Study On Profile Control Of Putaohua Reservoir In Shu 103 Block Of Yushulin Oilfield

As a low permeability reservoir,Yushulin Oilfield has reached more than 60%of the water cut in the early development blocks and entered the stage of medium and high water cut.At present,there are obvious problems of water drive dominant channel,low liquid production,fast oil production decline and difficult water injection.It is found that conventional adjustment techniques such as strata subdivision,optimization of well pattern layout and adjustment of water injection scheme are often difficult to tap the remaining oil in potential blocks.Only by carrying out the Adaptability Study of profile control agent in Putaohua reservoir and optimizing the profile control agent,and putting forward a reasonable injection scheme,can we achieve the goal of slowing down production decline,controlling water cut rise and improving oil recovery.According to the characteristics of low permeability in Yushulin Oilfield,the poly/Cr3+profile control system was screened out,and the polymer with molecular weight of 12 million was determined.The suitable concentration was 500-1500mg/L.The crosslinking agent is composed of chromium chloride and lactic acid mole ratio 1:3,suitable concentration130~160mg/L,thiourea suitable concentration of 900~1000mg/L,sodium chloride suitable concentration of 600-800mg/L,low viscosity before gel forming,which can ensure the injection effect.After gelation,it has better compatibility,stability,rheology and high plugging rate of formation water.Through three-dimensional geological modeling of Shu103 block and historical fitting,the remaining oil distribution in the block is analyzed,profile control wells are preliminarily screened,RS profile control and well selection method is simplified,profile control wells screening system is established,profile control wells are finally determined.The dosage of profile control agent,injection speed,injection timing are optimized by CMG numerical simulation method,and the dosage is obtained 0.125 PV,injection rate 30 m~3/d.The best profile control time is 60%~70%water cut.