Study On The Regulation Mechanism Of Sealing Channel Pressure Gradient Under Extreme High Water Consumption Zone

At present,most of China’s onshore oilfields have entered the high water cut stage or even the ultra-high water cut stage.Due to the influence of the horizontal and vertical heterogeneity of the reservoir,the water flooded condition of the reservoir is complex that tends to develop the extreme water consumption zone.How to block the water consumption zone and expand the injected water wave and volume is crucial to the further improvement of the water drive recovery.In this paper,numerical simulation method and indoor physical simulation method are used to establish the simulation model of channeling sealing with extreme water consumption belt.It can be used to carry out numerical characterization and physical model characterization of the pressure gradient field distribution in the stationary channeling sealing environment.In the aspect of numerical characterization,the mechanism model of typical well group was established,and the dynamic characterization of the displacement field before and under the control threshold was simulated.In the aspect of numerical characterization,the mechanism model of typical well group was established,and the dynamic characterization of the displacement field before and under the control threshold is simulated.In the aspect of physical model characterization,the physical simulation system for the pressure field distribution of plugging agent residence and channeling sealing is established.With the combination of dynamic pressure monitoring and visual water flow line description,the physical model characterization method for the pressure gradient field distribution of plugging agent residence and channeling sealing is formed.The pressure gradient field is described from three aspects of water drive velocity,plugging agent location and plugging agent size with the variation law of the pressure gradient field of plugging agent residence and channeling sealing under different conditions clarified.It is found that the formation of dominant channel is affected by both physical property difference and injection production control in ultra-high water cut stage.If the water is directly injected,the water will be displaced along the dominant flow channel first.With the development of injection and production,the water cut increases gradually,and the channeling flow will be formed in the dominant flow channel.When plugging the water consumption zone,the heterogeneity of reservoir between layers and on the plane should be comprehensively considered.When selecting the plugging agent dosage and plugging position,it is considered that the plugging agent dosage of 0.3 PV has the highest channeling sealing degree for the dominant channel,which reduces the water cut of the reservoir by4.71%;when considering the economic benefit,the plugging agent dosage of 0.05 PV is the best,the oil increase per unit plugging agent is 1.3 m~3;The best channeling sealing position is situated on the high permeability strip near the production well.The evaluation system enriches the channeling sealing method of extreme water consumption zone in ultra-high water cut stage,and has important significance for tapping the potential of remaining oil in ultra-high water cut stage.