Large-size true triaxial hydraulic fracturing simulation test device and test method

Abstract

The invention discloses a large-size true triaxial hydraulic fracturing simulation test device and a test method. The test device comprises a large-size true triaxial loading module, a hydraulic servopumping module, an acoustic emission positioning module, an infrared monitoring module, a sample loading and unloading module and a computer, wherein a loading plate is formed by combining an inner plate and an outer plate which are matched with each other through a spherical surface. The test method comprises the following steps of manufacturing and loading a test sample, and performing hydraulic fracturing simulation test, sample unloading, data processing and analysis and the like. The device and the method for a hydraulic fracturing simulation test of shale have the following advantages that the accuracy of a test result is not influenced by the sample processing size and the parallelism deviation, so that the requirements for the sample size processing precision are reduced, and thetest reliability is improved; a loading condition of the shale in a triaxial loading chamber in a test process can be monitored in real time; the fracturing conditions of the multi-size samples can bemet; and a high-speed camera is matched for a uniaxial hydraulic fracturing simulation test, the dynamic expansion rule of hydraulic cracks can be observed directly, and multiple purposes of one machine can be realized.

Description

technical field [0001] The invention relates to the technical field of shale gas exploitation, in particular to a large-scale true triaxial hydraulic fracturing simulation test device and test method. Background technique [0002] Shale gas refers to natural gas existing in mudstone, high-carbon mudstone, shale and silty rock formations in an adsorbed or free state. my country is rich in shale gas resources. With the advancement of mining technology, the development and utilization of shale gas has entered a period of rapid development. [0003] Shale gas reservoirs are characterized by dense quality and low permeability. In the natural state, shale gas reservoirs cannot obtain industrial production capacity through conventional natural gas extraction technology. It is currently the most important prospect to use hydraulic fracturing technology to fracturing shale reservoirs to obtain industrial gas flow. The main way to extract shale gas. Hydraulic fracturing has obvious ...

AI Technical Summary

Problems solved by technology

[0005] 1. The loading plate that applies load to the sample is a single flat plate, and the flat plate loading plate has extremely strict requirements on the size and parallelism of the sample

Due to the large size of the sample, when the size and parallelism of the sample cannot be guaranteed due to processing deviation, the force of the irregular sample will be eccentric under the load applied by the flat loading plate, which will affect the loading effect; Pouring concrete to make it a regular sample will affect the accuracy of acoustic emission positioning and reduce the reliability of test results

[0006] 2. The sample and the loading plate are in close contact, the loading space is limited, and the internal conditions of the triaxial loading chamber cannot be monitored in real time during the test

[0007] 3. The loading device is fixed on the reaction frame, the stroke of the loading device is small, and the applicability to the size of the sample is poor

[0008] 4. The function of the device is single, it can only be used for load application and hydraulic fracturing, and it cannot record the crack initiation and expansion status of shale surface cracks in the process of hydraulic fracturing in real time

Images