Study On The Mechanism Of Water Plugging And The Rational Water Shutoff Period In The West 16-9 Block

The reservoir heterogeneity is strong in west 16-9 block,the contradiction between plane,interlayer and innerlayer is outstanding and water flooding effect is low.The comprehensive water content is 96.9%and the recovery percent is 33.2%.Water plugging can control water-cut and stabilize production.In order to improve the success rate of water shutoff,it is necessary to clarify the mechanism of oil increasing in the layer between plane,interlayer,innerlayer and provide the basis for the selection of water plugging well.In order to fully utilize the low and low part reserves in the flooded layer,it is necessary to determine the reasonable water plugging period of the positive rhythm thick oil layer,which is very important for the promotion of water plugging measures.First of all,in this paper,using 37 plugging wells in west 16-9 block for water plugging effect evaluation,the results show that the amount of liquid produced after the water shutoff decreased by 2974 t/m,oil production increased by 292 t/m,The water content decreased by2.2%,water plugging efficiency is 89.19%.By using the numerical simulation method to study the mechanism of planar oil increment.The formation pressure around the O3-2 well was increased and the injection water of W2-2 well turned to the O3-3 well,and the O3-3 well was increased liquid by 0.4m~3/d,increased oil by 0.0103 m~3/d in the plane.The 70%of horizontal oil-enhancing wells in West 16-9 block are located at the edge of the river,the side edge of the underwater distributary channel,or the bay mud where the remaining oil is abundant.Indicating that plugging the main body of the main channel can be forced to change the direction of the injected water line and drive to the remaining oil enrichment area to drive the oil,so that the adjacent wells can increase oil level.In the interfacial oil increasing mechanism study,using the inter-layer interference mechanism model and numerical simulation methods,the results show that the water injection volume in the fourth layer of W2-2 well increases 0.2 m~3/d after the water plugging of the oil well,and the water injection amount in the fifth layer is reduction of 0.6 m~3/d,reduced water absorption in hypertonic layers,increased water absorption in low-permeability layers,and improved inter-floor conflicts after plugging of oil wells.The low permeability layer has a low recovery,the remaining oil is more,the pressure in the surrounding formation increases after the oil well is plugged,and the production pressure difference increases.The production capacity of the unplugging layer of the plugging well is calculated using a multi-layer combined production well productivity model and a numerical simulation method.The results show that the oil production per day of wells 1-4 in well O3-2increased by 0.0147 m~3/d after water plugging in the well,and the oil increase between the intercepted wells was increased.The numerical simulation method was used to study the mechanism of oil increase in the layer.After plugging the 8th and 9th layers of the O3-2 well,the W2-2 well was injected with the T1-T9 type tracer to the 1-9th layer,and the T8 and T9 tracers were used.The concentration of the agent is higher near the well O3-2 in the upper layer of the injection layer,which means that when the bottom of the positive rhythm oil layer is plugged,the injection water of the injection well moves upwards in the flow direction to the plugging layer,and the swept volume is enlarged.Accumulation of 25.17 m~3 of oil within the layer.Through the numerical simulation study of West 16-9,the reasonable water-plugging period is 6 years,and the recovery factor is 35.5464%.