Study On The Flooding Scheme Of CO 2 Sub - Oil In Deep Heavy Oil Reservoir In M ​​area

With the development of petroleum exploration and exploitation, the reserves and production are reduced in high quality field year by year. The exploitation of heavy oil is significant to relieve the energy supply in our country.CO2is used widely as a kind of oil displacement agent in petroleum industry. CO2flooding is an effective method to improve well productivity, which has been proved by indoor experiment and field experiment. With the discovery of CO2gas source in China and the improvement of the supporting technology, CO2becomes a new technology to improve unconventional oil resources, such as the heavy oil reservoir, which has been widely used and has a good application prospect.This paper study CO2flooding of heavy oil reservoir with using indoor experiment and numerical simulation in M well block. Under simulated formation conditions, formation oil PVT characteristics are determined by laboratory experiments and the law of oil-gas phase is studied after the injection of CO2.With the increase of CO2injection rate, saturation pressure, volume factor, oil/gas ratio and expansion coefficient increase, but density and viscosity decrease. It obtained pseudo-component characteristic parameters of formation fluid, with using PVT module of Eclipse and gas injection expansion experiment to match. Using tubule experimental measurement and numerical simulation technology to, the minimum miscible pressure of heavy oil in M well block and CO2is77.69MPa.According to the geological characteristics and development status in M well block, geological model is established using FloGrid module in Eclipse. Using component model of Eclipse, well pattern deployment, well spacing,CO2injection pattern, injection-production pressure and injection-production method are simulated. Recommendation project as follows: the scheme of water alternating gas flooding is adopted. Well spacing is150m.The injection is opposite7points. Gas injection strength of single well is10000m3/d. Gas water ratio is1:2.Alternate cycle is6:4(months).Gas injection pressure is not higher than35MPa. bottom-hole flowing pressure of production well is about3MPa. After simulation development10years recovery efficiency can reach27.45%, the water drive can increase by more than18%, the oil wells increase obviously, and daily oil production can be increased2.5times. It is visible that water alternating is advisable for deep heavy oil reservoir of M well block.