Studies on seepage law considering stratigraphic dips

Abstract Currently, water injection is widely used for oil field developments. For reservoirs with complex geological structures, large stratigraphic dip angles, low porosities and extra-low permeabilities, the effect of water injection is not satisfying. This paper establishes a modified radial flow formula on the dip angle, and uses the plane radial seepage theory to get formation pressure distributions and a production formula in tilted strata. For injectors with their threshold pressures greater than their formation in-situ pressures, the effective radius for waterflooding is derived for a given injection pressure and then it is used to evaluate waterflooding effect and well pattern suitability, and guide the oilfield production. This method can also be applied to other waterflooding oilfields with similar geological conditions.