Research On Interlayer Interference Mechanism In Offshore Light Oil Reservoir

The offshore oil reserves are rich,and the development of offshore oil fields needs to be strengthened.Due to the limitation of surface space,offshore oilfield development generally adopts the development method of multilayer production,because of the difference between layers,the problem of interlayer interference is easy to occur in the development process.This paper takes the two blocks of Bozhong 35-2 and Kenli 10-1 as the research objects.First,the basic physical properties of the block are analyzed,and the Lorentz method is used to characterize the heterogeneity of the block.Summary of development characteristics analysis.On this basis,physical simulation experiments are designed to achieve layered measurement and saturation dynamic monitoring,and combining the water injection profile data to obtain the starting limit of the low permeability layer.In order to make up for the shortcomings of the physical simulation experiment,an orthogonal experiment is designed,and numerical simulation calculation is used to find the main controlling factors of interlayer interference.Finally,the theoretical model of multilayer reservoir is established,and the physical parameters of the model are obtained by the Lorentz curve.The equal thickness model and equal Kh model are obtained respectively to study the changes of the seepage resistance and the ratio of production during the multilayer production process.It is finally concluded that the physical properties of Bozhong35-2 are better than Kenli10-1.The Lorentz coefficient of both blocks is greater than 0.5,which belongs to a strong heterogeneous reservoir.This leads to a rapid increase in water cut in the initial stage of development,and the problem of interlayer interference is prominent.The permeability of the low-permeability layer was less than 50 m D,and the layer could not be used at normal displacement speed.After increasing the displacement speed,the lowpermeability layer can be used.The main controlling factors of interlayer interference are mainly the difference in permeability of each layer and the degree of connectivity of the reservoir.The water breakthrough time of the equal thickness model is later than that of the equal Kh model.When the permeability ratio of the multilayer reservoir is 4-5,the production rate of the low-permeability layer does not exceed 5%.