Experiments on nitrogen assisted gravity drainage in fractured-vuggy reservoirs

WANG Jing,JI Zemin,LIU Huiqing,HUANG Yitao,WANG Yishuang,PU Yulong

Table 4 Types and formation mechanisms of remaining oil in experiment ④.

Remaining oil type Existence form Formation mechanism Type A Blind ends of upper fractures and vugs Poor connectivity of fractures and vugs Type C The lower parts of the reservoir Regions not effectively controlled by the injector and producer Type D Small-aperture fractures and their connected vugs Fracture heterogeneity