Experimental Evaluation And Quantitative Characterization Of Seepage Mechanism During Commingled Production In Bohai Oilfield

Because of the complicated geological problems such as deep buried sand bodies,diverse sedimentation types,rapid lateral changes of sediment bodies,and unclear vertical sedimentation periods,the Bohai multi-layer thin oil reservoir has a large number of layers and uneven thickness,interbedded mud and sand,and a complicated connection relationship,which leads to more serious heterogeneity than shallow reservoirs.At the same time,in order to take into account the characteristics of short development period and high cost,the multi-layer combined production mode is adopted,which will lead to more serious inter-layer interference phenomenon.It is significant to establish a dynamic evaluation method in order to estimate the degree of inter-layer interference accurately.Firstly,the main control factors of inter-layer interference in the target oil field are determined through the comprehensive statistical analysis of the field geological static data and the production test dynamic data,which provides the basis for the design of the following indoor experiment scheme.Secondly,based on the main control factors research,the physical simulation scheme of multi-stage differential inter-layer interference is designed,and the experiments are carried out to compare the difference of oil production,liquid production,extraction degree,oil production index and fluid production index.Thirdly,according to the experimental results and the actual production dynamics,the characterization formula of the interference coefficient of multi-layer combined production and recovery is established based on the analysis of influencing factors and correlation analysis.Finally,based on the results of the field stratification test,the variation law of interlayer interference in different water-bearing stages of multi-layer production in target field is predicted,and some suggestions are given to alleviate the interlayer interference problem.The research shows that the dynamic evaluation method can effectively evaluate the influence degree of inter-layer interference in different stages.In order to reduce the influence of inter-layer interference and ensure the maximum reservoir capacity in actual production,the oil field should subdivide the stratification system as far as possible in the early stage.The dynamic evaluation method based on the physical simulation experiments and the actual oilfield production data can provide a basis for the efficient development of similar reservoirs.