Oil extraction method with polymer-surfactant binary oil displacement system assisting in carbon dioxide huff and puff

Abstract

The invention discloses an oil recovery method with the assistance of a carbon dioxide huff and puff by a poly-surface binary flooding system, and belongs to the technical field of enhanced crude oil recovery. The method is as follows: sequentially inject the pre-slug of the poly-surface binary flooding system, the main slug of carbon dioxide, the post-slug of the poly-surface binary flooding system, the plugging agent slug and water; Open the well after the time for crude oil production; the pre-slug of the poly-surface binary flooding system and the post-slug of the poly-surface binary flooding system include the following components in mass percentage: polyacrylamide, 0.10% to 0.40%; ten Surfactant compounded with dialkyldimethylbetaine and cetyltrimethylammonium bromide, 0.05% to 0.20%; water, balance; plugging agent slug includes the following components in mass percentage Parts: partially hydrolyzed polyacrylamide, 0.25% to 0.50%; crosslinking agent, 0.20% to 0.50%; stabilizer: 0.01% to 0.03%; pH regulator: 0.01% to 0.02%; water, the balance. The method can reasonably control the mobility ratio, improve the oil washing efficiency and the utilization rate of carbon dioxide, and enhance the recovery factor.

Description

technical field [0001] The invention relates to the technical field of enhanced crude oil recovery, in particular to an oil recovery method with the assistance of a carbon dioxide huff and puff by a poly-surface binary flooding system. Background technique [0002] Carbon dioxide huff and puff oil recovery technology is an important enhanced oil recovery technology, which has been widely used in oil fields such as Daqing Oilfield, Jilin Oilfield and Jidong Oilfield. Carbon dioxide huff and puff oil recovery technology refers to injecting a certain amount of carbon dioxide into the oil layer under a certain pressure, soaking the well for a period of time to make the carbon dioxide diffuse in the formation and dissolve in the crude oil, and then open the well for production. [0003] The mechanism of CO2 huff and puff oil recovery technology to enhance oil recovery is: after injecting carbon dioxide into the oil layer, the carbon dioxide will dissolve in the crude oil and form...

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Problems solved by technology

[0004] In the process of realizing the present invention, the inventors have found that there are at least the following problems in the prior art: due to the heterogeneity of the reservoir, after multiple rounds of carbon dioxide stimulation, carbon dioxide will flow along the high permeability zone in the reservoir Or the channeling of large pores, the affected area is greatly reduced; when the well is opened for production, the carbon dioxide will return along the original path of the injected pores, which causes the ineffective circulation of carbon dioxide; The stripping effect of crude oil is small, so that even after passing through the area affected by carbon dioxide, there is still a large amount of remaining crude oil that cannot be recovered

In summary, the existing CO2 huff and puff oil recovery technology cannot play a good role in enhancing oil recovery

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