Oil Displacement Scheme Design Of Lipopeptide Compounded Weak Alkali Ternary System For Class ? Reservoir In Block Z

Since the research of ASP flooding in Daqing Oilfield began in 1980 s,the field test of ASP flooding with strong alkali and weak alkali system has been completed.The results show that the ASP flooding with strong alkali and weak alkali has achieved good effect of increasing oil and reducing water,which can enhance oil recovery by more than 18%compared with water flooding.In order to save cost and improve efficiency,SN Development Zone has carried out the test of Petroleum Sulfonate / lipopeptide surfactant combined with weak alkali compound flooding,and achieved the effect of enhancing oil recovery by 22.4%.According to the understanding of ASP flooding,in order to further reduce the cost and increase the efficiency and enhance the development effect of oil recovery,based on the detailed reservoir description,according to the laboratory test results of two kinds of weak alkali ternary composite system with different surfactant formulations and the field test results,the weak alkali ternary composite system of lipopeptide and petroleum sulfonate was designed,based on the mature experience of Sanyuan block,the optimization of injection parameters of system,slug and well group is highlighted according to the principle of maximum recovery and economic benefit,in block Z,the injection parameters of ASP flooding with lipopeptide and weak alkali are as follows:Two kinds of polymers with molecular weight of 25 million and 16-19 million were used,and the injection rate was 0.15-0.17 PV/A.The pore volume of prepolymer slug is0.05-0.07 PV,the average polymer concentration is 1440 mg/L,and the wellhead viscosity is35-45 mpa·s.The main and secondary slugs are made of petroleum sulfonate and lipopeptide surfactant weak base system.The main slug injection pore volume is 0.35 PV,and the average polymer injection concentration is 1810 mg/L,the concentration of alkali is 1.2%,the concentration of petroleum sulfur acid is 0.2%,the concentration of lipopeptide was 0.2%,and the wellhead viscosity was 30-40 mpa·s.The secondary slug injection pore volume is0.15-0.20 PV,and the average polymer injection concentration is 1700 mg/L,the concentration of alkali is 1.0%,the concentration of petroleum sulfur acid is 0.1%,the concentration of lipopeptide was 0.1%,and the wellhead viscosity was 30-35 mpa·s.The pore volume of subsequent polymer protection slug injection is 0.20-0.25 PV,the average polymer concentration is 1350 mg/L,and the wellhead viscosity is 30-35mpa·s.The numerical simulation method is used to predict the development index of the block.When 0.41 pv chemical agent is injected into the ASP flooding of the class ? reservoir in block Z,the water cut reaches the lowest value of 89.7%,and the water cut decreases by8.4%,in the chemical flooding stage,the EOR is 16.59%,the cumulative oil increase is1.9654 million tons,and the final oil recovery is 62.26%,after tax financial internal rate of return is 6% higher than the industry standard.