Study on the development techniques of Chang 6 ultra-low permeability reservoirs in Yanhewan block in Changqing Oilfield

More than 1/3 non-producing reserves of Changqing Oilfield is in the ultra-low permeability reservoirs,but there are no effective development techniques to them.To rationally develop the ultra-low permeability reservoirs and enhance their recovery factor,Changqing Oilfield develops the studies on the development techniques of the ultra-low permeability reservoirs. Chang 6 ultra-low permeability reservoirs in Changqing Yanhewan block being taken an example,the unstable water injection and alternative gas/water injection are numerically simulated using Eclipse numerical simulation software.The simulation results show that,the development result of alternative gas/water injection is the best,that of continuous water injection is secondary,and that of cyclic water injection is the worst.The simulation results also show that to alternative gas/water injection,the development results of alternating cycle of six months is better that of alternating cycle of three months,the development results of the water injection after gas injection is better than that of the gas injection after water injection.