A nitrogen-assisted emulsification and viscosity reduction production method for heavy oil formations

Abstract

The invention provides a thickened oil exploitation method. The thickened oil is explored by employing the nitrogen-aided thickened oil formation emulsification and viscosity reduction exploitation method. According to the method, a certain amount of emulsification and viscosity reduction system comprising 0.3-0.5 percent of surfactant A, 0.03-0.08 percent of polymer B and the balance of water is injected into the formation through a pump truck, so that the emulsification and viscosity reduction system is mixed with thickened oil in the formation, and the viscosity of the thickened oil is improved; a certain amount of nitrogen is injected into the formation from the wellhead, the emulsification and viscosity reduction system is replaced to the deep part of the formation, the acting radius is enlarged, the emulsification and viscosity reduction effect is enhanced, and the construction cost is reduced; and moreover, after nitrogen is injected, the wellhead is closed, soaking is performed within 1-2 days, and then the well is opened for normal production. The field test shows that the construction effect is good, and the method can be widely applied to the field of thickened oil exploitation.

Description

technical field [0001] The invention relates to a nitrogen-assisted emulsification and viscosity-reducing mining method for heavy oil formations, which belongs to the field of heavy oil mining. Background technique [0002] Viscous oil, known internationally as heavy oil and asphalt, is a complex, multi-component homogeneous organic mixture. poor ability. China is rich in heavy oil and ultra-heavy oil resources, accounting for about 28% of my country's total oil resources. Currently, the proven recoverable reserves of heavy oil and ultra-heavy oil are about 1.2 billion tons, accounting for 28% of the total proven oil recoverable reserves. 7.5% of reserves. [0003] At present, heavy oil at home and abroad is mainly exploited by thermal recovery. However, due to scattered blocks, small oil-bearing area, and thin oil layers in many oil reservoirs, thermal recovery cannot be used to recover heavy oil economically and effectively. The method of chemical emulsification and vis...

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Problems solved by technology

However, due to its high cost and other reasons, it is not used much in the field.