Fault-karst carbonate reservoir is a new object for oil and gas exploration in carbonate fractured-vuggy reservoirs. Based on the further study of development dynamics and water flooding mechanism

and in order to solve three typical problems in the development of Tahe oilfield

which are the poor matching of well storage relation

the water-like coning formed by conventional water injection

and the combination of multiple fractures and caves

an injection method by imitating bottom-water is proposed

which is more suitable for the well-reservoir relation

different distribution patterns and complex internal structure of the fracture and vug. In this way

the water flooding sweep rate is increased

and efficiency of water injected increased from 60% of conventional water flooding to 75% of simulated bottom water flooding. Three problems of poor water injection channel between borehole and fracture-vug are common

that is

there is an offset between the fracture and vug

no effective channels are established for the borehole and fracture-vug

and the reserve recovery degree of well-controlled fracture-vug is high but the untapped fracture-vug exist in far wells. A low-cost water injection method by imitating fracturing for establishing effectively fracture network producing system is proposed

which can effectively expand well controlled producing reserves

and the average productivity per well increase by 22 t/d. Practices show that these two technologies can increase the total water injection volume and water injection pressure

make the water injection efficiency improved greatly

so as to improve the effect of water injection and stimulation obviously.