Method for improving recovery ratio of non-homogeneous pay

Abstract

The invention relates to a method for improving the recovery ratio of a non-homogeneous pay. The method is a method for alternately injecting a foam slug and an alkali and surfactant binary solution slug to improve the recovery ratio of the non-homogeneous pay, and comprises the following steps: injecting the foam slug into an oil layer; and then injecting the alkali and surfactant binary solution slug to complete one injection period, wherein the total injection amount of the foam slug is 60 percent to 100 percent of the total pore volume of the oil layer, the total injection amount of the alkali and surfactant binary solution slug is 20 percent to 40 percent of the total pore volume of the oil layer and the one to four injection periods are carried out. The method for improving the recovery ratio of the non-homogeneous pay, which is provided by the invention, is low in cost, has obvious effect of improving the recovery ratio, can obtain good economic benefits and has wide application prospect.

Description

technical field [0001] The invention relates to a method for increasing the recovery rate of an oil field, in particular to a method for increasing the recovery rate of a heterogeneous oil layer, and belongs to the technical field of oil field production. Background technique [0002] Polymer flooding technology has developed rapidly in China. For example, the industrialization and application of polymer flooding in Daqing Oilfield has achieved remarkable economic results. The recovery rate is about 10% higher than that of water flooding. The current annual oil production It has exceeded 10 million tons and has become a major technical measure for the sustainable development of oil fields. [0003] Nevertheless, about 40-50% of the crude oil in the oil layer remains unrecovered after polymer flooding, and how to further enhance the recovery after polymer flooding is a current research hotspot. According to the experimental research, the recovery of ASP flooding is generally...

AI Technical Summary

Problems solved by technology

ASP flooding and foam composite flooding have better effects, but the cost is higher. Moreover, when foam composite flooding directly injects foam into the formation, due to the high injection pressure and the limitation of formation fracture pressure, continuous injection cannot be promoted. App is restricted

However, due to the complexity of the technology and the immature technology of microbial flooding, it is difficult to popularize and apply it for the time being.

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