A Study Of Wellbore/Oil Pool Coupling Simulation On Foam Acid In Horizontal Well

In the process of drilling and completion of horizontal well,the drilling and completion fluids will inevitably contact with the oil and gas layer for large area and long time,which formed a larger-scale pollution area and increased the flow resistance of fluid in the fluid.This pollution is more serious than vertical wells.In addition,the capacity of low permeability reservoir is very low.Therefore,the horizontal wells face the same problems of deluging the pollution formation surrounding wellbore,dredging the fluid channel of the near wellbore,improving and restoring the capacity of oil and gas well.The acid can improve formation permeability around the wellbore so as to improve the seepage force around the wellbore.Compared to vertical wells,the matrix acid of the horizontal wells is more complex,due to the different soaking time in the working fluid in different well horizontal sections and the variable mass flow of horizontal section itself.Foam possesses temporary block characteristic.Foam diversion can effectively solve the problem that acid distribution among layers of different permeability,which is important to equably unblock in horizontal well.The key in successful use of foamed acid technology is full understanding the diversion mechanism of foamed acid in horizontal well.In order to investigate the flow mechanism and flow process for foam acid of horizontal well and track the flow position of acid front,the flow model of acid along the horizontal well,seepage model of reservoir around the well,the model of the foam acid diversion and coupling model of three flow systems are established.At the same time,the reservoir around the horizontal well is divided into pollution zone,acid zone,and non-polluted zone.The model is solved by numerical method.The flow state of foam acid solution along horizontal well,the flow rate into reservoir around well,and the acid front arrival time are analyzed.And,relevant parameters' effects on the foam acid diversion is analyzed.Results show that the influx into each layer around well increases with the increase of the foam acid injection volume;reservoir acid rates around well are very different because of permeability;the reservoir acid solution of high permeability layer is much larger than that of the low permeability reservoir.The results provide a theoretical reference for the implementation of horizontal well.