Dual-stimulation swelling gel particles used in carbon dioxide flooding process to prevent gas channeling and preparation method thereof

Abstract

The invention discloses a preparation method of a double-stimulation expanding gel particle for preventing gas channeling in the process of carbon dioxide oil displacement. The method includes: 1), dissolving an acrylamide monomer into water to form a solution, adding a crosslinking agent, a temperature response monomer methacrylic acid N, an N-dimethylaminoethyl ester monomer and carbon dioxide response monomer (2-(methacrylenyl oxide) ethyl) dimethyl-(3-sulfonic acid propyl) ammonium hydroxide to the solution with even stirring to form a mixed monomer solution polymerization system, and feeding nitrogen to the polymerization system to remove dissolved oxygen in the system; 2), mixing the mixed monomer with an initiator solution for polymerization reaction. The gel particle continuous expands under CO2 and thermal stimulation, secondary expansion of the gel particle under the acidic environment is achieved, and long-time blocking function can be played.

Description

technical field [0001] The invention belongs to the field of oil and gas exploitation, and in particular relates to an expanded microsphere used for preventing gas channeling during carbon dioxide flooding and a preparation method thereof. Background technique [0002] Petroleum is the most important strategic material in the world and one of the most important energy and chemical raw materials in the industrial field. In the current oil recovery process, due to structural reasons such as high viscosity and low hydrophilicity of crude oil itself, more than 50% of the crude oil has not been effectively recovered after "secondary oil recovery". Gas injection, especially CO injection 2 Enhanced oil recovery is one of the key technologies for tertiary oil recovery. CO 2 The oil recovery is enhanced through the mechanisms of interphase mass transfer, volume expansion, oil-gas miscibility, viscosity reduction, and oil-gas interfacial tension reduction during the contact process...

AI Technical Summary

Problems solved by technology

[0005] Compared with the traditional WAG process, although the chemical agent-assisted WAG has made some progress in improving the gas flow ratio, it still has the following shortcomings: (1) The concentration of small molecule surfactants to achieve effective viscosity increase is relatively high, and the industrial cost is low. High; (2) For polymer tackifiers with a molecular weight over one million, CO 2 The ability to dissolve such molecules is poor, and it is difficult to achieve effective viscosity increase

Although the gel plugging agent has obvious advantages compared with other control and displacement technologies, the water-absorbing gel is prone to heat-induced dehydration during the long-term plugging process in the high-temperature reservoir environment, and the plugging ability is damaged

In addition, traditional water-absorbing gels have insufficient tolerance to acidic environments, and are prone to water shrinkage in environments with low pH

However, this phenomenon has rarely been dealt with in the existing research

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