A model for gas transport in tapered noncircular nanopores of shale rocks with integrating real gas effect, molecular kinetic, and transport behavior was presented. The proposed model is well validated with experimental and simulation data, including six kinds of gases, under different pressures, and temperatures. Results show that neglect of real gas effect results in the misleading transport conductance. The adsorbed gas transport ratio and the ratio of area occupied by adsorbed gas increase along the length of nanopore. Pore proximity induces the faster gas transport and omitting pore proximity leads to the enlargement of the adsorbed gas-dominated region. Increasing taper ratio (ratio of inlet size to outlet size) and aspect ratio weakens real gas effect and lowers free gas transport. Moreover, it lowers the total transport capacity of the nanopore, and the tapered circular nanopore owns the greatest transport capacity, followed by tapered square, elliptical, and rectangular nanopores. (c) 2017 American Institute of Chemical Engineers AIChE J, 63: 3224-3242, 2017