A method for determining the degree of gas channeling during nitrogen foam flooding

Abstract

The present invention relates to a method for determining the degree of gas channeling during nitrogen foam flooding, comprising the following steps: (1) injecting nitrogen foam fluid into an injection well, and measuring the gas production Vg and liquid production Vl of production wells at different times; 2) calculate the gas production rate fg of the production well at different times; (3) draw a curve according to the fg calculated at different times, and calculate the gas production rate increase index Ig of the production well; (4) determine the gas channeling in the foam flooding process degree. Utilizing the method for determining the degree of gas channeling in the process of nitrogen foam flooding provided by the present invention, it is possible to qualitatively and quantitatively determine the degree of gas penetration in the production well of the oil field, whether there is gas channeling, the degree of gas channeling, and when to start sealing channeling measure.

Description

Technical field [0001] The invention relates to a method for determining the degree of gas channeling in a nitrogen foam flooding process, and belongs to the technical field of oil and gas field development. Background technique [0002] Foam flooding is a tertiary oil recovery method that uses foam fluid as the displacement medium. Foam fluid has the advantages of high apparent viscosity, selectivity to permeability and oil-water layer, and strong oil washing and plugging profile control. Oil flooding has become an efficient method of enhancing oil recovery, and good application results have been achieved in field experiments in some oil fields. Compared with other gases, N 2 Wide sources, economical and reasonable preparation process, and N 2 It is not easy to scale, corrode pipelines and many other advantages, so N 2 Foam flooding has been favored by major oil fields. [0003] After the foam is injected into the formation, the stable foam will effectively plug the high permeabi...

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Problems solved by technology

[0005] However, the methods given in the above literature can only qualitatively judge gas channeling, and there is no way to quantify the timing and intensity of gas channeling based on experimental data

At present, domestic and foreign 2 There are few studies on the phenomenon of gas channeling during foam flooding, and the existing studies mainly focus on N 2 Foam flooding mechanism, and feasibility analysis, etc., lack of N 2 Quantitative judgment of gas channeling timing and definition of gas channeling degree during foam flooding

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