Cross-linking agent for carboxymethyl guar gum acidic fracturing fluid and preparation method thereof

Abstract

The invention relates to a cross-linking agent for carboxymethyl guar gum acidic fracturing fluid and a preparation method thereof. At present, water-based fracturing fluid is preferably selected for the fracturing of most of reservoir beds at home and abroad, so that the fracturing reconstruction effect is greatly influenced, particularly the reservoir bed is greatly damaged by an alkali-sensitive stratum. The cross-linking agent consists of 132 parts of aluminum chloride, 100-200 parts of ethylene glycol, 50-70 parts of triethanolamine, 200-300 parts of acetic acid and 10 parts of corrosion inhibitor. The preparation method comprises the following steps of: adding the ethylene glycol in a closed container with a stirrer; starting the stirrer; slowly adding the aluminum oxide; then stirring for 30-60 minutes; heating to 80-100 DEG C; adding the triethanolamine; keeping the temperature to react for 3 hours; then cooling to 50-70 DEG C; adding organic acid; keeping the temperature to react for 1-1.5 hours; and then adding the corrosion inhibitor to react for 30 minutes to form brownish yellow homogeneous phase fluid. The fracturing fluid formed by the cross-linking agent and a thickening agent is of an anionic system, so that an additive is prevented from being adsorbed to the stratum; and thus, the wettability of rock is changed, and the implementation of the performance of the additive in the stratum is realized.

Description

technical field [0001] The invention relates to a crosslinking agent for carboxymethyl guar gum acidic fracturing fluid and a preparation method thereof. Background technique [0002] Due to the reliability and economy of the technology, water-based fracturing fluids are mainly used in the fracturing of most reservoirs at home and abroad, and Changqing Oilfield is no exception. Conventional water-based fracturing fluids mainly use the alkaline cross-linking system of guar gum series, which has the following deficiencies: [0003] ① The pH value of the system is high, and there is potential formation damage after encountering formation ions; [0004] ② The matching is mainly cationic additives, which are prone to adsorption, causing changes in the wettability of formation rocks and degradation of additive performance; [0005] ③The system is highly acidic and can partially acidify the formation. [0006] The above factors greatly affect the effect of fracturing, especiall...

AI Technical Summary

Problems solved by technology

[0004] ② The matching is mainly cationic additives, which are prone to adsorption, causing changes in the wettability of formation rocks and degradation of additive performance;

[0006] The above factors greatly affect the effect of fracturing, especially for alkali-sensitive formations, which will cause greater damage to the reservoir