Water cut rising laws of positive rhythm reservoirs with bottom water and their influential factors

To figure out the water cut rising laws of X bottom water reservoir, determine the factors influencing water cut rising and explore the method to alleviate water cut rising, the overall water cut rising laws of Block X was defined based on its actual production data by means of the linear regression method, and the single-well water cut rising laws were classified. Then, 2D positive rhythm single-well profile model was established using CMG numerical simulation software. Finally, the factors influencing water cut rising laws were investigated by means of orthogonal method, and the corresponding relationships between water cut rising laws and influential factors were concluded. It is indicated that the overall water cut rising law of Block X is in the shape of "S" and the single-well water cut rising laws can be classified into five types, i.e., low dipping type, inverted "Z" type, "Γ" type, high wave type and low wave type.It is revealed that the factors influencing water cut rising laws are ranked as oil/water viscosity ratio, opening degree, vertical-horizontal permeability ratio, water size and certain liquid volume if interlayers are not taken into consideration, and they are ranked as interlayer position, interlayer permeability and interlayer size if interlayers are considered independently.