Research On EOR Technology Of Steam Drive In Light-oil Sandstone Reservoir After Water Flooding

The oil development of in Daqing oilfield has already entered the period of high water-cut. The remaining oil distribution is very complicated and further enhanced the recovery become more and more difficult. Therefore the complement of tertiary oil technology shouldn't be delayed for one minute, while the data showed that average EOR of steam flooding is over 10%.This paper analyses the displacement mechanism of steam drive in light-oil sandstone reservoir after water flooding. Combined with Sa north transition zone in Daqing oilfield developing character, concept model is built to study factors affecting steam drive performance, such as the reservoir rock, fluid properties and design, operating parameters. Besides, the dynamic production models of pre-selected area of field test of steam flooding in Sa north transition zone were established, designed and optimized rational combination of layer system, the deployment options of well spacing. The results showed that the main displacement mechanisms of steam drive in light-oil reservoir after water flooding are steam distillation, viscosity reduction, thermal expansion and temperature dependence of relative permeability curves. Rational combination of layer system is the whole Sâ…¡reservoir of north transition zone in Daqing oilfield. Reasonable well pattern is 125m of anti nine point areal well spacing. Reasonable injection parameters are as follows: reservoir pressure should be dropped to 6-8MPa when the performance steam drive will be the best; the speed of steam injection should be 100~120t/d; steam quality in the bottom hole should be greater than 50%; fluid production capabilities during steam flooding process should be maximized to enable production factor access 1.2.Results of the research will be a good guide for expanded application of steam flooding technology in light-oil reservoir. This will provide technical reference for the efficient development in transition zone of Daqing placanticline. Meanwhile this will provide a scientific basis for implementation of measures to further improve recovery.