A device and method for analyzing the mechanical properties of hydrate sediments based on low-field NMR

Abstract

The present invention proposes a device for analyzing the mechanical properties of hydrate deposits based on low-field nuclear magnetic resonance, which includes: a micro-reactor body installed on a low-field nuclear magnetic resonance analyzer, a confining pressure chamber located in the reactor body, and a micro-reactor body installed on the reactor body The outer radio frequency coil, the upper end cover of the reactor, the lower end cover of the reactor, the pore pressure control module and the confining pressure control module also include: the axial pressure loading plunger, the axial pressure loading reaction frame and the axial loading control module. The present invention is based on the experimental device combined with low-field nuclear magnetic resonance detection and triaxial shearing and the corresponding test method. The macroscopic mechanical data of the hydrate reservoir is obtained on the low-field nuclear magnetic resonance platform, and the hydrate storage during the loading process is simultaneously obtained. The evolution characteristics of the microscopic pore structure of the gas hydrate reservoir provide technical support for the cross-scale study of the mechanical properties and deformation mechanism of the gas hydrate reservoir.

Description

Technical field[0001]The invention relates to the field of basic physical property evaluation of natural gas hydrate reservoirs, in particular to a device and method for analyzing the mechanical properties of hydrate deposits based on a combination of low-field nuclear magnetic resonance (LF-NMR) and triaxial experiments.Background technique[0002]The dynamic response characteristics of reservoir mechanics parameters during the hydrate mining process are very important for the safety evaluation of hydrate trial production. The main method to obtain the mechanical properties of hydrate reservoirs is to artificially synthesize hydrate samples indoors and conduct core-scale mechanical testing and analysis. However, large-scale testing can only obtain macroscopic mechanical parameters, and cannot describe the meso-destructive process of hydrate deposits. Therefore, combining macro-mechanics simulation methods with micro-detection technology is an important trend in current development.[0...

AI Technical Summary

Problems solved by technology

[0007] Aiming at the inability to evaluate the change of the smaller-scale microscopic damage process during the sediment loading process in the prior art, the present invention proposes a device for analyzing the mechanical properties of hydrate sediments based on low-field NMR, including: The micro-reactor body installed on the low-field nuclear magnetic resonance analyzer, the confining pressure chamber located in the reactor body, the radio frequency coil arranged outside the reactor body, the upper end cover of the reactor, the lower end cover of the reactor, and the pore pressure control module and The confining pressure control module also includes: an axial pressure loading plunger, an axial pressure loading reaction frame and an axial loading control module; the upper end cover of the reactor is the same as the outer diameter of the reactor body, and the upper end cover of the reactor is provided with a pore pressure fluid outlet and the confining pressure fluid outlet, the lower end cover of the reactor is provided with a confining pressure fluid inlet; the axial pressure loading plunger is installed through the lower end cover of the reactor, and its center is provided with a hole pressure fluid inlet, and its lower part is provided with a diameter larger than the axial pressure loading plunger. The disc of the plunger, the axial pressure loading reaction frame is set on the lower part of the axial pressure loading plunger, the disc divides the inner cavity of the axial pressure loading reaction frame into two, and the axial pressure loading reaction frame is set The axial pressure loading fluid inlet and the axial pressure unloading fluid inlet; the end of the axial pressure loading reaction frame is provided with a displacement sensor bracket, and the displacement sensor is in contact with the axial pressure loading piston to dynamically monitor the displacement of the axial pressure loading piston; the axial loading Control module to control loading and unloading of axial pressure

Images