摘要
对醇致盐沉积法用于油田调剖堵水及提高采收率的可能性进行了室内实验研究。简介了此方法的基本原理 ,选择无水乙醇和NaCl水溶液 (盐水 )作为注入剂 ,并考察了适用的盐水浓度。在室温下 ,等体积的饱和( 2 6.4 % )盐水和无水乙醇充分混合后 ,NaCl析出量约为 4 5%。如注入 0 .3PV饱和盐水和 0 .3PV无水乙醇 ,析出的盐可堵塞 3 .5%的孔隙体积。用不含油和含油的单层模型 (单一渗透率 )和双层模型 (渗透率有级差 )进行了不同方式的驱替实验 ,在注地层水之后依次注入饱和盐水段塞和无水乙醇段塞 ,再后继注地层水 ,结果表明 :注入饱和盐水 无水乙醇段塞使模型渗透率降低 ,降低率随初始渗透率的增大而增大 ;盐优先沉积在高渗透层 ;两个单层含油模型的采收率分别提高了 5.9%和 1 7.2 % ;两组含油双层模型高、低渗透层的采收率都有所提高 ,两层平均采收率分别提高了 2 1 .2 % (渗透率级差 6.5)和 1 1 .8% ( 3 .5)。
A laboratory experimental study is conducted for the possibility of using alcohol induced salt precipitation for water injectivity profile modification, reservoir permeability control and enhanced oil recovery. Absolute ethyl alcohol(AA) and NaCl solution are used and the proper salt concentration is established. Some 45% of the salt is precipitated when saturated salt water(SSW, 26.4% solution) and AA are mixed at ambient temperature. 0.3 PV of SSW and 0.3 PV of AA injected can plug 3.5% of pore volume in the reservoir formation. The core flooding experiments on monolayer and bilayer(with different permeability) oil free and oil saturated models are performed by warying injection ways in order of: formation water→SSW(→spacer)→AA→formation water and it is shown that the injection of SSW AA slugs decreases the permeability of models the more the higher is the model permeability; salt precipitation occurs preferentially in highly permeable layers; for two monolayer oily models the enhancement in oil recovery is of 5.9% and 17.2%; for two bilayer models oil recovery is enhanced both in higher and lower layers and average enhancement of 21.2% (permeability ratio 6.5) and of 11.8%(3.5) is observed.
出处
《油田化学》
CAS
CSCD
北大核心
2001年第3期246-250,共5页
Oilfield Chemistry
关键词
醇致盐沉积
盐析
饱和NaCl盐水/无水乙醇体系
地层内盐沉积
堵水调剖
深部调剖
原油
提高采收率
Alcohol Induced Salt Precipitation
Saturated Salt Water/Absolute Ethyl Alcohol System
Salt Precipitation in Reservoir
Injectivily Profile Modification
Reservoir Permeabitily Control
Enhanced Oil Recovery
