特低渗透油藏天然气非混相驱实验

利用单层和双层物理模型，开展了特低渗透油藏注天然气开采模拟实验。单层模型实验结果表明，特低渗透油藏天然气驱同水驱相比不仅可以提高驱油效率，还能提高微观波及效率；天然气驱采收率比水驱采收率高4.50%，水驱后注天然气的开采效果更好，可提高采收率幅度达12.50%；未见气与低气液比阶段内油井的产能高，是主要生产期。双层非均质模型实验结果表明，由于油藏内实际的层间渗透率级差比实验室内测定的级差大得多，同一套开发层系内低渗透层不具备吸气能力，气体完全进入高渗透层，高渗透层的开发效果非常好；天然气在高渗透层中形成窜流后，剩余油主要分布于低渗透层中，需要用凝胶体系对高渗透层进行封堵；封堵后，低渗透层的吸气能力非常强，能被充分开发利用，双层非均质模型的采收率由30.85%提高到55.91%。

An experimental investigation of the nature gas immiscible displacement in ultra-low permeability reservoirs

With a monolayer or two-layer physical model,a simulation experiment of the natural gas displacement in ultra-low permeability reservoirs was carried out.The results from the monolayer physical model showed that compared with water flooding,gas flooding in ultra-low permeability reservoirs might enhance not only the displacement efficiency but also the micro-sweep efficiency,increasing the recovery ratio by 4.5%.The subsequent natural gas injection after water flooding could gain a better effect of developm...