油水体系天然气水合物浆液流变特性研究

Research on rheological characteristics of natural gas hydrate slurry in oil-water system

水合物浆液流变特性是衡量其流动风险的重要因素。利用高压水合物实验环道,研究了含水率(体积分数)、压力、阻聚剂含量(质量分数,下同)和流速(剪切率)等参数对油水体系天然气水合物浆液表观黏度的影响。结果表明:当含水率从15%增加到20%,水合物浆液的表观黏度平均增加了8.3%;当初始压力从5 MPa增加到7 MPa,浆液的表观黏度平均增加了15.9%;阻聚剂含量与表观黏度呈负相关,表明加入一定量的阻聚剂有助于水合物浆液流动;水合物浆液的表观黏度随剪切率的增大而增大,表明水合物浆液具有剪切增稠性。同时,结合实验规律及浆液特性建立了水合物浆液幂律经验模型,预测误差在0.5%~5.0%,表明该模型能较好地预测油水体系天然气水合物浆液的表观黏度。

Rheological characteristics of hydrate slurry are important parameters to measure the flow risk control of hydrate slurry.The effects of experimental factors such as water cut(volume fraction),pressure,polymerization inhibitor content(mass fraction,the same below)and flow rate(shear rate)on the apparent viscosity of natural gas hydrate slurry in oil-water system were studied by high-pressure hydrate experimental loop.The results show that when the water cut increases from 15%to 20%,the apparent viscosity of hydrate grout increases by 8.3%on average.When the initial pressure increases from 5 MPa to 7 MPa,the apparent viscosity of slurry increases by 15.9%on average.The content of copolymer inhibitor is negatively correlated with the apparent viscosity,indicating that adding a certain range of copolymer inhibitor contributes to the flow of hydrate slurry.The apparent viscosity of hydrate grout increases with the increase of shear rate indicating that hydrate slurry has shear thickening behavior.At the same time,the power-law empirical model of hydrate slurry was established according to the experimental rules and slurry characteristics,and the prediction error is 0.5%-5.0%,indicating that the model can better predict the apparent viscosity of natural gas hydrate slurry in oil-water system.