Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

The effect of variable-apertures was found to be significant on recovery of oil from water injection tests performed on fractured rocks in a laboratory scale. Statistical parameters such as coefficient of variation, skewness coefficient, and anisotropy ratio are obtained from measurements of aperture distributions by a casting method. The results show that morphology of a fracture has a significant effect on oil recovery as well as water injection rate. As coefficient of variaiton and skewness increase, overall efficiency of oil recovery decreases. Anisotropy ratio affects the breakthrough time of injected water and overall oil recovery as significant as coefficient of variation. At lower anisotropy ratio such as less than one, early breakthrough and poor oil recovery have occurred. The effect of the statistical parameters is pronounced as injection rate increases. A point is observed where imbibition rate shows identity regardless of fracture morphology, if both flow rate of injected water and matrix characteristics are the same.