Cr^3+聚合物凝胶与水交替注入调驱作用机理--以渤海LD10-1油田为例

Profile control and flooding effect of alternative injection of Cr^(3+) polymer gel and water and its mechanism: taking Bohai LD10-1 Oilfield as an example

针对渤海LD10-1油藏减缓吸液剖面反转技术需求,通过层内非均质岩心驱替实验,发现Cr^(3+)聚合物凝胶与水交替注入工艺具有较好的增油降水效果,运用并联岩心驱替实验,从驱替过程和驱油效果两方面探讨了交替注入增油机理。结果表明,相比整体凝胶段塞注入工艺,"Cr^(3+)聚合物凝胶+水"交替注入方式具有更好的封堵和驱替效应。凝胶前置段塞对高渗透层实施封堵后,后续水段塞一方面可使弱凝胶分子线团膨胀加强封堵效果,改善后续流体的转向能力,另一方面还可增强驱替效果,减缓吸液剖面反转现象。在实际设计交替轮次数时,应考虑水段塞过多易引起高渗透层突进的问题。

Aimed at the technical demand for relieving the inversion of imbibition profile in Bohai LD10-1 reservoir, this paper studies the profile control and flooding effect of alternative injection of Cr31 polymer gel and water and its mechanism. During core displacement experiment in in-layer heterogeneous cores, alternative injection of Cr3＋ polymer gel and water has a better effect of increasing oil and decreasing water, then the mechanism of alternative injection was studied in details from the dynamic behavior and oil displacement efficiency through parallel cores displacement experiment. The results show that, compared with the whole injection of Cr3＋ polymer gel, alternative injection of Cr3＋ polymer gel and water has a better effect of ＂blocking and flooding”. After pre-slug of polymer gel flows into and blocks off the high permeability layer, subsequent water slug on one hand can expand the molecular coils of weak gel and then strengthen blocking effect, thus improving the diverting ability of subsequent fluid. On the other hand it can enhance the displacement efficiency and relieve the phenomenon of imbibition profile inversion caused by polymer gel flowing into medium and low permeability layers. In the actual design of alternative frequency, the incursion in high permeability layers caused by too many water slugs should be considered.