Oil well response stage dividing and distinguishing method under carbon dioxide miscible displacement condition

Abstract

The invention provides an oil well response stage dividing and distinguishing method under a carbon dioxide miscible displacement condition. The method comprises the steps that original carbon dioxide content Ci and original solution gas-oil ratio Rt of an oil reservoir and carbon dioxide solubility Ri under different pressure P conditions are obtained; the static pressure Px of the stratum where an oil well is located is obtained through a pressure recovery curve; the production gas oil ratio Rx and the well mouth carbon dioxide content Cx recently are monitored; the changing situation of daily output recently is analyzed; an oil well response stage dividing standard under the condition of the static pressure Px of the stratum where the oil well is located is established; the well mouth carbon dioxide content Cx, the production gas oil ratio Rx and the output changing situation are compared with the oil well response stage dividing standard to judge the current response stage of the oil well. The method is closely combined with production practice, emphasizes the objectivity and overcomes subjectivity, the scientificity is enhanced remarkably, operation procedures are clear and reasonable, and a firm theoretical basis is laid for reservoir engineering analysis and site dynamic regulation.

Description

technical field [0001] The invention relates to the field of oil reservoir dynamic analysis research, in particular to a method for dividing and discriminating effective stages of oil wells under the condition of carbon dioxide miscible flooding. Background technique [0002] At present, carbon dioxide miscible flooding technology, as one of the enhanced oil recovery technologies, has very obvious advantages in the development of low permeability reservoirs, especially ultra-low permeability reservoirs that are difficult to develop by water injection. However, no systematic research has been conducted on the effect characteristics of oil wells under the action of carbon dioxide miscible flooding and how to divide the effect stages. Conventional reservoir engineering methods and experience are not suitable for oil wells under gas flooding conditions. The production characteristics are highly subjective, lack of clear, reliable and scientific operation steps, and at the same t...

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Problems solved by technology

[0002] At present, carbon dioxide miscible flooding technology, as one of enhanced oil recovery technologies, has very obvious advantages in the development of low permeability reservoirs, especially ultra-low permeability reservoirs that are difficult to develop by water injection. A large number of laboratory theories have been carried out on carbon dioxide miscible flooding technology However, no systematic research has been conducted on the effect characteristics of oil wells under the action of carbon dioxide miscible flooding and how to divide the effect stages. Conventional reservoir engineering methods and experience are not suitable for oil wells under gas flooding conditions. The production characteristics are highly subjective, lack of clear, reliable and scientific operation steps, and at the same time, there is no set of effective discrimination methods in the daily production management process to recognize the performance characteristics of the oil well, the performance stage and the production trend , which leads to blindness and unscientificity in the process of carbon dioxide miscible flooding reservoir engineering research and production management

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