Research On Cause Mechanism And Evaluation Method Of Interlayer Interaction

The oil wells adopt the exploitation means of commingled production with big intervals, facing the problem of serious interlayer interaction. In view of this kind of situation, cause mechanism of interlayer interaction was analyzed. Based on cause mechanism, the evaluation method was determined. More details are as follows:Firstly, through the literatures, and combined with field actual data analysis results, determining the factors of interlayer interaction. The factors include mean permeability, permeability contrast, average porosity, total layers, gross thickness, average thickness, thickness contrast, viscosity, average reservoir pressure, formation pressure contrast, formation pressure coefficient contrast, average flowing pressure, flowing pressure contrast, commingled drawdown pressure, drawdown pressure contrast, zonal testing mean water cut, commingled water cut and water cut contrast.Secondly, adopting multiple correlation coefficient method, the factors were screened. Comprehensive threshold method and extremum method screening results, delete indexes were determined as gross thickness and zonal testing mean water cut. According to the grey correlation method based on weighted entropy, the correlation degree between the factors and the interlayer interaction coefficient was calculated. Through sorting the correlation degree from large to small order, adding factor weight in turn, when the sum was greater than or equal to 0.7, the factors were determined as the main control factors. The final main control factors were permeability contrast, layers, formation pressure coefficient contrast, commingled water cut, drawdown pressure contrast and flowing pressure contrast.Thirdly, based on the main control factors, establishing interlayer interaction mathematical model. The model considered the influence of factors which including layers, permeability, formation pressure, flowing pressure, porosity, viscosity, supply radius, water cut, oil/water relative permeability and filtrational resistance. In addition to these factors, the effect of wellbore also was considered.Finally, making used of statistics method, mechanism of interlayer interaction can be studied. Come to a conclusion, the greater the difference between layers, the stronger the interlayer interaction, the separate zone production should be implemented.Research results provide a theoretical basis for the reservoir adjustment and arrangement of oil field development.