摘要
低渗透砂岩油藏注水过程中,注入水对储层孔隙的长期冲刷会对储层岩石的矿物组成、物性、渗流特征带来影响,针对该问题运用X射线衍射、核磁共振、液测孔渗等实验技术,开展了岩心长期水驱前后储层矿物组成、物性、渗流特征的对比实验研究,得到了不同渗透率级别岩心的各项实验参数。研究结果表明:在注入水长期高压差、强冲刷作用下,低渗透岩心中的黏土矿物含量下降0.98%~3.39%,伊蒙混层含量下降5.00%~40.92%,渗透率和孔隙度分别增大0.94%和17.67%,且储层物性条件越好,物性特征变化越明显;同时,长期注水会导致水驱启动压力梯度降低25.81%~38.86%,岩心储层物性越差,该特征表现越明显。总体来看,低渗透岩心经过长期水驱后,储层的各项非均质性加剧,导致开发过程中注入水沿高渗带的窜流增强。研究结果为低渗透油藏后期驱替方式的调整提供了理论依据。
During the waterflooding of low-permeability sandstone reservoir,the long-term water flushing to reservoir pore will lead to the variation of rock mineral composition,physical properties and seepage mechanism.The X-ray diffraction,nuclear magnetic resonance,porosity and permeability liquid-tests were used to compare the reservoir rock mineral composition,physical properties and seepage mechanism before and after long-term waterflooding,which presents the various parameters of core samples with different permeability levels.Research indicates that due to the long-term high pressure difference waterflooding and strong water flushing,the clay mineral content decreases by 0.98%~3.39%,the content of illite-smectite formation decreases by 5.00%~40.92%,and the permeability and porosity increase by 0.94% and 7.67% respectively.There is a great variation of reservoir physical properties with the increase of reservoir quality.In general,the reservoir heterogeneity increases after long-term waterflooding of low-permeability core samples,which leads to the water channeling along the high-permeability zone.This research could provide certain theoretical basis for the displacement adjustment of low-permeability reservoirs in the late development stage.
作者
张洪军
李二党
牛海洋
高月刚
黄炜
Zhang Hongjun;Li Erdang;Niu Haiyang;Gao Yuegang;Huang Wei(PetroChina Changqing Oilfield Company,Xi′an,Shaanxi 710200,China)
出处
《特种油气藏》
CAS
CSCD
北大核心
2019年第6期78-81,共4页
Special Oil & Gas Reservoirs
基金
国家科技重大专项“鄂尔多斯盆地大型低渗透岩性地层油气藏开发示范工程”(2016ZX05050)
关键词
低渗透油藏
水驱实验
物性
渗流特征
矿物组成
low-permeability reservior
waterflooding experiment
physical properties
seepage mechanism
mineral composition
