Performance evaluation and reservoir adaptability of deferred crosslinked gel profile control system
Deep profile control is an important means to control water and increase oil in view of the high water cut problem in late development of oilfield.In order to understand the performance characteristics of the delayed crosslinking gel profile control system and its adaptability to oilfield reservoir,this paper analyzed the gel-forming performance and temperature resistance of the delayed crosslinking gel profile control system(hereinafter referred to as the initial low-viscosity gel)through evaluation experiments on viscosity increasing characteristics and sand filling pipe fluidity.A parallel experimental study was conducted on the plugging performance of the conventional phenolic profile control system(hereinafter referred to as phenolic gel).The results show that the gelation time is adjustable and the gelation strength is large for the initial low viscosity gel system.Different concentrations of crosslinking agent,auxiliary agent and curing agent have influence on the effect of gelling,among which curing agent and crosslinking agent have great influence on the strength of gelling.The viscosity of 0.3%polymer,0.3%crosslinking agent and 0.2%assistant agent reached 20000 mPa·s,and the gel viscosity retention rate remained above 60%after 4 months of storage at reservoir temperature.Compared with the conventional phenolic profile control system,the initial low viscosity gel plugging performance is better.In the sand-filled tube experiment,the plugging rate of cores with three permeability levels(500,1500 and 3000mD)can reach 95%after 0.15PV initial low viscosity gel is injected,and the plugging rate can maintain 90%when 0.05PV initial low viscosity gel is injected.
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