Carbon dioxide energy storage, high pressure and viscosity reduction cold recovery method in heavy oil reservoirs

Abstract

The invention provides a heavy oil reservoir cold recovery method adopting carbon dioxide energy storage and high pressure viscosity reduction. The heavy oil reservoir cold recovery method comprises the steps that carbon dioxide is injected into a heavy oil reservoir to accumulate energy for a stratum and initial viscosity reduction is carried out to crude oil; and a high-efficiency cold-recoveryviscosity-reducing agent is used to achieve further viscosity reduction of heavy oil in a carbon dioxide low-temperature effect environment, interfacial tension is reduced, colloids and asphaltene precipitated from the heavy oil are dissolved, thus mobility of underground heavy oil is improved, driving power of the crude oil is increased, and the degree of exploitation of the heavy oil reservoir is improved. According to the heavy oil reservoir cold recovery method adopting carbon dioxide energy storage and high pressure viscosity reduction, the improvement of the reservoir energy of heavy oilreservoirs and the improvement of the flowability of underground crude oil are realized, and the cold damage effect caused by the precipitation of the colloids and the asphaltene by the low-temperature effect during the heavy oil cold recovery process is reduced, thereby greatly improving the degree of reserve utilization of the heavy oil reservoirs.

Description

technical field [0001] The invention relates to the technical field of heavy oil reservoir development, in particular to a carbon dioxide energy storage high-pressure viscosity-reducing cold recovery method for heavy oil reservoirs. Background technique [0002] Heavy oil refers to crude oil with high viscosity, which mostly contains heavy and long-chain hydrocarbon components such as colloid, wax and asphaltenes. Colloids are mainly carbon-heterocyclic structures containing heteroatoms, and the super-strong cross-linking and winding effect formed by π-π interaction and electrostatic attraction between them leads to high viscosity of crude oil; asphaltenes are mainly composed of polyphenyl rings conjugated The formed macromolecular structure has a molecular weight of about 700-1000. Due to the high viscosity of heavy oil, poor flow capacity, large flow pressure difference, and low mobility in underground reservoirs, it often leads to rapid formation energy decay and low rec...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of low recovery degree of cold recovery of heavy oil reservoirs, and to provide a kind of energy storage system combined with the low-temperature cooling effect, which can effectively reduce the viscosity of heavy oil and overcome the coalescence effect. Heavy oil viscosity reducer, so as to realize the carbon dioxide energy storage high-pressure viscosity reduction cold recovery method to improve the cold recovery effect of heavy oil reservoirs

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