳定的乳状液,减小流体流动性,增加流体有效黏度,减小其相对渗透率;在CO2埋存过程中,可以预先将纳米颗粒放置在可能产生泄漏的路径上,CO2通过时可自发与盐水形成乳状液从而达到自封堵效果。

CO2 sequestration in deep saline reservoirs is one of the feasible methods to storage currently.The CO2 sequestration can transport up along the larger pores or cracks in the caprock and return to the atmosphere.CT scanner is used to measure the changes of fluid saturations in the cores to study the effects of nanoparticles on CO2 migration.Experiments show that CO2 flooding has an inconsistent leading edge in the brine,resulting in fingering phenomenon.In the nanoparticles experiment,the lateral variation of CO2 can slow or even eliminate fingering in the flow.And the pressure drop of nanoparticles experiment is 1.5 to 2.5 times as much as that of brine test.Nanoparticles can make stable emulsions between CO2 and brine,reducing the fluid flow,increasing the effective viscosity and decreasing the relative permeability.The nanoparticles can be pre-placed along potential leakage paths,and the CO2 encounters such a path,a CO2/brine emulsion will form,achieving the self-sealing emulsion.