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Mechanism study on multi-round profile control technique in fractured water flooding reservoir
He Tao,Wang Jian,Yu Heng,Xu Peng,Liu Xuwen
Reservoir Evaluation and Development    2018, 8 (2): 68-72.   DOI: null
Abstract   (171 HTML7 PDF(pc) (1977KB)(147)  

In order to discuss the technical measures of the multi-directional water breakthrough, it is essential to find out the water breakthrough discipline and the understand the mechanism of the multi-round profile control technique. Therefore, we designed and the established the fracture-matrix visualization model with one-injection well for three production wells. The permeability between the different injection-production ends was inequality. By this model, we studied the migration characteristics and the plugging mechanism of the gel, the fluid diverting of subsequent water flooding and the distribution characteristics of the residual oil on the condition of the fracture-matrix. Through the core flow experiment of the shunt-wound sand-filled pipes with different permeability. And by the simulation of the interlayer heterogeneity, we compared the experimental data of the single and multi-round profile control measures. The results show that the multi-round profile control can fully play the synergistic effect to improve the performance and plug the fractured seepage channel effectively along with the promotion of the fluid diverting, and the profile control effect reduces with time of the injection. The multi-round profile control technique is better than the single profile control technique in the respect of adapting the fractured geological structure, and has a better effect on relieving the interlayer contradiction.


Fig. 2 Model saturated water, saturated oil and water displacing oil
Extracts from the Article
模型饱和水—饱和油—水驱油的过程对比见图2,各轮次凝胶调剖后剩余油效果对比见图3,各轮次凝胶调剖及后续水驱后剩余油效果对比见图4.水驱结束时的剩余油状态见图2(c),水驱油过程中注入水优选选择高渗透区域,而含窄小孔道多的低渗透区域启动较慢,与实际开采中水驱沿高渗通道水窜现象相符.上侧,下侧和右侧3个出口端均见水,右侧和上侧出水最多,下侧见水较少,具有明显的多方向见水特征,整个模型中,离开主流线较远的区域(图2c左下角和右上角区域)水驱波及效率低,剩余油富集.对比图3中各驱替阶段过程图可知,注入弱凝胶后,第一轮效果最好,剩余油明显启动,波及效率明显增大;第二轮较第一轮效果次之;第三轮效果最差,但对模型仍有调剖效果.对比图4中各驱替阶段过程图可知,蓝色区域出现的位置发生变化,弱凝胶的注入具有明显的流体转向作用.在平面驱替实验中还发现,在弱凝胶驱替过程中大量小孔隙中的油被驱替出来,在大孔道中逐渐汇集成油块往前推移,驱替前缘油驱油,油驱水现象也很常见.在驱替前缘还可以形成连续的油墙,油墙的厚度随着驱替的进行而变厚,最后以油块形式运移到出口流出.
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