The Optimization Method Research About Well Pattern In Low Permeability Sand-Gravel Reservoirs

The low permeability sand-gravel reservoir composed by multi-stage sands,due to the strong reservoir heterogeneity,its degree of recovery far below the conventional sandstone reservoir.Considering the characteristics of low permeability sand-gravel reservoir,it has a significance to launching flooding patterns optimization study about improving the reservoir degree of recovery.On the basis of regularity between injection and production wells,we use flow resistance method to deduce the formula of limit well spacing as well as plot the chart of limit well spacing under different permeability and injection-production pressure drop.Considering combined effects about the provenance and crustal stress in low permeability sand-gravel reservoir,we search for the main factors of well development effect and the fitness well form by numerical simulation.For the complex of sands stacked relationship in low permeability sand-gravel reservoir,we build models to find the reasonable well deployment.Finally we combine partition production calculation method with genetic algorithm method,eventually optimize the position of injection well.Studies have shown that reservoir more readily available to use while large permeability,thin thickness,higher water saturation,smaller injector spacing and greater pressure drop.Limit injector spacing is significant correlation with permeability,permeability is the main factor in the effect of limit injector spacing.The low permeability sand-gravel reservoir suitable for deployment of five-spot well pattern,well development effect perform the best when injection wells row parallel to stress direction and injection wells controlling a plurality of sand.Based on the best encryption method can effectively locate wells infill wells,we can achieve higher recoverable reserves during the high water cut stage.The above findings are applied in Yong1S4^th low permeability sand-gravel reservoir and achieve better development results,so this study could provide guidance for injection-production patterns optimization in low permeability sand-gravel reservoir.