Delayed cross-linking water-based fracturing fluid

Abstract

The invention relates to a water-based fracturing fluid for delayed cross-linking and resistance reduction, which is used for high-pressure construction in the process of fracturing and increasing production in low-permeability reservoirs. The fracturing fluid includes base fluid and cross-linking fluid, the base fluid and cross-linking fluid are used in a weight ratio of 50:1; the base fluid consists of 0.55-0.40% of hydroxypropyl guar gum and 0.20-0.25% of anti-wetting surfactant , anti-emulsification demulsifier 0.15-0.20%, anti-swelling and anti-migration treatment agent 0.60-1.20%, bactericide 0.10-0.15%, pH regulator 0.05-0.08%, silicone defoamer 0.05-0.10% and the balance of water Composition: The cross-linking solution is composed of 8.0-14.0% of composite cross-linking agent, 0.1-0.2% of gel breaker and the balance of water. The dosage of the thickener and the residue content of the fracturing fluid are greatly reduced, which can reduce the damage to the cracks of the reservoir and the proppant, and improve the effect of the fracturing measures.

Description

technical field [0001] The invention relates to the application field of oilfield chemistry, and is a water-based fracturing fluid for delaying crosslinking and reducing resistance and applied to the fracturing and stimulation construction of reservoirs with low permeability and deep burial and high construction pressure. Background technique [0002] The Haita Basin of Daqing Oilfield is the main potential area for stable oil production in the future. Among them, the proven reserves of Nantun Formation reservoirs are 139 million tons, accounting for 1 / 3 of the reserves in the Hailaer Basin. With the deepening of exploration in the Hailaer Basin, it is more difficult to transform The average reservoir depth in 2005 was 1850m, and it was deepened to an average of 2530m in 2007. The fracturing success rate was only 77.6%, which affected reservoir evaluation and oilfield development [0003] Due to the deep burial of the reservoir, various rock types, complex lithology, high sh...

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Problems solved by technology

[0005] For deep Nantun reservoirs with large burial depth (the burial depth of most reservoirs is greater than 2500m), high fracturing operation pressure under the rated pressure of the equipment, resulting in low sand ratio sand plugging or pressure failure, etc.

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