Shale oil resources are rich around the world and have extraordinary exploitation prospects. However

drilling horizontal wells and huge amounts of hydraulic fracturing measures had sharply increased the cost. A large number of experiments and numerical simulations showed that the gas injection could significantly improve the shale oil recovery. Nevertheless

this technique had not been implemented to the practical exploitation of shale oil. Consequently

it was still controversial whether shale oil recovery could be optimized through gas injection or not. By the comparison of the gas displacement experiments of the shale cores

the numerical simulation of shale oil recovery by gas injection and the gas injection pilots in practical fields

it was found that the results from experimental conditions and numerical simulation models were different from those in field pilots. Li Chuanliang insisted that the shale reservoir was consisted of myriad micro-lithologic traps. It was concluded that only if the gas was injected after fracturing

or establishing an orthogonal horizontal well pattern to dense the well spacing

would the shale oil recovery be improved. It has essential guidance for the improvement of shale oil recovery in China or even in the world.