A method of using an anti-swelling agent to help a steam flooding in improving the recovery ratio of water-sensitive heavy oil reservoirs

Abstract

The invention provides a method of using an anti-swelling agent to help a steam flooding in improving the recovery ratio of water-sensitive heavy oil reservoirs. The method comprises the steps of injecting mixed steam and anti-swelling agent solution in a steam injection well of a water-sensitive heavy oil reservoir at the same time and injecting steam in the steam injection well continuously and separately, wherein the anti-swelling agent solution is prepared by diluting a high-concentration mother solution by using preparing water until the concentration is 1% and the mixing ratio of the anti-swelling agent solution to the steam is 1:5. It is needed that the mixed steam and anti-swelling agent solution is injected in the steam injection well continuously for not less than 110 days. The anti-swelling agent is a cationic anti-swelling agent; the injection speed of anti-swelling agent is 1t / h; the injection speed of steam is 5t / h; the degree of dryness of a well bottom must be greater than 40% and the degree of dryness of a well mouth is correspondingly greater than 85%. The effect of heat in the vicinity and prevention in the distance is achieved by using the high temperature steam and the anti-swelling agent, so that the recovery ratio of highly water-sensitive heavy oil reservoirs is improved.

Description

technical field [0001] The invention relates to oil recovery technology in oilfields, in particular to a method for improving the recovery rate of water-sensitive heavy oil reservoirs by assisting steam flooding with an antiswelling agent. Background technique [0002] In 2002, nearly 100 million tons of strong and strong water-sensitive heavy oil reservoirs were discovered in the exploration of Shengli Oilfield in China, which is the first large-scale strong and strong water-sensitive heavy oil reservoirs discovered at home and abroad. As a new type of reservoir, water-sensitive heavy oil reservoir has no universal definition in the world. We call the heavy oil reservoir whose permeability decreases after the reservoir encounters external water injection as water-sensitive heavy oil reservoir. For strongly water-sensitive oil reservoirs, supporting technologies for heavy oil development such as cold recovery and huff-and-puff of strongly water-sensitive oil reservoirs have ...

AI Technical Summary

Problems solved by technology

For strongly water-sensitive oil reservoirs, supporting technologies for heavy oil development such as cold recovery and huff-and-puff of strongly water-sensitive oil reservoirs have been initially formed, but the recovery rate is only 10%-20%, which means that more than 80% of the remaining oil has not yet been recovered. A large amount of crude oil remains underground, and new oil recovery technologies are urgently needed to solve the problem of how to further improve the recovery rate of heavy oil reservoirs

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