摘要
CO_(2)驱可以改善低渗透油藏的开发效果,并通过置换油气等方式实现CO_(2)地质埋存,但由于油气密度差的存在,会形成CO_(2)重力超覆而影响驱油效果。为明确油层厚度较大的低渗油藏中CO_(2)混相驱条件下注气速率对重力超覆程度的影响规律,分别采用室内物理模拟实验和数值模拟等方法进行研究,并通过建立的数值模型和超覆程度表征方法,系统评价注气速率的影响规律,从而对注入量等参数进行优化。结果表明,混相驱条件下仍存在一定程度的重力分异,且随注气速率的增加,重力超覆程度减弱,混相驱采收率提高,但相比非混相条件,超覆程度较低,通过注气速率优化减弱其影响的效果更为明显。针对给定模型的模拟计算结果表明,当注入量大于10 t/d后超覆程度影响减弱,因此,为保证厚油层CO_(2)混相驱油效果,在不发生气窜的前提下应适当采用较大的注气速率以减弱重力超覆的影响。研究结果对于CO_(2)驱油现场试验方案设计和注气参数优化具有一定的指导意义。
CO_(2) flooding can improve the development effect of low-permeability reservoirs,and realize CO_(2) geological storage by replacing oil and gas.However,due to the existence of oil and gas density difference,the CO_(2) gravity segregation affects the oil displacement effect.In order to clarify the effect of gas injection rate on the degree of gravity overlay under the condition of CO_(2) miscible flooding in low-permeability and thick oil reservoirs,laboratory physical simulation experiments and numerical simulation methods were used respectively.The research was carried out,and parameters such as injection rate were optimized through the established numerical model and the characterization method of the degree of segregation.The results showed that under miscible flooding conditions,there was still a certain degree of gravity differentiation,and with the increase of gas injection rate,the degree of gravity segregation decreased,and the recovery rate of miscible flooding increased.Compared with immiscible conditions,the degree of segregation was lower,the effect of reducing its influence by optimizing the gas injection rate was more obvious.The simulation calculation results for the given model showed that the influence of the overburden degree was weakened when the injection rate was greater than 10 t/d.Therefore,in order to ensure the CO_(2) miscible oil displacement effect in thick oil layers,a relatively large injection rate should be appropriately adopted to reduce the influence of gravity segregation without gas channeling.The research results have certain guiding significance for the design of the CO_(2) flooding field test scheme and the optimization of gas injection parameters.
作者
赵凤兰
刘淼淼
黄世军
宋黎光
王雨
ZHAO Fenglan;LIU Miaomiao;HUANG Shijun;SONG Liguang;WANG Yu(College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing,102249,P R of China;Jidong Petroleum Branch Company,PetroChina,Tangshan,Hebei 063200,P R of China)
出处
《油田化学》
CAS
CSCD
北大核心
2023年第2期322-329,共8页
Oilfield Chemistry
基金
国家自然科学基金“页岩油注CO_(2)过程中重有机质沉积机理表征及预测”(项目编号52174039)
国家自然科学基金“页岩储层条件下水对甲烷-二氧化碳竞争吸附的影响及相互作用机制研究”(项目编号51974328)
中国石油战略合作科技专项“注气提高单井产量技术研究”(项目编号ZLZX2020-02-04-04)。
关键词
碳捕集、利用与封存
低渗厚油层
CO_(2)混相驱
注气速率
重力超覆
carbon capture
utilization and storage
low permeability thick reservoir
CO_(2)miscible flooding
gas injection rate
gravity segregation
