Abstract: In recent years,many serious CO poisoning accidents have occurred during high-energy gas fracturing of low permeability reservoirs,which poses great threat on safety production of oilfields.In this paper,the mechanism that CO gas generates after the deflagration of several formulations of HEGF gun powder is investigated systematically based on using the detection technology to simulate the deflagration of closed bomb vessels.Taking the five wells in a low permeability oilfield in northern Shaanxi as an example,the CO gas accumulation law is analyzed during HEGF operation.Therefore the countermeasures to prevent CO poisoning accidents are proposed,which is of great significance to ensure HEGF operation to increase output.