Study On Production Splitting Method For Multi-layer Reservoir

Due to the difference of reservoir physical property between different layers,the interlayer interference is pretty serious in the process of water flooding development and the degree of producing reserves of different layers varies greatly.The measures aims to reduce the negative impact of the interlayer interference,such as separated layer water injection technology and layer recombination,need to be clear about the production performance and remaining oil distribution among different layers.An accurate splitting of oil well production is the basis of the dynamic analysis,the development effect evaluation and the research on remaining oil between different layers.Therefore,the splitting of oil well production is of great significance for the development of multi-layer reservoirs.In this paper,a single well production model of multi-layer combined mining is established,in order to simplify the production model of multiple wells to multiple single well model for research,according to the actual situation of reservoirs.Through the automatic history matching of the single well model,the reservoir parameters in the small layers near the single well are retrieved and updated.Using the fitted single well production model to split the yield,a more accurate single well splitting result can be obtained,and the distribution of residual oil in each small layer can be clearly defined.As for reservoirs with complex layers and well networks,we proposed a production splitting method based on automatic history matching.Based on the principle of optimization and Bayes theory,the objective function of inverse problem of automatic history matching for large-scale reservoirs is established.The Ensemble Kalman Filtering method was used to solve the automatic history matching problem so as to updating and inverting reservoir parameters.The research results show that both of the two methods proposed in this paper can effectively reverse the accurate reservoir parameters with well history matching of the well production data.And the accurate production splitting is achieved based on the history matching results.Moreover,according to these production splitting methods proposed in this paper,the production splitting software based on single well automatic history matching and the production splitting software based on EnKF automatic history matching method were worked out,which provide a strong basis for adjustment of oilfield production and development plan.