Channeling-preventing agent for extra-low permeation oil accumuiation carbonic anhydride oil displacement and application thereof

Abstract

The invention provides a fleeing proof agent for the carbon dioxide flooding of oil reservoirs with ultra-low permeability and the application of the fleeing proof agent. The invention is characterized in that: the main agent of the fleeing proof agent is the amine substance of organic compounds; the fleeing proof agent comprises at least one amine substance and a release agent; the release agent is the ethanol comprising a certain amount of water, a hydrocarbon substance or nitrogen; the release agent is used to prevent the chemical reaction caused by the premature contact between the amine and the carbon dioxide. The invention is suitable for the gas channeling inhibition during the carbon dioxide flooding process for oil reservoirs with ultra-low permeability. The invention has the advantages that: the fleeing proof agent mainly block the gas channeling channel by the salt precipitation generated by the reaction between the carbon dioxide and the amine; the generation time of the salt precipitation is controlled by the injection volume of the release agent; the swept volume displaced by the carbon dioxide is enlarged, and the improvement of the economic benefit of carbon dioxide flooding is favored.

Description

technical field [0001] The invention relates to an anti-channeling agent for enlarging the swept volume of carbon dioxide during carbon dioxide flooding, in particular to an anti-channeling agent for carbon dioxide flooding in ultra-low permeability reservoirs and its application. technical background [0002] As we all know, ultra-low permeability reservoirs contain relatively abundant crude oil reserves, but the development of ultra-low permeability reservoirs is difficult by water flooding, so they are generally more suitable for carbon dioxide displacement. Due to the heterogeneity of reservoirs, there is obvious gas channeling in almost all CO2 flooding processes, which limits the extent to which CO2 expands and sweeps volume. The water phase after additives generally increases in consistency, which is more difficult than water injection displacement, and it is difficult to achieve deep channel sealing, resulting in poor final carbon dioxide flooding effect. [0003] T...

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Problems solved by technology

Among these two methods, chemical expansion is mostly used in China, while inflatable expansion is used abroad. Chemical expansion is easier to see from the construction, but it is prone to side effects. The existing chemical expansion cannot solve the gas well. The problem of channeling, expansion is to offset part of the cement shrinkage caused by hydration. After offsetting, the cement stone does not shrink or expand, and the volume does not change. This method does not solve the problem of gelling weight loss, and the cement slurry itself does not shorten. The characteristics of excessive time do not compensate for the pressure loss caused by gelling. In this process, cement slurry only plays a basic role, and gelling weight loss is inevitable. However, this method does not have any improvement measures. During the gas channeling process, the role of the cement slurry itself and its factors are no longer the main factors in the whole process. The displacement efficiency and well environment conditions will become the absolute main factors affecting the channeling prevention. Therefore, the existing chemical expansion cannot It is a good solution to the problem of gas channeling; there is a view that chemical expansion can perform pressure compensation in the early stage of cement solidification, which is beneficial to prevent gas channeling, but it is that the cement body expands from the inside to the outside, and it is bound to Uneven stress distribution results in increased brittleness of the cement stone, and a little change from the outside world may cause a new stress distribution and destroy the cement stone body, creating new channels for gas migration and channeling

It is also recorded that a new anti-channeling agent was synthesized by using polyethylene polyamine, epichlorohydrin, trimethylamine, etc. as raw materials, mainly for anti-channeling of rock cores. The flow rate ratio of high and low permeability layers decreases, but it is not suitable for CO2 flooding in ultra-low permeability reservoirs, especially not suitable for reservoirs with permeability lower than 10×10 -3 μm 2 Carbon dioxide flooding in ultra-low permeability reservoirs