Dynamic Interconnectivity Evaluation And Program Design For Early Stage Of Foam Flooding

Nitrogen foam flooding is an effective way to improve oil recovery in the middle and late stages of development of heterogeneous reservoirs.It is a tertiary oil recovery technology in the development stage,and nitrogen foam flooding has the advantages of sufficient gas source,low price and no corrosion.Research on foam flooding technology and field application is relatively late.In recent years,many research experts have conducted research and field tests on it.The domestic business community has also carried out more experiments on its application and obtained many research and application results.This paper is aimed at the QK18-2 oilfield research.Because the oilfield reserves are small and distributed on multiple independent small fault blocks,the later harvesting degree is lower.The oil field is exploited by natural energy exhaustion,and the initial daily oil production is high.As the formation pressure drops,the output decreases rapidly.The formation pressure drops rapidly,the development pressure is lower than the saturation pressure,and the formation degassing is serious.In addition,the oil field adopts conventional stimulation measures,the effect is not obvious,the average single well cumulative oil increase is only 0.0535×10~4 m~3;the average adjusted single well cumulative oil increase is 1.19×10~4 m~3.Based on the geological understanding results and dynamic corresponding characteristics of the experimental area,this paper qualitatively evaluates the connection relationship between injection and production wells,establishes a three-dimensional fine geological model,studies the development characteristics of the reservoir,and uses the results of water drive well connectivity evaluation to guide the foam flooding scheme.The design and the numerical simulation method are used to design and calculate the scheme,so that the nitrogen foam flooding implementation scheme can achieve the maximum economic oil increase.The results show that nitrogen foam flooding can effectively improve the development effect,preferably alternate injection of nitrogen foam(6 months cycle)at a gas-liquid ratio of 3:1 and an injection rate of 23000 m~3/d;the basis for determining the optimal nitrogen foam flooding scheme The corresponding injection and production parameters are further optimized,and the injection amount is 0.35 PV,the injection speed is 23000 m ~3/d,and the gas-liquid ratio is 3:1,and the gas-liquid alternating(6months period)injection method is the most The best solution will eventually increase the harvest by nearly 7%.In addition,according to the calculation of the pressure gradient,the interwell connectivity changes before and after the foam is regulated.The seepage resistance between the wells before and after foam flooding increased by 39%,indicating that the foam drive played a significant profile control role.