低渗油藏储层物性及敏感性对高速注水效果的影响

低渗透油藏具有孔隙度小、非均质级差大、敏感性强等特征，注水开采效果差异较大。本研究开展室内长岩心高速注水实验，探究不同储层物性及敏感性对采出程度和压力传导的影响。结果表明：岩心渗透率越低，高速注水效果越明显，低渗岩心注入端压差是高渗岩心的8.5倍，采出程度是其1.04倍；裂缝的存在会导致蓄能效果下降，裂缝长度占比从12.5%上升到37.5%，最终采出程度降低4.5%，蓄能效果降低26%；水敏越强的岩心在低矿化度注入水的注入能力变低，使驱替压差大幅提高，但采出程度相比无水敏时降低21.5%；注水速度越高对岩心的采出程度和采油速率提高的越显著，高速注入压力为低速注入的2.5倍，注采压差为低速注入的6倍以上，注水速度存在最佳值为1.5mL/min。该研究结果对低渗油藏注水开发生产具有重要指导意义。

Influence of Reservoir Physical Properties and Sensitivity on High-Speed Water Flooding Effect in Low Permeability Reservoir

Low permeability reservoirs have the characteristics of small porosity, large heterogeneity and strong sensitivity, which make the effect of water injection mining different. In this study, low-permeability long cores were used to carry out high-speed water injection experiments, and the effects of different reservoir properties and sensitivities on recovery and pressure transmission were investigated. The results show that the lower the core permeability, the more obvious the effect of high-speed water injection. The injection end pressure difference of low permeability core is 8.5 times that of high permeability core, and the recovery degree is 1.04 times that of high permeability core. The existence of fractures will lead to the decrease of energy storage effect. The proportion of crack length increases from 12.5 % to 37.5 %, and the final recovery degree decreases by 4.5 % and the energy storage effect decreases by 26 %. The stronger the water sensitivity of the core in the low salinity of the injected water injection capacity becomes low, so that the displacement pressure difference increased significantly, but the recovery is reduced by 21.5% than without water sensitivity. The higher the injection rate, the more significant the increase of the recovery degree and oil production rate. The high-speed injection pressure is 2.5 times that of the low-speed injection, the injection-production pressure difference is more than 6 times that of the low-speed injection, and the injection rate has an optimal value of 1.5 mL / min. The research results have important guiding significance for water injection development of low permeability reservoir.