微观剩余油分布模式及提高水驱效率实验研究

以大港油田孔南地区7种不同类型储层为基础,设计了恒压和变压条件下注水驱替微观实验,研究了水驱油的微观驱替特征、剩余油分布模式和影响水驱效率的因素。通过实验观察,将储层孔喉划分为大孔粗喉、中孔中喉和小孔细喉3种类型,相应的剩余油也划分为3种分布模式,不同模式又可进一步分为几种类型。恒压注水时,影响水驱效率的主要因素是储层的孔喉结构,变压注水受孔喉结构影响较小,不同储层都可以通过变压注水来提高水驱效率,从而提高最终采收率。

Experimental Study on Microscopic Distribution of Remaining Oil and Improvement of Waterflood Efficiency

With respect to the seven types of reservoirs in Kongnan area, Dagang oilfield, an experiment on microscopic waterflood displacement under conditions of constant and variable pressure is designed, and the microscopic characteristics of water/oil displacement, microscopic distributions of remaining oil and the waterflood efficiency are analyzed. According to our observation, there are three types of reservoir pore throat: big-pore wide-throat, medial-pore medial-throat and small-pore slender-throat. Accordingly, the remaining oil shows three types of distribution, which can further be classified into several sub-types. When flooding in constant pressure, the main factor affecting waterflood efficiency is the pore-throat structure of reservoir. The effect of pore-throat structure is small under variable pressure. The waterflood efficiency can be enhanced by flooding in variable pressure, which in turn will increase the final recovery ratio.