Large-load core holder capable of integrating CT scanning and true triaxial experiment device

Abstract

The invention discloses a large-load core holder capable of integrating CT scanning and a true triaxial experiment device.The large-load core holder comprises an upper force transmission end, a lower force transmission end and a barrel; a sample cavity and four capsule containing cavities are formed in a hollow cavity of the barrel; two capsule bodies located in the left capsule containing cavity and the right capsule containing cavity are used for X-direction flexible loading force transmission, and two capsule bodies located in the front capsule containing cavity and the rear capsule containing cavity are used for Y-direction flexible loading force transmission; each capsule body is provided with an inwards-turned skirt edge connector; a sealing plug is in interference fit connection with the interior of each inwards-turned skirt edge connector; a liquid injection pipe communicated with an inner cavity of the corresponding capsule body is arranged on each sealing plug in a penetrating mode; all the liquid injection pipes penetrate out of the upper force transmission end; in addition, a Z-direction loading piston rod is arranged in the center of the lower force transmission end in a penetrating mode. The large-load true triaxial experiment device comprises the large-load rock core holder, a Z-direction loading cylinder, an X-direction hydraulic loading system, a Y-direction hydraulic loading system and a Z-direction hydraulic loading system.

Description

technical field [0001] The invention relates to a large-load rock core holder capable of combining CT scanning and a true triaxial experimental device, belonging to the technical field of rock mechanics and engineering. Background technique [0002] Due to the obvious heterogeneity and anisotropy in the permeability, mechanical properties and crack growth law of oil and gas reservoir rocks, it is necessary to study the seepage characteristics, mechanical properties and crack growth mechanism of cores under true triaxial stress state. will be of great significance. [0003] In addition, because CT non-destructive scanning technology can realize the dynamic characterization of the microstructure inside the rock, it is an effective method to reveal the seepage characteristics of the core, the mechanism of crack growth, etc., and will not cause damage to the internal structure of the rock. It is widely used in the field of oil and gas field development at home and abroad. The ...

AI Technical Summary

Problems solved by technology

Since this sealed connection structure will generate a lot of stress locally, and there are obvious boundaries between the upper and lower gaskets and the capsule wall, so that the rubber wall at the interface of the capsule body will be sheared, therefore, in the liquid When the pressure reaches several MPa or even below one MPa, shear fracture may occur locally, so that the pressure cannot be increased any more.

That is to say, the sealed connection structure between the existing capsule body interface and the external joint of the pressurized liquid causes the pressure in the capsule body to reach a few MPa at most. The local extrusion or shearing of the gasket results in local rupture and loading failure, so the core holder described in this patent still cannot actually meet the loading requirements of three axial superloads

[0006] Chinese patent application 202010911726.6 discloses a rigid-flexible true triaxial grouting-seepage coupling test device for CT scanning. The first principal stress loading system and the second principal stress loading system in the device are both rigid loading systems, and the third principal The stress loading system is a flexible system. Although this patent eliminates the stress concentration problem at the corners of three-way stress loading by using a composite loading form of two-way rigid loading and one-way flexible loading, this patent has only one flexible loading direction, so CT scanning and photographing can only be realized in this direction. It is necessary to load the sample to a certain load first, and then remove all connected pipelines before putting the true triaxial test box into the CT scanning equipment for CT scanning in this direction. Not only Can not realize all-round scanning of the sample, and still can only realize the loading force of several MPa (4-7 MPa disclosed in the article)

[0007] To sum up, it can be seen that there is no existing technology that can realize miniaturization and light weight, and can also realize independent super-large load (up to tens of MPa, or even hundreds of MPa pressure) loading in three axial directions, and A report on a large-load core holder and a true triaxial experimental device that can be combined with CT scanning

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