The　evaluation　of　oil　productivity　in　unconventional　reservoirs　with　complex　fracture　networks　is　essential　in　practical　design　for　improving　the　production　performance.　A　three-dimensional　unified　pipe-network　method　(3D　UPM)　is　developed　to　understand　oil　flow　behavior　in　fractured　unconventional　reservoirs　by　considering　the　compressibility　of　both　fluids　and　solids.　Governing　equations　for　transient　pressure　analysis　are　discretized　based　on　a　pipe　equivalence　technique.　The　complex　flow　transfer　between　the　rock　matrix　and　fractures　is　solved　using　the　superposition　principle　at　the　media　interface,　greatly　simplifying　the　matrix-fracture　coupling　process　in　the　3D　pipe-network　system.　The　results,　calculated　in　an　implicit　time　scheme,　are　verified　against　commercial　software　COMSOL　to　demonstrate　the　reliability　of　this　method　for　evaluating　well　performance.　A　single　multi-fractured　horizontal　well　(MFHW)　is　numerically　investigated　to　evaluate　the　influences　of　natural/hydraulic　fracture　numbers　and　properties　on　the　well　productivity,　which　also　indicates　the　necessity　of　using　a　3D　model　for　oil　production　simulation.　Finally,　a　double　MFHWs　system　was　adopted　to　analyze　the　influences　of　fracture　networks　formed　by　the　interconnection　between　natural　fractures　and　hydraulic　fractures,　demonstrating　that　natural　fractures　greatly　contribute　to　high　well　productivity.