Disclosed are methods and systems for modeling and controlling production of an oil and/or gas, for example from a shale reservoir. The modeling includes receiving data associated with a fluid reservoir, including a viscosity of a fluid in the reservoir and a radius of a pore in the reservoir, and not including a permeability of the reservoir. The resulting model includes a reservoir fluid drainage rate that is proportional to the fluid viscosity and a reservoir fluid drainage speed that is independent of the pore radius. The model may be used to control a pump which pumps a fluid into and/or out of the reservoir.