Abstract: In the late stage of waterflooding, the key efforts of reservoir operation or management focus on the understanding of remained oil distribution, the rational arrangement of producer-injector spacing and the measures making for development modification, of which to grasp the interwell communication and the injected water flow direction is the chief task. Spearman's order correlation coefficient is applied to study of them by taking the production performance data from producers and injectors in Sangonghe reservoir of Shinan-4 Wellblock in Shinan oilfield as analytical parameters. The case study indicates that this method is simple, save-time and suitable for field application.

Key words: water flooding, flow direction, order, correlation coefficient