储层层间非均质性对油藏改建储气库影响实验研究OA

The interlayer heterogeneity in the Nanpu 1-5 Block is strong,which significantly impacts the displacement me-chanism and storage capacity formation during the process of converting the reservoir into an underground gas storage facility.Using natural cores and two-dimensional(2D)sand-packed cemented slab models from this block,dual-core parallel long-core flooding experiments and 2D model gas flooding experiments were conducted to investigate the influence of interlayer heterogeneity on enhanced oil recovery coupled with gas storage construction.The results show that both the dual-core long-core flooding and the 2D model gas flooding,as well as cyclic injection-production operations,lowered the mobilization threshold of the low-permeability cores,improved the oil displacement efficiency of the low-permeability cores,reduced the differences in oil displacement efficiency and sweep efficiency between the high and low permeability cores,and effectively alleviated interlayer conflicts.The gas flooding stage is the main phase for oil production and storage capacity creation,contributing 59%of the total oil recovery and 72%of the gas sweep efficiency.The dominant oil displacement mechanisms during this stage include gas cap drive,gravity segregation,and crude oil swelling and viscosity reduction.For UGS construction in heterogeneous multi-layer reservoirs,a slow gas flooding strategy should be adopted to prolong the gas flooding duration,thereby fully leveraging the roles of gas cap drive and gravity drainage to maximize the ultimate oil recovery and storage capacity.This study provides experimental guidance for EOR research during UGS construction in similar reservoirs.