Study On Technology And Economic Evaluation Of Polymer+Surfactant Flooding

Costing as little as possible to gain oil recovery ratio as big as possible is the final purpose of oilfield development activities. After high efficient development for more than 40 years in Daqing Oilfield, it has entered high watercut stage, and the water cut is higher than 90%, especially in some blocks, is near to 98%. So, how to make the development strategy at high watercut stage, and at the same time, to save money, is the key to achieve the goal of"Hundred Oilfield".To improve the oil recovery, ASP flooding is an effective method, but because of the causticity of alkali, injection and gathering pipelines will easily be corrupted, normal production work will of course be influenced, so, injected agent without alkali should be studied. Its technology feasibility was proved by lab experiment and numerical simulation, and its economic feasibility was proved by static and dynamic economic assessment.On the basis of lots of experiment and study, we concluded as followings: 1. From 35 different kinds of surfactant, multi-system of non-ionic surfactant and polymer was selected, surfactant concentration is between 0.1% and 1.0%, this multi-system can form ultra-low IFT(10-3mN/m) with oil and water of Daqing oilfield; 2. Lab experiments with artificial cores and nature cores indicated an 18% OOIP above that of waterflood; 3.Economic assessment showed a good benefit, internal rate of return was above 78.56%, and investment recovery term was only 2.19 years, its feasibility was good; 4.Breakeven balance analysis and sensitivity analysis showed a good potential to gain a great economic efficiency; 5. Technical and economic indexes were united reasonably by fuzzy analysis method, and the comprehensive results indicated a good result.All the lab experiment and economic assessment show a good result of SP flooding, and this new method is a new technology method and a new direction for EOR method, and it will certainly supply important technology support to maintain 40,000,000 tons per year in Daqing Oilfield.