摘要
井筒内温度、压力对二氧化碳物性参数影响较大,且三者之间相互影响,需进行耦合求解。基于连续性方程、运动方程、能量守恒定律和传热学理论,建立了超临界二氧化碳压裂井筒非稳态温度-压力耦合模型。采用交错网格全隐式离散模型,并调用Refprop软件计算二氧化碳物性参数,采用循环迭代求解。计算结果表明:在目前施工条件下井底二氧化碳能达到超临界状态;井口二氧化碳注入温度对井筒温度影响明显,而对井筒压力影响较弱;二氧化碳注入压力和油管粗糙度对井筒压力影响较大,而对井筒温度影响较弱;二氧化碳注入排量对井筒温度、压力均有明显影响。二氧化碳的高摩阻和低黏度分别限制了施工排量和砂比的提升,因此需进一步加强流体减阻和增稠方面的研究。
Wellbore temperature and pressure have a great impact on the physical parameters of carbon dioxide,and these three factors interact with each other,which requires coupled solution.Based on continuity equation,motion equation,law of conservation of energy and heat transfer theory,a coupling model for wellbore transient temperature and pressure of fracturing with supercritical carbon dioxide was built.The model was secreted by staggered-grid fully implicit format; the REFPROP software was used to compute the physical parameters of carbon dioxide; and the coupled solution was made using loop iteration algorithm.The computation result shows that the down-hole carbon dioxide can reach supercritical state under the present operation condition; the injected temperature exerts a significant influence on wellbore temperature,and weak influence on the wellbore pressure; the injected pressure and tubing roughness have great effect on wellhore pressure,and weak effect on wellbore temperature.The injection rate has impacts on both wellbore temperature and pressure obviously.The high friction and low viscosity of carbon dioxide limit the increase in injection rate and sand ratio respectively,and thus studies on fluid friction reduction and fluid thickening should be further enhanced.
出处
《石油学报》
EI
CAS
CSCD
北大核心
2015年第2期203-209,共7页
Acta Petrolei Sinica
基金
国家自然科学基金项目(No.51374178)
四川省青年科技创新研究团队资助计划项目(2011JTD0018)资助
关键词
超临界二氧化碳
压裂
非稳态
井筒
温度
压力
耦合
supercritical carbon dioxide
fracturing
transient
wellbore
temperature
pressure
coupling
