Chemical agent composition for crude oil displacement and crude oil displacement method

Abstract

The invention discloses a chemical agent composition for crude oil displacement and a crude oil displacement method. The chemical agent composition comprises a silicate aqueous solution, a foaming agent aqueous solution, an initiator and a surfactant aqueous solution for reducing oil-water interfacial tension which are independent from one another, wherein the initiator is CO2 (carbon dioxide). According to the method, four slugs, namely the silicate aqueous solution, the foaming agent aqueous solution, CO2 and the surfactant aqueous solution for reducing the oil-water interfacial tension, are injected into a target oil reservoir, so that a high-permeability layer can be blocked or the water absorption capacity of the high-permeability layer can be reduced, and the swept volume can be enlarged; and the sweep efficiency and oil washing efficiency are improved through the energy supplement of CO2, the oil washing of the surfactant and the comprehensive action of a plurality of slugs, and finally, the crude oil recovery rate is improved.

Description

technical field [0001] The invention belongs to the technical field of oilfield development, and more specifically relates to a chemical agent combination for crude oil displacement and a crude oil displacement method. Background technique [0002] With the deepening of oilfield development, the efficiency of water flooding is getting lower and lower, and the water cut of produced fluid is getting higher and higher. The usual practice in oil reservoirs is to carry out profile control and water shutoff, chemical flooding, and gas flooding to enhance oil recovery. Foreign chemical flooding technology has been rarely used in recent years. In the past 20 years since chemical flooding reached its peak in the United States in the 1980s, chemical flooding has been used less and less in the United States. The few mine projects are the continuation of previous projects. . Chemical flooding projects are dominated by polymer flooding, followed by composite flooding. For surfactant fl...

AI Technical Summary

Problems solved by technology

There are two problems in the application of silicic acid gel: the two-liquid method is not mixed enough, and the single-liquid method reacts too fast; the generated gel is too brittle

If CO 2 To initiate silicic acid gel, because the gas is easier to penetrate the spacer, so the gel formation is easier, and the formation of the gel is more selective, that is, the silicate solution will go there where the gas goes, and the CO 2 When it comes over, the large pores are blocked; CO2 is used to 2 Although the method as an initiator of water-soluble silicate solution can expand the sweep rate, it cannot improve the oil washing efficiency