深部咸水层超临界CO_2灌注毛细压力对盐沉淀的影响  

Impact of Capillary Pressure on Salt Precipitation during Supercritical CO_2 Injection into Deep Saline Aquifers

作　　者：房琦[1] 李义连[1] 喻英[1] 刘丹青[1] 

机构地区：[1]中国地质大学(武汉)环境学院,湖北武汉430074

出　　处：《安全与环境工程》2015年第2期61-65,共5页Safety and Environmental Engineering

基　　金：国土资源部公益性行业基金项目(201211063)

摘　　要：以江汉盆地江陵凹陷高盐度卤水层为例,采用数值模拟的方法研究了超临界CO2灌注到深部咸水层中毛细压力对盐沉淀的影响及其机理。结果表明:低毛细压力作用下,岩盐固体饱和度与盐度存在着显著的线性关系,高毛细压力作用下,盐度不再是控制岩盐沉淀量的主导因素,即便是较低的盐度也会造成盐沉淀的严重积累,直至完全堵塞孔喉;通过液体流速曲线分段解析,发现较高的毛细压力虽会提高滞留咸水量,但持续的咸水回流对注入性严重受损起着致命作用;另外,盐沉淀还受到注入速率的控制,随CO2注入速率的增加而降低,因此以较高的速率注入CO2可有效缓解盐沉淀的影响。This paper carries out numerical simulation to investigate the impact and mechanism of capillary pressure on salt precipitation during supercritical CO2 injection into the deep saline aquifer of Jiangling Depressin in Jianghan Basin. The results show that under low capillary pressure,salt precipitation is in a significant linear relationship with salinity, under high capillary pressure, the initial salinity is no longer the dominant factor controlling the solid saturation;even in the formation of low salinity,salt precipitation can continuously accumulate near the injection well until it completely blocks the pore throats. After the subsection analysis of the liquid flow curve, the paper finds that although salt precipitation under the retention is enhanced ,additional salt imbibition from the strong capillary backflow is fatal to severe injectivity impairment for high capillary case. In addition, salt precipitation is highly controlled by injection rate. The higher injection rate is,the lower salt precipitation is. Therefore,injection of CO2 with high rate can effectively mitigate the effect of salt precipitation.

关 键 词：超临界CO2 深部咸水层 毛细压力 盐沉淀 盐度 注入速率 

分 类 号：X701[环境科学与工程—环境工程] X141