不同驱动力条件下改性淀粉、羧甲基纤维素钠和黄原胶对水合物形成的影响

Effects of modified starch,CMC and XC on hydrate formation under different driving forces

研究不同温压条件下加量(质量分数)为0.1%~0.5%的改性淀粉、羧甲基纤维素钠(CMC)和黄原胶(XC)对CH_(4)水合物形成影响。结果表明3种增黏剂通过对体系中水分子的束缚,不同程度地抑制了水合物的成核及生长;驱动力较弱时,CMC加量达到或超过0.3%后几乎彻底抑制了水合物的形成,XC加量达到0.3%时同样可实现这一抑制效果,但随着XC加量继续增大,受其发泡性及稳泡性较强影响,水合物抑制能力有所弱化,与CMC和XC相比,改性淀粉的水合物抑制性相对较弱;驱动力较强时,3种增黏剂可微弱减缓水合物的形成速率,且XC因其在水溶液中空间结构更复杂,能束缚更多水分子,抑制效果最佳;温度为5~20℃条件下,XC提黏能力较强,且在低温条件下其水溶液的流变性具有较强的可控性,更适用于水合物钻井液体系。

The effects of 0.1%-0.5%modified starch,CMC and XC on CH_(4) hydrate formation under different temperature and pressure conditions were studied.It is found that three thickeners inhibit the nucleation and growth of hydrate with different degrees by binding water molecules in the system.When the driving force is weak,hydrate formation is almost completely inhibited when CMC dosage reaches or exceeds 0.3%.When XC dosage reaches 0.3%,the same inhibition effect can be achieved.However,with the increase of XC dosage,the hydrate inhibition ability is weakened due to its strong foaming and foam stability.Compared with CMC and XC,the hydrate inhibition ability of modified starch is relatively weak.When the driving force is strong,the three thickeners can slightly slow down the formation rate of hydrate,and XC shows the best inhibition effect because of its more complex spatial structure in aqueous solution,which can bind more water molecules.The results show that the viscosity of XC is strong and the rheological property of its aqueous solution is controllable at low temperature of 5-20℃,which is more suitable for hydrate drilling fluid system.