An experimental device and method for stimulating shale gas reservoirs by pulse hydraulic fracturing

Abstract

The invention relates to an experimental device and method for pulse hydrofracture transforming of a shale gas storing layer. The experimental device comprises a high pressure water pump, a fracturing fluid pond, a filtering device, a waterpower pulse generating device, a triaxial stress loading device, a pressure sensor, a sound emission device, a throttle valve, an overflow valve, a data collection recording system and a core test specimen. The device provided by the invention can simulate the operating environment of a shale sample under main operating parameter such as different pulse pressures and impulse frequencies on a certain confining pressure condition; moreover, the device can monitor a space-time developing rule of cracks and can test permeability change before and after fracture in real time; therefore, an experimental platform is provided for researching pulse hydrofracture of a shale gas storing layer. The experimental device provided by the invention has strong practicality, is easy to assemble, convenient to operate, is compact in structure, and can better imitate fracture damage and permeability change mechanism of a shale sample of the shale gas storing layer under the actions of static pressure and pulse hydrofracture.

Description

technical field [0001] The present invention relates to an experimental device and method for simulating different formation pressure environments, different pulse pressures and frequencies, the experiment of pulse hydraulic fracturing to transform shale reservoirs, real-time monitoring of fracture type and development, and measurement of permeability before and after core fracturing . Background technique [0002] my country has abundant shale gas reserves and great development potential, but complex geological conditions and deep burial make it difficult to exploit. Hydraulic fracturing technology is one of the key technologies for the development of shale gas with high efficiency and low cost. While it is well applied, there are still bottleneck problems such as large amount of fracturing fluid, low energy utilization rate, and ineffective volumetric fracturing effect. Pulse hydraulic fracturing is a new method of shale gas reservoir stimulation, which can effectively us...

AI Technical Summary

Problems solved by technology

[0005] 1. Only under constant hydraulic pressure, no pulse frequency, and no triaxial stress, it is not possible to simulate the formation of pulse hydraulic fracturing reservoir experiments

Or simulate hydraulically fractured reservoirs only at pulsed pressures, but without triaxial stresses

[0006] 2. The monitoring of fractures can only be observed with the naked eye after experimental fracturing, lacking the ability to monitor the development of fractures in real time

[0007] 3. The original experimental device can only simulate the situation where the hydraulic energy directly impacts the rock, but cannot simulate the state where the pulsed hydraulic energy fractures the rock from the radial direction in the wellbore filled with liquid.

[0008] 4. The same kind of experimental equipment cannot measure the change of permeability before and after fracturing at the same time. If the permeability needs to be measured, the core needs to be taken out and carried out on another experimental equipment.

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