Foamed gel blocking agent for blocking gas coning and construction method of foamed gel blocking agent

Abstract

The invention discloses a foamed gel blocking agent for blocking gas coning and a construction method of the foamed gel blocking agent and belongs to the technical field of oil exploitation. The foamed gel blocking agent is prepared from a liquid-phase component and a gas-phase component through mixing and foaming, wherein the liquid-phase component comprises the following components in percentageby mass: 5.5-6.5% of xanthan gum with the relative molecular weight of 1*10<6>-5*10<6>, 0.2-0.3% of hydrated polyacrylamide with the molecular weight of 9-12 million, 0.2-0.25% of a phenolic resin cross-linking agent, 0.5-0.8% of an alkyl glycine betaine surfactant, 0.5-0.6% of a dodecyl dimethyl amino oxide foam stabilizer and the balance of water. The foamed gel blocking agent is small in density, can be accumulated into a high-angle crack to infiltrate into the top of a bottom water reservoir, is capable of retarding advancing of an oil-water interface, improving the percolating resistanceof a permeable layer, inhibiting gas channeling, and meanwhile increasing waves and sizes of displacing mediums to less permeable layers.

Description

technical field [0001] The invention relates to the technical field of oil exploitation, in particular to a foam gel plugging agent for plugging a gas cone and a construction method thereof. Background technique [0002] With the continuous development of oil field development, gas injection flooding technology has become an important way to enhance oil recovery following chemical flooding technologies such as water flooding technology and polymer flooding technology. However, for bottom-water buried hill reservoirs with high-angle fractures, three fluid distribution zones are formed after gas flooding in test areas that meet gas injection conditions, namely, artificial gas cap, oil-rich zone and water-flooded zone. bring. Local abnormal high pressure is formed at the top of the reservoir. For the oil wells in the gas cap area of ​​the buried hill, due to the three-phase distribution of gas, liquid and water in the wellbore, problems such as gas channeling and bottom water ...

AI Technical Summary

Problems solved by technology

The feature of the gel channeling technology is that it enters the high-permeability layer with the aqueous solution, and forms a gel to block the channeling channel. However, the problem is that the density of the gel system is greater than 1, which cannot effectively exist at the oil-gas interface, reducing the plugging efficiency.

Patent application CN1052350A discloses a polyurethane foam formation plugging agent, but the density of polyurethane is 1.1g / m 3 , greater than water, so that the plugging agent cannot be effectively placed on the oil-gas interface, reducing the plugging efficiency

In addition, organic amine salts are also toxic and flammable

[0007] To sum up, in the process of realizing the present invention, the inventors have found that there are at least the following problems in the prior art: the existing method for sealing gas cones is not effective for oil reservoirs containing high permeability layers