可控自聚集胶体颗粒对特低渗透非均质油藏的封堵能力及适应性评价

Evaluation on plugging capability and practical adaptability of controllable self-aggregating colloidal particles in an ultra-low permeability heterogeneous reservoir

为研究可控自聚集胶体颗粒(CSA胶粒)对特低渗透非均质油藏窜流通道的封堵能力及其注入量变化对油藏开发效果的影响,利用人造均质柱状岩心和非均质板状岩心开展调堵-水驱渗流实验和调堵-天然能量开采模拟实验。依靠自主研发的边底水油藏天然能量开采模拟实验装置,实现了室内实验对目标油藏实际开发动态特征的相似性模拟,明确了CSA胶粒注入量对控水、增油、保压、提高采收率和启动基质剩余油的影响。实验结果表明,平均粒径为0.5μm的CSA胶粒针对目标油藏条件兼具较好的注入性和较高的封堵强度;增加CSA胶粒注入量有助于控制油藏水窜、提高低渗透基质波及效率、提高采油速度和降低油藏压力衰减速率,对延长油井稳产期、提高油藏采收率效果明显,但当CSA胶粒注入量超过某一临界值时,继续增加其注入量并不会明显改善油藏开发效果。对于目标油藏,其适宜的注入量为0.3倍窜流通道孔隙体积倍数,此时油藏采收率可达到32.43%。由此可知,特低渗透非均质油藏调堵工艺需要选用适宜的调堵剂和适度的注入量。

This paper studied the plugging capability of controllable self-aggregating(CSA)colloidal particles to channeling paths in an ultra-low permeability heterogeneous oil reservoir as well as the influence of different injection volumes of CSA colloidal particles on reservoir development effects.Specifically,the synthetic homogeneous columnar cores and heterogeneous plate cores were used to perform a percolation experiment of plugging control and water displacement as well as simulation experiment of plugging control and production by natural energy.On the basis of the independently developed experimental devices for oil reservoirs that have an edge and bottom water and are produced by natural energy,the similarity simulation of the practical production characteristics of a target reservoir was achieved in the laboratory.Moreover,we clarified the effect of the injection volume of CSA colloidal particles on controlling water channeling,the increasing oil production,maintaining reservoir pressure,enhanced oil recovery,and matrix remaining oil activation.The results show that the CSA colloidal particles with an average particle diameter of 0.5μm have both good injectability and high plugging capability under the target reservoir conditions.The increase in the injection volume of CSA colloidal particles is conducive to controlling water channeling,improving sweep efficiency of the low-permeability matrix,increasing the oil production rate,and reducing the releasing rate of reservoir pressure.Moreover,it has a profound effect on prolonging the stable production period of an oil well and enhancing reservoir recovery.However,when the injection volume exceeds a certain critical value,the continuous injection does not significantly improve the reservoir production performance.For the target reservoir,the laboratory results reveal that the appropriate injection volume is 0.3 PVc(PVc represents the pore volume of the channeling path),and at this injection volume,the recovery can reach 32.43%.Therefore,an effective plugging control technology for an ultra-low permeability heterogeneous reservoir should provide both suitable plugging agents and an appropriate injection volume.