Composite fracturing prepad fluid and application thereof in hydraulic fracturing of tight reservoir

Abstract

The invention provides a composite fracturing prepad fluid and an application thereof in hydraulic fracturing of a tight reservoir. The composite fracturing prepad fluid composition is prepared from apropping agent and microemulsion, the compounding weight ratio of the propping agent to the microemulsion is (0.1-2): (0.02-1.5); the microemulsion is prepared from the following components in percentage by weight: 8 to 35 weight percent of surfactant, 10 to 30 weight percent of alcohol, 3 to 25 weight percent of oil, 1 to 10 weight percent of salt and the balance of water based on 100 weight percent of the microemulsion. The composite fracturing prepad fluid not only can improve the effective fracture flow conductivity of artificial microfractures after hydraulic fracturing construction of the tight reservoir, but also enhances the spontaneous imbibition performance of a tight reservoir matrix, and is helpful for improving the final recovery ratio of the tight reservoir.

Description

technical field [0001] The invention belongs to the technical field of petroleum exploitation, and in particular relates to a composite fracturing prefluid suitable for hydraulic fracturing of tight reservoirs to enhance oil recovery and its application in hydraulic fracturing of tight reservoirs. Background technique [0002] For tight reservoirs with a permeability lower than 0.1 mD, hydraulic fracturing technology can form an artificial fracture network near the wellbore, improve the seepage capacity near the wellbore, and thus increase the efficient production of formation fluids. On the one hand, in the process of hydraulic fracturing, not only primary fractures will be formed around the wellbore, but also induced secondary micro-fractures formed by the extension of primary fractures will be formed in the area away from the wellbore. Due to the large particle size of conventional proppant particles, these induced secondary micro-fractures cannot enter the fractures to a...

AI Technical Summary

Problems solved by technology

Due to the large particle size of conventional proppant particles, these induced secondary micro-fractures cannot enter the fractures to achieve effective support after construction, thus losing the oil and gas flow channels provided by these fractures

On the other hand, due to the low matrix permeability in tight reservoirs, the original wettability of rocks is mostly neutral wet or oil-wet, which leads to the direction of capillary force opposite to the direction of water flooding, resulting in low recovery and high cost of water flooding in conventional water flooding methods. If the value is too high, at present, the method of adding surfactants that can achieve the effect of wettability reversal to the fracturing pre-fluid is often used to enhance the spontaneous imbibition of tight reservoirs for mining.

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