Study On Production Capacity Of Polymer Flooding In Jinzhou 9-3 Oilfield

After the polymer flooding,the liquid production capacity usually decreases in a certain extent.Compared with onshore oilfield,offshore oilfield has many characteristics,such as multiple layers,serious heterogeneity,loose reservoir cementation,large well spacing and large displacement.Therefore,the liquid production capacity of offshore oilfield has decreased greatly after injection.For Jinzhou 9-3 oilfield that began injecting polymer in 2007,the total liquid production decreased by about 48% compared with the pre injection,and maximum drop of liquid production in single well is about 82% as of August 2015.It has a great influence on the development effect of polymer flooding.So it is necessary to carry out research on variation law and influencing factors of liquid production of polymer flooding by combining the reservoir characteristics and development characteristics of offshore oilfield,so as to guide the formulation of adjustment plan for improving production capacity during polymer flooding.Taking Jinzhou 9-3 oilfield as the object of study and combining reservoir engineering,numerical simulation and indoor physical simulation methods,this paper studys the effect of 4factors,which are water cut,polymer viscosity,permeability and permeability ratio,on the liquid production index.what's more,a large number of domestic and foreign research on liquid-producing capacity is also investigated.The results show that: the variation curve of liquid production index is divided into three sections,which are ascending section,descending section and upturned section,from water flooding to 95% of water cut of polymer flooding.The earlier the polymer flooding is,the smaller maximum drop of liquid production index is,and the converse is also true.The maximum drop of liquid production index is between 60% and 73% at different times of polymer flooding.The higher the permeability is,the smaller the extreme distance is,and the extreme distance varies from 0.27 PV to 0.83 PV.The higher the viscosity of polymer is,the greater the maximum drop of liquid production index and extremal distance are.The maximum drop of liquid production index is between11% and 75%,and the extreme distance is between 0.22 PV and 0.55 PV.The bigger the permeability ratio is,the smaller the maximum drop of liquid production index and extremal distance are.The maximum drop of liquid production index is between 53% and 63%,and the extreme distance is between 0.19 PV and 0.59 PV.On the basis of the historical matching of Jinzhou 9-3 oilfield,the variation law of liquid production index of 34 wells was studied.The result shows that: the maximum drop of liquid production index is generally between 35%and 45%,and the extreme distance is generally between 0.1PV and 0.3PV.