Due to the limitations of platform resources,offshore oilfields adopt large well-spacing development.Due to the planar heterogeneity of the reservoir,the problem of low reservoir control and poor planar injection-production correspondence is prominent.In response to this problem,based on the anatomy of single sand body level reservoirs,the concept of non-connectivity ratio is introduced,and it is proposed that a new method for characterizing the control degree of single sand body level well pattern suitable for reservoirs with rapid lateral changes in the reservoirs.This method overcomes the limitation that indicators such as injection-production correspondence ratio only reflect the connectivity status of production wells,and cannot comprehensively and truly reflect the connectivity status between injection and production wells.Therefore,five types of sand body disconnection models have been established:two-way injection and no production type,two-way production and no injection type,one-way disconnection type,single point disconnection type,and single point connection type.At the same time,numerical simulation methods were used to establish,the technical limits of small well spacing infilling for different disconnection modes:the infilling limits for the two-way injection and no production type,and the two-way production and no injection type are the disconnection rate greater than 30%;The one-way disconnected encryption limit is the disconnection rate greater than 40%;the threshold for single-point disconnected encryption is the disconnection rate greater than 60%;and the single-point connected encryption limit is the disconnection rate greater than 70%.Based on this,a pilot field test of small well spacing infilling was carried out in the SZ Oilfield in the Bohai Sea.After infilling,the degree of water flooding production increased by 13%and the oil recovery increased by 4.5%.The research results provide a reference for the quantitative evaluation of the control degree of well patterns in offshore oilfields and the formulation of strategies to improve the control degree.
reservoir anatomynew method of well pattern controldisconnected ratiodisconnected modesmall well spacing infilling
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