Research on the re-enrichment velocity of remaining oil after shut-in of high water cut oil wells
At the end of the development of high water cut fault-block oil reservoirs,the phenomenon of remaining oil re-enrichment will occur in wells located in the structural high position after the well is shut in for a period of time.In the current research on the re-enrichment velocity of remaining oil,consideration of inflencing factors of the migration process of remaining oil is not comprehensive enough,which affects the calculation accuracy.To address this problem,based on the microscopic mechanical analysis of the remaining oil in the migration,the re-enrichment velocity models of small-oil-droplet-shaped and column-shaped remaining oil were established.The main sensitive factors of the re-enrichment velocities of two kinds of remaining oil were clarified through orthogonal experiment,and the chart of two kinds of remaining oil re-enrichment velocities and re-enrichment times were established.The results show that when there is a displacement pressure difference,reservoir permeability is the main controlling factor affecting the re-enrichment velocities of two kinds of remaining oil.When the reservoir permeability is certain,the increase of displacement pressure difference and the decrease of crude oil viscosity are conducive to the increase of two kinds of remaining oil re-enrichment velocities.The closer the small oil droplets at the same injection production well distance to the column-shaped remaining oil in the pores,the longer the time of remaining oil re-enrichment in the accumulation process,but the value increase is small.This study has reference significance for evaluating the re-enrichment potential areas of remaining oil in high water cut oil reservoirs.
high water cut oil wellsremaining oilre-enrichment velocitysensitive factorsreservoir permeability
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