Study On The Influence Of Shut-down Of High Water Cut Wells On Production And Recovery Scheme In SG Oilfield

SG oilfield was put into development in 1975.At present,the comprehensive water cut is81.54 %,and the production decline rate is fast.The number of wells with water cut greater than 95.0 % accounts for 29.8 %.The main measure for this part of high water cut wells is shutdown.At the beginning of the measures,the water cut in the whole area was effectively reduced,but with the extension of development time,there were problems such as low injection-production correspondence rate and low water flooding control degree.Therefore,it is necessary to study the influence of shut-down of high water cut wells on production,and give a reasonable recovery plan for shut-down wells.Based on the heterogeneous model,this paper established the calculation formulas for the loss ratio of oil production and liquid production after shutting down the high water-cut wells in the well pattern of five-point method,nine-point method and seven-point method,and clarified the influence of shutting down the high water-cut wells on oil production and liquid production.The results showed that after shutting down 48 high water-cut wells,the loss ratio of oil production and liquid production in 24 months of high water-cut wells in SG oilfield was39.2 % and 51.4 %,respectively.The numerical simulation tracer method was used to compare the change of sweep coefficient before and after shut-down of high water cut wells,and the calculation formula of control reserve loss ratio was established.The results show that when the water cut reaches 98 %,the control reserve loss ratio of high water cut wells in SG oilfield is 29.3 %.Based on the history of numerical simulation,the high water-cut wells in SG Oilfield are divided into three types according to the reproduction potential index,namely,type I high water-cut wells,type II high water-cut wells and type III high water-cut wells,including 23 type I high water-cut wells,14 type II high water-cut wells and 11 type III high water-cut wells.Based on the evaluation of remaining oil potential of various types of high water cut wells in SG oilfield,different shut-in and shut-in schemes are put forward.Among them,for type I high water cut shut-in wells,fracturing measures are used for re-production,and the effective rate of re-production after 3 years is 92.7 %.Type II high water cut shut-off wells are reproduced by high aquifers with low plugging potential,and the effective rate of recovery is 90.1 % after 3years of measures;class III shut-in wells with high water cut are diverted to improve the injection-production relationship of surrounding well groups and realize the recovery of such wells.The effective rate of recovery after 3 years of measures is 76.7 %.