摘要
为了明确纳米级孔隙半径对最小混相压力的影响,针对新疆吉木萨尔页岩油藏注CO_(2)驱最小混相压力进行了研究。通过建立临界参数偏移模型,改进PR(Peng-Robinson)状态方程,建立吉木萨尔页岩油藏流体相态模型,考虑纳米约束研究流体相态特征并确定最小混相压力。结果表明,孔隙半径的变化对临界参数有显著影响,流体临界温度和临界压力均随孔喉半径的减小而降低。当孔隙半径小于100nm时,限域约束下的临界性质与常规临界性质有明显的偏移。随着孔隙半径的减小,流体P-T相图向右偏移,两相区面积减小,相图明显呈收缩状态,相态特征更近乎重质油特征。当孔隙半径小于50nm,相图的偏移趋势显著,临界点向右下方偏移度大。吉木萨尔页岩油藏注CO_(2)驱最小混相压力采用常规确定法与纳米孔约束的相态模拟法相结合,兼顾目标区纳米孔分布权重计算得到的最小混相压力为21.6MPa。研究页岩油藏中的流体相态,确定纳米孔隙约束下的最小混相压力,对同类油藏最小混相压力的确定具有指导意义,同时可为目标油藏注CO_(2)驱提高采收率开发方案的制定提供理论支持。
In order to clarify the influence of nanoscale pore radius on the minimum miscible pressure,the minimum miscible pressure of CO_(2) flooding in Jimsar shale reservoir of Xinjiang was studied.By establishing the criticalparameter migration model and improving the PR(Peng-Robinson)equation of state,the fluid phase model of Jimsar shale reservoir was established.The characteristics of fluid phase were studied and the minimum miscible pressure was determined by nano-constraint.The results show that the change of pore radius has significant influence on the critical parameters,and the critical temperature and pressure of fluid decrease with the decrease of pore throat radius.When the pore radius is less than 100nm,the critical properties under the constraint are obviously offset from the conventional critical properties.With the decrease of the pore radius,the P-T phase diagram of the fluid shifts to the right and the area of the two-phase region decreases.The phase diagram is obviously in a contracting state,and the phase characteristics are closer to the characteristics of heavy oil.When the pore radius is less than 50nm,the phase diagram has a significantmigration trend,and the critical point has a large deviation to the lower right.The minimum miscible pressure of CO_(2) flooding in Jimsar shale reservoir is 21.6MPa calculated by combining conventional determination method with nanopore-constrained phase simulation method,taking into account the weight of nanopore distribution in the target area.The study of fluid phase in shale reservoir and the determination of the minimum miscible pressure under the constraint of nanopore have guiding significance to the determination of the minimum miscible pressure in the same reservoir.At the same time,they can provide theoretical support for the formulation of CO_(2) injection enhanced oil recovery development plans for target oil reservoirs.
作者
李菊花
王洁
梁成钢
陈依伟
张金凤
胡可
LI Juhua;WANG Jie;LIANG Chenggang;CHEN Yiwei;ZHANG Jinfeng;HU Ke(Key Laboratory of Drilling and Production Engineering for Oil and Gas,Hubei Province(Yangtze University),Wuhan 430100,Hubei;Jiqing Oilfield Operation Area,Xinjiang Oilfield Branch,CNPC,Jimsar 831700,Xinjiang)
出处
《长江大学学报（自然科学版）》
2022年第5期37-44,共8页
Journal of Yangtze University(Natural Science Edition)
基金
中国石油天然气股份有限公司重大科技专项(吉木萨尔凹陷页岩油勘探开发示范工程)(2019E-2609)。
关键词
页岩油
纳米级孔隙半径
相态
最小混相压力
新疆吉木萨尔页岩油藏
shale oil
nanoscale pore radius
phase behavior
minimum miscible pressure
Jimsar shale reservoir of Xinjiang
