Low-tension foaming agent for improving crude oil extracting rate of high-salinity oil reservoir and preparation method thereof

Abstract

The invention discloses a low-tension foaming agent for improving crude oil extracting rate of a high-salinity oil reservoir and a preparation method thereof, belonging to the field of foaming agents for oil extraction of the oil reservoir. The foaming agent comprises the following components in percentage by weight: 20-70 percent of alkyl-dimethylamine acetolactone, 10-50 percent of lauryl alcohol polyethenoxy ether sulfate sodium salt, 10-50 percent of coconut oleic acid monoethanol amine and 10-60 percent of water. Compared with the prior art, the low-tension foaming agent has the characteristics of strong foaming ability, high foam stability, temperature resistance, high mineralization resistance, high calcium and magnesium ion resistance, good compatibility with stratum water, and the like, and is suitable for the foam flooding of the high-salinity oil reservoir to improve the crude oil extracting rate.

Description

technical field [0001] The invention relates to a foaming agent for oil recovery in oil reservoirs, in particular to a low-tension foaming agent for improving the recovery rate of crude oil in high-salt oil reservoirs. Background technique [0002] At present, most of the oilfields in eastern China have entered the late stage of development—the stage of high water cut and ultra-high water cut. How to improve the development effect of high-salt oilfields and how to increase the recovery after polymer flooding have become urgent problems for petroleum workers. New tertiary recovery technologies are needed to improve the recovery of high-salt old oilfields and increase the oil recovery. mining reserves. [0003] Foam flooding and foam composite flooding are new technologies developed under the current technical background that have broad application prospects and can greatly enhance oil recovery. Foam flooding is a simple foam system oil displacement method formed by mixing f...

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Problems solved by technology

[0004] At present, the foaming agents on the market are mainly sodium lauryl sulfate, sodium α-olefin sulfonate, sodium alkylbenzene sulfonate, sodium alkyl succinate and other products. Although the foaming ability is relatively strong, there are the following deficiencies: First, the compatibility with formation water is poor, especially for high salinity reservoirs with high salinity and high calcium and magnesium ions, it is easy to form precipitation with calcium and magnesium ions in formation water; second, the formed foam is very unstable, It is very easy to burst, and foam and foam composite flooding require the foam to remain in the formation for as long as possible, so the foam performance needs to be as stable as possible; 3. Conventional foam agents cannot reach ultra-low interfacial tensions with crude oil Therefore, the ability to improve the oil displacement efficiency is relatively poor, and the residual oil in the reservoir cannot be cleaned, and affected by the residual oil, the foam stability is poor, and it is difficult to form a stable plugging and profile control capability

Although using this foam agent for foam flooding can improve oil recovery, it is not compatible with high-salt and high-divalent ion formation water, and is only suitable for salinity below 50,000mg / l and calcium and magnesium ion concentration below 10,000mg / l of oil reservoir

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