Efficient urea-formaldehyde resin plugging agent and application thereof

Abstract

The invention relates to a plugging agent for plugging petroleum wells, and particularly relates to an efficient urea-formaldehyde resin plugging agent and application thereof. The efficient urea-formaldehyde resin plugging agent comprises the following raw materials in parts by weight: 55-75 parts of urea-formaldehyde resin, 0.01-2 parts of sodium persulfate, 0.1-5 parts of sodium polyacrylate and 5-35 parts of medical stone powder. The plugging agent is used for plugging petroleum wells at a temperature of 30-120 DEG C. When the plugging agent is used, the plugging agent is prepared into mixed liquid according to the weight parts above, the mixed liquid is uniformly stirred and is injected into the stratum, a petroleum well is closed, and reaction is carried out for more than 24 hours. When a production well is plugged by using the plugging agent disclosed by the invention, the later maintenance workload and capital investment of the production well can be greatly reduced; and meanwhile, the plugging agent achieves a uniform, integrated and efficient plugging effect, and is long in period of validity, high in strength and wide in applicable temperature range.

Description

technical field [0001] The invention relates to a water shutoff agent for oil well water shutoff, in particular to a high-efficiency urea-formaldehyde resin water shutoff agent and its application, belonging to the technical field of oil field chemistry. Background technique [0002] The urea-formaldehyde resin water blocking agent for oil well water plugging is generally a mixed solution synthesized by various chemical materials. When using it, add a curing agent and mix it evenly, and pump it into the formation that needs to be plugged, so that it can be cured under the formation conditions. The pores form a physical blockage to achieve the purpose of blocking. [0003] Formation pores are affected by many complex factors such as natural micropore structure, channel size, and pore inner surface properties, which determine their flow capacity. The liquid enters the plugging target section locally, and the distribution is very different. It cannot evenly enter all the pores...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the defects that the existing urea-formaldehyde resin water blocking agent has a large distribution difference when it is squeezed and injected, cannot enter the formation pores uniformly, and cannot achieve a complete and effective plugging of the formation pores with high strength. One is to provide a High-efficiency urea-formaldehyde resin water-blocking agent that can realize independent, complete and effective sealing of formations. The second is to provide an application method of high-efficiency urea-formaldehyde resin water-blocking agent