Coated microgel particle profile-control agent and preparation method thereof

Abstract

The invention discloses a coated microgel particle profile-control agent and a preparation method thereof. The preparation method comprises following steps: stirring a water solution containing acrylamide monomers, a crosslinking agent, a stabilizing agent, and an initiator and a hydrophobic nano material at a high speed to form a dry-powdery coated body pre-reaction system, and subjecting the pre-reaction system to free radical polymerization and drying to obtain the coated microgel particle profile-control agent. The solid content of the coated microgel particle profile-control agent is almost 100%; the gel core is wrapped by a hydrophobic nano material, and the average particle size is a micro meter level. The coated microgel particle profile-control agent has a surfactant responding performance, will not swell in clean water, and swells in a surfactant solution. By utilizing the responding performance, in profile-control operation, the delay and control of the swelling time of thecoated microgel particle profile-control agent can be realized, and deep profile-control of oil reservoir is realized. The preparation method of the coated microgel particle profile-control agent hasthe advantages of reliable principle, convenient operation, and wide market prospect.

Description

technical field [0001] The invention relates to the technical field of oil field chemistry in the enhanced oil recovery technology, in particular to a coated microgel particle profile control agent and a preparation method thereof. Background technique [0002] In the late stage of water injection development in oilfields, the problem of channeling of injected water along high-permeability channels will occur, which will result in low sweep efficiency of injected water, and most of the crude oil will be trapped in the formation and difficult to recover, resulting in poor economic benefits. At present, the deep liquid flow diversion technology based on the gel profile control system is the main means for oilfields to solve the problem of channeling in high-permeability channels of injected water. Among them, the microgel particle profile control system is widely used in oilfield profile control operations due to its good temperature and salt resistance performance, precise an...

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Problems solved by technology

The most widely used environment-responsive microgel particle system at this stage is the "Brightwater" system jointly developed by BP, Chevron, Nalco and Texaco and other institutions. This system contains two cross-linking agents, one of which is cross-linking The agent will slowly decompose at high temperature to prolong the expansion event of the system, but the application process of this system is relatively complicated and the salt resistance effect is not good, and its temperature-sensitive characteristics will limit its applicable reservoir temperature range

[0004] In addition, in the prior art, the microgel particle system is usually prepared from acrylamide monomers through inverse (micro) emulsion polymerization, suspension polymerization, dispersion polymerization and other synthetic methods. The above preparation methods will use a large amount of liquid to produce After the product is obtained, it is difficult to separate and purify. Common separation methods such as centrifugation and membrane filtration in the laboratory will cause high operating costs in industrial applications.

In order to save costs, commercial products of microgel particles are usually sold in the form of suspension together with the liquid used for synthesis, but the effective content of microgel particles in the suspension is only about 30% to 60%, and a large amount of useless liquid in the suspension Can increase business costs of product storage and transportation

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