为研究冻胶在裂缝性油藏中的封堵效果,通过室内可视化裂缝模型,开展冻胶对裂缝封堵强度评价,观察冻胶在裂缝中的失效特征,评价冻胶与预交联颗粒复合时的封堵效果。室内实验表明:在裂缝中单独使用冻胶的封堵效果优于使用冻胶和预交联颗粒组合的封堵效果,只有当预交联颗粒通过布满裂缝降低裂缝宽度,使用冻胶和预交联颗粒组合的封堵效果才优于单独使用冻胶的封堵效果;随着裂缝宽度增加,裂缝中冻胶被后续注入水由整体顶出变为中部突破,裂缝中冻胶封堵强度降低。通过实验分析认为:由于预交联颗粒的注入性差,难以实现大剂量注入,封堵裂缝应以冻胶为主体堵剂,同时提升冻胶本体强度是增强冻胶在裂缝中封堵强度的关键。研究结果可为优化裂缝性油藏调剖工艺方案提供借鉴。

In order to study the blocking effect of gel in ultra-low permeability fractured reservoir, the blocking strength of the gel to a single fracture and the failure characteristics of the gel in different fracture width are studied by indoor visual fracture model, and the blocking effect of the gel combined with the pre-crosslinked particles is evaluated. Experiments show that the blocking effect of single gel is better than that of combination of the gel and pre-crosslinked particle for single fracture. Only when a large number of pre-crosslinked particles are filled with a large number of fractures, and the width of fractures was greatly reduced, can the blocking effect of combination of the gel and pre-crosslinked particle be better than that of single gel. As the width of fracture increases, the gel in the fracture changed from overall ejection to central breakthrough after injected with water, and the blocking strength of the gel decreases. The experimental analysis concludes that due to the poor injectability of the pre-crosslinked particles, it is difficult to achieve large doses of injection, and gel shall be the main plugging agent to block the fracture, while improving the strength of the gel itself is the key to enhance the blocking strength of gel in the fracture. The results of the study provide a reference for optimising the process in fractured reservoir.