Enhanced Recovery of Crude Oil From Shale Formations by Gas Injection in Zipper-fractured Horizontal Wells

摘要

The zipper-frac technique is implemented in two adjacent horizontal wells to maximize the exposure of shale rocks. The hydraulic fractures are propagated in a manner in which they are connected with natural fracture network to improve the fracture complexity. In this study, the authors exploit the advantage of stimulated fracture complexity to access more of the hydrocarbons trapped in very low permeability of shale matrix. The recovery process efficiencies by cyclic CO2 injection and CO2 flooding in zipper-fractured horizontal wells are compared. The role of diffusion recovery mechanism in recovering oil from fractured shales will be discussed.