Preparation method of environment-friendly water-saving fracturing fluid

Abstract

The invention relates to a preparation method of an environment-friendly water-saving fracturing fluid. The fracturing fluid comprises 0.1-0.5wt% of a thickening agent, 0.1-1.0wt% of a cross-linking agent, 0.05-0.1wt% of a synergist, 0.1-10wt% of other assistants and the balance reinjection water. And the reinjection water comprises hypersalinity brine, seawater, oil and gas field produced water,and oil and gas field fracturing flow-back fluid. The preparation method comprises the following steps: burdening: uniformly mixing the thickening agent and the reinjection water; adding the cross-linking agent and mixing the substances uniformly; adding the synergist and mixing the substances uniformly; and adding the other a assistants, and mixing the substances uniformly. The invention furtherprovides application of the fracturing fluid in oil and gas reservoirs, and the fracturing fluid is used for stratum oil and gas well fracturing. The fracturing fluid system is prepared from reinjection water, the obtained fracturing fluid has the advantages of stable gel, temperature resistance, good sand carrying performance and the like, a large amount of water resources can be saved, and the cost caused by reinjection water treatment is saved.

Description

technical field [0001] The invention relates to the technical field of fracturing, in particular to a method for preparing an environment-friendly and water-saving fracturing fluid. Background technique [0002] Hydraulic fracturing, referred to as fracturing, is an important technical measure for increasing production of oil and gas wells and increasing injection of water injection wells. It uses the surface high-pressure pump group to inject high-viscosity liquid (fracturing fluid) into the well at a displacement that greatly exceeds the absorption capacity of the formation, causing high pressure at the bottom of the well, and exceeding the formation closure stress at the well wall and the tensile strength of the rock. , to break the formation and form fractures, and then continue to inject liquid with proppant into the fracture, so that the fracture continues to extend, and fill the fracture with proppant, and a sufficient length and a certain width will be formed in the ...

AI Technical Summary

Problems solved by technology

The above fracturing fluid systems have relatively strict water quality requirements during the preparation process. Generally, local tap water or clean groundwater should be used. Water that does not meet the standards (such as oilfield production fluid reinjection water) will seriously affect the cross-linking performance of the above systems and fail to form. The jelly is not even cross-linked, so it cannot achieve the purpose of carrying sand

As the oilfield enters the tertiary oil recovery stage, the average water content of the oilfield produced fluid has already exceeded 90%, and the separated water has been reinjected, but the amount of reinjected water is limited, and there is still a large amount of water that cannot be reinjected. The current method is to Pulling the water that cannot be reinjected back to the sewage treatment plant for treatment wastes a lot of road transportation and sewage treatment costs (especially the distance from remote oil areas to the sewage treatment plant is hundreds of kilometers or even thousands of kilometers away)

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