Plugging Behavior of Polymer Gel in Fractures by Multi-Slug Injection

Abstract

In order to understand the plugging mechanism, experiments of multi-slug gel plugging in single fracture and multiple fractures system were simulated by indoor visual fracture models. The experiments showed that there were two stages in the process of multi-slug gel plugging in single fracture: gel filling stage and gel compaction stage. When the total injection of gel is consistent, the brine flooding pressure gradient after multi-slug gel injection increased more than 2 times than the pressure gradient after single slug gel continuous injection. While there were three stages in the process of multi-slug gel plugging in multiple fractures system: Gel selectively entrance stage, gel filling stage and gel compaction stage. However, there would be no gel compaction stage, even no gel filling stage in the process of single cycle gel plugging in multiple fractures system. Key words: Fractured reservoir; Multi-slug; Polymer gel; Plugging process