二氧化碳驱封窜体系的室内研究

Laboratory Research on Channeling Sealing System of Carbon Dioxide Flooding

小分子胺颗粒沉淀体系在低渗地层中反应生成不能完全溶解的有机盐,可堵塞孔隙,抑制CO2气驱采油过程中发生的气窜。为此,实验考察了不同温度下压力变化对体系沉淀量的影响。结果表明,固定温度下,沉淀质量随压力的增加呈"波峰"变化规律,说明每个温度点存在一个最佳压力点;而当温度升高时,最大沉淀量也逐渐增大。并联岩心CO2气驱提高采收率实验结果表明,乙二胺在CO2以及高温(120℃)下具有良好的适应性,对CO2气驱具有较好的封窜性能。

In low permeability formations, precipitation system of small - molecule amine generates organic salt which is not completely soluble. And the salt can seal pores and inhibit gas channeling during carbon dioxide flooding. So the effects of changing pressure on precipitation quantity of the system under different temperatures were investigated by experiments. The results showed that precipitation quantity varied presenting ＂crest＂ with the increase of pressure under fixed temperature, which indicated the presence of an optimum pressure value at each temperature; the maximum quantity of the precipitation also increased when temperature rised. The experiments of parallel core carbon dioxide flooding EOR showed that ethylenediamine had good adaptability in carbon dioxide and high temperature（ 120 ℃ ）, and had good channeling sealing performance in carbon dioxide flooding.