Adaptability Study Of CO₂ Assisted Steam Stimulation Technology In Heavy Oil

The special heavy oil is developed into the middle and late stages by steam stimulation technology.The cycle water content is high and the development effect is poor.The single development mode of steam stimulation alone can not meet the mine production demand.In view of the fact that CO₂ has the effect of reducing the viscosity of crude oil and improving the oil-water mobility ratio in the formation.Therefore,the adaptability study of CO₂ assisted steam stimulation technology for special heavy oil is provided,which provides a new direction for enhanced oil recovery in M oilfield,and provides reference for finding replacement technology in the middle and late stage of similar oil storage steam stimulation.In order to clarify the adaptability of CO₂ auxiliary steam stimulation technology in M oilfield development,a typical model of thermal recovery was established by using reservoir numerical simulation method,and the influence law of reservoir,injection and production process on throughput was studied,and well selection criteria were given.The single well model representing the typical production characteristics of the block is used to carry out the research on the remaining oil distribution and key parameters optimization;the tracking development of the preferred well development effect in the test block is carried out.The main points of understanding are as follows:?1?For relatively closed single wells,there are fewer sensitive factors for CO₂assisted steam stimulation.Pilot testing in such wells is less risky and effective.For the intrusion of water at the bottom and bottom,there are many sensitive factors for CO₂assisted steam stimulation.The pilot test is more risky in such wells.Once the bottom water breaks through the bottom of the well,the throughput will be greatly reduced.Less than 3m,while properly reducing steam dryness and liquid sampling speed.?2?After adding CO₂,the range of steam stimulation is expanded,and the remaining oil distribution is more uniform.The key parameters of optimized CO₂assisted steam stimulation are:no energy supplement C28 well CO₂ injection volume200t,boring time 10d,and well production speed 60t after opening/d;There is energy to supplement the C139 well CO₂ injection volume 150t,the boring time is 3d,and the liquid recovery rate after opening the well is 20t/d.?3?CO₂ assisted steam stimulation technology can be applied to special heavy oil reservoirs with high round steam stimulation.It can better control water and oil in the relatively closed single well and the water intrusion well far from the bottom water.However,in the horizontal wells closest to the side water,the effect is limited.