Process of deep profile control over low-permeability oil reservoir

Abstract

The invention provides a process of deep profile control over a low-permeability oil reservoir. The process comprises the steps that firstly, an RD movable jelly profile control agent is injected into an oil layer; secondly, retarding swelling soft particles are carried by the RD movable jelly profile control agent in a suspended mode and injected into the oil layer; thirdly, a composite particle profile control agent is injected into the oil layer so as to block a high-permeability channel; fourthly, an RD movable jelly profile control agent is injected into the oil layer again to push the particles to the deep so as to perform deep profile control. The RD movable jelly profile control agent comprises, by mass, 0.05%-0.25% of amphoteric ionic polymer, 0.05%-0.25% of cross-linking agent A, 0.05%-0.25% of gel promoting agent B and the balance of water. The composite particle profile control agent comprises, by mass, 0.2%-2% of retarding swelling soft particles, 0.05%-0.25% of amphoteric ionic polymer, 0.1%-0.5% of cork particles and the balance of water. By means of the process, the gelling performance and gelling strength of a profile control system under the low-permeability oil reservoir condition can be improved, so that deep profile control over the low-permeability oil reservoir is achieved, and the crude oil recovery ratio is increased.

Description

technical field [0001] The invention relates to a deep profile control process for water injection wells in the petroleum industry, in particular to a profile control process for deep profile control in low-permeability oil reservoirs. Background technique [0002] In the process of waterflooding development of low permeability reservoirs, with the long-term scouring of injected water, dominant seepage channels are formed, forming the phenomenon of fingering of injected water, which makes the heterogeneity of reservoirs increasingly prominent, seriously affecting the effect of waterflooding development in oilfields. Currently, the most widely used polymers in deep reservoir profile control are biopolymer xanthan gum and partially hydrolyzed polyacrylamide (HPAM). Since these two polymers have viscosity-increasing properties, the initial viscosity of the prepared solution is relatively high, and it is difficult to perform deep profile control on low-permeability reservoirs; i...

AI Technical Summary

Problems solved by technology

Since these two polymers have viscosity-increasing properties, the initial viscosity of the prepared solution is relatively high, making it difficult to perform deep profile control on low-permeability reservoirs; in addition, under the conditions of low-permeability reservoirs, general profile control agents Difficult to gel