System and method for the optimized production of hydrocarbons from shale oil reservoirs via cyclic injection to achieve an improved and optimal recovery of oil. The method can determine and optimize the composition of injected fluids to be injected, the rate, pressure and duration of injection, the production rate and pressure of produced fluids; can determine and utilize the optimum number of injection and production cycles; can determine the amount of soaking time (if any); and can determine the equipment design and operating characteristics to provide for the optimized injection of injection fluids, and the separation of produced fluids for both reinjection and delivery to sales or storage.