Physical Simulation Of Injection Parameters And Production Dynamic Evaluation For Air Foam Flooding In Tang 80

Air-foam flooding has been paid much attention to because it can effectively improve the recovery of high water cut reservoirs after water flooding.Foam can selectively block high permeability drive channels in reservoirs,which solves the profile control problem in heterogeneous reservoirs.especially in low permeability reservoirs,it can effectively improve the recovery factor.As a typical low permeability reservoir in China,the air-foam flooding test has been carried out in batches in well Gangu yitang 80 area of Yanchang oilfield,which has achieved good results.however,there are also some problems such as unreasonable injection-production parameters,unbalanced injection-production and high water cut in some well groups.In order to provide more reliable production guidance for the field production of tang80 air-foam flooding,based on the similarity principle,this paper establishes the similarity criteria of tang80 air-foam flooding according to the characteristics of tang80 well area,and designs the physical simulation similarity model with the similarity criteria as the core,and verifies the rationality and applicability of the similarity criteria of the physical simulation of tang80 well area through three sets of core displacement experiments under different permeability.The air-foam flooding experiment of low permeability core was carried out by using the similar model.the gas-liquid ratio and injection rate in tang80 well area were evaluated by four groups of experiments respectively.the influence law of two factors on foam flooding effect was analyzed and the improvement measures were put forward.The production status of 60 well groups from 2003 to 2017 in four batches of air-foam flooding test in tang80 well area was analyzed.the injection cycle of 6 typical well groups and injection pressure of 25 characteristic well groups were evaluated and the stimulation countermeasures were given.According to the mechanics and motion law of injected water and air foam flowing in reservoir,seven physical simulation similarity criteria deduced by dimensional analysis and equation analysis are applicable to tang80 well area.the closer the permeability is to the actual permeability,the more accurate the simulation results are.The four batches of air foam flooding tests showed that the high permeability channel was blocked by foam and then entered the low permeability reservoir,the liquid and oil production increased,and the water cut increased first and then decreased.Increasing the gas-liquid ratio of air and foam liquid injection to 3: 1 and using long-period slug injection is beneficial to further enhance the regional recovery ratio;On the premise of no water channeling and gas channeling,increasing injection rate and pressure difference is beneficial to enhance regional recovery.