Multiple thermal fluid composite system oil displacing method

Abstract

The invention discloses a multiple thermal fluid composite system oil displacing method and particularly relates to a method for economically and effectively improving the oil recovery rate for the later period of water displacing normal heavy oil reservoir exploitation. The method comprises the steps of a, injecting mixtures, which is 0.15-0.2 time the formation pore volume, of hot water and flue gases; b, injecting a foaming agent solution into a water injection well for 25-30 d; c, injecting a viscosity reducer solution into the water injection well for 5-10 d; d, injecting the mixtures of hot water and flue gases for 60-80 d; e, repeating the steps b, c and d. The method displaces a great amount of residual oil which cannot be extracted through common water displacing in an oil reservoir, the heavy oil reservoir recovery rate after water displacing is improved greatly by 26.4%, and the final reservoir recovery rate can reach 48.8%. Meanwhile, flue gases generated by combustion are directly injected underground, the thermal efficiency can be improved by more than 10%, and environment pollution is reduced.

Description

technical field [0001] The present invention relates to the technical field of multi-component thermal fluid oil recovery for heavy oil reservoirs, in particular to a multi-component thermal fluid composite system oil displacement method using foaming agent, flue gas and viscosity reducer to assist hot water flooding to enhance recovery . Background technique [0002] With the deepening of oil exploration and development, it is more difficult to find high-quality reserves, oil resources are dwindling, and oil prices continue to rise. How to improve the development effect of high-water-cut old oil fields has become an urgent task to increase their recovery. [0003] There are abundant ordinary heavy oil resources in China (formation condition viscosity>50mPa·s), only Shengli Oilfield has geological reserves of 10.5×10 8 t. The early thermal recovery technology was immature, and water injection development was the main method. Due to the high viscosity of crude oil, the ...

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Problems solved by technology

The early thermal recovery technology was immature, and water injection development was the main method. Due to the high viscosity of crude oil, the recovery rate of ordinary heavy oil in water flooding was low. When the viscosity of formation crude oil was >150mPa·s, the recovery rate was generally <20%, which means 80% The above crude oil is trapped in the ground, and it is urgent to change the development method to improve the recovery rate of this type of oil reservoir

[0004] At present, relatively mature oil displacement methods to improve the development effect of ordinary heavy oil by water flooding include chemical flooding and steam flooding, among which the chemical flooding method is currently only suitable for reservoirs with crude oil viscosity <150mPa·s

Although steam flooding can greatly increase the recovery of heavy oil, the heavy oil in Shengli water flooding belongs to the marginal reservoir of steam flooding, and the reservoir is buried 1200-1600m. Edge and bottom water, sufficient energy replenishment, difficult to reduce pressure, and high formation pressure is not conducive to the diffusion of steam belt, and the steam flooding effect is poor; at the same time, it is difficult to protect the heated casing of the original conventional old wells, and new wells need to be drilled, so that the steam flooding benefits become worse