亲水纳米SiO2对CH4水合物形成的影响

摘要

水合物钻井液体系中的纳米颗粒可有效维持井壁稳定并降低钻井液对储层的侵入,但对水合物形成和生长的影响具有不确定性.在相同试验条件(5.0 ℃,5.0 MPa)下,对蒸馏水及模拟钻井液中CH4水合物形成的诱导时间、形成量及形成速率进行测试研究,并结合多种试验方法揭示影响机制,模拟钻井液配方为蒸馏水+亲水纳米SiO2(粒径为30和50 nm,加量为1.0% ~5.0%).结果表明:粒径为50 nm的亲水纳米SiO2颗粒在模拟钻井液中加量为4.0%时对CH4水合物的形成具有较强的抑制能力,相比于蒸馏水,这一体系中水合物形成诱导时间延长了74%,形成量减少了21%,形成速率降低了56%.%Addition of nanoparticles into drilling fluids can maintain the wellbore stability and decrease the invasion of drill-ing fluid into near wellbore formation when drilling hydrate bearing sediments,which may also affect the formation of gas hy-drates in the wellbore. In this study, laboratory experiments were carried out to investigate the effect of nanoparticles on methane hydrate formation,and the induction time,the amount and rate of hydrate formation at an experimental condition of 5 ℃ and 5 MPa) using pure water and various drilling fluid formulation were measured,including distilled water added with hydrophilic nano-SiO2particles (30 nm and 50 nm of particle sizes) with concentrations of 1%-5%. The results show that nano-SiO2particles can efficiently inhibit the formation of methane hydrate. In comparison with pure water,addition of nanop-articles (50 nm and 4%),the hydrate induction time can be increased by 74%,with the amount of hydrate formed reduced by 21%,and the rate of formation reduced by 56%.