致密砂岩油藏能量补充方式评价及优化

Evaluation and Optimization of Energy Supplement Methods for Tight Sandstone Reservoirs

针对致密砂岩油藏大规模体积压裂开发后能量补充困难的问题,利用自主设计制作的大型人造三维岩心物理模型和物理模拟实验舱,开展致密砂岩油藏能量补充方式优化研究。实验结果表明:致密砂岩油藏压裂开发过程中,地层能量损耗严重,采取注水或注气的方式可有效进行能量补充;地层中裂缝规模越大,越有利于原油渗流,后续补充能量的传播范围越广,有助于进一步提高原油采收率;从提高驱油效率和扩大波及系数方面优选吞吐渗吸介质,CO_(2)均优于活性水,CO_(2)吞吐开发在矿场试验中取得了显著的增油效果,因此,CO_(2)吞吐作为一种有效的能量补充方式在致密油开发中展现了良好的应用前景。该文分析了致密砂岩储层水平井压裂开发的渗流规律,优选出致密砂岩储层大规模压裂开发后最佳渗吸介质,可为致密砂岩油藏开发设计提供重要的理论依据。

In view of the difficulties in energy supplement after large-scale fracturing by stimulated reservoir volume of tight sandstone reservoirs,a large artificial three-dimensional core physical model and a physical simulation lab module designed and manufactured by ourselves were used to study the optimization of the energy supplement methods for tight sandstone reservoirs.The experimental results showed that during the fracturing development of tight sandstone reservoirs,the formation energy was greatly lost and could be supplemented by water or gas injection effectively;the larger the fractures in the formation,the more conducive to crude oil seepage and the wider spreading scope of the subsequent supplemented energy,which was helpful to further improve the oil recovery;CO_(2) was better than active water in terms of being used as imbibition medium which was selected in terms of improving flooding efficiency and the sweep efficiency;the CO_(2) stimulation has achieved a significant oil recovery enhancement in the field test.Therefore,CO_(2) stimulation,as an effective way of energy supplement,has a good application prospect in the development of tight oil reservoirs.In this paper,the seepage law of horizontal well fracturing in tight sandstone reservoirs was analyzed and the best imbibition medium after large-scale fracturing in tight sandstone reservoirs was preferably selected,providing an important theoretical basis for the development design of tight sandstone reservoirs.