Method for preparing emulsion cross-linking agent

Abstract

The invention relates to a method for preparing an emulsion cross-linking agent. With raw materials in a reaction still, the method comprises the following steps of (A) preparing a chromium lactate aqueous solution containing 3-7 parts of chromium lactate and the rest being deionized water; B) preparing an oil phase, wherein white oil is added into the reaction still, 1-3 parts of sorbitan fatty acid ester and 1-3 parts of polyethylene glycol are added at the stirring speed of 50-100 rpm, and the rest is white oil; (C) preparing a water-in-oil emulsion, wherein 4-7 parts of chromium lactate aqueous solution is added to the oil phase at the stirring speed of 1000-3000 rpm, and stirring is continued for another 30 min; (D) preparing a continuous water phase, wherein deionized water is added into the reaction still, and 1-2 parts of polyoxyethylene sorbitan monooleate is added at the stirring speed of 50-100 rpm; and (E) preparing the target object, wherein the water-in-oil emulsion is added to the continuous water phase with the ratio of continuous water phase to water-in-oil emulsion being 1:1 at the stirring speed of 50-100 rpm, and stirring is continued for another 30 min afterwards.

Description

Technical field: [0001] The invention relates to a preparation method of an oilfield chemical agent, in particular to a preparation method of an emulsion crosslinking agent. Background technique: [0002] The multiple emulsion cross-linking agents currently used in oil fields mainly include high-valent metal ions such as Cr3+, Al3+, Ti3+, aldehydes such as formaldehyde and resins such as phenolic resin. The high-valent metal ion cross-linking agent mainly uses Cr3+, and the applied product is a redox system, mainly a mixture of dichromate and reducing agent and organic acid chromium, mainly chromium lactate and malonate. The publication number is CN1560119A, and the Chinese patent published on January 5, 2005 discloses a "Preparation Method of Slow Crosslinking Agent for Polyacrylamide Gel". The slow crosslinking agent prepared by it is made of sodium dichromate, Concentrated sulfuric acid, sodium sulfite, humic acid, acetic acid, citric acid, 40% sodium hydroxide solution,...

AI Technical Summary

Problems solved by technology

These cross-linking agents have the following disadvantages or deficiencies: ① redox systems basically do not have the effect of slowing cross-linking, and the currently used organic acid chromium delays cross-linking for a limited time, and there is a certain risk in field application; ② In field oil displacement tests, In some well areas, the wellbore and the near-well area are blocked, which leads to the problem of lower injection capacity in the subsequent water flooding stage; ③In the profile control of water injection wells, profile control agents appear in well areas with high pressure of water injection wells and low formation permeability The pressure increases too fast during the injection process; ④ During the preparation and injection process, if the outdoor temperature is high, it is easy to cross-link with the polymer on the ground, which not only affects the injection of the electric pump, but also causes a lot of waste of raw materials; ⑤Easy Blocking the wellbore and increasing construction costs such as well washing; ⑥ The gel formed is low in strength and easy to degrade; ⑦ No cross-linking delay function