Pre-crosslinked gel granulate for profile control and polymer flooding as well as preparation method and application of pre-crosslinked gel granulates

Abstract

The invention provides a pre-crosslinked gel granulate for profile control and polymer flooding as well as a preparation method and application of a pre-crosslinked gel granulate. The pre-crosslinked gel granulate belongs to a reagent for oil exploitation, and is obtained by polymerizing and crosslinking a composite monomer and an instable crosslinking agent under initiation of an initiator so as to obtain body gel, drying and grinding, wherein the composite monomer comprises acrylamide and acrylic acid; and the instable crosslinking agent is selected from polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate, glycol diacrylate, trimethylolpropane triacrylate, ethoxy trihydroxymethyl triacrylate and the like. The volume of the gel granulate is expanded by absorbing water; after the gel granulates are injected into an oil deposit, big pore canals and ultrahigh pervious layers are plugged in the immediate vicinity of wellbore of an oil layer, so that the injected water enters into a low pervious layer area to start residual oil; after acting for certain time, the gel granulate is automatically hydrolyzed into a solution, so that oil-water mobility control is realized; and the gel granulate has double functions of profile control and polymer flooding, is suitable for the oil deposits of a high water holding period, and can be used for improving the recovery rate of petroleum.

Description

technical field [0001] The invention relates to a gel particle for profile control and flooding in oil exploitation, specifically a pre-crosslinked gel particle with dual functions of profile control and polymer flooding, its preparation method and application. Background technique [0002] With the continuous development of the oil field, the heterogeneity of the reservoir is becoming more and more serious. A large amount of injected water scours, the clay and cement in the oil layer expand and dissolve, the migration of particles, and the sand production become heavier, which further deteriorates the geological heterogeneity. During the development process, the following problems often appear, such as: prominent plane contradictions, plane injection water rushes along the high permeability zone to form waterways; prominent interlayer contradictions, uneven production and suction profiles, and single-layer rushing phenomenon in the vertical direction; high viscosity of under...

AI Technical Summary

Problems solved by technology

In recent years, although tertiary oil recovery measures such as polymer flooding have achieved better results, there are still problems such as high cost of oil displacement and difficulty in field implementation; ” in the reservoirs, there are still serious problems of channeling and accumulation in some wells, which affects the effect of polymer injection, and due to the limitations of the polymer itself, the effective viscosity loss in high-temperature and high-salinity formations is very large, often Can't achieve the expected purpose

ASP flooding technology has gradually been widely used in Daqing and other old oilfields. The use of surfactants to reduce interfacial tension greatly reduces capillary force, and oil and water achieve miscible flow, thus starting the low permeability reservoir. Residual oil, but ASP flooding technology and polymer flooding have similar problems: shear thinning, affected by reservoir conditions, and both polymer flooding and ASP flooding will pollute oil-bearing low-permeability layers, making subsequent water flooding unable to achieve best results

Flexible particles can form dynamic plugging in the deep part of the reservoir, but for fractures and ultra-high permeability layers caused by high-intensity water erosion near the well, high-strength plugging agents must be used for anti-channeling operations, otherwise the flexible diverting agent can improve recovery The effect of the rate cannot be brought into full play

[0007] To sum up, so far, in the water plugging and profile control technology of oil production, the profile control and the adjustment of the oil-water mobility ratio cannot be carried out simultaneously, and no prior art reports have solved this problem.

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