摘要
对传统驱油实验装置进行改进,建立裂缝-基质模型以模拟裂缝性油藏。应用该模型开展CO_2混相连续注入和吞吐实验,研究CO_2混相注入提高裂缝性油藏采收率特征,并测试产出原油组分,据此分析不同连续注气时间下基质原油产出机理。结果表明,CO_2混相连续注入很难显著提高裂缝-基质模型原油采收率,基质长度为10.0 cm时采收率仅为18.2%,长度为20.0 cm时采收率降至14.1%。原油组分测试结果表明:CO_2注入初期(0~8 h),产出原油组分基本不变,溶解膨胀为主要产油机理,是主要出油阶段;注气后期(8~40 h),产出原油组分明显变化,萃取为主要产油机理,但产油量较少。CO_2吞吐可在连续注气基础上大幅提高采收率72.8%~73.9%;但吞吐效果受生产压差影响,当生产压差为5 MPa时,累积采收率仅为7.9%~12.4%;当生产压差增至20 MPa时,累积采收率最高可达73.9%。
The fracture-matrix model was designed by improving traditional oil displacement experimental device to simu-late fractured reservoirs.Miscible continuous CO2 injection and CO2 huff-n-puff process were carried out in fracture-ma-trix system to investigate the EOR characteristics of miscible CO2 injection.The composition of produced oil during CO2 in-jection was tested to analyze the main mechanism of oil production at different continuous gas injection times.The results indicate that the miscible continuous CO2 injection cannot significantly increase oil recovery of the fracture-matrix model.The oil recovery factor was only 18.2%when the length of matrix was 10.0 cm,and decreased to 14.1%when the length of matrix was 20.0 cm.The compositional tests of crude oil show that after 0-8 h of CO2 injection,the content of produced oil was similar to that of the initial crude oil.Oil swelling were the major production mechanism contributing to the oil recovery during this period.The most of the produced oil during continuous CO2 injection was produced by oil swelling.After 8-40 h of CO2 injection,the content of produced oil changed obviously because the hydrocarbon extraction is the main oil produc-tion mechanism.However,the incremental oil content is little during this period.The oil recovery during the CO2 huff-npuff process may be significantly enhanced by 72.8%to 73.9%after continuous CO2 injection.But the oil recovery is strong-ly influenced by differential production pressure.When the production pressure difference was 5 MPa,the oil recovery fac-tor varied between 7.9%and 12.4%.When the production pressure difference was increased to 20 MPa,it was up to 73.9%.
作者
王业飞
高苗
谭龙
元福卿
陈旭
曲正天
丁名臣
WANG Yefei;GAO Miao;TAN Long;YUAN Fuqing;CHEN Xu;QU Zhengtian;DING Mingchen(School of Petroleum Engineering,China University of Petroleum(East China),Qingdao City,Shandong Province,266580,China;Research Institute of Exploration and Development,PetroChina Xinjiang Oilfield Company,Karamay,Xinjiang,834000,China;Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying City,Shandong Province,257015,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2018年第5期87-92,共6页
Petroleum Geology and Recovery Efficiency
基金
国家自然科学基金项目"强CO_2-原油传质作用的化学改性CO_2驱油体系构筑及其驱油特征研究"(51504275)
中央高校基本科研业务费资金资助"基于CO_2-原油传质作用的低渗绕流原油排驱机制及提高采收率研究"(17CX02076)
关键词
裂缝-基质模型CO2混相注入
连续注气
原油组分CO2吞吐
fracture-matrix model
CO2 miscible injection
continuous CO2 injection
composition of produced oil
CO2 huff-n-puff
