Temporary plugging agent for acidization of water injection well of low permeability reservoir

Abstract

The invention relates to a temporary plugging agent for the acidization of the water injection well of a low permeability reservoir. The temporary plugging agent is prepared from stearate, borate and acrylate in a weight ratio of 3:1:6; 0.2wt% of polyacrylamide aqueous solution is used as the carrying fluid of the temporary plugging agent, the mass concentration of the temporary plugging agent is10%; the construction pressure is 1-2MPa higher than the water injection pressure, the low-pressure low speed injection is adopted; the injection speed is kept to 10-15m<3> / h; the temporary plugging agent can generate a filter cake with lower permeability near the wall of the well, thus effectively preventing the particles of the temporary plugging agent from intruding the deep part of the oil-gas reservoir; the temporary plugging agent has better compatibility with water, acidizing fluid, additive and the like under the formation condition; and when the shunting and turning functions of acidization are realized, the temporary plugging agent can be washed away fast and completely and the well which is not plugged temporarily can be recovered.

Description

Technical field: [0001] The invention relates to a temporary plugging agent applied to the acidification of water injection wells in low-permeability oil fields. Background technique: [0002] The existing conventional acidizing profile control technology uses packer tools to perform selective acidizing profile control on water injection wells with large intervals between layers or perforation intervals, so that most of the water injection wells with profile unbalanced water injection can be effectively improved. However, there are two limitations at the same time. On the one hand, due to the strong formation heterogeneity in the conventional acidizing process, the acid liquid is likely to "finger" in the large pores and fractures of the high-permeability layer, and it is impossible to make the low-permeability layer and small pores On the other hand, for wells with small distances between layers or perforation intervals, it is impossible to use tools for isolation and acidi...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is aimed at low-permeability oilfield water injection wells with unbalanced water injection and prominent contradictions. For the same layer, there are more than two perforation sections, and the distance between the perforation sections is small, or the distance between the water injection layers is small, and it is impossible to In the case of using packer acidizing profile control, a temporary plugging agent for water injection well acidizing profile control is provided to realize balanced water injection in the profile of the water injection well