缝洞型介质结构对水驱油采收率影响的物理模型实验研究

为了研究缝洞型油藏的复杂结构对水驱油的影响,制作4类17个不同结构的缝洞介质物理模型,开展一系列水驱油物理模拟实验.结果表明:①单缝连通单洞的缝洞型介质,洞在缝上时水驱油最终采收率低,洞在缝下时高.②单缝不同洞密度的缝洞型介质,水驱油的最终采收率随着洞密度的增大而减小.③洞隙度比增大,水驱油的最终采收率减小.④缝洞网络结构对水驱油采收率有重要影响;相同连通度的网络结构,存在洞时最终采收率小;连通度越大,最终采收率越小.实验结果表明重力、洞密度、洞隙度比以及缝洞网络结构对缝洞型介质水驱油的采收率有重要的影响.研究结果对提高缝洞型碳酸盐油藏的水驱油采收率具有重要的指导作用.

Experimental study on the effect of the structure of fracture-vuggy media on oil recovery factor of water flooding

In order to investigate the effect of the complex structure of fracture-vuggy oil reservoir on water flooding recovery factor,4 types(including 17 different structures) of fracture-vuggy media models were made and a series of simulation experiments of water flooding were carried out.The results show that,①to the fracture-vuggy media with single vug connecting with single fracture,the water flooding recovery factor is higher when the vug is under the fracture than when the vug is above the fracture;②to the fracture-vuggy media with single fracture and the vugs of different density,the ultimate water flooding recovery factor will decrease with the increase of the vug density;③the ultimate water flooding recovery factor will decrease with the increase of the volume fraction of vug;④fracture-vuggy network structure has a significant influence on water flooding recovery factor.Among the network structures of the same connectivity,the network structures with vugs have the lowest recovery factor.The greater the connectivity is and the more complex the network structure is,the lower the recovery factor is.These experimental results show that gravity,vug density,the volume ratio of vug to total pore and fracture-vuggy network structure have a significant influence on oil recovery factor.The study results can be used for guiding enhancing the water flooding recovery factor of the fracture-vuggy carbonate reservoir.