A kind of shale gas development using reduced oxygen air/liquid CO 2 Double Interface Layer Foam Fracturing Fluid

Abstract

The invention discloses an oxygen-reduced air / liquid CO 2 Dual interface layer foam fracturing fluid. The reduced oxygen air / liquid CO 2 Double interface layer foam fracturing fluid composed of liquid CO 2 phase, gas phase, and nanoenhancers; liquid CO 2 The phase consists of an aerosol-soluble surfactant complex dissolved in liquid CO 2 Formed in the middle; the gas phase is oxygen-reduced air and liquid CO 2 The mixed gas of saturated steam; the nano-strengthening agent is an aqueous solution of hydrophobic silica nanoparticles, particle co-solvents, and water-soluble surfactant complexes. Liquid CO in the fracturing fluid system prepared by the present invention 2 The encapsulation of oxygen-reduced air forms an interface layer, and the nanoenhancer encloses liquid CO 2 Another interface layer is formed, and the double interface layer improves the structure of the fracturing fluid system, enabling the fracturing fluid to obtain relatively high viscosity and good temperature stability.

Description

technical field [0001] The invention relates to an oxygen-reduced air / liquid CO 2 The invention relates to a double interface layer foam fracturing fluid, which belongs to the technical field of shale gas development engineering. Background technique [0002] my country's shale gas resources are extremely rich. According to statistics, the total resources of major domestic shale gas blocks are higher than 26×10 12 m 3 , is at the forefront of the world, and has huge economic potential. The efficient development of shale gas resources is of great strategic significance for optimizing my country's energy supply structure and ensuring national oil and gas security. However, shale gas reservoirs are born with insufficient development, complex geological conditions, generally poor reservoir physical properties, extremely small matrix pores, ultra-low permeability and porosity, and no natural flow capacity. The implementation of fracturing and stimulation An inevitable choice f...

AI Technical Summary

Problems solved by technology

However, the water-based vegetable glue, cellulose, artificial polymer and other polymer reinforcements used in conventional hydraulic fracturing fluids have a series of problems: after the polymer substances enter the shale reservoir, they are easy to adsorb inside the porous medium, making the original The small pore volume is further reduced; at the same time, it is difficult for the polymer reinforcement injected into the ground to break completely, and the residue generated will not only damage the formation matrix, but also damage the proppant filling layer that opens the fracture, affecting the fracturing flow The connectivity of the channel; water-based fracturing fluid will also cause clay swelling after contacting the formation matrix, which can cause damage to water-sensitive reservoirs; in addition, water-based fracturing fluid is purely slow in flow rate, see The gas time is long, the reverse flow is not complete, and the residual liquid remains in the formation, which affects the effect of reservoir stimulation

[0004] In addition, the shale gas water-based fracturing operation also faces the problem of huge consumption of water resources, and its application in deserts, next-doors, plateaus, mountainous areas and other water-scarce and arid areas is greatly restricted, and it has great impact on the environment. There are potential risks of water pollution, in order to solve these problems, it is necessary to provide a new type of foam fracturing fluid

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