Deep oil displacement and profile control agent for oil deposit and preparation method thereof

Abstract

The invention provides a deep oil displacement and profile control agent for an oil deposit and a preparation method thereof. The deep oil displacement and profile control agent comprises the following raw materials in parts by weight: 0.15 to 0.45 part of viscoelastic polymer particles, 0.2 to 0.4 part of a chemical crosslinking agent capable of reacting with amide radical or carboxylate radical, and 99.15 to 99.65 parts of water with the degree of mineralization of 0 to 30000 mg / L. According to the deep oil displacement and profile control agent, after a mixture system of the viscoelastic polymer particles and the chemical crosslinking agent is injected into the oil deposit, the viscoelastic polymer particles and the chemical crosslinking agent are subjected to chemical cross-linking reaction at the oil deposit temperature, so that a gel system with high viscoelasticity and high strength is produced. Compared with the existing deep oil displacement and profile control agent, the system has the advantages that the system has a pore and pore throat plugging performance of the viscoelastic polymer particles when the viscoelastic polymer particles pass a stratum, further has the characteristics of high viscosity and high viscoelasticity of a crosslinking polymer gel system, has good profile control effect on oil deposits with high anisotropism degree, and meanwhile has the function of improving the oil displacement efficiency.

Description

Technical field: [0001] The invention relates to the field of water plugging and profile control in tertiary oil recovery, in particular to a preparation method of a novel high-efficiency oil reservoir control and displacement agent. Background technique: [0002] At present, most of the mature oilfields in China have entered the ultra-high water cut period. During the long-term water injection development of the oilfield, the pore structure of the reservoir will change greatly, and the heterogeneity of the oil layer and the change of the pressure of the oil layer will increase the permeability of the reservoir. Large, the pore throat radius increases, thus forming secondary high-permeability strips in the reservoir, making the reservoir heterogeneity more serious, and the strong water absorption strips in the reservoir with strong heterogeneity will lead to channeling of the injected solution , not only causes waste of chemical agents, but also makes it difficult to form hi...

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Problems solved by technology

[0002] At present, most of the mature oilfields in China have entered the ultra-high water cut period. During the long-term water injection development of the oilfield, the pore structure of the reservoir will change greatly, and the heterogeneity of the oil layer and the change of the pressure of the oil layer will increase the permeability of the reservoir. Large, the pore throat radius increases, thus forming secondary high-permeability strips in the reservoir, making the reservoir heterogeneity more serious, and the strong water absorption strips in the reservoir with strong heterogeneity will lead to channeling of the injected solution , not only causes waste of chemical agents, but also makes it difficult to form high-quality chemical agent slugs, resulting in ineffective or poorly effective production wells around them, seriously affecting the chemical flooding effect

[0003] In order to solve the above problems, at present, water-swellable particles are used to control the profile of high-permeability strips in oilfields, but it is difficult to achieve "accessible, plugged, and energy For the purpose of "long-term effect", that is, when the particle size of the water-swelling body is too large, the system is difficult to inject into the reservoir, and if the particle size is too small, it cannot achieve a good plugging and profile control effect. For this reason, a A viscoelastic polymer particle cross-linked gel system control and displacement agent. The biggest feature of this system is that the initial viscosity is low, it is both viscous and elastic, and it is easy to inject into the reservoir. When the system enters the pores of the reservoir, the viscoelastic particles will Elastic deformation occurs in the pores of the reservoir, and the oil in the reservoir is driven out. At the same time, when the system migrates to the deep, multiple viscoelastic polymer particles undergo chemical cross-linking reactions under the conditions of reservoir temperature and the presence of cross-linking agents , so that multiple viscoelastic polymer particles with smaller particle sizes form a large gel particle, which can block the deep reservoir. This system solves the problem of difficult compatibility of particle control and displacement agents with reservoir pores and throats. , and achieve the purpose of "injection, plugging, and long-term effect" of the control and displacement agent in the reservoir, and realize the plugging and profile control of the high permeability zone of the reservoir. Among them, its particle effect and viscoelasticity can be used to achieve a good oil displacement effect. Therefore, this system not only has the effect of profile control on large pores, but also has the effect of improving oil displacement efficiency. It is a new type of high-efficiency oil reservoir. Deep conditioning agent

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